The cost/benefit ratio for improving NA-1 1991 - 1994 NSX 5M acceleration is not so bad if you simply want to dip into the 12s and get closer to a 4 second 0-60.
Adding free flow intake, headers and a free flow muffler will yield increases all through the rev range. Mine registered 203 rwt @6400 and 264.5 rwhp @7500 - 7600. The fat midrange and high range felt like another 1/4 liter of displacement felt much more lively.
A few years later I added a lightened flywheel and rebuilt my own clutch with 2 non-spring discs each with 5 pairs of Kevlar pucks. During this time I had a Japanese short gearset installed. The dreaded non-VTEC flat spot going into second gear was almost totally gone, and both second and third picked up 12% more torque relative to distance - essentially the same as going to a 4.4+ ration rear end. The difference was now quite noticeable because second gear was producing more torque engaging at 500 more rpm as well as having 10% more leverage. Same story going into third.
Stock Tranny 1-2 shift @ 46 mph 2-3 shift @ 82 3-4 shift @115.
JDM gearset 1-2 shift @ 46 mph 2-3 shift @ 73 3-4 shift @101
The final mods to the engine were a DAL Racing trick -complete removal of VVIS and extreme porting of the intake - eliminating the divider and milling pronounced paths criss crossing from one bank to the other to enhance the impact of the shockwaves caused by high speed airflow rebounding off of closing intake valves to aid the opposite bank's intake flow.
The result was amazing. The low end torque was actually enhanced, and the entire rev range was fatter. The problem was that the power was no longer rolling off past 7600 rpm; it felt like a plateau continuing to that bitch of a rev limiter. The VVIS trick seemed to generate as much additional kick - especially from 7400 - 8000 as the original intake and exhaust mods.
After a few years of cussing at my rev limiter, I ordered a chip from SOS to kick the peak revs to an indicated 8500. The downward past peak horsepower curve is totally unnoticeable at the 1-2 shift at the new redline, but reving past 8100 at the 2-3 shift is a waste. The important factor is that the car stays in VTEC during maximum effort runs to high speed.
I am guessing that the engine gained 12 -15 horsepower in addition to the intial 264.5 on the Dyno. The chokers on the exhausts probably reduce those gains to 5 - 6. I'm guessing it has about 270 rwhp @ rpm and about 207 rwt with chokers in place.
The fastest stock US spec NSX coupe tested ran 0 - 60 in 4.5 and a 12.9 quarter mile @110 mph with a 3020 # curb weight and 290 hp at the crank which works out to about 260 rwhp. Considering the transmission and final drive ratios are very similar, I imagine mine would perform similarly - better with the chokers pulled. My stock rear wheels & tires don't even come close to the traction of my 275-35 x 18 rears.
I don't plan on drag racing Camaros, Mustangs, and Corvettes which are all faster, but the additional 35 + rwhp and more usable gear ratios transform this 18 year old car into a much more stimulating ride.
Considering all of the brake and chassis mods my wife allowed me to do, the motor is a good fit. She said that several years from now if I decide to forego a new car and the portfolio does well, I can do another more extensive round of mods. Will that include an SOS "weaponized" powerplant? Perhaps a twin turbo ZO6 motor longitudinally with a seven speed sequential shifter?
Ponyboy's car @ 369 rwhp is beyond my comfort zone. 7 seconds in my car gets me to 3rd gear while 7 seconds in his probably gets him into 4th. All things considered PB can handle it; Me? Nearly 70 years of age with arthritis and the wrong hard ateries? What a way to go!.:biggrin:
Adding free flow intake, headers and a free flow muffler will yield increases all through the rev range. Mine registered 203 rwt @6400 and 264.5 rwhp @7500 - 7600. The fat midrange and high range felt like another 1/4 liter of displacement felt much more lively.
A few years later I added a lightened flywheel and rebuilt my own clutch with 2 non-spring discs each with 5 pairs of Kevlar pucks. During this time I had a Japanese short gearset installed. The dreaded non-VTEC flat spot going into second gear was almost totally gone, and both second and third picked up 12% more torque relative to distance - essentially the same as going to a 4.4+ ration rear end. The difference was now quite noticeable because second gear was producing more torque engaging at 500 more rpm as well as having 10% more leverage. Same story going into third.
Stock Tranny 1-2 shift @ 46 mph 2-3 shift @ 82 3-4 shift @115.
JDM gearset 1-2 shift @ 46 mph 2-3 shift @ 73 3-4 shift @101
The final mods to the engine were a DAL Racing trick -complete removal of VVIS and extreme porting of the intake - eliminating the divider and milling pronounced paths criss crossing from one bank to the other to enhance the impact of the shockwaves caused by high speed airflow rebounding off of closing intake valves to aid the opposite bank's intake flow.
The result was amazing. The low end torque was actually enhanced, and the entire rev range was fatter. The problem was that the power was no longer rolling off past 7600 rpm; it felt like a plateau continuing to that bitch of a rev limiter. The VVIS trick seemed to generate as much additional kick - especially from 7400 - 8000 as the original intake and exhaust mods.
After a few years of cussing at my rev limiter, I ordered a chip from SOS to kick the peak revs to an indicated 8500. The downward past peak horsepower curve is totally unnoticeable at the 1-2 shift at the new redline, but reving past 8100 at the 2-3 shift is a waste. The important factor is that the car stays in VTEC during maximum effort runs to high speed.
I am guessing that the engine gained 12 -15 horsepower in addition to the intial 264.5 on the Dyno. The chokers on the exhausts probably reduce those gains to 5 - 6. I'm guessing it has about 270 rwhp @ rpm and about 207 rwt with chokers in place.
The fastest stock US spec NSX coupe tested ran 0 - 60 in 4.5 and a 12.9 quarter mile @110 mph with a 3020 # curb weight and 290 hp at the crank which works out to about 260 rwhp. Considering the transmission and final drive ratios are very similar, I imagine mine would perform similarly - better with the chokers pulled. My stock rear wheels & tires don't even come close to the traction of my 275-35 x 18 rears.
I don't plan on drag racing Camaros, Mustangs, and Corvettes which are all faster, but the additional 35 + rwhp and more usable gear ratios transform this 18 year old car into a much more stimulating ride.
Considering all of the brake and chassis mods my wife allowed me to do, the motor is a good fit. She said that several years from now if I decide to forego a new car and the portfolio does well, I can do another more extensive round of mods. Will that include an SOS "weaponized" powerplant? Perhaps a twin turbo ZO6 motor longitudinally with a seven speed sequential shifter?
Ponyboy's car @ 369 rwhp is beyond my comfort zone. 7 seconds in my car gets me to 3rd gear while 7 seconds in his probably gets him into 4th. All things considered PB can handle it; Me? Nearly 70 years of age with arthritis and the wrong hard ateries? What a way to go!.:biggrin:
