Wingman's "Low Power Time Attack" Build
 

Hello all. I am Wingman.

This thread will document the conversion of my 1994 BP powered NA(also known as "Blue")into a K24Z3 powered rocketing deathtrap.

For an in-depth dive in to what this car was and where it/I started, there is a previous build thread/log that chronicled both this car, and the NB that gave its life/drivetrain so Blue could be born.
https://www.mx5atlanta.com/forum/mx5...on-of-thoughts

For the 99% that are sensible enough to not dive into that thread, a brief summery of the car as it currently sits:

https://cimg4.ibsrv.net/gimg/www.mia...e7bd0fb1be.jpg
T12, HPDE session at Road Atlanta

1994 Chassis. Complete NB subframe/driveline swap, powered by a 12:1 N/A BP4W/VVT hybrid. Honestly, that combination did quite well for an N/A BP. Other then a few teething issues early in its life, it was rock solid and I almost never had an engine issue sideline the car, something I aim to maintain for the Z3 swap.

Blue was used both for HPDE lapping, as well as SCCA TT and Hillclimbs, claiming podiums several years running in both those events. Fully gutted, stripped, and with driver/quarter tank of gas, it tips the scales at 2240lb and tickles the dynamometer at 150whp/126tq. The addition of both 9LR and DIY aero made it quite a fun car to drive when I have some good tire to throw under it.

https://cimg3.ibsrv.net/gimg/www.mia...647e08a3c8.jpg
Downhill return grid, Pine Mountain Hillclimb

The K24 swap option arrived on my gaydar basically as soon as the OG K24A2 swap kits went public. I loved everything about it. More power, more RPM, Honda reliability. However, the high price point of both the swap and the motors turned me off.
This changed early 2019 when Kpower dropped the K24Z3 swap option. Can't really say it better then the man himself, but this option ticked all the previous boxes, but at a much lower entry price.
"The engines are inexpensive, widely available, strong, reliable, should be good for over 200whp with a tune. The K24Z3 single exhaust port could give us the tighter exhaust packaging needed to run a stock, unmodified subframe."- David Calzada

I was hooked and preparations began. Thanks to the shitshow that was 2020, I was unable to make any headway into the swap, so I was stuck with the lead block BP for another year. I've been slowly accruing parts and plans to pull this off, and its finally time.

The Goals:
#1. Produce, for the lowest cost feasible, a fully fleshed out, running, driving K24Z3 swapped TT/Time Attack/Hillclimb/HPDE miata, maintaining all the reliably of a stock BP, but with an extra 60whp. 60whp for now anyway
#2. Prove beyond all reasonable doubt that Miata's are a bad time attack car.
#3. In keeping with the reliability point of #1, where possible, use fully OEM parts, or slightly modified, easily obtainable parts that can be sourced anywhere across the country without the need for specials orders, overnighting parts from Japan, or going any farther then the closest generic parts store for replacements. Where it is not feasible to use OEM parts, beefcake one off/custom/mission critical parts to the point their failure means I have much bigger issues to worry about.
#4. Dial this thing in to the point it can be driven, tire trailer in tow, 5+ hours to a multiple day event, turn every lap of every session, and still return home. Yes, this car is still street legal, and driven to ALL TT events.
#5. Claim the title of fastest NA/NB Miata to lap Road Atlanta, period, no asterisks. Currently 12 seconds off that mark so this K24 has some work to do. If I can claim that over an NC too, that's cool, but unlikely once NC development catches up.
#5b. Claim King of the Hill two consecutive years at the annual Chasing the Dragon Hillclimb. 8 seconds off last years P1 so again, this K24 better be ready to play ball.
#6. DIY everything even remotely possible. The more in house this car is, the better. Obviously the basic swap items will come from Kpower, but the rest of the build is... well its a garage build. And not a fancy garage either, but we will get back to that.

Now, with those housekeeping items out of the way, lets get started, shall we?

Any good engine swap saga starts with an engine. So, here it is.
Rona19 kinda screwed up engine pricing. Pre-rona it seemed sub $500, low mile Z3's were falling out of the sky. In the last few months of keeping my eye out for one, prices were absolute crackhead prices, local junkyards wanting $1100+ for 150K mile specimens.
I eventually found one though at a yard a state over and had it shipped to me. 95K miles, known runner, $550 delivered to my place of work, where our American V8 loving parts guy joked that I was "going big block"
https://cimg9.ibsrv.net/gimg/www.mia...092a4c0094.jpg

I was told over the phone that it did not come with any wiring harness, but I was pleasantly surprised to find that I had been lied to, and there was plenty to build a harness from scratch with. Big W
I wasted no time and found the sketchiest bolts possible to mount it to my HF engine stand and take a peak at what was under that dress.

I told myself if I died trying to remove a Honda crank bolt with 8ft worth of leverage and a can of PB blaster, it was just what was ment to be.
https://cimg8.ibsrv.net/gimg/www.mia...a04e54324f.jpg

Spoiler alert, I did not die, but it was frighting the amount of bouncing on that bar it took to break it loose.

https://cimg6.ibsrv.net/gimg/www.mia...129fb5c24d.jpg

Very happy. Much cleaner then 90% of BP's I'm used to working on. Could hear it make compression when rotated, cams and head have a nice gold oil color, not a smeared poo brown oil color.

https://cimg4.ibsrv.net/gimg/www.mia...fccf937cf8.jpg

Yall hang out for awhile, get to know each other. I'm expecting a long, healthy relationship.

I've been planning most details of this build for the last 8-10 months, but only recently did I finish the majority of my wiring plans.
I have an MS3 EVO currently installed, but its obviously wired to run a BP, and is half hacked OEM harness, half aviation grade wiring. the OEM parts of it have started giving me a few minor issues, so I figure its better to start fresh and throw everything away(except for the MS3) and start fresh, with both the engine harness and the body harness. Planning out the wiring is 9/10th of the battle, I've found that once I have diagrams with neat little pin numbers in hand, I can chew though several hours of wiring work without too much trouble.

I've been using RapidHarness for most of my planning as opposed to my normal hand drawn stuff. It took awhile to get a workflow down, but once I got used to the software it wasn't to bad. There are some SERIOUS limitations and quirks to it that frankly ticked me off. Don't know if I would want to use it again for any future projects, but I'll stick with it for this one as I'm committed.

The heart of the electrical system is a Bussmann 15303-4, populated for five, 280 solid state relays, and ten type 2 solid state auto reset CB's. First time I've used solid state stuff on a personal project, but this should work out nicely and really wasn't as expensive as I was expecting.
https://cimg8.ibsrv.net/gimg/www.mia...44354179e5.jpg

Oh, speaking of costs, small detour.

