Congrats! SO satisfying to see it moving under its own power. And subtle flex with the NSX and the other NB. Love it.

 

I bought this




and I bought this



Hopefully will be an NC version of what CRXGUY52 has someday.

 

Thanks for the kind words everyone! I'm trying to enjoy the journey... but I am also very excited to drive it. When I first pulled out of my neighborhood I gave it quarter throttle and... it moves. Very un-Miata like

Haha I was not intending to flex with the NSX, that's just where it lives. I don't drive it as much as I should, unfortunately, and it'll probably be for sale once I get the Miata on the road. Don't get me wrong, it was my dream car and it's amazing. It's just too... nice. When I drive it I'm always worried about taking a rock to the windshield or putting a hole in a condenser because I have no idea where I'd get replacement parts. Rare cars are cool until you have to fix them. That being said it's been dead nuts reliable in the 8 years I've owned it, including (mostly) the 3400 mile trip home after I bought it.

Everyone I've talked to who has made brake hardlines has struggled initially. So I'm trying to avoid it if possible. But yeah I had the same thought, if I wanted to add a MK60E5 I'd have to run all new lines to the back. If that happens they will be soft lines.

Looks like you've got a fun project ahead of you! That engine looks like it came out of a FWD application, my parts spreadsheet has everything you should need to convert it over to RWD. If I were to do it again I'd just buy the Keisler alternator and bracket, it's cheaper than the GM one and it'll actually fully charge the battery. And the power steering pump bracket (as well as power steering reservoir bracket) are a PITA to locate, but I think the NC has electric power steering so you may not need those parts. Anyways feel free to reach out if you've got any questions, happy to help.

 

One of the (many) issues I had with the V8R parts was the shifter. To explain why it sucked I first need to explain how it mounts. Below is an image of the MGW shifter for a Camaro application.



When you buy it from V8R it only comes with the central part, not the parts that bolt on the front and back. V8R's solution to mounting it is to cut a hole in a plate, assemble the shifter up through the plate, and then retain it with two blocks where the front and back parts bolt on. Like so, but without the set screws:



The problem is that everything needs some small clearance to be assembled. This clearance allows the shifter to translate fore and aft, side to side, and to rock. When shifted the assembly bangs around in the plate, which is quite loud considering it mounts to sheet metal. I added the vertical M5 setscrews in both blocks to take up the slack. This solved the problem but it was after I'd already modified the baseplate - when it arrived the mounting holes didn’t line up with the chassis. I don't understand how a company can sell such a half-baked solution but when you're the only game in town I guess that's how it goes.

On the bright side I was able to McMaster up a cheap shift **** using a threaded rod and machine handle



Working my way down my todo list I needed a way to connect the intake manifold to the brake booster. This is really only an issue because the hoses aren't the same size and the factory check valve is somehow inside the Miata hose. I could have probably found an adapter but where's the fun in that? I made one using a $10 stick of 0.75" aluminum tubing and leftover AC fittings.



The AC fittings come with a crimp sleeve on the outside, I cut those off and just used the hose barb. These are the fittings I incorrectly ordered the first time (for standard barrier hose) so I'm glad I got some use out of them. I think this came out alright, the factory hose routing looks a little funky but otherwise I like it.



Currently working on building the air intake, I think my only option is to weld an elbow on to the throttle body, otherwise there's not enough space for a coupling. That'll be fun since I can't remove the plastic gears, but I'll save that for another post.

 

Start a build thread! I want to see that project come together haha.

That's hella annoying about the shifter. I thought KP were the kings of "we're the only option so f*ck you", but the more I hear about V8R, the more it sounds like they're the same. I get that it's super difficult to have an off the shelf solution for everything involved in one of these swaps, but instances like that shifter among other things just rub me wrong. Obviously drilling the plate out to line up with the factory mounting holes isn't too labor intensive, but as someone with limited fab skills, I'm dead in the water if anything requires welding, adding material, etc lol.

My BP to ZF6 trans adapter from KP shipped with two bolt holes that didn't perfectly line up and had to be drilled out. Irritating after dropping that much coin on said trans swap kit haha.

 

Thanks for the list. My engine is FWD and new with only 11 miles. I also bought a junk LFX from a Camaro to get the intake, heater lines, etc. It has the alternator bracket, but I may go with the Keisler one anyway for the charging reason.

I'm just at the planning stage, but I did pull the engine last week to see what I am going to be dealing with.

Thanks for the offer. I'm sure I'll be taking you up on it!

