performance increase for automatic transmission

[druby]

Hey Folks:

Well I had talked my wife into getting headers and new exhaust for my NSX and my DE (who I trust a great deal) told me that the extra horsepower with the automatic transmission could cause problems. So, I am asking if anyone knows of anything else that can be done safely for about the same price range (approximately $2,000) that will give some extra horsepower safely on a 98 NSX with an automatic transmission.

Thanks,

 

[matteni]

I wouldn't look to bump up power too much. You might get a nice bump from Headers and Exhaust but your best bet is weight reduction. The automatic was detuned because the powers that be at Honda decided it couldn't handle the extra power so be carefull you don't ruin your automatic tranny.

See this information in the FAQ for weight reduction: http://www.nsxprime.com/FAQ/Performance/weightreduction.htm

 

[spdntckt]

Hard to imagine that another 10ft/lb of tq will make a difference here... its not in the same league as adding FI to the nsx.. H/E is a pretty minor power increase (from my experience)

 

[NetViper]

Nick, do you really think H/E will cause any trouble for that car? I don't think so. I drove a 91 auto with 90K and it has both comptech h/e and it was fine. However, the transmision was replaced at about 89,000 miles while it was for sale. So, I don't know if that was due to age or perhaps it was ragged while it was for sale at the dealership. Who knows.

His car is a daily driver, so I don't think drastically reducing the weight is the option.

I would at least do the exhaust.

 

[matteni]

Hey gang. We are all on the same page / it's cool!

I guess my post wasn't clear. I am recommending H/E here:

I wouldn't look to bump up power too much. You might get a nice bump from Headers and Exhaust

I still think their best bet is to loose a LOT of weight:

best bet is weight reduction.

I am warning him here about getting FI, Nitrous, or trying to up displacement significantly here:

Honda decided it couldn't handle the extra power so be carefull you don't ruin your automatic tranny.

 

[NetViper]

Ok, missed your recommendation totally.

David, now your just have to decide:

a) comptech headers, anytime exhaust
b) taitec headers, anytime exhaust

 

[druby]

Thanks Folks:

Now I need to know what the concensus is as to which H/E system is considered better and or the best deal. I have talked to one person who recommended TUBI exhaust and comptech headers. What do ya'll think?

 

[matteni]

I wasn't aware the Tubi was availible anymore.

I really like the Anytime exhaust (looks great / sounds better / not too loud) and the DC Sports, CompTech, or Taitec headers.

If you are looking for single tips - my personal favorite is the DC Sports and CompTech with the 4" tips.

There is a new vendor (speedwithinreach.com) that has some very interesting Titanium options at pretty good prices - but don't know about sound and availibility.

For performance - the weight savings are as important as the overall design. Just make sure you can live with the sound as the smaller the can - the louder the boom!

 

[NSX-Racer]

I added a K&N open intake system and a Fujitsubo exhaust to my former '95 automatic and dynoed it at 272 PS crank power (instead of the stock 256). Acceleration seemed to be slightly better, topspeed was nearly the same as before, transmission had no problems to deal with it.

 

[Dr.Honda]

I realized about 12-15 hp increase with Comptech headers and exhaust on my '92 auto. No transmission problems after 3 years.
Agree with the above comments re large hp increases, wouldn't do it.

 

[mlambert890]

It's a shame there arent more options for the auto on the NSX. This was definitely my only real disappointment with it. Of course the numbers are the direct cause here; there are just too few out there to make a market.

I was kind of spoiled by the Vette where you can really do a ton with an auto and, I've recently learned, the same holds true for the 911 as well where H/E and FI are all fine on the stock tiptronic

In moving to the 911 Im going with a 2000 C2 and adding H/E and SC (with ECU upgrade). End result of that combination is about 470hp at the flywheel and the stock auto handles it fine.

 

[NSXDreamer2]

I don't think there's no reason to lose sleep about getting a 20hp bump (and some torque) will ruin the transmission... Like all others have been mentioned unless it's an FI, Supercharged or nitrous, it won't damage your transmission in one day.

