My gain was 15whp on e85 compared to 91. That was pre ported tb/intake manifold so I don't know if those added anything.

I have been running the standard gm fpr/filter w/ a dw300 for a couple years with zero issues, so I doubt this was your problem, but it may work.

Edit: I believe you can see pre hpfp and post hpfp pressure in hptuners (but it's been a while since I've been in there)

Good luck!!

HPT shows a pre pressure, but it never changes or oscillates and that makes me think it is a bogus number that isn't actually being pulled from somewhere. Is there an actual sensor on the car to read the low pressure line's psi? Probably chasing my tail with the regulator and filter, but wanted to upgrade anyways. I'm out of ideas after this on the misfires. Probably just have to wait for Griff's stand alone.

Not sure on the pre as the sensor would have to be right at the pump since there is nothing but an lines between that and my dw300, but I know it does show hp fuel rail pressure for sure.

It's a bummer you are having these issues as the gm ecu seems like it's pretty solid.

It shows the actual HPFP pressure from the rail sensor, but the LPFP is an ECU calculated value that is NOT correct. Best to just get a sending unit or analog gauge and put it inline just before it goes into the fuel rail at the engine. Like LukeG said, I don't have much confidence that this will cure the misfires, but it is nice to be able to set your LP side right where you want it and having a good 5 micron filter is just cheap insurance if you ask me.

Thought I would comment - have an inline -8 10micron AN filter on my dads build, and I've been fighting the "hard start/low battery voltage" issue - last time it needed 2 battery packs to start. Finally decided to instrument everything (benchtop power supply, separate electrical systems starter vs ECU, oscope to watch everything) and it wouldn't start on freshly rectified and smoothed 15v. Threw in spare ECU, no joy.

Turns out, 10 micron filter was clogged. Argh. And yeah, I also believe the low pressure is simulated value after that debacle. Though I also had 1600psi in the rail and it still acted like the injectors weren't firing. Weird.

Working on the fuel system and realized that my return dump in the tank is too high and needs to be dropped down to prevent foaming. Will be welding on a small stainless tube to the miata fpr location. Fuelab 535 fuel pressure regulator and Fuelab 6 micron fiberglass filter are on the way from Summit. I'm running a holley hydramat for the pickup and it acts as a 15 micron pre-filter, so should be golden on the filtering side.

https://cimg9.ibsrv.net/gimg/www.mia...0d8fd411ad.jpg
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Loaded up on E85 this morning and got to around 45% ethanol with 93 octane mixed in. Holy shit... the car can now spin the RC1's in fourth gear. Hopefully I can hit the dyno in the next couple weeks. I'm super curious where the car is at now in power. All the issues I was having are gone with E85 in the car. Misfires on cylinders 2+5 totally disappeared. I don't fully understand why, but I'm very happy. New fuelab fuel filter and FPR are on the car. Also welded up a stainless tube to extend the return drop all the way into the bottom of the tank. Came across a video that shows how bad fuel foams when you return drop isn't low enough and I am pretty sure I was driving with a tank full of foam. Got the pressure set at 62psi. Going to be picking up some of the new Nankang AR1's in the 275 flavor in the next couple weeks. Oh, and I am running a DW300 fuel pump with a Radium adapter for the Holley Hydramat for reference. I had completely forgotten what pump I had.

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Noticed that the connector on my throttle body had a broken locking clip. Searching around it seems pretty common to have issues with these connectors. Ordered a couple since they are cheap and I want a spare.

Part # 1-1438153-3
https://www.mouser.com/ProductDetail/571-1-1438153-3

Looks like all of that work is paying off...big time. Eventually I see myself going down this same path.

Not sure the power level I am at right now, but guessing a healthy 300+whp. That is the perfect level for the exocet. I have toyed with the idea of going forced induction, but I don't think that makes sense for the exocet. The LFX on E85 is more than enough to do some absolutely retarded things and the torque down low vs bp turbo is insane. I know V8R doesn't recommend anything higher than a 3.23 for gears, but I am in love with my 3.91 OS Giken setup. Roll-ons in any gear will make you giggle. And so far the miata diff with a kmiata brace plate has held up to everything I have thrown at it.

