The "J" Swap

Coots said:

Keep up the awesome work, man!

Mad props for designing and actually following through on manufacturing your own mounts.

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Thank you.

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The axle bracket is back from the welder.

I had the welder add some gussets at the top, in the final version I will add another gusset on the lower left.



Even the heat shield will bolt back on.





Axle bracket prototype 1 is complete!

On with the wiring, I am using an OBD2b straight through extension/tuner harness which makes splicing into the ECU wires a lot easier. I had already picked up an “A” plug for my ECU and had started connecting wires to the NSX chassis plugs before I got the extension harness. Now that I have the extension harness, I didn’t need the “A” plug, for that matter I didn’t “need” the extension harness either, I could have just cut and spliced into the J-series wire harness. So, I guess it boils down to; I needed either the “A” plug or the extension harness.









Here I am connecting wires from the NSX chassis plugs (C158, C159, C160 and C161) to the extension harness as well as connecting the DLC plug, ECU “E” plug and the IMRC plug, to the extension harness.



I am reusing/remapping many of the wires that were used for the automatic transmission so that I don’t have to tear the entire J-series harness apart.

Keep up the good work man. I always enjoy reading your updates! Pave the way!

and when you're all done put together a conversion kit!!!!!!!!!!! I'd love to have a second NSX (salvaged) with a J swap and a monster turbo build!

Keep goin :applouse:

Amazing work! I haven't been back to prime lately since I got rid of my car a while back but this will definitely get me coming around more! everything looks awesome, only constructive remark I would make is find another welder you have done some amazing work on those mounts but I wanted to cry when seeing the welds. Then again this is testing peices so who knows what the future holds.. I am sure it will work just fine

BluryNSX said:

Amazing work! I haven't been back to prime lately since I got rid of my car a while back but this will definitely get me coming around more! everything looks awesome, only constructive remark I would make is find another welder you have done some amazing work on those mounts but I wanted to cry when seeing the welds. Then again this is testing peices so who knows what the future holds.. I am sure it will work just fine

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That is exactly what I said when I got the axle bracket back from the welder. I saw it and thought, that looks like crap, he also welded one of the gussets on wrong and put a seam weld where I told him not to weld. I had to do a lot of cleanup on that bracket just to get the axle back in. Then again, this is a prototype. I now have a referral to a new welder and I will ask to see a sample of the welds first. I have also had some parts cut by water jet which look really cool.

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JoseJA1979 said:

and when you're all done put together a conversion kit!!!!!!!!!!! I'd love to have a second NSX (salvaged) with a J swap and a monster turbo build!

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I am definitely working on putting together a "Kit", and you shouldn't have to worry about finding a salvage NSX as I am sticking very hard to my rule of not modifying anything on the NSX for this swap. You should be able to swap to a J-motor and back to a NSX C-motor pretty much plug and play.


Thanks for all your support guys!

Keep up the great work...you are sure to be inducted into the NSX hall of fame once complete- The world rewards visionaries like you. *hats off* to you sir.

I want this kit. How much will you set it at roughly? Is there a specific jengine year that I should look for.

You are doing great work, props for keeping it as detailed as possible. this is one of the only threads I frequent outside of the track forums. good job sir :encouragement:

glad this is still going

keep it up, please.

rj45 said:

I want this kit. How much will you set it at roughly? Is there a specific jengine year that I should look for.

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It is hard to say what the "kit" is going to cost as I still have to get the passenger side adapter bracket done. But I am thinking it will be in the $700 range for the three brackets and the pilot bushing. Although the price may come down depending on interest and when I am able to have everything make at once.

The j-series engine you pick pretty much depends on the car that you have. For a 91-94 OBD1 car, I would use a J32A2 from a 01-03 CL/TL Type-S or a J35A3 from an 01-02 MDX. In 95 the NSX changed to OBD2 and drive-by-wire. Just try to match your engine choice with your drive-by-cable or drive-by-wire.


Thanks for the support guys! I have started to pull /drop the engine in my NSX, so you should see real progress in the coming weeks.