But the durability of the transmission/ torque converter life would be different story though... It really comes down to that if you still want a 100,000 miles trouble free nsx, or in case anything bad happened, you may just change to a manual or even rebuilt the transmission, beefing up the torque converter...etc..

If the transmission is good enough for more power, I really don't see there would be any reason HONDA decided to detuned the automatic nsxes... Yes, if the Acura TL auto transmission can handle 270hp, you will think HONDA got what it takes to improve the 04 nsx to handle the then(pre97) stock hp... NAAAAAaaaaa...
(and most of you heard about the 02 TL TypeS auto tranny failure, right?)

 

[ACCD]

automatic boost

Nice to know I'm not the only one scratching my head on how I can have my "automatic cake" and eat it too.

Dal Motorsports mentioned using 3.2L headers on the 3.0 as well as a cam swap.

Can anyone comment on this? I was / am looking for an additional 30-35 hp. I'm not looking to do stoplight burnouts, just a little more......stuff.

Either way I LOVE this car

ACD

 

[Auraraptor]

This is a common misconception amoung many people.

Adding the headers and exhaust will NOT damage your trany or your torque converter.

Why?

Simple: HP does not damage the trany, torque does. A very high quality exhaust or header setup, like the tubi, will reduce back pressure, sacrificing torque at lower rpms, for gains in horsepower at higher. Often times when dynoed a car will show more hp in the higher range, with less torque in the lower.

Adding both headers & exhaust really reduces backpressure, you you definately will be going this route of more high rpm hp and less low rpm torque. Less torque = less damage to your trany.

PS, Netviper its nice to see you are still on 'Prime. I stop in sometimes.

On a side note, a cam swap will add torque and put more stress on your trany.

 

[nsxtasy]

HP does not damage the trany, torque does. A very high quality exhaust or header setup, like the tubi, will reduce back pressure, sacrificing torque at lower rpms, for gains in horsepower at higher. Often times when dynoed a car will show more hp in the higher range, with less torque in the lower.

Hmmm... I understand what you're saying, but I just don't think it's true. Here's why.

For a given RPM, the only way horsepower can be increased is by increasing torque. (Remember, horsepower = torque * RPM / 5252) Granted, you can increase horsepower and torque at certain RPMs and not others... but the torque curve on the NSX is pretty flat. Any exhaust and/or header that increases peak horsepower is likely to increase peak torque as well - not only because the torque curve is so flat, but also because peak torque also occurs at high RPM (5500), although not quite as high as peak horsepower (7100). And, as you note, peak torque IS what (potentially) damages the transmission.

Note - I am not saying that exhaust/header mods are, or are not, sufficient to cause damage to the automatic transmission. What I am saying is that if they increase peak horsepower (which they usually do), they are likely to also increase peak torque.

 

[Auraraptor]

Any exhaust and/or header that increases peak horsepower is likely to increase peak torque as well - not only because the torque curve is so flat, but also because peak torque also occurs at high RPM (5500), although not quite as high as peak horsepower (7100). And, as you note, peak torque IS what (potentially) damages the transmission.

... What I am saying is that if they increase peak horsepower (which they usually do), they are likely to also increase peak torque.

I am speaking for experiance with Ferraris where the addition of headers and exhaust often lead to a minor decrease in peak torque as well as low end for a minor gain in hp. It might not hold true for the NSX, but seeing how they both run similar principles (ie peak hp at high rpms with high readline and relatively high peak torque) I think it would hold true for NSXs as well. I admit this may not be the case though.

 

[NetViper]

PS, Netviper its nice to see you are still on 'Prime. I stop in sometimes.

I would never leave here. The people are the best. Ferrarichat is nice, but I would say it is like 35% car guys, 65% trolls.

At least here 95% of the people own the car they are talking about

I am glad to hear you still miss your NSX from time to time.

 

[mlambert890]

But the durability of the transmission/ torque converter life would be different story though... It really comes down to that if you still want a 100,000 miles trouble free nsx, or in case anything bad happened, you may just change to a manual or even rebuilt the transmission, beefing up the torque converter...etc..