Car is now perfect except for one issue that has been pretty elusive. Randomly every now and then the car will go into limp mode when going from a stop. It's still doing this after replacing the accelerator pedal and going through every detail in the tune to see if that was causing it. The throttle body is brand new so I am fairly certain that isn't it either. The code it throws is P2138. Unfortunately this is a pretty vague code and I have seen hundreds of posts on forums about this code and what potentially caused it. The actual code is defined as an issue with the throttle connector/wires or accelerator pedal sensor in many cases. I have inspected all of the wiring and everything looks fine. Trying to find more info on this I came across an old post by Ryan Passey on another forum... https://forum.miata.net/vb/showthrea...610911&page=10

"I blasted through this and forgot to take all but one picture - V8R advised that the throttle pedal signal is very sensitive to interference, so for this I ran a 6-wire shielded cable on both the chassis and engine side"

I also saw a single post on the Camaro5 forum about someone having the exact same issue and they took it into the dealer. They claim the dealer replaced the throttle position sensor wire bundle with shielded wire and it fixed the issue. Fingers crossed!!!

So I am now ordering all new pins for the throttle body connector and the pedal connector to run some prowire shielded 6-conductor wire on both sides.
https://prowireusa.com//p-2112-20-aw...ded-cable.aspx

I have heard I'm not the only one with this issue and it has been a total pain in the ass to try and figure out what it is. Never would have guessed invisible electric pixies infiltrating my wiring, but at this point I'm down to try anything to fix it.
Will update in the next week if the shielded wiring fixed the issue.

Can't believe you are spinning in 4th! Wow. Very cool, I hope the 275's help get the power down for you.

I hope the new wiring fixes your issue with the limp mode. You are so close to everything well sorted! I'm about to start wring things so will definitely be paying attention to what you find out here. Good Luck!

Thanks man! So close, only one issue left to resolve! Took the car on an hour long drive on Monday. Absolutely blown away at how well it drives, corners, accelerates, etc. The LFX engine is an amazing platform and on E85 that motor comes alive. All the work I put into this car was 100% worth it, and for the price I don't think there is anything that will come close in fun factor.

Started going through the accelerator pedal wiring last night and I can get a clean shielded run all the way to the ecu with no breaks if I bypass the Delphi lever connector. Ordered plugs for the lever connector to replace the soon to be missing wires.

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https://cimg1.ibsrv.net/gimg/www.mia...2d42df4d17.jpg

Pedal connector now has shielded wires and made everything nice and tidy. Just waiting on the pins to wire it directly to the ecu. For reference, all six of the accelerator pedal sensor wires connect through the blue connector on the ECU.

https://cimg4.ibsrv.net/gimg/www.mia...8ea86fd7bb.jpg
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Few updates...
- Nankang 275/35/15 AR1's will be here Thursday and are getting mounted as soon as they show up
- Shielded accelerator pedal wiring is done and the ecu connector pins are a pain in the ass
***Lastly and most important, if you have an LFX swap check your accelerator pedal connector. I was trying to seat the connector all the way and realized it wasn't going down far enough to lock into place. A slight tug on mine and it would come loose. I even pulled the pedal off the car to try and seat the connector with no luck. Pretty sure my connector has never been fully seated and may have been the cause of this craziness. Not sure if this is normal, but I had to file about 2mm off the top lip of the connector frame on the pedal so that the connector would fully seat and lock into place.

245/40/15 Maxxis RC1 next to Nankang 275/35/15 AR1


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I was gonna ask if it looked shorter, definitely does, looks like it's 1/4"-1/2" smaller diameter?

It was hard to shoot it at the right angle to show it properly, but I'd guess about 1/2" smaller diameter. Not sure if that changes when they are inflated???

