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SC or TT or Natural.... and a Thanks...

6 March 2001
Austin, TX
First, I'd like to thank everyone who has spent they're time providing input based on your knowledge and experiences. I was about to sign on the dotted line for a 1997 Lotus Esprit V8TT when a friend of mine, (another Brian) turned me onto this site. I was so impressed with the support and following for this car, I had to go check it out further. As of Friday I can say I'm the proud owner of a 95 NSX-T because of everyone on this site. Thanks!

Now, onto my question. Since I cant seem to ever leave well enough alone, I'm feeling the need to perform some upgrades to my new baby. Beside tires, brakes, and some suspension things that I think I already have a good grasp of because of the information on the site, I find myself wanting more horsepower. Lots more. Can't help it, it's in my blood. There has been quite a bit of discussion about which SC is better or if the TT unit is better or worse than the supercharger, etc. Everyone's circumstances are different and their needs tend to be different. What I'm looking for is as follows;

*This car is my daily driver, it has to be reliable
*I live in Austin, TX... It gets pretty damn hot here in the summer
*Looking for 350-400HP
*Minimum cash outlay
*Reasonable maintance
*Good response at low and high end

Can somebody help point me in the proper direction? I've seen good and bad about the SC solutions, good and "REALLY BAD" posts about the TT solutions, and nobody really talks about a high HP naturally aspired engine (would seem really expensive). The TT option seems to be the most intriguing to me right now. Any insight would be helpful.

Austin, TX
95 NSX-T Black/Black

[This message has been edited by BlackMonster (edited 06 March 2001).]

[This message has been edited by BlackMonster (edited 06 March 2001).]
"...and nobody really talks about a high HP naturally aspired..."

I would also like to see some discussion on the options for increasing horsepower without necessarily going the turbo or supercharger route. There's not a lot of info on this.

I suspect the engine is pretty much optimized and there's not as much in the way of gains to be had as there would be with a more conventional engine.

There's headers and exhaust of course, that's well documented...

But what about head work, different cams, blueprinting, balancing, injectors, intake, slightly higher compression, etc, and the more "traditional" techniques?

Anyone have any ideas what could be acheived with these mods while still maintaining durability and driveability?

I would think it shouldn't be too hard to squeek out another 10%-15%.


1991 NSX Blk/Blk
1974 Vette 454 4 spd
then adding a sc or tt on top of that
I am new to NSX engines and how they work so someone please correct me if my general logic is off here.

I'm sure it's a possibility to get 350-400 horsepower out of a naturally aspirated NSX engine. Since the stock is already near 300 at 270 or 290, getting at least another 60-90 horsepower should not be impossible. However, you are limited in that regard compared to "there is no substitute for cubic inches" american design engines. Although they are not as refined, heavier, and consume more gas, they are made to modify. A stock corvette ZR1 engine is 405 horsepower stock. That engine has been tuned by companies like Lingenfelter to produce over 660 horsepower "naturally aspirated."
No turbos, no superchargers.
There is a 0-150-0 article mentioned on this forum where the NSX beat a stock corvette. I have that issue. That portion was a side comparison to the main shootout. In that article, the Lingenfelter Corvette ZR1 went 0-150-0 in just over 23 seconds. 0-60 in 3.6, 1/4 mile mid 11s. It beat a couple of Hennesy modified vipers, mustangs, and other heavily modified cars by over 2 seconds to the next competitor. Why? It had the best horsepower to weight ratio. All engine.
Because the NSX is more technologically advanced and refined it does not need the cubic inches to produce all that power. Imagine if Honda used the S2000 technology of 120hp per liter and produced a 5 liter engine. A naturally aspirated 600hp engine.

However, if you ever wanted to get that kind of power out of the NSX engine without forced induction, you would spend a ton of money and end up with an entirely different engine from when you started.
To me, one of the greatest advantages of the NSX is it's body and light weight. With probably half the money you would spend bumping an NSX to that kind of horsepower (without forced induction), you could lighten the car by another few hundred pounds. You would be faster with a 2500 lb car and a 320 horsepower engine than you would with a 3100 lb car and a 400 horsepower engine. The engine lacks torque more than horsepower. There is only so much torque you can get out of a 3 liter engine without forcing it.
A car that is 600 lbs lighter will make up for that loss in torque more than a higher horsepower rating will. Once at speed, I think acceleration is the NSXs strong suite. It's that "pull you like a black hole from the start of a viper that is missing." The stock ZR1 gets 300ft/lbs of torque at 1500 RPMS. CRAZY!
So what am I saying with all this pointless ranting?
1. The weight reduction option is not an option for most of us because we enjoy the comfort and value of the NSX. We don't just race it, we drive it.
2. It would be cheaper to buy a supercharger than to try and get that kind of power out of the engine naturally. This isn't the case with larger american engines with more displacement, but it is here.
3. With a supercharger, you keep the reliability of the engine intact and do not lose too much of the great mileage. You have an ultra fast and dependable car.
Personally, I wouldn't try to get 400 horsepower out of a naturally aspirated NSX. I'd be afraid to kill the car in the process. It was not designed with that in mind. This car is refinement, not brute force. You can add brute force on top of refinement, but I don't like messing with the engine too much. Do you want your NSX to feel like a big block? why? just buy a zr1.