 

I would normally not complain about adding a few set screws, drilling out holes, etc. What bothers me is that basically every product I received had at least one of these little "gotchas". The shifter is just the latest example. The driveshaft was wrong, they sent the wrong clutch kit, the power steering kit didn't fit at all, the sway bar mounts don't have the correct hole spacing, there were a few instances of not receiving the correct hardware... I'm sure there's more but I don't even want to think about it. I'd heard they weren't great before I ordered but I didn't think it would be this bad...

Geez, I thought my engine with 3k miles was shiny . Happy to help! And I know a few other members are as well. You were smart to buy a junk Camaro engine, I spent a ton of time looking up part numbers, what hardware to use, etc. You'll probably need to get the CTS coolant pipes and hopefully the Camaro engine came with a wiring harness (it's discontinued now), but otherwise you should have most of what you need between the two engines.

 

Not helpful now, but Keisler has the part numbers for the fwd to rwd conversion on his site:

https://drive.google.com/file/d/1w-n...SfyUm-sYJ/view

 

I did start with that list and then added all of the other little stuff I needed, mostly power steering stuff (since the RX8 has electric PS) and gaskets, sensors, etc. that would be otherwise very difficult to replace.

 

Gotcha! I figured, but also figured that someone else coming across this thread might not know.

 

As mentioned previously I've painted myself into a corner by using the Giant Radiator of Inconvenience - there's just not enough room to route a 3" tube from the throttle body to behind the driver's headlight without modifying something. I considered moving the filter elsewhere but each alternative had its own issues which were more substantial than my initial plan. I had three options: move the throttle body, make a cobra-style elbow, or modify the throttle body.

Moving the throttle body initially seemed pretty promising - bolt a plate to where it mounts to the intake, weld on a tight-radius tube, and mount the TB to the other side. It definitely solved the radiator clearance issue but it had two flaws: The TB would interfere with one of the remaining ribs in the hood and I'd be adding a lot of mass to the end of a tube. Which was screwed into a plastic intake manifold. This, plus the fact that the engine would twist side and put more stress on the manifold, made me steer clear of this option.

Option 2 was to print (or buy) a cobra-style elbow. I've seen this used on at least one other build but… I don't know. I just didn't like it. It might flow fine-ish but it's probably not as good as bent tube. Plus it's front and center and I didn't want a goofy looking part to be the first thing you look at when the hood is opened.





I settled on the most difficult option - modifying the throttle body. I wasn't super excited to do this since there's electronics and plastic gears inside that I couldn’t remove. Googling shows it was possible on older throttle bodies to remove the gears and circuit board but not this one. The motor leads are welded to the PCB inside making it impossible to non-destructively disassemble.



I started by ordering an expensive aluminum donut and a cheap aluminum intake tube. First order of business was making the throttle body shorter. Stock it has a ~1" flange to clamp a hose to before the actually butterfly valve:



A somewhat-sketchy trip to the bandsaw later and it was shortened:



I was a little concerned about affecting the flow around the valve but I was careful to only cut up to the machined "step" - everything after that appears to be part of the valve, whereas the tube ahead of it appeared to be there only to mount an intake. The rest of the fab would require the hood to be installed so that was trimmed.



A popsicle stick did a great job of removing the glue dots after the webbing was removed. With the hood installed I could check how much room I had. A 90° segment of the donut and a short straight tube were tacked onto the TB and I took some pictures looking into the passenger headlight hole:





The first image does a good job of showing how much vertical clearance there is to the hood - quite a lot around the TB, actually. The problems are more obvious in the second image. Not only does the elbow almost touch the radiator shroud but it must also snake between a hood rib and the upper radiator hose. I was skeptical that I could fit a 3" tube in the gap but it does indeed clear. With a more solid plan in place I started cutting and welding. I was most concerned about the throttle body so I started by welding the parts I could get to from the outside.





This wasn't actually all that difficult. Welding 1-2" at a time and quenching between kept the part at or below normal under-hood temps and the cast aluminum welded …fine. Because the drive-side was impossible to get at from the outside I had no choice but to weld it from the inside. This actually ended up being easier than I anticipated once I removed the blade… which was held in place with penta-lobe screws. These weren't too difficult to remove but required a new tool purchase. Hint taken, GM, you did not want me messing with these screws. The shaft actually made a nice torch-rest



The rest of the fabrication was pretty straightforward, just a lot of cut-check-cut cycles. I'm happy with how this turned out. The welds aren't the nicest looking but I did learn and important lesson: small parts are a pain to weld. The final welds were way easier to get consistent results. I realized it was probably because the bulk temperature of the part was changing a lot slower than when I started - when I was welding two small pieces of tube together. I may be misinterpreting the results but I'm definitely going to tack the whole part together before I weld it out next time



The MAF bung weld looks like trash because I didn’t realize it was anodized before I started welding. Can't say I'm surprised from a $10 amazon part, and I need to check next time. Next up was modifying the radiator shroud. I made some cuts with an angle grinder (and a special aluminum cutoff wheel - I've seen what they can do when they explode) and welded in a ~0.100" thick replacement piece. I was hoping these welds would come out nice but the difference in thickness made that difficult. Definitely not my lack of skill. I ended up also welding the back side and then cleaned up the front with a flap disk.