I have a running spreadsheets listing EVERY part, item, and bolt I'll be buying for this swap, as well as the dreaded totals. If "Purchased Cost" line is empty, it means I have yet to lay my grubby hands on that item. Rest of the doc should be pretty self explanatory.
https://docs.google.com/spreadsheets...Ks4/edit#gid=0
At the very bottom is a *tentative* schedule of when I hope to roll it out of the garage under its own power, but that timeframe really depends on a lot of things, i.e, Kmiata's backlog, and how much I can stomach dropping in a month on car stuff.
Back to wiring.

Thankfully this is a "rAcEcaR bRuH", but that being said, it still is street legal and will remain that way, more or less. I'm located in the deep south so I have some good leeway on what's "legal" vs what's *actually given a fuck about*
My point being its not going to be quite as simple for me as throwing in some fuel pump wiring, building an engine harness and off you go, but its not too complex with only 3-4 additional load sources.
The basic overview:
https://cimg2.ibsrv.net/gimg/www.mia...b78964ef73.png

The only subsystem that has given me major headaches has been the MS/Engine harness. I.e, it only occurred to me yesterday that BOTH cam sensors are not required, MS only needs to see one cam for sequential.
There's not quite as much information out there on running a Z3 with stock sensors, but I've found a few nuggets on here and some Haltec information that makes me think I have a slight chance of getting it to fire.
https://cimg8.ibsrv.net/gimg/www.mia...6fe630b0fc.png

I'll be reusing my switch panel with some modifications, as I'm quite used to it. Its also heavily integrated into the car itself at this point, and makes everyone ooooo and ahhhh at Cars and Coffee. Its wired on two disconnects so most changes can be made on the chassis side of the harness with messing to much in the panel itself.

https://cimg2.ibsrv.net/gimg/www.mia...2c4c7e3166.jpg

The OEM body harness will be tossed and rebuilt from scratch with an eye on weight savings and simplicity. Its really not to much, mostly lights and a few interior items.

I dig it. Been following on Instagram, but glad to see a detailed build thread here. Looking forward to following along.

What tire/wheel setup are you usually running? K24 will be at home in this build!

Street is a 205 or 225 on a 8".
Track depends, I have 9.5" freeforms that fit anything from a normal 245 to a hella stretched 205 Hoosier. Just depends what I can get my hands on.

This is relevant to my interests.



Subscribed.

Friends TT6 car lost an engine due to oil starvation, so my old BP found a new home.

Last time I pull a BP out of this car. God knows I've done this to many times already.
https://cimg6.ibsrv.net/gimg/www.mia...edfafdb0ff.jpg


Ironically the point in time I'm ditching the BP is the same time I have two of them sitting in my garage.
https://cimg9.ibsrv.net/gimg/www.mia...036a73fabf.jpg

With that lump of iron out of the way, I can finish ditching everything that doesn't need to be there any more.
Messy engine bay, fresh from the pull:
https://cimg4.ibsrv.net/gimg/www.mia...6d5749b62b.jpg

"Clean" engine bay, ready to be worked in.
https://cimg2.ibsrv.net/gimg/www.mia...71eb1a08ae.jpg


And an entire Miata worth of wiring. I have no idea how this hacked up harness hadn't given me a host of issues, there's three years worth of work into trimming it down into just that, and varying levels of workmanship and solder joint quality.
https://cimg0.ibsrv.net/gimg/www.mia...f7d96d6489.jpg

Preface: I hate slave cylinders inside the transmission bellhousing, I.E, corvette/350Z style. Slave failure means dropping the transmission and some very annoying clutch bleeding. When I saw that Kmiata had moved to this style for their K24Z3 kits I... well lets just say I was NOT a fan of that change. I know Kmiata claims their custom quartermaster bearing is extra robust and will have less/no failures, but I've seen several early adapters have issues with it, or have slaves that needed additional machining to properly work. AND, the kit requires you run a Wilwood master cylinder, not an OEM Miata master that you could find at any parts store in a pinch. All this to say, I did not want to add $600 to the build cost, just to have a system I could not source parts for trackside, and any failure meant I was dropping the trans to fix.
The obvious issue with keeping the Miata clutch hydraulics is that the exhaust doesn't fit down the passenger side of the transmission. There simply isn't room to fit fuel lines, a slave, AND a 3" downpipe without going to a tubular subframe(K24A2 style) or choking down the exhaust to 1.5" oval.

My solution? Sidepipes, Passey style.

I first want to thank Ryan for doing this many years ago on his LFX swapped car and providing pictures of how he did it, as well as advising me on material choices. Without knowing what I was getting into and what was under there, I would not have had the confidence to start chopping up my own rockers.

First obvious issue: 3" pipes obviously don't fit in the wheelwell when sharing space with a wheel of any size. Shocking, I know.
Pictured: 3" tubing trying to find a home between a Miata pinchweld and a 245 RC-1 on a Konig 15x9.5.
https://cimg1.ibsrv.net/gimg/www.mia...3b7962bee8.jpg

Second issue. I want to be able to run this car at more strict tracks like AMP and NCM, and not blowing out my own eardrums would be nice. I'll have to stuff some noise reduction in there, not just a raw 3" straight pipe. Mufflers mean I'll need to make space for them in the rockers as well, as if fitting 3" wasn't going to be enough of a challenge. I picked up two straight though mufflers with an outside diameter of 4", the biggest I figured I would be able to package. If this doesn't mute the car enough I'll have to get creative, but that's future me's problem.
I planned to take the exhaust all the way back to the rear wheel like shown, however this didn't end up working. More on that later.
https://cimg0.ibsrv.net/gimg/www.mia...a7cfcf8d65.jpg


Okay... all the planning I could do had been done... time to start. Rockers getting cut. Scary. No turning back now!
https://cimg1.ibsrv.net/gimg/www.mia...4b6ac770dc.jpg


Didn't take me long to realize I had already made a booboo and there was probably a reason that Passey ended his exhaust where he did. I cut all the the way to the rear wheelwell straight away before taking a peak at what was back there.
https://cimg5.ibsrv.net/gimg/www.mia...722c4d7e0c.jpg

Turns out there's some internal webbing that comes down along the rear door sill that looks fairly structural, and would be a complete pain to cut/reroute the load paths. The view inside the rocker, looking to the rear:
https://cimg2.ibsrv.net/gimg/www.mia...bb64dba3fa.jpg

I opted to not get into that, and reweld the paneling I had already cut, shortening the exhaust. I hadn't been stupid enough to cut the rocker off the internal webbing, so I could tack it back without comprising anything structural.
https://cimg9.ibsrv.net/gimg/www.mia...e391f582a3.jpg

Little bondo over that and some spray paint, and its like it never even happened. Thankfully its low down on the car and not a high visibility location.

