3.0 to 3.2 engine upgrade

S

snipesusaf

Contributing Member
Joined
2 January 2012
Messages
171
Location
Sacramento, CA
Hi, I have a 92 NSX with the standard 3.0 engine. Due to high miles 180XXX I recently found a 3.2 with 50,XXX miles. I wanted to buy this engine asap before it's gone, but wanted to know what I was getting into first. What is ALL required to complete this work? Is it just plug and play or do you have to change a Ton of other components? <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
 
If there is nothing wrong with your current motor, don't be in such a big rush.
Have you had the newer 3.2 gone over? Compression, leak down, history of maintenance etc? Can you get it with the 6 speed? This is not my area of expertise however there are a good amount of used and rebuilt motors on the market.

A 3.2 with 50k is not a Unicorn.
 
What is ALL required to complete this work? Is it just plug and play or do you have to change a Ton of other components? >>

It is not plug and play:)

Regards,
LarryB
 
snipesusaf said:
Hi, I have a 92 NSX with the standard 3.0 engine. Due to high miles 180XXX I recently found a 3.2 with 50,XXX miles. I wanted to buy this engine asap before it's gone, but wanted to know what I was getting into first. What is ALL required to complete this work? Is it just plug and play or do you have to change a Ton of other components? <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
Click to expand...

Depending on how much you're getting the 3.2 for and if you plan to keep your Nsx STOCK for it's entire life it will depend on if it's a "good idea" or not.

I'd personally just get the normal checks done on the 3.0 first. If it's acting up just get it rebuilt. If it's got major problems get it rebuild with forged internals and things like that. If you're like me and want a turbo car years down the line build it up and maybe get it sleeved as well...
 
As Larry hinted...you need the entire wire harness/ecu to run that engine via its thottle by wire and more intrusive obd-2 ecu requirements.Physicaly it will fit no problem.The real question to ask is has anyone retrofited a 3.2 l engine to the obd1 ecu and throttle cable actuation....
 
Y not rebuild your 3.0. In the end you will probably pay out more for swap. Labor and parts, etc.. Unless you plan on doing it yourself.. I would just rebuild.
Lets say u get that 3.2 engine @50k on it. Put it in, then something happen. Then what? Since you dont know whats going on inside it and all.
 
Switch out the block, and re use your old heads after they have been re-built by a machine shop and re sell the extra cylinder heads. My buddy sent his head to portflow. If you're worried about tuning, upgrade your ecu to an AEM EMS version 2 with harness adapter from autowave.
 
Thanks guys for the advice. I’ve had my NSX for about a year. The head gasket blew 4 months after I had it and the clutch went out shortly after that too... along with the ABS pump (keeps making a clicking sound) drove me nuts so I took the fuse out. And various other things... windshield wiper motor, starter, electrical problems. I’ve spent about 10k this year alone just to keep it running. I’m in the military and currently in Afghanistan, so that’s allot for me. I managed to save up a fair amount and plan to return to Sacramento this month. Point being a well-known NSX shop informed me my head gasket blow again and it fail a compression check. Not sure if I should rebuild or buy a local 3.2 for 6K. I think I could get at least $1500 for my current 3.0 which would offset the cost to just 4500. Its 3K to do another head gasket for my NSX. What’s a little more for a new engine with half the miles? Either way I think I need a new engine or a rebuild. I have about 10K I’m willing to spend when I return this month. Shitty part is I’m spending all this money to keep it running and NOT and cool aftermarket parts I see on SOS. I think I bought a lemon. I bought it with a clean title but with an accident history for 13,500. What do you guys think? I know one day I want to supercharge or turbo the NSX but want to make sure the vehicle is sound first. I don't want to give up on this car. I’m still hopeful! <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
 
you are going to need someone who types faster and has more time to help you at this point....good luck..and thankyou for your service to our country.
 
If you are not giving up on the car, use your $$ efficiently. If you don't plan to track or drag race your car, you don't need all that additional horsepower. Plus the it is labor intensive to install a SC or turbo sys. If you want the reliability factor, either rebuild your motor or swap the block out and sell your 3.0 and heads if the 3.2 comes with cylinder heads. Any funds left over can be used on those cool SOS products/wheels/suspension/exhaust/brakes etc. ;) Good luck. Thanks for serving our country. 1*: One ass to risk.
 
I hear how reliable NSX's are.. so thinking its just mine that sucks ass. i guess 13K for a NSX was to good to be true! but money,time and patience can fix almost anything! I'm determined. so just got the 3.2 checked out heres the compression results.
NSX 1998 JH4NA216WT000228, miles 63,804
on cluster.
Engine and drive train.
Compression test looked good #1=210 psi,#2=210 psi,#3=205 psi,#4=215​
psi,#5=210 psi,#6=215 psi.
 
snipesusaf said:
I hear how reliable NSX's are.. so thinking its just mine that sucks ass. i guess 13K for a NSX was to good to be true!
Click to expand...