Too bad there is no source for 15" wheels 12" wide now that we have cheap, good tires for them......

https://cimg5.ibsrv.net/gimg/www.mia...70de2f294c.jpg
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It looks like a double scale go kart, I love it.

Damn! Those are huge...almost comical how big those tires are on the Exocet! Bet you can’t spin those bad boys over in 4th gear! Interested in your thoughts after you get a few miles on them. I’m not a 1/4 mile guy per se, but I really would love to know what the 1/4 mile time of your car is.

I definitely need to change out my diff housing first. I'm nervous about snapping an arm on the miata diff housing even with the kmiata diff brace. I have a much beefier RX7 housing that I'm putting on over the winter that should hold up better.

Also got a dyno appointment scheduled for next friday. Very curious to see where she is at now that everything is sorted.

Yeah, it's basically just a big ridiculous go kart at this point. Too much fun!

Took the car out for a test drive... the tires are amazing! No more spinning in 4th and they have some serious grip. It did the throttle/limp mode thing again though about 5 minutes into the drive. Back to the drawing board. Talked to Griff and he is gonna see if we can use an LGX ecu as a test to see if it fixes the issue. I have a brand new throttle body I'm going to throw on for the hell of it in the mean time just to see if it does anything. Doubtful, but it is one of the last things I haven't replaced recently, so why not.

The old throttle body I pulled off had a date stamp of 2014, new one is from 2020. Took the car out for a quick drive with the new one and no limp mode. Even stopped a ton of times trying to trigger it and nothing. I'm going to take it out three more times tomorrow and try to trigger it. Will report back. Interesting so far...

Three separate drives now and no limp mode with the new throttle body. I need to get a few more in for a more definitive answer, but we may be on to something. The last two drives were 15 min each way to get E85 and I purposefully hit every stop light I could. Car drove great, zero issues.

Got up to 62% ethanol in the tank, so she's ready for the dyno on Friday.

Got the car dynoed last week and it put down 286whp/266tq to the wheels with 62% ethanol in the tank. I was bummed it didn't hit 300, but Griff has beat it into me that for the most part comparing dyno numbers on different cars, dynos, weather, etc. is dumb and if you are happy with it ignore the dyno pissing contest. One odd thing I noticed when reviewing all of the LFX dyno numbers posted on the camaro 5 forum is that everyone runs their camaros on the dyno in 3rd gear (manual trans), when 5th gear is actually the 1:1 gear. I am assuming this is because of the factory speed limiter. I tried digging around to see if this changes what the dyno sees and couldn't find a definitive answer other than "possibly by 5% or less." In hindsight I would have loved to have done a 3rd gear pull just for shits and giggles and for science.

All that being said, I am thrilled with the power output and delivery on this car. In regards to the throttle/limp mode issue... since replacing the throttle body I have driven the car six times now with zero issues. I'm going to get a few more drives in this weekend and I am confident if I can get to 10 separate drives with no issues I can call this fixed. Fingers crossed!

Getting ready for winter and I am going to be switching out the wheels to the JP19 15x10's with -32 backspacing so I can ditch my spacers. Also, going to replace the front and rear hubs with the gorgeous billet enduro miata hubs. Then I am going to swap out the miata diff housing to the 91 NA FC RX7 housing. Now that the car is sorted out, goal is to get some track time next year and enjoy it.

Decided to solder and pot the accelerator pedal pins after the P2138 came back again. Have heard from a few people this connector is notoriously a piece of crap and had the same experience. Got my carbon fiber sheet in to replace my aluminum wiring cover. Cut it to size and just need to drill it for mounting holes now. I'm tempted to start replacing all the body panels with carbon fiber since it looks amazing. Won't save a whole lot of weight, but damn carbon looks great.

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Where did you source your carbon fiber panels? I'm also looking at replacing some panels with carbon fiber. I've only found suppliers that are asking $$$$$$.

https://www.protechcomposites.com/shop/

Not cheap, but the best pricing I could find and the sheet is beautiful. They did a custom cut for me with no charge too.

