Does anyone know how much HP I should be getting for headers, hi flow cat and a cat back? I'm guessing 10-15hp.

I doubt it, probably more like 5-7. Our exhausts relly arent that restrictive. we have the exact same piping as the turbo cars so you would gain more top end and lose some bottom end. Headers really dont do much for our cars. Unless you plan on making some serious power NA, I wouldnt waste my money on headers. After putting on my exhaust I felt a slight difference, but Im already used to it now and want more power.

man, are you serious 5-7 hp for a whole new exahust?? I would agree that it wouldnt add crazy hp but I would hope that you would end up above ten anyway....

nah judging by the gains i got i would have to agree with about 7-8 hp. like he said our cars do pretty well with exhaust. and actually your best bet and a cheap way out would be to get a muff with a 2.25 inch opening so you can put it on the stock pipe. if it's a straight through muff your gonna gain on the top end and minmize loss on the bottom end. headers aren't worth the money if you wanna do it for looks get the pacesetters cause they're so cheap. the best exhaust mod you can do is to take out the resonator and (i didn't tell you this) catalytic converter

Butt dyno is 10-15. I wish someone would get us a freakin dyno besides that damn magazine.

I'd say 5-7 is a good conservative guess too. Unless you are pushing alot of air through your exhaust, a high-flow cat won't do much. Exhaust may or may not give you a good power gain. It depends on the piping and muffler. Not all mufflers are created equal. I would aim for a "straight" through perforated tube type. You'll probably see some gains with a header. They may not be peak HP gains. You may gain at 3500-4500 RPM and lose at 6000. It depends on the design. I've seen alot of dyno graphs testing headers showing minimal gains. Thats alot of trouble and cost for "possible" gains. $250-350 that could have gone to headers is a good start on a NO2 kit with guaranteed gains.

Corbin

'95 ESI-T
HRC+FMIC+ETC...

yea... import tuner being the only one who dyno's? Make me uncomfortable too.. i think they were a little low.. but they probably weren't off by that much.

Ok, Thats probably going to be my last mod. OBX shit is so cheep and stainless. The cat-back is like $270 and hi-flow cat's arer $50. I have a test pipe right now but i'm getting a failed cat converter so I just want a hi-flow cat. the headers are like $200 so the whole set up would be $520 or so. Some cat backs are more than that. but first i'm getting Venom Basic Nitrous and a MSD DIS-2.

There is a dyno about 2 minutes from my house. It's $25 a run and $75 for a tuning session. I don't have a header, but maybe i'll due a run next month and see what we get from a Catback and CAI.

my car dynoed at 127.5 w/ i/h/e...from what i've see thats 17hp over stock. i have the chart sitting rite infront of me and all i had on the car at the time was an aem cai, greddy 4-1 headers, a highflo cat, and a greddy sp cat back exhaust. answer your question specificly enough??

There's a problem with slapping on a high flow cat, high flow exhaust and header. You need to make sure you are not outflowing your intake. If you aren't pulling enough air in to match the exhaust set up. You will loose low end. There won't be enough exhaust gas velocity to keep low end power. The key is balance.

I feel headers gain good power (obviously not worth it if going turbo but good NA mod). a high flow cat isn't needed until you have a good intake setup. Unless you have everything bored out and ported and polished, I wouldn't think it's needed. A good high flow exhaust will help though. I feel right now my set up is being held back by my exhaust. (I have a 2.5" cat-back on my Neon and feel 2.5" is a good setup for out engine, the 2" stock piping and GS-T muffler aren't cutting it for me anymore, Borla cat-back is my next step.)

"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein



Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

Injen CAI, 55mm TB, Hooker 4-1 Stepped Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, SS Clutch Line, NRG Susp. Motor Mount Ins., FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730 215/45ZR-17. Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: Ported/Polished Intake Manifold 1/2, Rear disc brake conversion kit w/, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines

Well Mike, if you think you need that 2.5 inch exhaust to catch me, go ahead and try it. We'll see how you do against my stock 2 inch exhaust pipe at the shootout }> you'll need it! heh heh heh :)

I'm still wagering the 2 inch pipe (with help, of course, in the form of a better muffler and cat) is fine for a streetable NT. I guess we'll see this summer.

I am glad someone has FINALLY posted a dyno with what fwhp these mods gave them. For comparison sake, I made about 119fwhp on 25lb 17" wheels with AEM CAI, AEM cam gears set to 0, and a Tanabe G-Medallion I installed for turbo. I ran the dyno before I did my turbo install hence the large exhaust. Tuning the cam gears popped me up to 125fwhp.

Another dyno worth mentioning only because I find it amusing in how drastic it is. Armond made around 115 I recall with only an exhaust and 18" wheels. We took off his air box and that jumped to around 120fwhp. The amusing part to me is the difference between 120 and 384fwhp he has now made and still going. That is more than triple the hp stock! :-0

The funny thing about the cold air intake, is that it is deceptive on a dyno run. The same goes for a front mount intercooler. These two mods require airflow to work properly. The faster the car is moving, the faster the wind. The faster the wind, the cooler the charge. The cooler the charge, the denser the air, and the more power that can be given. I know that for a FMIC, it is a big difference, but I would be interested in seeing what effect motion has on a CAI. It might not be as large of a difference as the filter is not sitting in as hot of a place, and it doesn't need the air movement to disperse the heat, as a FMIC does. More dyno runs anyone?
-=B-=

Good point Bill. I would suspect that would hold true with a CAI as well. Even though the placement of the intake is drawing in colder air you gotta consider the fact that the air traveling under the car while moving dispersses some engine heat. Also it would seem that the air is being "forced" into the filter more while moving. And we know that air feels cooler when moving then it does while sitting still, so it seems to me that the forward motion would have a lot to do with numbers...

Anyone disagree?