3.00 vs 3.2 turbo - pros and cons

[derpziIIa]

Hello NSXers! First post here - I'm in the market for an NSX and I've narrowed it down to a dark colored Targa, but now I'm debating 3.0 vs 3.2, as I eventually do want to put a turbo in.

I understand the 3.2 is simply a bored and stroked 3.0, is that correct? If so, does it make more sense to go for the 3.0 for a more reliable turbo setup? I'd prefer 400-450 rwhp (not going for super big numbers here, reliability is my main concern after 400 whp).

Also related - I'm in California and I've seen NSX turbos for sale here, yet I've also heard they can't pass smog .. shouldn't you be able to tune /detune the turbo to pass smog here?

Thanks!!

 

[Zoom]

3.2 is bored only, stroke is identical. Cylinder walls are different, FRM for 3.2l. Also the 3.2 has got a lot of small revisions (check the wiki for full list), and a 6-speed transmission. In terms of boost you'll need less to reach your goals with the 3.2l obviously.
Now if you dont get a coupe, the targa is heavier.

 

[TURBO2GO]

If you want a 3.2 6 speed you are going to get a targa.

 

[bngl3rt]

Also related - I'm in California and I've seen NSX turbos for sale here, yet I've also heard they can't pass smog .. shouldn't you be able to tune /detune the turbo to pass smog here?

Yes, it's been done. The issue is the visual inspection. And even if you manage to pass the visual inspection somehow (by finding a shop that doesn't bother to do it, for example) you are still technically in violation of the letter AND the spirit of the law - you have just avoided being caught until your next smog check. This matters more to some than others :smile:

 

[OKI-BOY]

If you want a 3.2 6 speed you are going to get a targa.

How it was explained to me was, if you want looks/targa and the 6speed go 3.2, if you planned on engine mods, go 3.0and you will be faster due to weight.

 

[Zoom]

..or get the best of both worlds and get a 3.2l coupe ? Took me a long time to find one but there are a few out there.

 

[peiserg]

If you blow your 3.0 it's. Significantly easier to find replacement, and less money. I have 3.2, and it was fair amount of money for a used one. If you're going to do motor build anyway... Get a 3.2/6sp. The tranny is awesome.

Fwiw 400rwhp is plenty in an nsx.... Not enough for me, but plenty nonetheless

 

[RYU]

5spd is apparently stronger than the 6spd...fyi

 

[derpziIIa]

5spd is apparently stronger than the 6spd...fyi

OK, so I've heard elsewhere (https://www.youtube.com/watch?v=uebXYuTYrPE) that the 5 speed is just a better transmission overall, but I've also heard that turbo-ing will require some drivetrain mods to keep things from breaking (something about a clutch or transmission connector? I forgot the name of the part, but it snaps when there's too much force).

So I'm leaning towards a 95 or 96 Targe 5-speed, then -- sounds like I want the 5 speed and an easier engine to maintain.. I'm guessing my goal of let's say 450 RWHP will be attainable in either 3.0 or 3.2 fairly easily.

Any other feedback about 5spd vs 6spd transmission, especially on turbos? What about the most commonly replaced turbo parts?

Thanks for the answers so far, this community seems awesome [:-]

 

[Stephen@NCAutoUSA]

5spd is apparently stronger than the 6spd...fyi

And truthfully I'd want the longer gears too so shifting is less.

 

[TURBO2GO]

If your are only talking 450 HP, I see no reason to go to a 5 speed. The 6 speed can easily handle that and it's just going to give you more. More acceleration, more top speed, more fuel efficiency. On most tracks the 6 speed would probably be slightly better. People go through all kinds of trouble to update their 5 speeds to a 6... Why do you want to go backwards? If you're making 900 HP, then the 5 speed might be better.

 

[Bram]

5spd is apparently stronger than the 6spd...fyi

I read this and laugh...are their any facts to back up this claim or is this all speculation?

