The "J" Swap

[Brock]

Some people seem to think that a 96 mm stroke makes a J37 slow revving.
I have a J37A2 with a 15 lb aluminum flywheel and I can assure you that
it is quick revving in typical Honda fashion. I'm not comparing it to a C-series
NSX engine as I've never driven one, but I've had K-series powered vehicles
in the past and my J-series engines are comparable.

The J37A2 (RL) and J37A4 (TL) engines are my favorite.
They have VTEC on intake AND exhaust despite only being
SOHC engines.

I too thought the J37 might be sluggish and was somewhat concerned
before installing it, but after the first time driving it I was pleasantly surprised
at how quick it revved.

Maybe this video can help. Note how quick 1st gear revs and bounces off
the rev-limiter.

https://youtu.be/OYZh8H58iLI

 

[ratley]

J swap options

I recently joined the forum and I have a 1991 NSX and located in So-Cal - a couple of questions:
Are the engines you use, made for US cars? I only ask because once I do the conversion, I have to get the car inspected by CHP prior getting it registered. The engines can't be for non US model vehicles - say from Japan, or it won't pass inspection. Assume that all smog related devices for the J engine is utilized during the swap/install.
Do you have both kits - J32 and J35 available?
Also, I'm not sure if you mentioned in the thread if OBD1 will be upgraded to OBD2 when doing the swap to either engine. It will make troubleshooting a little easier.
Which kit do you recommend for more HP upgrades - SC, turbo, ITB?
Do you know how much horses are produced by Coz's J swap motor with turbo?
Is it available from you and what will it cost?
I'm so stoked about your thread and happy to know there are options for our cars given the parts are getting more scarce each day.
I may have more questions for you as I read more of the J swap thread - hope you don't mind.

 

[ratley]

I recently joined the forum - I have a 1991 NSX and located in So-Cal. I have a couple of questions:
Given that I live in So-Cal, are the engines you provide for US cars - I only ask because I will need to the car inspected prior to registering and be able to pass smog.
Also, I'm not sure if you mentioned in the thread if OBD1 will be upgraded to OBD2 when doing the swap to either engines. It will make troubleshooting a little easier.
Are both J32 and J35 kits available? Which kit is more readily upgraded for more horses? (SC, turbo, ITB). Which kit can be upgraded for more horses now vs. later?
I'm not sure if you mentioned if OBD1 will be upgraded to OBD2 when doing the J swap. It would make troubleshooting easier with OBD2.
How much HP will it be with the J swap? Is there a difference in HP in J32 and J35?
Do you know how many ponies Coz's engine puts out with the turbo? Is this same set up available through you?
I may have more questions as I continue to read your thread.
I'm stoked that you have the knowledge and the guts to put together this build - it gives us NSX owners a viable alternative option to keep our cars on the road given that parts are becoming more scarce each day. Good job!!!

 

[Mario92NSX]

Sorry to open up an old thread.

I want to say that I am very impressed by your build. Very well done and thought out process. I have a 92 NSX with many mods and others coming (see my profile), I currently have a JDM type R 5 speed trans and I always wanted to go 6 speed, however the cost on the NSX 6 speed in crazy... So I have been doing some research to see if a J trans from a J32A would work on the C30A. From my findings it looks like it will all line up however it would need to modification, custom shafts, different size throw out bearing, NSX clutch and flywheel? I know you have done extensive work on fabrication to make this build work and i'm hoping you can shed some light on this? Another option I perhaps found would be a K trans? Inlinepro makes a gen1 J trans to k bell housing adapter, if the J32 housing lines up then perhaps we could even use much more common k transmission on the c engines. Since you did some customization on the C to J I was wondering if you knew what may be involved going this route?

Otherwise I want to give you 2 thumbs up to your build, very well done!

 

[Velocitized]

Sorry to open up an old thread.

I want to say that I am very impressed by your build. Very well done and thought out process. I have a 92 NSX with many mods and others coming (see my profile), I currently have a JDM type R 5 speed trans and I always wanted to go 6 speed, however the cost on the NSX 6 speed in crazy... So I have been doing some research to see if a J trans from a J32A would work on the C30A. From my findings it looks like it will all line up however it would need to modification, custom shafts, different size throw out bearing, NSX clutch and flywheel? I know you have done extensive work on fabrication to make this build work and i'm hoping you can shed some light on this? Another option I perhaps found would be a K trans? Inlinepro makes a gen1 J trans to k bell housing adapter, if the J32 housing lines up then perhaps we could even use much more common k transmission on the c engines. Since you did some customization on the C to J I was wondering if you knew what may be involved going this route?

Otherwise I want to give you 2 thumbs up to your build, very well done!

Hi Mario,

Short answer, yes, the J32A 6 speed will bolt up, however now you have to use a J clutch, custom axles, custom shift linkage and custom trans mounts. The K trans has the starter on the block side and the J and C have the starter on the trans side, so if you put a K trans on the J or C block, where do you mount the starter....more custom fabrication, under the oil pan, then where do you route your front exhaust?

I would imagine the cost of the J32a trans and all the custom work to put it in will be more expensive than just waiting and sourcing a NSX 6 speed trans. The gear ratios from your JDM Type R 5 speed are not that much different than the first 5 gears in the 6 speed trans. Unless you also have the lower final drive in your trans, which if you do, then you might consider going back to the 4.06 if you are adding power to your C motor.

 

[syndicate]

Sorry to open up an old thread.

I want to say that I am very impressed by your build. Very well done and thought out process. I have a 92 NSX with many mods and others coming (see my profile), I currently have a JDM type R 5 speed trans and I always wanted to go 6 speed, however the cost on the NSX 6 speed in crazy... So I have been doing some research to see if a J trans from a J32A would work on the C30A. From my findings it looks like it will all line up however it would need to modification, custom shafts, different size throw out bearing, NSX clutch and flywheel? I know you have done extensive work on fabrication to make this build work and i'm hoping you can shed some light on this? Another option I perhaps found would be a K trans? Inlinepro makes a gen1 J trans to k bell housing adapter, if the J32 housing lines up then perhaps we could even use much more common k transmission on the c engines. Since you did some customization on the C to J I was wondering if you knew what may be involved going this route?

Otherwise I want to give you 2 thumbs up to your build, very well done!

You can use gears from various Honda and Acura transmissions to make a custom trans geared for your needs. There is a guy on the Facebook group that has already done this. I am working with him to verify his findings, track and street test a sample gear set and make a kit for the nsx community. Stay tuned!


Sent from my iPhone using Tapatalk

 

[Mario92NSX]

Hey syndicate,
Thanks for taking the time to reply. I do have the short final drive in the trans, it drives great, my only complaint is the highway. When you are on the highway for a long time the higher revs get a bit annoying but otherwise for spirited or track driving the type r 5 speed is good. Would you know if a j35a8 from a tls would work? I read the bell housing is different compared to the c engine?