Just thought I would share. All just my opinion and good luck in whatever you decide. And you know what they say about opinions. They're like a__holes. We've all got one and they all stink.
BlackMonster and Jimbo, I'm currently in correspondance with Comptech about their PowerMax Head/Cam Package. They claim 50HP. I've asked them for some dyno results to determine where in the power band these gains are made.

The reason I avoid forced induction is because I drag race my 98 Coupe. I like Time Trials and Autocross as well, but my real passion is drag racing. However, once you use a power adder (Turbo, Supercharger, or NOS) you compete in Power 6 (6 cylinder with power adders). Cars in this class run in the 10's. It would require significant mods to more than just the engine to create a competitive car. On the other hand, if I can achieve high 11's normally aspirated, I will be competitive in both NIRA and IDRC heads up drag racing classes. I am currently in the high 12's and I feel that the high 11's are within reach with engine mods, suspension mods, and some weight reduction.

Also, there is nothing like the sound of a high revving normally aspirated high compression engine.

[This message has been edited by dswartz (edited 06 March 2001).]
Brian...this is Richie, nice to see you got the nsx and went with the 95, esp after this past weekend of perfect weather i wish i had a T. If you and david meet up i would love to tag along. See you tonight at the game.

92 Red/Blk
Originally posted by dswartz:
BlackMonster and Jimbo, I'm currently in correspondance with Comptech about their PowerMax Head/Cam Package. They claim 50HP. I've asked them for some dyno results to determine where in the power band these gains are made.>>

I have the complete CT IEM kit on my 3.0L. it made +22 HP on the Dyno, that is cams, heads, EVERYTHING. Get that "50HP" in writing.

need more info? private me @

[email protected]

Mark Johnson, CEO of Custodial Services @ Dali Racing, a Not For Profit Company.
Mark, The question on the table is what's possible with Heads, Cams, & Compression in terms of HP and Torque at the rear wheels? What if the compression is bumbed to, for example, 11.5:1? What about porting, multi-angle valve jobs, bigger valves, more lift/duration? What is possible and practical for a daily driver (pronounced "reliable")?
If you really, really, really know what you are doing, you could probably build a 13:1 compression engine that ran reliably on 92 octane gas. By the way, once you go past 14:1, on any gasoline type fuel, you rapidly get into diminishing returns. HOWEVER, in my opinion, you would have to completely revamp the fuel and ignition system to do it. I don't think you could safely tweek the stock system to reliably run at very high compresion. 12:1 would probably work with a good programable system.

There are lots of things you can do. Extrude Hone everything air moves through, high lift cams, headers, lighten all the internal parts, etc.

Keep in mind those NA race engines making 450 - 500hp are 3.5L and get rebuilt fairly often. Also, I really doubt they would be any fun to drive on the street.
I think my goals in a modified NSX engine would be much less than 400 HP.

Taking a 270 HP engine up to 320-ish HP is more what I would have in mind.

Has anyone done this with normal aspiration and without nitrous?


1991 NSX Blk/Blk
1974 Vette 454 4 spd
My stock 98 has a compression ratio of 10.2:1. Does it use flat top pistons?

What compression ratio can be achieved by just milling the heads? Would this reduce the volumetric efficiency?

Bottom line is that I would like to maximize normally aspirated power by reworking the heads alone. What power gains should I reasonably expect? Is 350-375 engine HP and 275-300 lb ft of torque realistic?

[This message has been edited by dswartz (edited 07 March 2001).]
If any of you have looked in the HyperRev Magazine, Japan offers quite a few NA mods for the NSX. To name a few, there are the GT1 style intake's (From the roof), I've seen the Velocity stacks with 6 individual throttle plates, and some extremely nifty looking intake manifold assemblies that actually duct air from both side vents. As someone mentioned before you can extrude hone the intake manifold and play with the Air/fuel mixtures to optimize for horsepower.
Or you could get a bigger throttle body.
I know that some Japanese tuners retrofit the C32B heads to the C30A engine for a 15hp gain. I also saw several ads for companies that would Balance/Blueprint/Extrude Hone/higher compression pistons/Cams/Heads etc etc for something like 8,000 US dollars. If I remember correctly the horsepower figures after the modifications were something like 340+ (Dont quote me on the Hp #'s)
You could probably get stiffer valve springs and raise the redline too. If you can keep the engine running peak torque for more RPM's at higher RPM's thats also more horsepower.

In any case I dont think 350 Normally aspirated horsepower is out of the question. Although if you throw the money factor into the equation, there isnt a better horsepower per dollar mod out there other than a Supercharger or Turbocharger.
Originally posted by Jimbo:
I think my goals in a modified NSX engine would be much less than 400 HP.

Taking a 270 HP engine up to 320-ish HP is more what I would have in mind.

Has anyone done this with normal aspiration and without nitrous?


I have a '94 3.0L that produces 268rwhp which, depending on the drivetrain loss factor you use...I think 12% is fair, translates to 305 at the crank. I am running CT headers, intake, exhaust, cat bypass pipes and a Dinan stage III chip. There was a '92 3.0 car that had all the CT internal engine mods done as well as similar bolt ons to what I run and he only got about 10 extra RWHP. He said those internal mods cost him about $12,000. Needless to say, he was very disappointed when he did the cost per HP calculation.