The "J" Swap

[Velocitized]

David, great work on your research so far! Can't wait to see it all comes together.
Sorry didn't make it up to the Street of Dream that weekend, had family emergency.
I'll be sure to come up one of these weekend to see your progress, can't wait to have you on a drive soon.

Hmmm since you're the master at swapping these now, can you put in a
VR38DETT in my NSX? LOL.

Brandon, no problem. Stop by anytime, I would be happy to show you the build.

The VR38DETT is a great motor. Who knows, maybe I will twin turbo the J32.

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is there a reason you went with the auto motor instead of the manual? Are you going to be using Aem Ems for tuning? I may be jumping into the j-series after my motor gives out. Im interested in doing a twin turbo J36 stroker with some aftermarket low compression pistons. Here is a thread comparing the j37 rods, crank, pistons to the j32. As you can see the forged j37 parts look a lot beefier.

http://cl.acurazine.com/forums/showthread.php?t=884537

Adrenaline, I went with the auto motor partly because of the AEM unit as a fallback but mostly because there are far more auto J-series motors out there and they are less expensive than the manual motors.

I have read about the J36 before and I think the short stroke of the J32 is a better match to the gear ratios and rev characteristics of the NSX, but who knows where this could end up. One great thing is that there are so many J motors out there and a lot of the parts are interchangeable. Once the build is up and running, I could pick up a J35A3 for $500 and swap that in very easy.

 

[Andyrew500]

I'm following both J swap build threads very closey and almost checking daily. Can't wait to see the results. My Ridgeline has a J engine, my brother's TL has a J-engine, and one day maybe my NSX may have a J engine?? I lay on WOT daily for work thru traffic and highway for the past 4 years and have never had any reliability problems. It's solid.

Thanks and Best of luck!!

 

[GRacer]

all this J-swap makes me real itchy since my car is an auto, how difficult is it to drop the complete j32a2 complete with its auto trans in the nsx ? manual conversion is out of the question here in NZ as parts for nsx is virtually impossible to get and to get it shipped from overseas will cost me arms n legs, hence the thought of dropping the complete J32a2 complete with its auto trans. is it possible at all or retaining the original nsx auto box is better ?

 

[mr envy]

They are still all experimenting, this will be the first of its kind ( that I can find documented ) the mix match of c and j bolt patterns has been played with before if the kit does get mass produced a j series full conversion incl auto box in theory wouldn't take much more

 

[Velocitized]

all this J-swap makes me real itchy since my car is an auto, how difficult is it to drop the complete j32a2 complete with its auto trans in the nsx ? manual conversion is out of the question here in NZ as parts for nsx is virtually impossible to get and to get it shipped from overseas will cost me arms n legs, hence the thought of dropping the complete J32a2 complete with its auto trans. is it possible at all or retaining the original nsx auto box is better ?

Converting an NSX with an auto trans to a J-series with an auto trans should be entirely feasible and you should pick up some extra power along with a gear or two in the transmission. That could bring some new life to an NSX with an auto trans. Throw in some paddle shifters and now it is fun! You would have different custom motor mounts and you would need custom axles.

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The NSX engine wiring harness consumes all of the plugs on the ECU and interfaces with the chassis through the C-158, C159, C-160, C-161, C-101 and C-102 plugs which are also all part of the engine wire harness. Since, I am not willing to cut my NSX engine or chassis harness and one of the goals of this build was to not modify anything on the NSX, I have to adapt the J32A2 engine wiring harness to plug into the NSX. The J32A2 engine wire harness plugs into the PCM though the B, C and D plugs, leaving the A and E plugs to interface with the chassis. The J32A2 also interfaces with the chassis through the C-101 and C-102 plugs. I will call the C-101 and C-102 plugs from the J32 JC-101 and JC-102 from now on to help eliminate confusion.

Here are some of the plugs I had to source from my favorite auto recycling yard. These had to come from various Honda cars, since they didn’t have an NSX wire harness. Not a problem, I prefer to get them from other Hondas anyway and not cut up an NSX wire harness.