Stay tuned.

Can't wait! Put me down for a kit....my favorite thread

If your looking for someone to manufacture I have some sources in china that does iso 9000 medical stuff, they can do anything to any spec you want.

Put me down for 50...

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Velocitized said:

It is hard to say what the "kit" is going to cost as I still have to get the passenger side adapter bracket done. But I am thinking it will be in the $700 range for the three brackets and the pilot bushing. Although the price may come down depending on interest and when I am able to have everything make at once.

The j-series engine you pick pretty much depends on the car that you have. For a 91-94 OBD1 car, I would use a J32A2 from a 01-03 CL/TL Type-S or a J35A3 from an 01-02 MDX. In 95 the NSX changed to OBD2 and drive-by-wire. Just try to match your engine choice with your drive-by-cable or drive-by-wire.


Thanks for the support guys! I have started to pull /drop the engine in my NSX, so you should see real progress in the coming weeks.

Stay tuned.

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So what engine would that be.

This is a fantastic thread. The fact that a "kit" may be developed is just amazing. This is excellent work, I love reading this thread. Keep it up!

Time to get that old engine out of there! That is my son helping out.


Once everything is disconnected from up top, I raise the car up high on the jack stands and disconnect everything from underneath.



Here is what I would call "Front Mount Adapter Bracket, production version 1". This was cut by water jet, then finished on the mill. I will make two more minor tweaks if it goes into production, but this works and I am really happy with the new machinist and he has referred me to a good welder for the Axle Bracket.

I hope it's a long time before I consider an engine swap but if I did, I'd want this kit! Having said that, considering the incredible amount of work it must be taking you to do this and the obvious talent required to develop what will make an impossible swap into a relatively simple one, I think you could/should ask a LOT more than the $700 you estimated!

Swiftscott said:

I hope it's a long time before I consider an engine swap but if I did, I'd want this kit! Having said that, considering the incredible amount of work it must be taking you to do this and the obvious talent required to develop what will make an impossible swap into a relatively simple one, I think you could/should ask a LOT more than the $700 you estimated!

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Thanks! Keep in mind that $700 is a target and is just for the three adapter brackets and pilot bushing. I am putting in all of this time, money and effort regardless of whether or not I make a "kit" and there are a lot more components that are necessary to complete the swap. I may also offer wiring components and exhaust adapters. Even with the development cost, I budgeted about $3,000 to complete my swap.

In the end, if I can offer a "kit" or components for others to complete this swap and recoup some of my costs that would be great. Also, if I can offer a kit, I view it somewhat as a way for me to give back to the community.

Amazing work. I think this would be a great route for folks who want a automatic-turbo build. Work in a newer Acura wheel with paddle shifters, and you've got one heck of a NSX.

Wouldn't a "kit" also have to include all the wiring harness adapters for the newer ECU, etc?

bngl3rt said:

Wouldn't a "kit" also have to include all the wiring harness adapters for the newer ECU, etc?

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The "kit" could include all the components that I have ended up needing or using and I might have that as an option. I am thinking of the basic kit to be just the motor mount adapter brackets and the pilot bushing, with this you could bolt up the transmission and install a J-series motor in your car. As "options" I might offer the wiring plugs that I ended up needing, the fuel rails and AN fittings, the ECU extension harness and FX01 immobilizer, custom exhaust pipes and custom A/C lines. I will just have to wait and see how it all turns out and what the demand might be for the different components. The OBD2/DBW cars use some different wiring plugs and don't need others.

This thread is becoming more and more interesting. Good job!!

The engine is out!



I ended up taking off both sides of the rear suspension, mostly due to a stuck drive axle and I figure that the J-series will probably go in and out a few times while I am fitting exhaust and A/C lines.








For perspective, the C30 is about 31” wide and the J32 is about 23” wide. From crank center to the top of the intake manifold, both engines are about 20” tall.







This felt like major progress!

Looks great. I cannot wait to see this as a final product and the kit made availible. Thank you so much for your hard work and dedication. Ohh and thanks to your son as well for contributing to the cause.