How much difference can I/H/E make?

[Mirroredshades]

Okay. I'm getting a little bored with the acceleration of my NSX. I have no interest in FI. I don't want to mess with the internals so I was thinking Intake, Headers, Exhaust. How much performance difference can I get for around $3-4k? Anyone have a setup they think made a big difference?

 

[BD]

You have a 1991, so yeah, Header and exhaust will make a difference. You will free up good amount of HP restricted by the stock unit.

Intake wise, a unfilter will do just fine.

By having an NA1, you do have a very good selection of header and exhaust. GTOneUSA has a very good package right now, probably will get you one of the best result.

check it out.

http://www.nsxprime.com/forums/showthread.php?t=97043

Good luck.

 

[Big_D]

I agree with Vance, headers on a early car is a good choice. Most agree 12 hp can be gained with headers and a good exhaust system.

I run the stock air filter though to give my engine the most protection. I think the gain on an intake is almost nil...some say 2-5 hp

I may go with a ECU chip later on. Since you have an early car it is OBD1 and you can add a performance chip. I have heard of gains of up to 10 hp from a chip. There is a group buy on a performance chip or Dali sells one. The chip should be added after the I/H/E is installed to take advantage of the increased flow.

I think with everything mentioned would give you an additional 25 hp which gets you 295hp.

After that, the next things to do are weight reductions...

 

[JBNSX719]

Okay. I'm getting a little bored with the acceleration of my NSX. I have no interest in FI. I don't want to mess with the internals so I was thinking Intake, Headers, Exhaust. How much performance difference can I get for around $3-4k? Anyone have a setup they think made a big difference?

I have a 91' with K&N Filter, CC Ram Air, SOS Test Pipes, Comptech Exaust, DC Header, and Iriduim Plugs. To me it moves nicely! Compared to stock, Big Difference!!! I dyno at 272 to the wheels with that setup last Nov of 06. A month ago i got the GT One F1 Exaust Version 5.1 and i already feel a difference with that! Shit is loooooudd!! Neighbors hate me when im coming home at night! lol Waiting for my GT One Pulley Kit. Debating about a S.O.S. E.C.U. I like having a naturally aspirated nsx. I'll re dyno and post my results. But its worth the change from stock!!! :biggrin:

 

[carmar]

I have a 91' with comptech header+ Tubi exhaust and Uni filter. It does give me a nice sound from both the exhaust and carbin intake. Because of the extra HP it gains the car runs better compare to stock set-up.

If you really want a BIG difference, go with CTSC set up. I had ridden on one and it is a BIG difference.

 

[davidf]

If funds allow, then go with short gears and 4.23 RP also. I can't wait for my clutch to go away. My luck it will last years.:frown:

 

[RON98]

we seen a 14.5HP gain from switching just the headers on a NA1 customer's car

stock exhaust, just changed over to the 3.2L headers.

its posted on the fourm somewhere with pictures and dyno

3.2L headers can be had for about 400$ if that...

:smile:

happy motoring and happy thanksgiving!

Rob

 

[MvM]

Okay. I'm getting a little bored with the acceleration of my NSX. I have no interest in FI. I don't want to mess with the internals so I was thinking Intake, Headers, Exhaust. How much performance difference can I get for around $3-4k? Anyone have a setup they think made a big difference?

When I bougth the car it was completely stock apart from a set of BBS wheels.
Since then, engine wise speaking, I've added Taitec headers, Taitec GTLW exhaust, SOS Big Bore Throttle body, Cantrell air intake, UNIfilter and Dali-chip. I started out at 242 RWHP and currently I am at 269 RWHP, that a nice difference of 27 RWHP which is Very noticable :biggrin: :biggrin:
Engine revs like crazy and it's pretty loud too.

The new ProSpeed Stage 2 chip is on it's way as soon as Brian is finished with the last few HP.
After that, camshafts or FI are that last mods I will do, still undecided about those though.

 

[GreyHoundSteve]

I too have been pondering I/H/E but have been sitting tight until i have as much data as can be collected on the subject. Some of us new guys here have many years of posts to read through and compare and it is a very time consuming process.

When i bought my 91 NSX my intentions where to keep the car stock and maybe add a better looking exhaust system down the road when i got tired of the supposed 270 hp the car put out. Well i havent had a chance to get it on a dyno yet but i can tell you from owning many other sports cars that there is no where near 270 at the rear wheels of my car and adding a I/H/E might only get me back to where i thought i was starting at.

Of course i didnt buy this car for straight line speed. I owned a TT Supra when i was younger and all i had to do for another 50 HP was to open up the waste gate bleeder valve i installed and that mod costs me about $10.