No offense but if you bought an NSX for 13k then you got yourself a rolling money pit because even salvaged NSXs are getting more than that these days. If the seller took 13k then he must have known it was, how should I put this, a POS.

Sorry but you do get what you paid for.

On the other hand, enjoy your trip back home. My brother in law came back from Lashkar Gah as his second deployment and is now enjoying his retirement as an ex-USMC Lt. Col.
 
Last edited:
NO NSX is a Lemon they were all hand built with PRIDE.

the reason your NSX needs so much love is it previous owner didnt give her the love she needed

once you get the engine issues solved she will treat you well.

goodluck
 
3k for a head gasket seems quite high. Did the shop that did the head gasket(s) offer a warranty? Perhaps you need to use one of the NSX shops that members here use and recommend.
 
I've done the swap on my car (well Pikes Peak Acura did). I ended up using the normal throttle by cable throttle body as came with my 92, and was able to sell the 3.2L's intake and throttle (by wire). I also ended up selling my old 3.0L and 5-speed for a decent amount (since both were going to end up in a race type application) and recouped a good amount of the cost back (damn near broke even with the cost of the new motor/transmission).

I bought the 3.2 from someone who wrecked 2004, and bought the 6-speed along with it. When I had to upgrade to the 6-speed, they had to source a 6-speed conversion kit from comptech to make sure that I select 6th gear as opposed to where the reverse used to be. It's a computerized lockout mechanism (only about another $200 or so).

I also went CTSC at the same time, and the only reason I know this works is because I am on a standalone AEM EMS that runs the whole thing. I do not know that my standard 92 ECU or the 2004 ECU I specifically asked for would have been able to run this whole setup on its own.

I too am military and had to have someone do this for me since I like you am always busy and always away from home.

Please let me know if you had any specific questions about the conversion because I may or may not have already had run into/had to address some potential concerns you might have.

-Dan
 
The lions' share of the horsepower gained between the NA1 and NA2 models was from the headers and exhaust NOT from the .2 bore. I would rebuild your 3.0 and upgrade your exhaust. If you're craving power.. There are easier ways to make power than swapping the engine.
 
You mentioned that you are from Sacramento. Shad at Driving Ambition is the premier NSX mechanic in this area. He has installed a 3.2 engine in an earlier model before. Give him a call.
Tom
 
docjohn said:
As Larry hinted...you need the entire wire harness/ecu to run that engine via its thottle by wire and more intrusive obd-2 ecu requirements.Physicaly it will fit no problem.The real question to ask is has anyone retrofited a 3.2 l engine to the obd1 ecu and throttle cable actuation....
Click to expand...

Yes, we have. It is not difficult. You will want to use the 91-94 intake manifold and 91-94 throttle body. If the engine is from a 2000-05, in addition, you will need to cap the air injection ports on the cylinder heads. We make an aluminum block plate with gaskets that will accomplish this. Lastly, you will want to increase the injector size to match the 3.2L engine. Do not use the factory injectors, they are not compatible. Aftermarket peak & hold injectors are available which match the flow (which we also have available).

In general however, 3.2L engines are expensive - around $8-9k - and are somewhat rare. A good alternative is to rebuild your 3.0L to 3.2L if you want the extra displacement. We offer this service as well.

regards,
-- Chris

-- Chris
 
8400RPM said:
The lions' share of the horsepower gained between the NA1 and NA2 models was from the headers and exhaust NOT from the .2 bore. I would rebuild your 3.0 and upgrade your exhaust. If you're craving power.. There are easier ways to make power than swapping the engine.
Click to expand...

Agreed. We can make more power from on a 3.0L NSX with proper modifications than a factory 3.2L NSX.

-- Chris
 
BerzerkFury02 said:
When I had to upgrade to the 6-speed, they had to source a 6-speed conversion kit from comptech to make sure that I select 6th gear as opposed to where the reverse used to be. It's a computerized lockout mechanism (only about another $200 or so).

I also went CTSC at the same time, and the only reason I know this works is because I am on a standalone AEM EMS that runs the whole thing. I do not know that my standard 92 ECU or the 2004 ECU I specifically asked for would have been able to run this whole setup on its own.
Click to expand...

One thing to keep in mind for the next guy that does this - the AEM EMS has the capacity to trigger the factory 6-spd lock out solenoid in the same way that the 97-05 NSX ECU does. A simple ground trigger from the EMS based on wheel speed can be used to activate a relay to control the solenoid. No additional controller needed. We've used this on several 6-spd conversions on early cars.

-- Chris
 
Chris@SoS said:
One thing to keep in mind for the next guy that does this - the AEM EMS has the capacity to trigger the factory 6-spd lock out solenoid in the same way that the 97-05 NSX ECU does. A simple ground trigger from the EMS based on wheel speed can be used to activate a relay to control the solenoid. No additional controller needed. We've used this on several 6-spd conversions on early cars.

-- Chris
Click to expand...

That is a seriously awesome tip.
 

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