With those hours of painstakingly tac welding miata tinfoil back together past me, I was able to return to the fun bits. I took the main exhaust body into work and fumbled my way though some tig work. I'll tig wherever it will be viewable to make it look pretty and professional, and then mig for ease and speed where its hidden.
Great news! Looks like the 4" mufflers will be juuuust a smidge higher then my pinch welds/frame rails, so I *shouldn't* have to worry about dragging pipes on the ground or over bumps.
https://cimg5.ibsrv.net/gimg/www.mia...4013b01646.jpg

I searched fruitlessly for someone selling 5" pipe in 16g, coming up short and worrying I painted myself into a corner before Ryan rescued me and said he just used 5" exhaust tubing. Seems like a rather obvious solution in hindsight, its even fairly cheap and NAPA sells it by the foot. I could get two sections out of a single run of pipe by cutting it in half, so I only had to order 3' worth and I ended up with about 10" uncut pipeing left over.
https://cimg7.ibsrv.net/gimg/www.mia...101b199151.jpg

Where possible I welded the backside to the miata sheetmetal, but I think it would be fine just welding the top to the door sill and the bottem to the pinch weld.
At the pinchweld inside the fender I added some thick steel vertically to add some strength I cut out of the jackpoint locations. Heads up, don't have anything flammable inside the footwell, because it WILL catch on fire from the heat... ask me how I know.
https://cimg9.ibsrv.net/gimg/www.mia...41301678c8.jpg

It ain't the prettiest, but you know what they say.. grinder and paint make me the welder I ain't. You also can't see any of this once the exhaust is mounted.

Ground and painted:
https://cimg7.ibsrv.net/gimg/www.mia...2481af29fe.jpg


And the exhaust mounted.
https://cimg3.ibsrv.net/gimg/www.mia...9b293c3409.jpg


Pleenty of room to clear the tire now. Pictured at full lock and droop, there's more clearance at normal ride heights. As pictured I can stick two fingers in there.
https://cimg3.ibsrv.net/gimg/www.mia...2c86a5b41c.jpg


I should have just enough room to snake 3" between the framerail and the subframe. Might have to bend some brake lines out of the way, but no biggie. Fuel lines will be moved out of there and relocated anyway. Plan is to ceramic coat the entire exhaust once done to try and keep the heat controlled.
https://cimg4.ibsrv.net/gimg/www.mia...a9d6093b5a.jpg



This is as far as I want to go before I receive my swap kit, I want to physically mount the engine in the bay so I know exactly where I'm aiming for my termination point. Kmiata says they are currently doing around 60 day wait times for kit shipments, so fingers crossed mine ships around the end of November.

Nice Job on the exhaust. That's so much work. It looks great! Can't wait to see your car when your done.

Oh my god, sooo many labor hours, and I didn't exactly take my time to make it perfect. I have at least 30hrs into just the rocker section(Not counting the 2-3 hours I spend welding back where I cut to far), and 5-6 into the actual exhaust, and its not even completely done lol.

Wires, wires, wires.
I had contemplated keeping my original Mazda harness and just making the needed changes for the K, but I rapidly nixed that idea and decided to strip the entire chassis of every scrap of wiring, and start from scratch. Looking back, I'm quite glad I made this call, as my harness had been changed/hacked up in so many places, and still had a good chunk of unneeded wiring in it.

The main harness building begins:
https://cimg4.ibsrv.net/gimg/www.mia...7abe036aa9.jpg

I'm using a Bussmann as my relay/fuse holder, it's really the cheapest easy button shy of shelling out for a fancy PDM. I filled it with solid state relays and type 2 auto resetting circuit breakers for the important stuff, and normal lame blow fuses for non-essential items. https://cimg8.ibsrv.net/gimg/www.mia...f05cc645da.jpg

I opted to run anything heading rearward along the trans tunnel instead of along the passenger sill. As my exhaust is now part of the rocker panel I don't know how hot that area will get even with ceramic coating and heatwrap, but I didn't want to take a chance on melted wiring causing issues down the road.
Switch panel disconnects through three molex connections, engine harness runs to a 30some pin bulkhead connector, digital dash also has two molex disconnects. Only OEM component I kept was the flasher box for turn signals and the fuel sensor/guage. Everything else is tefzel wiring, 20g and 16g for most things, 12g for heavy loads, and a few twisted pairs for sensor lines.
https://cimg0.ibsrv.net/gimg/www.mia...9aa2001829.jpg
Everything under the dash completed, secured, and ready for the dash to go back in. Don't look too closely at the mess of wires at the back of the Bussmann, it got pretty crowded back there.
https://cimg5.ibsrv.net/gimg/www.mia...80608c6a45.jpg

I got a little antsy and wanted to make sure what I had done so far was working, so I grabbed the battery off the shelf and connected it in a completely non-ghetto way.
https://cimg2.ibsrv.net/gimg/www.mia...76a33938fb.jpg
Buuuuut nothing caught fire, and the Megasquirt/Pi dash booted up without issue for the first time in three months. Definitely good to see.
https://cimg0.ibsrv.net/gimg/www.mia...7ab8df4b5f.jpg

I still need to wire up the headlights/taillights, but I've done the heavy lifting, the rest is easy stuff. Good to get this chunk of labor done and out of the way now, as once my Kmiata kit arrives I'm sure I'll have zero drive to fiddle with wiring stuff.

Obviously nothing on a K24's fuel system matches what the NA Miata supplies. K24's come with a returnless fuel system and of course need MUCH more fuel then the lowly Miata pump can supply.
I dropped a walbro 255 into the tank to solve the quantity issue and give me plenty of headroom, nothing new there.
For the supply lines, I replaced all my rubber lines with Continental fuel line that's rated for E85. $30 bought 25ft of line, which is plenty to do everything twice over and still have hose to spare.
K24 has the intake on the drivers side, so I bent the OEM hardline up and back to the firewall, flared it and ran rubber from there across the top of the tunnel and into a regulator.
https://cimg7.ibsrv.net/gimg/www.mia...89d0420ebb.jpg

I had gone back and forth between a dead head or a through system, decided to dead head it for simplicity for the time being. If I need to change it in the future its fairly easy, just need more AN fittings.
Fuel lines wrapped in some harness sheathing to protect against abrasion in critical areas. In lieu of a traditional analog fuel pressure gauge, I installed a 0-5v pressure sensor I'll feed to MS so I can have fuel pressure live on my Pi dash. This probably will not prevent me from running out of gas trying to outrun the fuel gauge needle, but hey, at least I tried.
Also added a GM E85 flex fuel sensor, as the plan is to run both 93 and E85 for all the horsepowers. Currently targeting NASA TT3 and SCCA U2 as potential competition classes, and I'll need all the horsepower I can squeeze out of the Z3 or find a good chunk of weight to drop for TT3, especially with the new tire modification allowances they just dropped.