I am starting to think now though that the X needs a little something to make her straight line speed match her great looks but it doesnt seem like that can be accomplished very easily or inexpensively (which i knew when i bought the car but had hoped i would be satisfied with the stock performance having not owned a sports car in three years).

I have always liked the way that turbo charged vehicles drove and many have commented that the CTSC is a nice way to spend $10k but ive never liked the idea of adding FI to a car that wasnt designed for it. Maybe its just my ignorance on the subject but i always felt more comfortable raising the boost on a FI car vs adding FI to an NA car. Not to mention all the work involved in adding FI to an NA car and then finding competent people to tune and service it.

Has anyone ever compiled an "ULTIMATE I/H/E" list with dyno numbers or track slips to back it up? I would be very interested in learning which of the many products available yield the largest usable power gains. To me $3500 is allot of money to spend on 20-27 hp. Especially when that usually only puts our cars back at the supposed factory perfomance numbers. The NSX has a very efficient engine and unfortunately for us doesnt leave allot of room for squeezing cheap hp out of it.

 

[Prospeed]

When I bougth the car it was completely stock apart from a set of BBS wheels.
Since then, engine wise speaking, I've added Taitec headers, Taitec GTLW exhaust, SOS Big Bore Throttle body, Cantrell air intake, UNIfilter and Dali-chip. I started out at 242 RWHP and currently I am at 279 RWHP, that a nice difference of 27 RWHP which is Very noticable :biggrin: :biggrin:
Engine revs like crazy and it's pretty loud too.

The new ProSpeed Stage 2 chip is on it's way as soon as Brian is finished with the last few HP.
After that, camshafts or FI are that last mods I will do, still undecided about those though.

Finally got the final tweaks to the Prospeed Stage 2 Rom. Here are the results. I believe A good filter, header and exhaust can make a large difference. The car picks up a lot faster and has a whole lot more torque throughout the power band.

Estimated cost for everything below?

-Comptech filter around $40 to $50
-Topspeed Header $625 shipped
-Taitec GTLW Exhaust $1,100 to $1247
-Prospeed Rom Stage 2 $349

Total $2271

Note: I believe you can get a better header that will squeeze out a lil more hp but you really can't beat that price.

DETAILS

Dyno: Dynojet

The car has about 62,XXX miles on it
Mods- Stock airbox with comptech filter, Taitec GTLW exhaust, Top Speed Headers, Prospeed Stage 2 Rom Chip.

Note: We forgot to delete the older text that says "prospeed chip version 2" and "Airfilter with 3.5 velocity stack" We did some extra tuning with it and made the same hp so we kept the existing OEM airbox.

RESULTS

Blue line indicates run with only comptech filter, taitec GTLW exhaust, and Top Speed Headers.

Purple line indicated run with comptech filter, taitec GTLW exhaust, Top Speed Headers, and Prospeed Rom Stage 2

-Peak 270 HP with 204ft lbs of torque
-As you can see we picked up around 8 hp to 14 hp Throughout the powerband. 11hp at 7000rpm.
-The NSX saw excellent gains in torque gain from 8ft lbs of torque to 15ft lbs of torque.
-I was impressed with the torque from around 3000 to 5000 as we gain around 15ft lbs of torque throughout.

So to answer your question... Yes, It made a big difference. At around $2000 to $2500 you can't touch that for the NSX. Since you are wondering what you can get for $3000-$4000 the fujitsubo headers are brilliant as well as some of the GT-One exhaust systems. You really can't go wrong! Hope this helps.

 

[MvM]

When i bought my 91 NSX my intentions where to keep the car stock and maybe add a better looking exhaust system down the road when i got tired of the supposed 270 hp the car put out. Well i havent had a chance to get it on a dyno yet but i can tell you from owning many other sports cars that there is no where near 270 at the rear wheels of my car and adding a I/H/E might only get me back to where i thought i was starting at...

....To me $3500 is allot of money to spend on 20-27 hp. Especially when that usually only puts our cars back at the supposed factory perfomance numbers. The NSX has a very efficient engine and unfortunately for us doesnt leave allot of room for squeezing cheap hp out of it.

I don't believe ANYONE ever claimed that a stock NSX puts out 270 HP AT THE WHEELS.
Official specs were 270 HP for the US NSX and 274 HP for the European spec NSX, and those are ENGINE HP's, not RWHP.
The NA2 NSX has, again 290 HP at the engine US Spec and 280 HP for the European version.
In both cases, the NSX will usually deliver those HP close to its specifications and not seldom does a stock engine actually put out a little more after it has been run in properly.