With that finished I could do a final test fit. There's so little clearance between the coupler and throttle body cover that I need to use a flat hose clamp, not the fancy silicone-style ones! Fortunately all of that moves together so it shouldn't be an issue. I'd like to get better looking hose clamps for this at some point but the one I had on hand was fine for fit-check. The other, more obvious remaining item is figuring out how to finish the tube - the bends are bead blasted and the straight section is polished. I'll probably just end up wrapping it in gold reflective tape since a local shop quoted me $85 to bead blast it and $150 to powder coat it. I'm open to ideas, though.



Plenty of clearance between the throttle body and radiator/hood now. That's less true for the intake tube and air filter but if those become an issue I can always fix that with the angle grinder - the hood rib can be a little smaller if needed.





It looks a little tight there but there's (hopefully) enough clearance. The last detail was securing the air filter fore/aft since the throttle body will do a good job of that side to side. I bent some welding rod and used a nearby leftover tapped hole. Simple, light, and easy, hopefully it's strong enough. If not I can always make something else out of thicker rod and/or a fabricated piece.



And there you have it, more than you ever cared to know about the intake on my car. I’ve got probably 20 hours into this intake - fab work always take so much longer than I expect. I do want to refinish the headlights before they get installed but otherwise I’m ready to reassemble the front end. The bumper will be the last thing that goes on since I don’t think the car will fit sideways in my garage with it installed.

 

I appreciate every bit of this post. End result turned out awesome, man!

 

Not a ton of technical content to post, just a photo of the car sitting in my driveway, looking like a car again.







Off to get an exhaust made on Friday and then it'll be street legal. Drove it around a little yesterday and after fixing a few small coolant leaks I think it's ready for it's maiden voyage back from the exhaust shop. A few observations from driving it around the block:

• Dear god it's loud
• Torque. So much torque. Feels strange in a Miata.
• The power level is about right, even on the factory wheels. Power doesn't dominate the experience, but she quick tho
• I definitely want to monkey around with the ECU tuning, the throttle response is not where I'd like it to be. Too much filtering as it stands, feels more like a minivan than a sports car.
• The AC works! Also, the 60lb flywheel does a good job of not letting the motor stall when the compressor kicks on. The revs barely drop, actually. Was not expecting that given that the ECU has no warning when the compressor engages.
• Intake tube gets really hot. Like, almost burn my hand hot. IATs were around 31°C when moving and >50°C at a standstill on a 25°C day. It's almost on top of the radiator so not a surprise, but something to fix.
• Brakes felt great, super firm.
• Steering also felt great. I eyeballed the restrictor diameter based on the Turn One part that didn't fit so it was nice to confirm that it felt like a factory car.
• It doesn't really like to go into reverse, you really have to force it. Almost feels like something's bent inside, but that's the risk you run with a junkyard transmission. Not worth tearing it apart to fix it since car go backwards
• My gauge cluster works fantastic, I love it.
• The ECU is throwing a P06B7 at high revs, it's probably because I haven't done the crank relearn procedure yet. CAN data doesn't indicate a CEL is active but I do need to hook up a LED to check.
• I refinished the headlights using the cerakote kit, that worked pretty well
• Did I mention it's loud? Like, the the whole chassis vibrates loud.

Dropping it off Friday and picking it up the following Friday

 

The car looks so good back together! I loved reading every post, your attention to detail is very satisfying. Looking forward to hearing this thing once you get the exhaust made

 

Hell yeah dude, so satisfying seeing it look like a car again. Does the P06B7 code correlate to crank relearn procedure on a GM? On our Fords, you might get an intermittent misfire, or misfire codes with no misfire if the crank relearn procedure isn't performed. Haven't seen a knock sensor processing code correlate with that. Just personally curious?

Need vids when the exhaust is done. Bet she's a riot!

 

Congrats on being able to drive it again (even if it's loud). Always a redeeming moment.

I'm a bit surprised as to how hot the IAT was getting. The close proximity to the radiator is doing you no favors, but maybe some reflective gold heat wrap on the tube and a heat shield / airbox at the filter element will help address some of that.

 

Thanks! I spend most of my day documenting things so it's sort of a habit now. This is at least fun to document.

I have no idea if the two are related, that's just my guess. If I keep getting the codes after the relearn I'll dig more into it, it may just be a bad sensor. Looking back at my orders it looks like I only bought one new sensor (the engine has two), so the old one may be giving me issues.

Yeah, I've got the gold tape on order and an air box is on my todo list. Right now the intake is basically sucking in radiator discharge which isn't great. I was sort of surprised by how hot the throttle body (and the elbow attached to it) got since there's no coolant running through it, my best guess is it's just bathing in that hot air. Most of the running I did was also idling up to temperature and slow speed driving, the fastest I ever got was 50mph for a minute or two which also doesn't help.

 

[rant]

I paid a local shop to build the exhaust after talking to @rdb138 - without a lift it would have taken forever and been a PITA. With some help from my dad we towed the car in last Friday



When we got there I told the shop I wanted something reasonably quiet (think sport exhaust from the factory) and I thought a dual 2.25" or dual 2.5" with cats, resonators, and mufflers would probably do the trick. They proposed a single exhaust because it would be quieter so I agreed. They quoted $1300 which was pretty reasonable - it's a mild steel exhaust but I'm not super concerned about rust in the south and I didn't want to pay for stainless. I'd priced out a SS exhaust and parts alone would have been $1k.

Of relevance, the guy I spoke to at the shop bragged about pissing off his elderly neighbors with his loud diesel exhaust because they asked him to keep it down. Keep that in mind.

They sent me some videos with different mufflers on Tuesday and I was able to pick one out without driving there (it's about 30 minutes away) which was a nice touch. They had it wrapped up by Tuesday evening, the plan was to pick it up on Friday (today) around 8 and drive over to my alignment appointment at 9. Here is where the trouble starts.

Wednesday morning I realized we'd never talked about tube diameter - I'd specified dual exhaust diameters but not a single. Surely they went up with the tube diameter, right? That's common sense, especially for people who build exhausts for a living. Texted them and …nope. They'd built a single 2.5" exhaust. At this point I was furious since an single 2.5" is HALF the area of the headers - they're dual 2.5". Either they thought I was stupid and wouldn’t notice or they don't know how circles work, but either way I was not a happy camper. Fortunately they agreed to remake the exhaust in 3" at no extra charge.

I took a Lyft this morning to pick the car up and the transaction was …chilly, since both of us were pretty pissed. They did indeed replace the system with a 3", I checked before I left. As I was driving away I noticed that the clutch was slipping, and it definitely wasn't when I dropped it off. I immediately assumed they went and did a bunch of burnouts because I'd pissed them off. I was seeing red. Fortunately my dash logs all the data so I could know for sure if they did or didn't, but I'd have to wait until I got home to check.

Went to my alignment appointment which went according to plan. When they wrapped up I moved the car, adjusted the clutch, and tried to start it again. And… nothing. Crank but no start. Great. After a few deep breaths I figured it was probably just due to a not-perfectly-charged battery since the exhaust shop started it a bunch of times but didn’t let it run. Borrwed a jump box from the place and it started right up.

The drive home went mostly smoothly - the drivers valve cover has a pretty significant oil leak (despite being a new gasket) and there's a coolant leak where it enters the cabin (same one as before) but otherwise the car drove fine. There's something going on with the shift linkage where it doesn't want to go into reverse - I'm pretty sure there's not enough range in the shifter, so I need to look at that. I'm also pretty sure there's STILL a leak in the AC system because it doesn't do much cooling.

When I got home I checked the data logs and… I was wrong. The exhaust shop didn't drive the car. It was just a really strange coincidence that the clutch needed adjustment immediately after the exhaust got installed. I'm home now, the car's here, the exhaust is too loud, but everything is fixable. I suppose the moral of this story is to be explicit about every detail when someone else is doing work - I usually am, but I deferred to the shop's judgement on this occasion and I shouldn't have.

[/rant]

 

Get us a sound clip. Single 2.5" exhaust is laughable, I run a 2.25 on my stock bp4w. Glad you got them to fix it. Hope the work was ok after all, other than being too loud. If you picked the muffler that's probably not their fault.

 

Damn yeah that's pretty agitating re: the shop's arbitrary decision on diameter. Super wild that they'd see your car roll in with some extensive fabrication work and think they could slip one past you. But if it really was an honest mistake, I'm not sure what's better or worse lol.

Regardless, I'm in for a sound clip either way. Putting the volume aside, how's the tone? Aggressive V6 exhaust notes are polarizing for me. I've heard plenty of sick ones but unfortunately the straight piped V6 Mustang guys have left a lasting bad impression on me