All the money I saved by not going full AN/braded line I put into something I know MiataTurbo will like, some insanely overkill, non-knockoff injectors.
https://cimg1.ibsrv.net/gimg/www.mia...85e2524ac2.jpg


These are Injector Dynamic 1050's, capable of supporting 600whp on pump gas, or 500whp on E85, and mounted to a K24 Radium fuel rail. Honestly the rail was not needed, but I got it for cheap and its quite pretty, as well as giving me complete access to all K24 injector sizes.
I guess you could call this.... futureproofing, but really it was simple economics to buy once, cry once. $500 for 1050cc injectors that will flow everything I need and more, or $300 for 550cc injectors that would already be nearing maxed with E85 and 220whp.
https://cimg9.ibsrv.net/gimg/www.mia...f225986db5.jpg

Enough engine and wiring stuff for the moment! Time to break out the angle grinder and build some aero.
My previous splitter had lasted a solid two years, but it was showing it. One can only ask it to eat so many curbs before the material starts to buckle. I have a local source that I can get 4'x8' sheets of alumalite from for $150, and I much prefur that over plywood. Carbon is a little to pricy for my tax bracket.
Fresh new sheet of 10mm alumalite mocked into place:
https://cimg8.ibsrv.net/gimg/www.mia...58b8823cef.jpg

Previous splitters were very conservative in size, 3" lips. As a result the 9LR dual element wing easily overpowered them, even with splitter ramps, and I would get terriffic understeer. The car really only balanced out once I removed the front swaybar completely. In an effort to not have the same problem at higher speeds, I cut the splitter for 5.5"(inside NASA's 6" limit), and left myself space to add additional splitter ramps if need be.

https://cimg6.ibsrv.net/gimg/www.mia...30220ee832.jpg

I added rubber edging for a smooth lip and skid plates to help the splitter survive, but apparently I didn't bother to take a photo after that.

After sitting in the garage for 3 months during extensive angle grinding and other dusty work, the car was filthy. I popped some wheels on and pushed it outside for a bath during a warm break in the weather. Sidepipe doesn't look half bad!
https://cimg6.ibsrv.net/gimg/www.mia...e96bca6187.jpg

Another K24Z3 going in at the same time as me! Looking forward to seeing this come together.

Way back when I bought this shell, the paint on the hood and trunk was pretty bad, so I sprayed it with some gloss black and moved on with my life, having much bigger priorities then aesthetics.
A few years of track use and Georgia sunshine didn't do that hasty spray job any favors, and it was really showing some wear. Additionally and more importantly, the black top was incredibly hot. Standing in the paddock of Road Atlanta one day, I placed my hand on the white stripe adorning the hardtop and found there was at least a 15* difference between it and the black paint. Between the black exterior and the exhaust right next to my leg, the interior was an absolute nightmarish oven in anything but the coldest winter days.
All that to say, the black had to go, and stat.
I was already dumping money into the car, so I didn't feel like adding the additional cost of a full wrap job into my plans. Instead, I whipped up a few designs, had IG vote on their favorite, and went with it.
I really, really hate body work, and hours of sanding is no fun. So I really didn't take any photos of the during process... just the final product.
https://cimg3.ibsrv.net/gimg/www.mia...7c99e7dc8d.jpg

https://cimg7.ibsrv.net/gimg/www.mia...22d2b7fe67.jpg
Its defiantly identifiable as a rattle can job, but it passes my requirements of 50/50 with ease... looks good at 50ft and 50mph.
Between this and routing the exhaust out the fender, hopefully this makes the interior much more pleasant.

I also got a "real" laptimer, tired of being hassled over using Harry's, and wanting the more accurate data that comes with a real system. Aim Solo 2, mounted conveniently just below immediate eyeline and hardwired into the car for power. Not configured to read off the MS3 as I didn't spring for the out of stock "DL" model that was also $300 more.
https://cimg5.ibsrv.net/gimg/www.mia...e3516b18c8.jpg

And now for a final item... and the reason there hasn't been any real activity here in over a month.

Kmiata, or as they are now known, K Power Industries.

/rant

KPower's communication is both awesome and complete garbage at the same time.
I placed my original order September 23rd for a "basic" swap kit and a few other items. No electronics, no flywheel, no trans adapter, just the oiling system, mounts, valve cover, and a few odds and ends. Nothing(I thought) that would be terribly held up even in this post Rona hellscape of material shortages.
Their website quoted a 45-60 day lead time. Around day 30 I sent an inquiry email asking if that was still correct and was told that no one had ever waited more then 90 days for a kit, most of my order was ready, and they were just waiting on a few things, but it was on track to be shipping around day 60. Great!
Day 60 came and went, so I sent another inquiry seeing how things were going, to which I was told they were having unforeseen holdups, and it would be another 2-3 weeks. Unfortunate, but it was what it was and I wasn't too disheartened.
Last week day 90 arrived(December 23rd), and I got an email from Kpower apologizing for the wait, and stating they still didn't have all the items on hand, but would be shipping what they did have ready. I was quite happy to at last get my hands on something, and thinking a late Christmas present would be VERY nice, and sent an email back thanking them and asking what would be shipping and what was still being held up... but didn't hear back.
No biggie, its now Christmas weekend... I'm sure I'll hear something from them early next week... Nope. So I send a follow up email the 29th(day 96 of waiting), only to get an autoreply stating they are all out of office till January 3rd. GAHHH. So now, once again, I sit, twiddling my thumbs and waiting, knowing full well I'm probably not going to hear anything from them till a week into the new year.

So back to my original point... their communication is both awesome and garbage.
Awesome at returning emails within 24hrs or so(generally) and being very helpful and understanding with questions and order changes.
But absolutely garbage at providing a good time frame and tempering my expectations, especially with the email stating parts of my kit was shipping... even though my kit was NOT shipping yet and wouldn't till after the new year. I get that supply chains are FUBAR right now... but just tell me that its not shipping till late February, and then make me happy when it shows up a month "early", not this "just another two weeks!" annoyance of being strung along.

Anyway, /endrant

Sooo... yeah. I'm at a dead stop now till I get swap stuff in. I need motor mounts to see where my exhaust terminates so I can finish it and send it out for ceramic coating. I need the motor mounted in the bay so I can order the final engine items and build the firewall side of the engine harness. I need an oil pan so I can see how my splitter will fit. I need all of the above in place so I can figure out how I'm routing my cooling system and a half dozen other things. But for now... I wait. *Slightly* impatiently.

I’m fairly certain if they quoted February, it wouldn’t show up till April. That’s how bad it is. You can’t just add a month, because sometimes it’s 2 months oops I mean 6.