 

[s14_tat]

I don't believe ANYONE ever claimed that a stock NSX puts out 270 HP AT THE WHEELS.
Official specs were 270 HP for the US NSX and 274 HP for the European spec NSX, and those are ENGINE HP's, not RWHP.
The NA2 NSX has, again 290 HP at the engine US Spec and 280 HP for the European version.
In both cases, the NSX will usually deliver those HP close to its specifications and not seldom does a stock engine actually put out a little more after it has been run in properly.

+1

I don't think anyone has ever claimed the NSX to have 270whp. That would mean the car is making over 300hp. Maybe you wouldn't be as disappointed if you drive the car knowing its a 230-240whp car. This car to me moves damn well for having only 230whp. Of course with the mods I have now, it pulls as good as my 320whp 240sx, esp on the top end.

 

[NetViper]

Okay. I'm getting a little bored with the acceleration of my NSX. I have no interest in FI. I don't want to mess with the internals so I was thinking Intake, Headers, Exhaust. How much performance difference can I get for around $3-4k? Anyone have a setup they think made a big difference?

I could tell the increase from my anytime exhaust. I never did get headers. You should expect around 25rwhp with i/h/e and you will feel the difference, but in the real world, you probably dropped a fives tenths in the 1/4 mile at best. That being said, it will pull harder, sound better and be a lot more fun to drive.

 

[Greg Z]

I ran a 13.1 @ 107 last week!

Nuff said, huh?

 

[NetViper]

I ran a 13.1 @ 107 last week!

Nuff said, huh?

Great time, but you have just a little more than i/e/h.

 

[s14_tat]

well Khajjathefang ran a 13.0 @ 108mph at ATCO raceway in New Jersey with 160K miles on the engine and only I/H/E on his 92

 

[Osiris_x11]

small potato's...

well Khajjathefang ran a 13.0 @ 108mph at ATCO raceway in New Jersey with 160K miles on the engine and only I/H/E on his 92

Not quite! He also has "gutted cats" and RC 250 cc injectors...

http://www.nsxprime.com/forums/showthread.php?t=96349


For the majority, a '91-'94 "bone" stock NSX 5spd. w/ OEM tires will run a 13.65 - 13.75 quarter-mile.

Usual weight-reduction from the removal of the spare-tire/bracket & engine-cover as well as the additional weight-loss from after-market I/H/E, a '91-'94 NSX 5spd. w/ OEM tires + I/H/E will run a 13.25 quarter-mile.

Larger-bore throttle-body, after-market ECU performance chip, after-market clutch w/ lightweight fly-wheel, high-flow cats', R-compound tires, larger injectors, different gears/R&P, etc' all can contribute towards an even lower quarter-mile time.

 

[s14_tat]

Re: small potato's...

Not quite! He also has "gutted cats" and RC 250 cc injectors...

http://www.nsxprime.com/forums/showthread.php?t=96349


For the majority, a '91-'94 "bone" stock NSX 5spd. w/ OEM tires will run a 13.65 - 13.75 quarter-mile.

Usual weight-reduction from the removal of the spare-tire/bracket & engine-cover as well as the additional weight-loss from after-market I/H/E, a '91-'94 NSX 5spd. w/ OEM tires + I/H/E will run a 13.25 quarter-mile.

Larger-bore throttle-body, after-market ECU performance chip, after-market clutch w/ lightweight fly-wheel, high-flow cats', R-compound tires, larger injectors, different gears/R&P, etc' all can contribute towards an even lower quarter-mile time.

i don't see how the injectors alone would yield any power gains. I'm not familiar with the stock nsx injector size but unless hes flowing so much additional air that he has maxed out his stock injectors ( which i seriously doubt ) I don't see how would getting different injectors would affect hp. He only has basic breathing mods so just a flash or a tuned rom chip should be able to trim the air fuel ratio closer to 12.5:1 on a n/a car. Remember there turbo or built n/a cars need larger injectors because they are flowing more cfms of air. They need the air fuel ratio in the 11.7:1 range for safety on pump and around 12.5:1 with race gas ( on boosted applications )to avoid lean conditions which could lead to knocking or pre ignition. Since they're running turbos that can flow anywhere from 50lbs ( a T04E .60 trim) to 65lbs (Garret GT35R) of air a minute. My 2.4 liter 240 runs 615cc injectors.

So why did he put the injectors in, esp without any means of fine tuning them? I have no idea, but I would not count that as even a mod. Also from what I've been reading test pipes or cats only gains 1-2 hp tops. So basically yeah his car has I/H/E, and 90% of other na1 owners have weight reduction mods done. I know I've taken around 90lbs off my car.

Now for Greg Z yes I will admit that he does have a little more than I/H/E since he has a light weight flywheel and a lightweight underdrive crank pulley.

 

[DrVolkl]

Short gears and rear end....that's the best bang for the buck. Do that, and it'll keep you happy for awhile.

 

[Greg Z]

Great time, but you have just a little more than i/e/h.

True, very true. But I kinda figured the super heavy 18/17 Volk AV3's took back what the lightened stuff gave me???

 

[RON98]

nice numbers 13.1

best i can do was 14.5 :tongue:

used up street tires with no tread and burned all the way through first.

13.1 is seriously fast tho.

 

[sonnynhoung]

Finally got the final tweaks to the Prospeed Stage 2 Rom. Here are the results. I believe A good filter, header and exhaust can make a large difference. The car picks up a lot faster and has a whole lot more torque throughout the power band.

Estimated cost for everything below?

-Comptech filter around $40 to $50
-Topspeed Header $625 shipped
-Taitec GTLW Exhaust $1,100 to $1247
-Prospeed Rom Stage 2 $349

Total $2271

Note: I believe you can get a better header that will squeeze out a lil more hp but you really can't beat that price.

DETAILS

Dyno: Dynojet

The car has about 62,XXX miles on it
Mods- Stock airbox with comptech filter, Taitec GTLW exhaust, Top Speed Headers, Prospeed Stage 2 Rom Chip.

Note: We forgot to delete the older text that says "prospeed chip version 2" and "Airfilter with 3.5 velocity stack" We did some extra tuning with it and made the same hp so we kept the existing OEM airbox.

RESULTS

Blue line indicates run with only comptech filter, taitec GTLW exhaust, and Top Speed Headers.

Purple line indicated run with comptech filter, taitec GTLW exhaust, Top Speed Headers, and Prospeed Rom Stage 2

-Peak 270 HP with 204ft lbs of torque
-As you can see we picked up around 8 hp to 14 hp Throughout the powerband. 11hp at 7000rpm.
-The NSX saw excellent gains in torque gain from 8ft lbs of torque to 15ft lbs of torque.
-I was impressed with the torque from around 3000 to 5000 as we gain around 15ft lbs of torque throughout.

So to answer your question... Yes, It made a big difference. At around $2000 to $2500 you can't touch that for the NSX. Since you are wondering what you can get for $3000-$4000 the fujitsubo headers are brilliant as well as some of the GT-One exhaust systems. You really can't go wrong! Hope this helps.

have you had any experience with the GTone exhuast/header or anything else?

is there anymore gains to be had by going with those units opposed to using what you did when you dynoed yours?

 

[nsxtasy]

A good header and exhaust combo can give you a nice increase in power and acceleration. (Comptech supercharger, even more, of course.)

Changing the gearing makes a big change to the perceived acceleration, but the actual change in acceleration is quite small.

Air filter, no significant difference - don't even bother.

 

[NSXGMS]

Re: small potato's...

Larger-bore throttle-body, after-market ECU performance chip, after-market clutch w/ lightweight fly-wheel, high-flow cats', R-compound tires, larger injectors, different gears/R&P, etc' all can contribute towards an even lower quarter-mile time.

This is inaccurate.

First, there's no measurable bottleneck at the TB for NA cars (except strokers). Increasing the bore of the TB adds nothing that a good TB cleaning won't give you. Same goes for intake manifold bore.

Second, there's no aftermarket ECU/chip that has been proven to give any measurable performance gains.

A lightweight flywheel and clutch can reduce drivetrain power losses resulting in more whp but not bhp. That is legitimate. Using R-comp or slick tires also can improve acceleration provided you're skilled enough to actually take advantage of them.

The cats are also not a measurable bottleneck on NA NSXs. Just replace your exhaust and headers.

Larger injectors will not increase power on NA NSXs. The engine is already using all the fuel and air it can handle. There's already a surplus of both on hand. In fact the stock injectors aren't even squirting at 100% on NA NSXs. That's why it's possible to retain the stock injectors when going low-boost FI.

And as Ken points out the short gears and R & P mostly give the feeling of faster acceleration. In reality the gain is miniscule. In fact the JDM short gears actually hurt 1/4 mile times in the NSX.

The only bolt-ons proven to give hp gains are headers and exhaust. The best intake is the stock airbox with the stock filter. Some argue the UNIfilter is better but there's absolutely nothing wrong with the Honda paper filter.

 

[Eclipsed]

Re: small potato's...

As far as i know my cars only mods are comptech headers/exhaust/suspension, and an akimoto intake. If anyone has a rough idea of the power gains the comptech headers/exhaust give on an stock 91 i'd be happy to hear it. But in regards to the other conversation, last time i took mine to the track with street radials i pulled a 13.3 at 106mph. Didnt smoke the rear end on launch either just faded the clutch out.