C-158, C-159, C-160, C-161

C-101 and C-102

J32A2 PCM A-plug

J32A2 PCM E-plug

JC-101, JC-102 plugs

JC-101, JC-102 plugs

I also needed wiring pigtails for the NSX backup light switch, neutral switch and VSS on the transmission.

 

[Nick675]

I got my subscription and popcorn. Don't loose heart. I just might steal your notes and copy as I have to drop the engine anyways for transmission work.

I admire your attention to detail and not willing to sacrifice the NSX in the process.

- Nick

 

[GRacer]

yep, thanks for your 'attention to details' - it's people like you who makes an engine swap easier for others

you just can't beat step-by-step pictures and documentations on something like this

 

[myw]

amazing thread thus far. subscribed.

 

[Velocitized]

Here are some more wiring pigtails I needed, the VSA/Traction Control throttle body and throttle position sensor on the J32A2 as well as the IMRC module and pigtail.

Intake Manifold Runner Control (IMRC) module

I mounted the IMRC module on the firewall.

I plan to install the OBD2 plug either behind the passenger seat or in the center console box.

I downloaded Google SketchUp and sketched these motor mount adapter brackets. The Front Mount is at the fabricator now.
Front mount adapter, this one will be machined out of steel.

Passenger mount adapter, this one will be machined out of aluminum.

I am trying to design the adapter brackets so that they will work for both the DBC and DBW blocks. Right now the front mount adapter should work for both.

 

[HondaDreamS]

Im hooked! Im a details junkie and this is my new fix.
Did you make a cross reference wiring diagram for the blended harnesses?

 

[bngl3rt]

To be clear - you must be using the newer ECU that came from whatever car the J engine came out of. How do you integrate this with NSX chassis functions? I imagine being much newer, the traction and power steering control functions must have moved into a single box. Is the many-box system in the NSX made redundant by this?

 

[Velocitized]

I got my subscription and popcorn. Don't loose heart. I just might steal your notes and copy as I have to drop the engine anyways for transmission work.

I admire your attention to detail and not willing to sacrifice the NSX in the process.

- Nick

Nick - No problem. I fully expect many people will be doing this swap and I will provide as much detail as I can.

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Im hooked! Im a details junkie and this is my new fix.
Did you make a cross reference wiring diagram for the blended harnesses?

I am definitely keeping track of the wiring cross reference. So far there are about 45 wires that I have to move, re-pin or connect. But keep in mind I am working toward getting all of the NSX systems working and adding the OBD2 connections. I will post a spreadsheet with all of the wiring when I have it complete and tested.

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To be clear - you must be using the newer ECU that came from whatever car the J engine came out of. How do you integrate this with NSX chassis functions? I imagine being much newer, the traction and power steering control functions must have moved into a single box. Is the many-box system in the NSX made redundant by this?

Yes, I am using the PCM that came with the J32A2 motor from a 2003 Acura TL Type-S. My NSX does have separate computers for the engine and traction control, however being a 1991 it does not have power steering. The PCM (Powertrain Control Module) has the engine and transmission functions in one computer.

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I didn’t get much done today because I broke my breaker bar trying to get the axle nut loose on the NSX, time to upgrade to a ¾” breaker bar. So instead I installed some RapidAir lines in my garage so that I can put my air compressor in the closet. Then I decided to change the spark plugs on the J32, easy enough task especially since the engine is out of the car, or so I thought. Dang those plugs are stuck in there good, doesn’t Honda use anti-seize? I cracked each one loose then squirted in some WD-40 and let them soak a minute, then tighten and loosen again and some more WD-40, it feels like the threads are ripping out! Finally, all the plugs come out and no threads are damaged. I put some anti-seize on the new plugs and some dielectric grease on the coil packs and everything goes back together. I was even able to index the plugs.

 

[06_typeS]

This is awesome. As people already mentioned you are paving the way for future engine swappers.

 

[Velocitized]

A ¾” breaker bar snaps ¾” to ½” adapters pretty easy, I went through three of them, then I finally bought a ¾” 36mm socket and that axle nut broke loose.