We've exchange a few DMs with my details. But I often look at my VVT and wonder if I would've been better off just leaving it in for another season. If come March (season start), my car is not back together, I'll be kicking myself.

I don't mind waiting for a kit. I was so sick of BP's. But yeah... If I my car doesn't run by early April I'll also be pretty peeved and scrambling to borrow/rent a car.
And I would be fine waiting even 6 months. If I have an accurate timescale I can plan ahead. But since the website quoted 60 days, and Kpower said 60 days... I foolishly believed it and planned accordingly. Had they said from the start "the wait may be up to 6 months" I just would have placed my order back in April. Hell, maybe I SHOULD have just placed my order back in April.

111 days after order placement, Kpower shipped the majority of my kit.

FedEx promptly "lost" the package.

Five days and several phonecalls later, they found it doing laps in one of their warehouses and I was able to pick it up. FINALLY. Box looked like it had taken a beating, but Kpower did a good job packing things and nothing inside was damaged in the slightest.
https://cimg2.ibsrv.net/gimg/www.mia...db3aca44f2.jpg

I of course wasted no time inventorying everything and starting to assemble what I could. I was happy to find they had shipped my entire order except for a valve cover modified to help fit under the hood. More on that later.

The kit instructions are adequate, but not the best. Several items are simple "do this" and leave you to figure out what bolts go where. Or that you have to remove an item they just had you install so you can add something to it.
The only "issue" I had was with the oil pickup tube. Kpower uses a "type S" Honda oil pump, and makes a machined part to adapt it to their custom oil pickup tube. When I tightened down the pickup tube the oring would seem to pinch and not seat cleanly, like so:
https://cimg0.ibsrv.net/gimg/www.mia...6fa368bd5d.jpg

I gave them a call late on a Friday and they picked right up, took a look at the photos, and told me its good, send it. I'll be running oil pressure/temp sensors as well as using MS3's shutdown for low oil pressure, so I'll just observe and hope that's normal, or at least, not to badly abnormal.

Rest of the assembly went smoothly and I was able to drop the motor in for a first test fit. MAN that looked nice already. Hype levels to the moon.
https://cimg4.ibsrv.net/gimg/www.mia...d2e236fd8f.jpg

Its really a tight squeeze to fit the oil pan around the subframe while keeping the transmission low enough to slide in. This would be a massive pain for an OEM car that still had its front structure in place.

With the motor in place I could finish the exhaust. Quite happy with the amount of room I had to work with.

https://cimg1.ibsrv.net/gimg/www.mia...95d946dde9.jpg

https://cimg2.ibsrv.net/gimg/www.mia...eb1931a811.jpg

After tac'ing it into place and confirming fitment, removed and tig welded the parts you can see while its in the car. Mig'ed the parts hidden in the wheelwell as its so much quicker and easier, as well as not being as picky about perfect cuts and non-existent gaps.

https://cimg4.ibsrv.net/gimg/www.mia...32849a10c9.jpg

Split it into two sections to both aid complete removal, and make it easier to get at anything buried down in the passenger side of the engine bay, as this is where the K24Z3 crank trigger and miata slave cylinder live. Upper "downpipe" can be removed with a Vband and four header nuts for nearly complete access. Exhaust will go off for ceramic coating Monday, and I'm contemplating heatwrapping the downpipe for an additional layer of heat control inside the engine bay. Anyone know if wrapping fiberglass insolation over ceramic coating causes any issues?

Possibly the most daunting unknown, Custom K24Z3 Crank Trigger Settings.

I haven't found anyone online running a Z3 motor with OEM sensors/trigger wheels on megasquirt. As such, I've had to figure out the crank trigger settings myself, with a few cues from the Haltech information on the motor.

The Z3 uses a 58 physical toothed crank wheel, mounted at the very rear of the crankshaft behind #4 rod. There are two additional missing teeth, making the "total" amount of teeth 60, or to use trigger terms, a 60-2 crank trigger.
The intake cam has a four toothed wheel also at the rear of the cam, not sure what the teeth relate to though, its not to TDC.
The Z3 has an additional cam wheel/sensor on the exhaust cam, but the wheel is a weird asymmetrical three tooth design I don't think MS will read. An additional cam sensor is unneeded anyway, and VTEC/VVT both live on the intake cam, so no need to track the exhaust cam.

Setting up for a custom trigger wheel is detailed in the MS3 EVO manual on page 70, so I won't detail the entire process, just the end settings and numbers I used to get them.

Trigger wheel position with the #1 cylinder at TDC. Its hard to tell from the angle, but the sensor lines up with the 7th tooth. The wheel is rotating from right to left in this orientation, meaning the wheel has a loooong way to go to find tooth #1 again.
https://cimg6.ibsrv.net/gimg/www.mia...4f4170e367.jpg

Counting the tooth gaps after this point yields us 51. At 6 per tooth(360°/60), this gives a 306° offset, which is then the number plugged into MS.

My theoretical trigger settings are as follows. Note that as of the time of writing this, these have NOT been tested or confirmed to work. If they do work, I'll come back make a note at the end of this post, or what changes were needed/suggested.

EDIT: Wingman from the future here, somehow I fumbled all that math and numbers. My only guess is that I somehow turned the motor over the wrong way while calculating. Reversing my trigger offset from 306° to 54° got the motor to fire, and once dialed in with the timing light I had the correct numbers below. Again, the above numbers are WRONG, the posted settings below are CORRECT.

https://cimg5.ibsrv.net/gimg/www.mia...5875ce64e6.png


For reference, here are the Haltech settings, as obtained from Supermiata.
Oh... did I say cues earlier? Because Haltech has the same tooth count numbers, even if their offset numbers don't make sense.
https://cimg1.ibsrv.net/gimg/www.mia...f8017264c0.jpg

With the important bits of the Kpower kit coming in, progress has jumped forward. I'm hoping to have first fireup by mid February at this point.
The sticking points:
1. Ceramic coating shop has a two week backlog.
2. I still need a valve cover and Kpower says their modfied covers are still a month out, more if you opted for the powder coating(which I did not).
3. Misc odds and ends I now need to order(why on earth does a new TPS sensor not come with its respective pigtail??)