I was considering sending them all four side panels to have them cut them perfectly for me. The exocet hood and rear cover are offered in carbon fiber. I think I remember someone saying they weren't impressed with the quality though and they are very pricey.

Thanks! I'll take a look. I've seen detailed pictures of the Carbon hood/rear and the joints and seams were pretty rough. For the price and quality I'll pass on those. From a couple feet away they look incredible though.

That would stretch the tire....275 works on a 10" rim

@LukeG how long does it take the tires to come up to temp?

Haven't gotten to run the car on track yet, so no idea on that.

Just read through the whole thing. I love this )re)build. So any things have changed since I was last around. The mind starts doing dangerous things.

Cheers and thanks Brother!

So when will this be destroying Harris Hill? Fresh pavement, smooth as hell and so much grip already.

I called Harris Hill and they wanted $2,500 to be a member and then an additional $200 per month if I remember correctly. Is there a way to drive there without being a member?

I also heard they have a pretty strict sound level and I'm not sure I would make the cut. Would love to drive there though! Let me know if you have any thoughts.

They do SCCA track night in america events. It'll be packed, but it's cheap track time.

That being said, the $200 per month is insanely cheap track time lol. A 2 day track night at COTA starts at about a grand.

Sports Car Membership - Harris Hill Raceway (H2R)

Looks like it's more now.

This is true, it's unlimited on member days. But if you can't go when they are having member days, etc, you are still paying for it.

As with any membership. It's like a country club but affordable and it's a racetrack. On average 5 days a week are member days, first week of the month the bike guys get a few extra days but that's it.

Anyway, sorry for the derail, OP send me a message if you want to check out the track, I'll be glad to let you right seat in my NC and check it out.

Yeah, it is a total steal and bargain for what it is. My only wish is that I lived closer! I'll hit you up as I need to make a trip down there anyways to see if the car will pass the sound requirements.

Starting on my winter to do list for the car. The front sway bar was moving horizontally a few inches every time I drove it, so I got some lateral locks from energy suspension. They work great and no more lateral movement. I'm currently redoing the entire fuse box side of the harness. I wanted to upgrade the wiring to Tefzel and also look everything over in detail. Found one loose connector wire on the fusebox for ecu power. Suspicious as to whether that could be causing my limp mode issues.

Winter Exocet To Do List:
Lateral locks on swaybar
Remove wheel spacers
Order and install JR19 15x10.5 ET-32 wheels
Install front and rear billet miata hubs
​​​​​​​Install carbon fiber wiring tray cover
Rewire and repin fusebox side of harness
Replace diff housing with RX7 NA FC housing
Weld baffles into side exhaust outlets to reduce sound for Harris Hill
Remove horn and use power wire for ecu (consolidate with other ecu power wire for 30amps)
Reprogram P12 to change horn power output to ecu power
Pull transmission to check rear main seal and oil pan for source of small oil leak
Run dedicated 2ga ground from battery to distribution block for everything other than engine block ground
Install new battery disconnect switch with separate post for alternator
Run dedicated 2ga power wire from battery kill switch to alternator (master kill switch doesn't work if car is running right now)

https://cimg7.ibsrv.net/gimg/www.mia...9b4544fa9e.jpg

Has anyone been able to remove the trans on the LFX without removing the engine from the car?

It's so close to coming off it's driving me crazy. The top of the bell housing is hitting the outer front of the tunnel.

Yes. Really do not suggest doing it that way, way easier to drop the subframe, engine, and transmission all at once. Highly dangerous, do not recommend, proceed at own risk.

You have to loosen the subframe bolts and tilt the engine back, and then twist the transmission counter clockwise nearly 90 degrees if memory serves, to get enough clearance between bellhousing and firewall (at least on our NA).

All over the place with what is going in next. Will update this when I make some progress.

...

