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swap 3.2L in to 91?

J

jacobzking

Contributing Member
Joined
29 December 2007
Messages
137
yep, I searched, found one thread with minimal info...

how involved is swapping the 3.2L motor in to an earlier 91? anyone done it?

"seems" like it would be pretty straight forward but what do I know.
 
 
Moses said:
um.......

http://www.nsxprime.com/forums/showthread.php?t=835&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=1535&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=4669&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=8398&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=25288&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=26778&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=50513&highlight=swap

http://www.nsxprime.com/forums/showthread.php?t=65841&highlight=swap
Click to expand...

1st thread: not much info, they basically said don't do it, cost too much

2nd thread: no info at all

3rd thread: The convential wisdom on this Frankensteinian operation is that it is much more cost effective to sell the 3.0 NSX and buy a 97+ 3.2 NSX.

4th thread: dead links

5th thread: a bunch of "random" links, but I did find some good info from NSXTech about using the 3.0L intake manifold on the 3.2L so you can keep the original 3.0 ecu, harness, etc...

6th thread: simply says no because of the obd1 to obdii crossover issues but there are ways around that

7th thread, found Bob Kenney's number who says he has a lot of info on the swap, but no actual info posted.

I know there's a ton of threads lightly discussing the topic but I haven't found much good info other than what is on that 5th thread from NSXTech.

Thanks for the links though
 
There is really not much difference between the 3.2 and 3.0 physically (externally). At most you are looking at a few sensors and injectors being different, if you used your 3.0 intake manifold and a few other parts (just like any other honda swap) it would drop right in, as far as spending the money and effort to do it, I would think it is really not worth it unless your motor is already gone.

There are people who have done it but if you look at those who have a 3.2 in a 3.0 car, they probably had a reason to change the motor first (i.e. blown motor)

If you look at the (rated) 20hp increase, how much of that is a result of the displacement increase and how much is a result of headers, tuning and/or camshafts etc.

I don't think many would say that $10k to gain 200cc/20hp (or less) would be worth it at all.

If on the other hand - you are the type of nut job who bought a certain '95 car and then proceeded on a quest to systematically change every single part on the car to '02 specs inside and out, with no regard for price or convenience - well then...
 
"there's no replacement for displacement" :) I was just curious about options in the event of a blown motor. thanks for the info Angus!
 
I've never attempted this engine swap (nor any other for that matter) but in theory this should work:

1) Transfer the '91 throttle body & associated hardware to the NA2 motor.
2) Retain the '91 harness & ECM
3) Install a fuel pressure regulator having a base fuel pressure of (3.2/3.0) * (stock '91 base fuel pressure), or about 7% higher fuel pressure than a '91 OEM FPR.

That being said, there may be intangibles between the 3.2 vs. 3.0 engine which may not play well with the '91 ECU cal. Or, it might just work!
 
I was already thinking about doing it, there is
this 2002 totaled NSX on e-bay for 19K I was
thinking if I bought it and took both cars apart
and swapped every little nut and screw and replace
the damaged parts. I would have a 02 Coupe. LOL in a 92 chassis.

lots of work but thats what you call A TRUE CONVERSION. LOL

But like what was said earlier how much is another 20HP? and ODB2 ya know
 
If you bore to 93mm or more, you need to re-sleeve the block. Per the service manual, the max bore permitted on the 3.0 is 90.52mm.

For the 3.2 swap, Russ's advice is good. Though, you can get about the same output from your 3.0 with a good header/exhaust setup. A better idea than the swap for only slightly more $ is doing a 3.6L or 3.8L stroker on your 3.0.
 
ralph cerbone said:
its not so much the difference between the engines as it is the difference between the trannys , 5 spd to 6 spd, :wink:
Click to expand...

Amen - that's what makes the big difference in excelleration. Why do so many change to JDM gears??? Ask Honcho. Lots cheaper than an engine swap.
 
The only reason you should consider this is if you are building up your engine. In which case you just buy bigger pistons and sleeve your block to a 3.2L engine. Everything else is pretty much the same on a C30A to a C32A I believe. I would also get the transmission since the 6th gear would be nice for highway runs.
 
Here is the quick and dirty swap list:

Swap intake manifolds
Swap AC compressor bracket(3.2's compressor are different!!! 3.0 must be installed on 3.2 motor).

You'll have to tune the motor to ensure it doesn't run lean, or swap the 3.2 injectors along with removing the injector resistor box. Even then I recommend watching the air/fuel ratios.

We have a customer that decided to preserve his original 3.0 for the shelf as he is the original owner of the car. His stock-swapped 3.2 makes 479WHP with our Stage 2 Turbo system.

http://www.youtube.com/watch?v=uQt1uwuxzWc
 

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