#1 Isn't a huge deal as long as they stick to their two weeks, I need time to build the engine harness and make the engine play nice in the bay anyway.
#2, I'm not waiting ANOTHER month just to try and fire the motor up. I'm already signed up for a late March NASA event, and there's a mid March local trackday I would like to attend to use as a first shakedown close to home and with backup near. Before it even goes on track I want to log as many street hours as possible to work out any initial kinks, and get the car on a dyno to tune for both 93 and E85.
I ordered an OEM valve cover from a junkyard. There's a zero percent chance its going to fit under the hood(hell, I'm not even sure the modified one will), so I'll just have to run around hoodless for awhile. Better then trying to cram everything else into a two week period.
#3, I thought I was pretty well prepared, but nope, there's always a half dozen items you don't even think of... but why doesn't a TPS sensor come with the pigtail??(looking at you, Acuity).

https://cimg7.ibsrv.net/gimg/www.mia...f75da637da.jpg

dats hawt

The acuity does have an option for an adapter to B-series when you buy it. Otherwise all TPS sensors sold assume you’re plugging it into a factory harness. If you’d like, you can switch to a 90-93 mustang TPS, which has a permanent pigtail from the factory

Somehow I missed that. Or assumed that if nothing was selected, it would just come with a bare pigtail.
It's not a big deal as the pigtail was only $20 from acuity, just an annoyance in the moment that stuck with me.

Engine and driveline assembled and installed in the car for the final time. I loved my Supermiata ceramic clutch so much I tossed it right on behind the K, it had only seen a season's worth of use.
https://cimg9.ibsrv.net/gimg/www.mia...105cb0d05b.jpg

Unfortunately while tightening up bolts under the car I realized my PPF was cracked. Having seen Marcus's break a few weeks ago and end a day at Barber I wasn't about to send it and hope it stayed together for another year.

https://cimg9.ibsrv.net/gimg/www.mia...d33988f914.jpg

While possible to separate the diff from the PPF while still in the car, I've found its much easier to do so while both are out of the car. So out they both came. I'll use the opportunity to add some supermiata diff bushings(current are stock) and weld in the arm reinforcement I've had sitting on my shelf for a few months.
https://cimg9.ibsrv.net/gimg/www.mia...ee75b18037.jpg

On the bright side, I lucked out with timing at the powdercoating shop and they had my exhaust ceramic coated and back to me within 48hrs(initially quoted two weeks). Very happy with the end product of how that turned out.

https://cimg6.ibsrv.net/gimg/www.mia...40102ece22.jpg

My temporary OEM valve cover also arrived today, so I tossed that in and got a jump on the engine harness wiring.

https://cimg6.ibsrv.net/gimg/www.mia...0c7842b2de.jpg

At this point the only thing that stands between me and first fireup is... me. While I'm still waiting on 2-3 items and need to grab some smaller things locally, I have what I need to finish the wiring, plumb the cooling system, and work on getting it started. Might get a chance to do just that this weekend depending on how much free time I find on my hands.
The excitement grows, and so do the nerves.

Solid progress, also big ups for the K24Z crank trigger info, will save me some time when I get there. I'm running an Emtron standalone and the stock trigger wheel is definitely much more appealing to use when compared to the K24A trigger that has WAY less teeth/resolution.

It runs. I don't know how, but the trigger settings posted earlier were wrong. I'll expand later once I calm down and figure out why.

But it RUNS

That feeling when an engine first starts after a major repair or swap never gets old!!! Nice work!

Nice work , that is a great feeling.

So yes, it runs. But first, a little backtracking

Diff welded and Supermiata bushings installed. People do not joke when they say that cast aluminum is a bitch to weld cleanly, and you cannot clean it enough. I got 2-3" of really nice looking welds, and the rest was... strong, but ugly. I ground down most of it, even though its not visible while in the car.
https://cimg8.ibsrv.net/gimg/www.mia...4c69c2f075.jpg

With the diff wrestled into place along with a new, uncracked PPF, the only thing needed was the radiator and fan setup. I splurged and got a nice spall fan, much lower profile then the OEM I had been rocking. This allowed me to push the radiator farther back and lower without hitting on the swaybar, a setup I had run with the BP and quite liked, as it both lowers a rather heavy fluid filled item sitting out on the nose, but also allows me to route the intake directly over the radiator to steal cold air from the radiator inlet.
I slapped the fan on with some quick and dirty aluminium brackets as I was getting impatient. I will definitely need to go back and redo those with steel brackets, or at least a stiffer aluminum, as the fan kinda gyrates into the radiator during use.
https://cimg5.ibsrv.net/gimg/www.mia...7f1f87198e.jpg

And once the engine had run and I confirmed all my wiring, I covered it in some split loom. There she lays, in all her K24 glory:
https://cimg2.ibsrv.net/gimg/www.mia...c021834a97.jpg

That intake filter is temporary. It was $10 from a vender I already had an order in with. I was unsure how much room I would have for filter space between the bumper and radiator ducting, once I know that I'll find a proper K&N to fit.

Now for the part that really stumped me. Somehow I managed to fuck up the process to determine tooth #1 for Megasquirt. During initial cranking I kept getting starter kickback, even when lowering the cranking timing to -5°. The engine also didn't really sound like it wanted to fire off at all either.
In a stroke of lucky genus, I reversed my tooth offset from 306° to 54°, and it sputtered to life first try.
I must have been turning the engine the wrong way while counting teeth is the only thing I can think of for how I managed that, except that 54° offset still wasn't correct, as I later found out.

The K24Z3 has two different set of timing marks on the crank wheel, and two different marks on the timing cover. Of course the one that I immediately saw and gravitated to was very much the wrong one. For anyone else, do NOT use the timing marks on the side of the timing cover to set your ignition advance. Pictured is the WRONG set of timing marks:
https://cimg3.ibsrv.net/gimg/www.mia...4f3e3aa2da.jpg

I honestly don't know what those line up to, I suspect TDC for cylinder #1? Regardless, that side has 5 timing marks on the crank, with one being marked white, one red, and the rest uncolored. Again, do NOT use those for your ignition timing.
How did I find out those are wrong? Well... I went out for a few pulls and the car felt super sluggish... like old worn out BP sluggish. I didn't trust my butt dyno, so I took it out on the highway and struggled to break 90mph in 4th gear. Yeah, bad.
I brought it back home and inquired on one of the Kswap FB groups, where I learned the proper place to set ignition timing was from a mark at the 12:00 position on the timing cover, with the other set of crank marks, shown here:
https://cimg3.ibsrv.net/gimg/www.mia...a059a9616b.jpg

Turns out that I had set the motor to 0° advance, thinking it was 10°. Yeah, 10° of ignition timing REALLY woke the motor up, like wow.
In the above picture, the white mark is 0°, and then 6°, 8°(red mark), 10°, left to right.