Going to keep the discussion going in the event that new info might surface (hope no one minds the bump)

The above is what I found to be the real problem. Personally, I considered very seriously adding the FI to the auto and not caring about the tranny. My thinking was that *if* the tranny went, I would replace it with a stronger trans.

That's where I ran into a problem. There is literally nothing in terms of an aftermarket for the auto NSX outside of Level 10. Personally, I've heard way too much mixed info to feel comfortable dealing with those guys.

The closest I got was some advice regarding some Japanese tuner who has basically no English on their website and sort of obviously doesn't deal directly with Western customers.

Outside of that, there was nothing at all. It was something of a rude awakening since, like I said, I was used to the Vette world where changing gearing, the torque converter, the AT computer profile, or even the whole darn tranny was no problem at all and had several vendors in each category addressing the market.

For the AT NSX, there basically IS no market, so we're stuck. I have to admit that this is pretty much the biggest reason I've decided to bail out of the X. I want to stick with an auto car if I can, but I want more performance (and ability to modify things without having a heart attack over every single HP addition), than the NSX can offer.

 

[Tony Montoya]

I just got back from the Canadian GP and the NSX pace car was cool. It was just a bit faster than the S2000 through the S bend just past the bridge. Also the NSX did not lean as much. A very nice 04 car in yellow.
Now the Mercedes pace cars, one was a wagon, absolutely would have killed the NSX. Those Benz were faster than the Ferrari Challenge cars.

 

[NetViper]

Why did acura made the auto tranny so weak in the first place?? I doesn't make sense to me. It sounds like they just picked something that would work... just barely..

Vettes have been auto forever and have had more power than the auto NSX.

I just don't get it.

 

[Lud]

The automatic was detuned because the powers that be at Honda decided it couldn't handle the extra power....

I think that theory is open to discussion.... See my theory here: http://www.nsxprime.com/forums/showthread.php?s=&threadid=26917

 

[nsxtasy]

I think that theory is open to discussion.... See my theory here: http://www.nsxprime.com/forums/showthread.php?s=&threadid=26917

That's an interesting theory, but I'm not sure it isn't basically the same theory. In other words, instead of Theory 1 "They lowered the horsepower because the tranny couldn't take it", we have Theory 2 "They lowered the redline and changed the cam profile (which, together, lower the horsepower) because the tranny couldn't take it"... no?

 

[mlambert890]

I just got back from the Canadian GP and the NSX pace car was cool. It was just a bit faster than the S2000 through the S bend just past the bridge. Also the NSX did not lean as much. A very nice 04 car in yellow.
Now the Mercedes pace cars, one was a wagon, absolutely would have killed the NSX. Those Benz were faster than the Ferrari Challenge cars.

Was that pace car an auto?

Benz is insane, btw. It's amazing to me how many staggeringly fast cars they currently produce. I just wish I could get into 4000lb sedans, but I can't no matter how quick they are

 

[Lud]

That's an interesting theory, but I'm not sure it isn't basically the same theory. In other words, instead of Theory 1 "They lowered the horsepower because the tranny couldn't take it", we have Theory 2 "They lowered the redline and changed the cam profile (which, together, lower the horsepower) because the tranny couldn't take it"... no?

No, my theory is that Honda decided they needed to lower the peak engine RPM for the good of the automatic transmission. I do not believe the extra 18 HP was a concern. This is more consistent with my understanding of torque converter based automatic transmissions.

I believe the decision to lower peak RPM, as well as the taller gearing in the 4-speed automatics, is what drove the other changes (cam profile, etc.) with the goal of producing more power down low. Producing more "oomph" at lower RPM helps the autos maintain the sporty driving experience by offsetting the taller gearing of the 4-speed auto and the lower redline. These changes resulted in a slightly lower peak HP, but I believe that was a result of their other goals, not a goal in itself.

But I'm not an automatic tranny guru by any means and that's just my theory that makes sense to me. As I said in the other thread I'm more than open to hearing facts to dispute it.

 

[JPS Europa]

What did they do to detune the motor for the automatic?