Dave is correct the 6 speed is a much better transmission for all types of driving.

Looking forward to seeing all the data...

Bram

 

[RYU]

I read this and laugh...are their any facts to back up this claim or is this all speculation?

Dave is correct the 6 speed is a much better transmission for all types of driving.

Looking forward to seeing all the data...

Bram

I read your reply and also laughed

First of all... w/o a full analysis how would really know. Us kids just need to make an educated guess and we have been since the true engineers left this site.

The high horsepower folks that actually race do not use the 6spd. They all use the 5spd and it is them who i've gained this knowledge from. Is it true? That is for you to decide. Though, if you think about it logically... you need to add one more gear in the same amount of real estate on the primary and secondary shafts. This would assume thinner gears so a 6th gear can be added. Hence WEAKER

 

[Bram]

Again all speculation ...no hard facts.
Why would you assume that thinner means weaker. Do you know if the gears were harden or made of another stronger material ...NO.
So no facts, all speculation....or in other words keyboard Engineering via hear say!... The Internet is a wonderful thing

Bram

 

[RYU]

Bram, congrats! You win. Your prize is in the mail. Don't you feel special now.

Its always easier to be a naysayer than to actually contribute.

 

[Bram]

Ryu,
There are no winner or losers, as stated I'm looking to get data to support the augment that the 5 speed is stronger than the 6 speeds.

So is there any data to support this, that would be great. For example, are the Gear set part numbers different between the 5 speed vs the 6 speed for all the gears?.....that would be one data point for consideration.

Bram

 

[TURBO2GO]

I have no data either. Just going by here say your honor. I present exhibit A: Chris@SOS stated the 5 speed is stronger. However... His testimony may fall apart under some Bram cross examination.

 

[docjohn]

Ask Larry ...

 

[Cody@LoveFab]

Or, do this:

Customer pulled his original 3.0 and shelved it. We swapped in a 3.2 and installed one of our turbo systems, running it up to 9psi. This was in December 2008, and he's had nothing but regular maintenance. 493whp for almost six years now....

 

[derpziIIa]

Cody, thanks for the info. What HP would you expect from a 3.0 with the same setup? Also what specific reasons did the customer have for going with a 3.2 engine swap (seems easier to unload the car and buy a 3.2 to start with, but .. obviously I wasn't there :-]

 

[peiserg]

6 sp. Here...90k miles, 80k with boost... 50k above 400rwhp, 20k above 600rwhp, 3k above 670rwhp.... 2nd motor, 4th clutch, 4th set of half shafts, maybe 6 to 7000 track miles....

No tranny problems.

 

[Cody@LoveFab]

Cody, thanks for the info. What HP would you expect from a 3.0 with the same setup? Also what specific reasons did the customer have for going with a 3.2 engine swap (seems easier to unload the car and buy a 3.2 to start with, but .. obviously I wasn't there :-]

We have stock 3.0's making 450-470whp for many years. He chose to swap because he found the 3.2 for a steal(I won't even post the price, you'll get mad). I will say, I've destroyed 3 stock 5 speeds, and fourth 5 speed with 4.55FD that failed. I've never lost a 6speed myself, nor with a customer. I believe, based on my experiences over the past 9 years with the NSX platform, that the 6pseeds are stronger.

 

[kookoo4nsx]

You can run a stock 3.0 or 3.2 up to 450hp+ but why? 390 to 410 Rwhp has been proven to be much more reliable.
Do you want the motor to last a long time or possibly blow a head gasket after 6 months? Not sayinit WILL but is it worth the unnecessary risk and possible 5-15k risk?

 

[kevgk]

Because most people are fear based. And lots of that fear is based on hearsay and speculation. Or simply never ever go above 400 and have moderate fun and be safe as heck but that's no way to live IMO.

 

[BATMANs]

What usually breaks is the 3rd gear...... especially when the boost kicks in violently.