Wow. MUCH better. Car actually pulled now. I can't wait to get it on the dyno and see what she makes, but I have a dozen bugs to work out for now, most of them Megasquirt related.
For reference, here are the ignition settings that I now use, and ARE CONFIRMED to be correct, as dialed in with the timing light. My old post a page back will be edited to match.

https://cimg3.ibsrv.net/gimg/www.mia...ed5c727002.png


The only other source of drama was bleeding coolant... you CANNOT have enough water on hand, or the nose too high in the air. A magic funnel is a REQUIREMENT.
I started with a gallon and a half of distilled water, along with a jug of Honda blue coolant. I used all that(just a dash of the honda coolant, its a trackcar remember?) just prefilling the system.
I had to do 5-6 heat cycles and lots of coolant line squeezing before I finally got it to hold a reasonable temperature and not shoot from 150 to 220 in seconds. Seems like the Tstat does NOT want to open up and release all its trapped air. But when it does, boy you better be ready. It blew coolant out of the funnel 3ft in the air, and then sucked down everything left, which was mostly air. I think I ended up using 4 gallons, 2 of which found its way to the floor. The temperature still does some weird stuff occasionally while driving, so there must be a bit of air left in there I guess.

At this point I've put about two hours of driving on it, combined put-putting around the block, and full blown pulls at my local tuning spots. No major issues, but a dozen small ones that need addressed. The car is defiantly too loud to pass sound at some of the more restrictive tracks, so I ordered an exhaust silencer that will hopefully kill some DB.
It also sounds like an open pipe tractor, but I'm not really sure what I expected from a 4 banger. In short, sounds like ass, moves a little quicker then before.

Rocking that hoodless look until Kpower ships me my modified valve cover.
https://cimg9.ibsrv.net/gimg/www.mia...7188dc9676.jpg

The side pipe looks absolutely incredible. I can certainly believe it's loud, but damn it looks good.

Congrats on getting it fired up! Even if it did take some trial and error.

It actually sounds crazy at WOT(volume aside). I cannot wait to hear it screaming down the back straight of Road Atlanta. Honestly if it wasn't for the concern of passing sound at AMP and NCM, and trying to maintain at least some form of good relations with my neighbors, I'd leave it... Although a lower DB would make highway cruising more comfortable...

Holy hell, these things do wonders for killing volume.
https://cimg4.ibsrv.net/gimg/www.mia...b5077d905d.jpg

My super accurate phone decibel reader tells me this took the car from 77db at 10ft away to 68db at 10ft away(both at idle). By ear its about the same noise level as the old BP was. Still loud, but much more liveable and will probably pass sound now. Hopefully it doesn't completely destroy power, Only a 6" long segment about 1.5" wide.

Well in most cases the DB meter at NCM is on the left at the 2 location’s used.
That is not the case at AMP.

Nice build.

Not a ton to report. I've been putting as many miles on it as possible to find any weak points and dial in my tune as much as I can on the street, but haven't had any gamebreaking issues as of yet. The exhaust is very rattly, I've had to hammer it in a few spots for some additional clearance, but no biggie.
I have had a bitch of a time getting it to warm up and stay warm while moving. I'm unsure if my cooling setup, which was designed to keep a raging BP in check even on hot August tracks, is just too much for the more efficient K, or if I have a stuck Tstat. At idle I can get it to 190-200°, but as soon as I start moving it drops rapidly to 130-150° and struggles to build temperature(with 30-40° ambient temps). I resorted to blocking off half of the radiator with cardboad, and this seems to be enough to keep it at ~160° during cruise with warmer ambient temperatures.

Had my first experience with corn. Man that stuff is fun and smells nice, but really burns quick. I *might* have gotten 200mi out of a full tank.
https://cimg4.ibsrv.net/gimg/www.mia...3c0b12ab23.jpg

I've only seen as high as E72, which I guess isn't too bad for this time of year. I have a buddy that says he can get his hands on pump E89, so hopefully I can get some of that for the dyno.

Had a little bit of cheeky fun once I had the car running on E85, $10 on ebay was well spent.
https://cimg6.ibsrv.net/gimg/www.mia...b45708c4d6.jpg

Finally got around to compression checking the motor, very happy with what I saw. Hopefully this motor has several years of track life in its future. As of yet it hasn't leaked or burned any oil *knocks on wood*
https://cimg9.ibsrv.net/gimg/www.mia...712bc30966.jpg


Other then that... just enjoying driving it. Had it up in some of GA's mountain roads, absolutely loved the extra TQ. I could leave it in 3rd and smoothly pull out of corners I used to hammer into 2nd for with the BP.
I have dyno time booked for the 19th. I would LOVE to make 205whp on 93, and 220 on E85(dynojet). Fingers crossed.
https://cimg7.ibsrv.net/gimg/www.mia...35f317b1f5.jpg

https://cimg5.ibsrv.net/gimg/www.mia...4b12681565.jpg

Definitely looking forward to your dyno results. I bet the car is a blast to drive!

Advice needed.
This is the first time I've logged fuel pressure, so while this behavior doesn't seem normal to me... well yall tell me.
1-5v pressure sensor, mounted to the FPR where there would normally be the analog guage. Fuel rail is setup as a dead head system, pump is a "new"(now used) Walbro 255. Fuel sock is new(installed with the pump), fuel filter has less then 6 months of use, and there are no leaks.
Fuel pump was rewired along with the entire car, its on its own 30amp relay with a 25amp breaker, 14 gauge wiring from the main battery buss to the OEM electrical plug on the tank, where it returns to 16/18 gauge for ~3" to the pump. Shouldn't be a voltage issue, rest of the car holds 14.5v solid.

Fuel pressure is set to ~60lb. Over the course of a pull, it *sometimes* drops as low as ~40lb, as shown here in this 2-3 pull:
https://cimg0.ibsrv.net/gimg/www.mia...e56c383f90.png

Does more or less the same in just a 3rd gear pull:
https://cimg1.ibsrv.net/gimg/www.mia...da881aef24.png


But also sometimes it just comes right back to full pressure without any reason(and sometimes it only drops to 50/55lb and holds there for an entire pull)
https://cimg6.ibsrv.net/gimg/www.mia...1b9174f301.png

I don't know if this points to either the fuel pump or the FPR, but it also doesn't hold 60lb when primed(holds it fine at idle and cruise), but immediately cuts to ~50lb and slowly drops from there, as shown in the video:

Does any of this point to a bad FPR, or a weak/bad pump? Or something else not right in the system that I'm not even considering?

I’ve seen a few issues, this is various cars lately: 1, clamp flew off the submersible hose, and it was gooey when removed, apparently not all submersible hose is made the same, definitely worth a look. 2, compact aeromotive FPR couldn’t keep up with boost. Swapped to the more expensive aeromotive FPR and dyno logs confirm, it’s nearly identical to MAP readings in the logs now. Not sure of it would have been an issue on a N/A car. Hope this helps.

Thanks for the suggestions curly. I opened the tank and checked over the pump assembly, everything was tight, and no internal leaks while running. I shotgunned in a new fuel filter as it was the only item I had on hand. It's still dropping, but only by 10-12lb now, I didn't see any huge 20lb swings. I could still blow though the old filter with ease, so I don't think that's the root of the issue anyway. The biggest thing is it's still not a consistent drop, sometimes it drop 10lbs and holds, sometimes it tapers off, sometimes it holds rock solid pressure, and I can't find any constants to it.
I don't have a spare FPR, and my spare pump doesn't arrive till next week. For now I'll just leave it, if it messes with my fuel map some while on the dyno, I can always fix it on the street.