Alright, had a bit of a wtf moment with the limp mode the ecu keeps throwing at me. Been chasing my tail for months with this. Had a conversation with Andrew at Keisler and he said they have seen this on a few cars and after replacing every sensor one by one they determined it was the high pressure fuel sensor. It is literally the only sensor on the car I haven't replaced and honestly I didn't even know there was one back there. You can't see it with the engine in the car. So engine is out and going over everything. Going to pull the oil pan and rear main seal and redo both with Ultra Black. That oem gm sealant sucks btw. Just go Ultra Black if you need to seal the pan or rear main. Also replacing the high pressure fuel pump because I hate pulling the engine and figured it was one of the only things that hasn't been replaced. Will be ordering the LFX flywheel and clutch from Spec Clutches shortly. Once everything is back in and running good, plan is to get my hands on an Eaton TVS 1900 roots blower and work with Griff to adapt it to the LFX.

2016 Equinox LFX with 0 miles/never installed factory crate motor is on the way. Will need to swap over all my engine accessories and change the pan out.


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wait, did I miss something? Why? What happened to the engine that's in the car?

That engine was always giving me weird issues. Random misfires and knock, oil leak at the rear (which could be a sign of the #3 thrust bearing breaking per a GM service bulletin) and accelerator pedal limp mode that drove me crazy. I got fed up with it and decided to pull it. Was planning on going through the whole thing and putting a lot of work into it, but came across a 0 mile engine that had never been installed. For all the work I'm doing on the car it would be really nice to have a brand new no issue motor, so now it is being replaced. The original motor only had 12,500 miles, but it was from a front impact totaled car. Learned my lesson on that one. ThePass also had issues with his first one or two salvage motors.

y i k e s

hopefully this gets ya rollin'.

That sucks (switching motors) but I hope this fixes those issues for you. That's awesome that you came across a brand new motor! I really need to get on the ball. You're going to have two engine swaps completed before I get my first one done. Hope this one goes together smooth & quick! Looking forward to seeing the supercharger too.

New engine just got here today. 2016 Equinox engine with 0 miles.

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I was having issues on clutch disengagement at high rpm shifting that leads to occasional grinding. I'm upgrading to a larger bore wilwood master cylinder to see if that resolves the issue. I read a couple hundred pages of people having issues with the MV5 and the master bore being too small from the factory to properly disengage the clutch. 1" bore master that I ordered is below for reference. Current one on the car is a 7/8" bore.

https://www.wilwood.com/mastercylind...emno=260-13622

Updates... got the new engine setup and all the parts transferred over. Waiting on the ATS-V windage tray that has been all over the country the last two weeks ( TX -> MI -> PA -> TX) thanks to the tards at USPS. Griff mentioned it has a better baffle setup so going to try it out if it ever gets here.

Also cut open my boom tube exhaust side exits to add some pretty serious baffling. I am attempting to get this car substantially quieter (<99db) to appease the race gods at Harris Hill. Fingers crossed this works. Threw in some more pics of the cut oem alternator bracket that should make the cut line more clear for anyone trying to do this.

After looking at the camaro and equinox oil filter housings, I prefer the equinox one. The camaro housing uses a cartridge style filter but it is substantially smaller than the equinox filter. Waiting on wheels (felgenwerks 15x10 -32) and the spec stage 3+ (unsprung) clutch/flywheel still. Attempted to order some carbon Tillet B6 seats, but they told me they are backordered by 27 weeks.Post covid supply chains suck ass. Everything is becoming harder to get.

Oh, and got to drive a C8 today. My buddy had his delivered yesterday with the Z51 package. Holy hell what a nice car. I am in shock this came from GM, very impressive and gorgeous car. We'll definitely be doing some roll-ons on deserted roads once I am running again. Curious to see how the C8 does against the beast.

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Just came across a channel on youtube documenting two miata lfx swaps going on at the same time. Great videos and very cool to see a well funded race team take on the swap.

LOL...Like I needed another reason to waste time watching YouTube! Thanks for posting this.

BTW...Adding all those baffles looks like a serious PITA. Exhaust work...deceptively a lot more work than it looks.

Yeah, I am easily 100+ hours in on this exhaust and it is by far the smallest exhaust I've ever made LOL.