Now I will be able to get my half shaft out of the NSX so that I can take some measurements and design the half shaft adapter bracket.


On with the progress, I got a FX01 immobilizer delete board (mobilizer module) and decided to replace the immobilizer board in the J32A2 PCM. This took a lot longer than I thought it would and a lot of patience, if I had to do it again I would just send in the PCM and let them do it, especially in a situation like this when I have a lot of time.

FX01 Mobilizer Module

So I feel that I have made it past hurdles #1 the clutch/flywheel and #4 OBD-2 immobilizer delete.

 

[illwillem]

^^^ nice. good steady progress

 

[2000NSXT]

Awesome build, Dave, I will be following it .

 

[Velocitized]

Thoughts for the initial exhaust are to run the stock J32A2 exhaust pipe with the cat and then straight out the back. But eventually I will create a dual exhaust that follows the factory NSX exhaust and uses the NSX cats and NSX muffler by merging the front section of the J32A2 pipe with the front NSX pipe and rear section of the J32A2 pipe with the rear NSX pipe. Then I will take those modified pipes to a muffler shop and have two pipes made, one from the front J32A2 exhaust manifold to the front NSX cat and one from the rear J32A2 exhaust manifold to the rear NSX cat. The NSX cats will remain in their stock location. I will sacrifice/modify the two NSX pipes for the mock up set but then I will be able to have more sets made.

 

[Velocitized]

I’ve looked at the exhaust some more and initially, I think I will just have short adapters made to go from the J32A2 manifolds to the NSX pipes, instead of cutting anything up.

I started looking at the axle adapter and I think the best option will be to just have a new axle bracket fabricated that will bolt to the NSX half shaft and the J-series block. I made a cardboard mock-up for my block and started on the CAD drawing, but then after reviewing some pictures of the DBW blocks, I need to revise the adapter so that it will work with both DBC (Drive-By-Cable) and DBW (Drive-By-Wire) blocks.

Notice the mounting bracket actually unbolts from the half shaft bearing carrier.

This is the NSX half shaft axle bracket that I will redesign so that it bolts to the J-series blocks.

First cardboard mock-up, this won't work on a DBW block.

As soon as I have the axle adapter bracket designed and is sent off to the fabricator I will get back to the wiring harness.

 

[myw]

keep the updates + progress coming!

 

[NSX1145]

Tell me more about the immobilizer delete?

 

[Velocitized]

keep the updates + progress coming!

Will do. Thanks!

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Tell me more about the immobilizer delete?

Some OBD2B ECU/PCM's have anti-theft devices that require a matching key/ignition/ECU or the car won't start. You can just remove the board in the ECU/PCM and the car will start but it will cause the CEL to come on. The immobilizer delete board prevents the CEL.

 

[Velocitized]

New half shaft axle bracket prototype. This should work for both DBC and DBW blocks and will be steel.



Now back to the wiring.

 

[adrenaline_nsx]

that axle bracket looks awesome, I like how you made compatible for both dbc and dbw blocks. any updates? btw are you able to pull a J motor through the top of the engine bay? that would be a big plus

 

[Velocitized]

that axle bracket looks awesome, I like how you made compatible for both dbc and dbw blocks. any updates? btw are you able to pull a J motor through the top of the engine bay? that would be a big plus

Thanks. The NSX engine bay has about 24" of clearance out the top and the J-motor is about 24" wide, so I think if you pull off the alternator, compressor and maybe the exhaust manifolds you could pull it from the top. Rouge Motorsports has been working with his J-swap from the top, but I don't know if he has tried putting in the complete motor yet.

As for updates, it has slowed down as I am busy with house updates and the start of the Holiday season. However I did get the front motor mount adapter bracket back from the fabricator and it was way off so he is re-working it now. I did get some wiring done and I have flipped the fuel injector rails. I will post an update with pictures soon. I take a lot of pictures.

 

[Coots]

Keep the progress coming. This thread is awesome!