Dyno Day! man, I was NOT disappointed!

Rolled onto the dyno and made more power on a basemap then my old BP had made cranked all the way up. 157whp/153tq
https://cimg2.ibsrv.net/gimg/www.mia...8973e37098.png

30 pulls later she put down 210whp/167tq on pump 93.
https://cimg7.ibsrv.net/gimg/www.mia...5fb4ec379b.png

And for the final coup de grâce, put down 227whp/182tq on E85 after another 10 pulls.
https://cimg7.ibsrv.net/gimg/www.mia...9cc35817b2.png

I've used this dyno several times in the past and compared it to other local dynojets. It reads bang on with the others, these numbers are as accurate as a dynograph can be.


Wow. Car is a rocket now, and absolutely screams though the upper RPM's.
I did the tuning start to finish, which was a first for me. Very nerve-racking to say the least! My mind was blown when I found out that VVT was worth a whopping 20whp over no VVT.

I cannot wait to get it on track. This year should be very, very fun.

Great number’s, congratulations.

It looks like you can still optimize the VTEC crossover. Seems like you're losing at least 10 ft-lbs by switching into VTEC too early, which is causing a fairly large hole in the torque curve between 4-5k rpm.

Yup, I realized that later as I was looking over the graphs. I've since moved the VTEC engagement to 4500RPM, where it was set to 4000RPM. It probably wouldn't be an issue except in 1st, as I only loose about 2500RPM in a shift.

As a sidenote while I'm thinking of it, that crappy generic cone filter lost me 4whp in back to back pulls. Now that I have my ducting in place I can find a good filter that fits and move to that instead.

And as a continuation to the fuel pressure issue, it happened on the dyno as well, so its definitely not a slosh or pickup issue. I never had a pressure warn kick on(set to warn at 45lb), but it did drop to ~53lb and recover to ~60lb during several pulls as per my logs.

Side exhaust sounds amazing!

Man, that sounds great! Awesome work, I'm looking forward to hearing about your first time on track with it.

Loving this build!

Great results. That gain from pump to e85 was way more than I expected, I think it's the first Z3 on e85 I've seen. This is good news for me because with the new NASA rules with the Toyo RR's that allow much more power I wasn't sure if I could max the car out in ST4 at 210 to 215whp.

With the couple of things I'm going to try it'd be interesting to see if I can hit 230whp. Ported headifold, underdrive ATI damper, straighter exhaust, velocity stack intake, e85. Also, if you use a velocity stack with the cone type filter I've seen those pick up power everywhere on the curve. On my nearly bone stock BP going from normal filter to a velocity stack and filter of same brand and surface area it went from 107whp to 109whp and that 2whp gain was everywhere on the graph. Swapped while on dyno with no other changes.

Do you have a link for the stack, preferably one that can be used with a filter/has a filter built in? I'm 3whp shy of 230 on E85, but I think I'm about maxed out in terms of exhaust and intake optimizations.
I'll probably be severely underpowered for TT3, even with taking the sidepipe hit and running RC-1's. The goal would be to get the car(sans driver) to ~1900lb, but that would be pretty tough with all the aero and limited interior options. I need to hit the scales at RRR and see how badly I'll be outclassed.

Is it just aero that puts you out of TT4? Put blanks in the ramps, remove the dual element, good to go?

Really any plastic velocity stack and filter combo will work. I didn't know you were going for TT3 at this point, you're going to be so outgunned on non-hoosiers that you should just spend the money on track time instead. Even at 2100lbs competition weight with 245 Toyo RR your max AVERAGE horsepower would be 265whp so you would need an engine that makes maybe 270 to 275whp peak to be competitive.

BUT. If you put 245 Hoosier A7 on, you could run at max average 230whp. Then that would make sense to try to squeeze out a little more power, get the vtec crossover dialed in and you'd be able to run pretty close to the limit.

I'd have to read the TT4 rulebook indepth, I'm not sure what else might DQ me from TT4. If it actually is just those two items I might consider it.
The plan was to use RC-1's for the first few events just to fully dial in the car and work though any teething issues. I have a set of Hoosier takeoff 205's and 245's, but I might save those for hillclimbs as well. Don't know for sure yet.

I believe the modded front fenders will also bump you out of TT4... ?

Correct. For NASA, Aero modded fenders are a no go w BTM aero. Rear wing end plates probably to large, rear bumper cut looks like it exposes crash bar which is no go.

I don't see that motioned anywhere in the TT4 rules, but its a moot point, as...
Yup to all of that(lol it's not even a bumper cut, I just straight up don't have one), as well as having splitter ramps and a 6" splitter. To run TT4 I'd have to:
Source a bumper, trim 2" off my splitter, find new fenders(?) make new endplates, and remove splitter ramps.
This car already struggles for front grip so removing the ramps and trimming the splitter would make it plow even harder. I'll pass on TT4. I'm starting to like the idea of running Hoosiers and 230whp in a maximum lightweight build for TT3 more. I'll just have to find a good source for 225/245 Hoosier takeoffs, as lord knows I don't have fresh purple crack money.

The rules state "shall be limited to the following:", and what's listed doesn't include fender mods, other than flares.

I didn't realize this until someone at a non-NASA event pointed out my Left Lane fender vents wouldn't be TT4 legal, so I'm kind of in the same boat. Don't really want to run TT3, so I guess I'm not running NASA unless I decide to spend a bunch of money going back to stock fenders.

Like you said, a moot point with your car. For me, that and my Singular hood vents will probably keep me from running NASA, unless they change the rules.

I think I'll be right there with you if I ever get my K-swap going. TT3 is the higher car count in Mid-Atlantic anyway, so I may go K24A2 and run in 3 with 245 Hoosiers. To run RRs I would need to add 50 HP haha.

I run with Singular hood vents with NASA. The only issue was having to push down the front gurney flap to no exceed the maximum height to be able to qualify for the BTM aero credit (which I currently claim in TT6). If you're not claiming BTM aero then having the vents shouldn't matter.

Oh yeah I forgot about the fender vents. I get the intent of the rule, keeping the ~$80k ST4/TT4 builds for going even higher, but I wish there was a way to get certain mods approved by price-point.

I'd keep the fresh Hoosiers for hill-climb, as that seems to be what you're more interested in. TT3 around here is either slow ppl show up, no people show up, or you gotta be running 1:30-even at Road Atlanta or 1:58 at ViR :rofl:

Good news, all your mods are 100% legal in GLTC ;)