wakeboardr42393

iTrader: (1)

ok so i recently got the car. the guy i got the car from gave me a set of edelbrock headers with the car. i painfully installed them. then, i realized the stock y pipe wont fit on the headers. haha. i called around a few places to get estimated prices for a custom made y pipe. i got an average of a little over $200 estimated price. the car is a gm goodwrench 350 but has (what appears to be) stock tpi on it. from what ive read on these threads, the tpi systems really have no high end power, and have a good amount of low end torque. i even had the engine started- and in nutral at wot, the engine pretty much stops revving at around 4600 rpm. my buddy said he could make a system for me, if i put small 2.5" pipes on the end of the headers so he can slip and clamp pipe on to them. i welded these peices on, and he cant do it anymore. the car already had an edelbrock high flow cat back.


my question is, will there really be any performance difference( less torque, more torque, more power) that i will physically be able to notice when driving with the headers and custom y pipe, then with the stock manifolds and y pipe? will there be less torque in the low end with the headers vs stock manifolds?

in the future i plan on doing a hi performance carb or stealthram setup, should i save the headers till that happens? i was thinking about putting the stock headers and y pipe back on for now. but not sure




any comments, suggestions, questions, anything appriciated. thanks

Stangski09

iTrader: (10)

She'll sound much much better. But to be honest, I have a 350 and I swapped to a fully ported SLP Runners and TPIS Baseplate intake, and Hooker 2460 Headers to a 2 1/2" Ypipe, and I don't feel she gained too much. Maybe a few tenths but nothing outrageous.
If I had to do it again i'd definitely throw headers on, just because you can't beat the look of them and they do improve performance and allow the exhaust to get out quicker which in turn improves performance.

92RS(real slow)

have you ever looked at your factory manifolds compared to a good set of shorties....there is all the evidence you need. So basically yes there is a big difference.

1bdbrd

iTrader: (1)

I put hedman shorties on mine and literally noticed NO difference. This was back before the Dyno Don's headers were out and all that. I also didn't do any sort of computer tuning after it was done, nor did I even monitor the air/fuel ratio to see if any needed to be done.

To me the first mod on ANY TPI engine should be to ditch the intake and get something better. I had enough in my headers, y pipe, cat, all the related bolts and spark plugs to have swapped intakes instead and picked up proven power.

kd5icr

iTrader: (2)

Yes you should get more low end tourqe, it will sound better and in some cases you will get a little better fuel milage.Not to mention the loss of weight compaired to stock manifolds.The stock TPI system was not made for high RPM breathing, You will need to get maybe tuned runners for it. There are tons of threads here to get the answer to your TPI questions.

Orr89RocZ

iTrader: (20)

When combined with a little tuning you can get abit more power out of it. Try giving it 2-4 more deg of base timing along with the headers/exhaust, it should pick up alittle. A good ecm tune will get more out of it but not necessary to have to run exhaust.

20whp is possible. Maybe more. Not a great gain but a gain nonetheless.

Alot of L98s dyno around 210-220 stock. Shorties/exhaust and no tuning really gives around 230-240whp on a good setup. So 20 hp or so is acceptable.

Not a great bang for the buck it seems but the sound improvement is always worth it.

Your talking 250-260whp on a good full bolt on car with little tuning done to it. Alot of money for 30-40whp but it does make a big difference at the track when combined with gears/converter/sticky tires. These cars dont have big cams or high flowing heads so intake exhaust mods only can give so much gain. Not like an LS1 car which easily gains 50 whp with just exhaust mods and tune.

1bdbrd

iTrader: (1)

Mine put out 230/360 at the wheels with a cutout, a ghetto fabbed cai and a holley afpr. Stock manifolds and cats and as far as I know, the stock prom. It also trapped 95mph in that state of mods on 7 cylinders.

The limited power gain from headers compared to the work involved is the biggest reason why I suggest a new intake first and then exhaust later. Go for an intake that DOESN'T sacrifice power in the name of torque. Later on, look into your exhaust options but for now, start with the things that are actually a power limiting factor.

wakeboardr42393

iTrader: (1)

allright, well, i got the headers for free, like i said. and theyre already on. i guess im just gonna have the exhaust made. i already wen thalfway. hey i woulda done it at some pouint anyways. and if i do the stealtham in the future, inm not gonna just ge tthe intake, im gonna save up and get the entire full package, with the intake, ecu, injectors, plus new pretty much everything that has to do with it.

about the timing,, i dont really know much about timing, i mean i could set the timing, if i knew where the mark was... haha i was looking at the pulleys and couldnt find the timing mark? what one would the mark be on?

88gta3508

the TDC mark.. is on the Harmonic balancer
the timing indicator is on the timing cover!!!!

wakeboardr42393

iTrader: (1)

ok i got the y pipe made, just got the car back..

im kinda pissed off cuz i paid them 400 dollars to do it and they said itd be "high quality" i went with them cuz they seemed to know what they were talkin about.

i mean it looks good and everything, its just that they connected the both collectors' 2.5" into a single 2.5" pipe, then they bumped it up to a 3" after both headers were dumped into a single 2.5"? does that even make sense? why would they do that, thats retarded?

i mean yay my headers are connected now but now there's no point in having a 3 inch catback, im kinda mad. i just got the car back.

im probably gonna re-fab part of it at some point, after i get the e check so i can take the cat out. i think i might just put the muffler right where the cat is. the muffler isnt too big.

wakeboardr42393

iTrader: (1)

3" glasspack, will fit niceley (: