Need Power What Should I Do Next? Thanks

[ewalker302]

First off, here's what I got. 1990 GT Auto, 3.55 gears, Stock size tires & rims. 100,000 Miles, Runs Like new, No problems to fix.

I have Installed a Mac cold air kit/K&N, H pipe 2.5 w/o cats, but all other exhaust componens are stock.

I have set the timing correctly and modified the throttle position sesor correctly, removed the screen from my mass air flow meter (should I?). I have also recently replaced rotor, cap, wires, belt, hoses, tires, plugs, struts, shocks, and rack & pinion unit.

Now Im looking for a little more kick in the pants. This is car is a daily driver in south Mississippi (very hot summers).

I'm more interested in all around performance, and power than ETs. I dont want to have to get into gearing, or transmission mods.

Here's what I'm considering:

1. Larger throttle body (size?)
2. Larger Mass air flow meter (size?) I could hone it myself, but is it worth it?
3. Underdrive pulley kit. I run a moderately sized stereo sytem w/amps, and it gets hot here in the summer, my ac blows almost to cold now so the ac pulley does not bother me. I'm only a little worried about slowing down my power steering pump because of the in town driving I do. I understand that they are supposed to increase the life of your accessories. but are they worth it for someone who is driving their car everyday?
4. Cat back system, it would give me 2.5 pipes from the stock headers to the rear w/o cats.
5. Triangular Strut tower brace (basic). Will I be able to tell a difference in everyday driving, or only when I am really carving a turn?
6. Computer mods (chips). From what i've heard they are'nt really worth the money, but what do you think?

Unless I hit the Powerball this week, I will most likely be installing components one at a time, What should I do first?

I apologise for the long post, but you guys know your stuff and I know I can get real answers from you, and not a sales pitch from some guy behind a parts desk trying to rip me a new one.

If you have the answers to any of my questions or advice about parts I can install myself that I have overlooked, please help I appreciate it.

Oh yeah my buddy has a 94 camaro with a sequential port 350 stock, but just rebuilt. I am itching to give him a good view of my gt's taillights.

Thanks, ewalker302

[Jeb_Bush_2000]

The cat-back is probably your best bet. You'll pick up a few horsepower, and it will probably give it a more pleasing tone.


With the stock intake and heads, there's no need for a larger TB and MAF. Underdrive pullies are a good buy, but beware that if you use an alternator underdrive, you'll proably wind up with a dead battery this summer. Heat + poor charging is a bad mix.

[ultraflo]

From your list of mods, I agree that the cat back kit would be a good choice. You should enjoy the enhanced exhaust note too...

Also, the pulleys are a good choice. Just make sure you get the billet alum. power and amp pulley setup. A smaller than stock dia. pulley is available from March performance, this will keep your amps up and your battery charged with that stereo system. You won't have to worry about your power steering performance with an aftermarket underdrive pulley kit. (get billet alum, super lightweight stuff, and less reciprocating mass)

I read a magazine article some time ago where they were testing basic mods on a dyno... Removing the screen is NOT recommended, it smooths out the airflow for a more accurate reading of incoming air or some BS and resulted in a net loss of 2hp if I recall correctly.

The bigger MAF, T.B., intake, injectors, (mild cam, stock ported heads or aftermarket), should be done as a package in my opinion; that is, its easier to do all at once... (and you don't have to send in the MAF you bought for stock injectors back to be recalibrated for your bigger injectors)

Hope I could help some...
I just thought of an electric fan setup, that frees up some hp (up to 10hp I believe) and you can control the temp of you car much easier in the hot air. And you get rid of that nasty clutch fan!!!

March billet pulleys and a Black Magic electric fan???
Or a cat-back system of your choice...

[chris91LX]

You should get a good idea of the diretion you want to go as far as performance. If this car is a daily driver it's going to make your choices a little differen't. I'd suggest going with headers and a cat back system as your first mods. Undeerdrive pullies would be a nice addition but i would highly recomend you go with a 130amp alternator as you live in a hot climate where you will need to use the A/C. An adjustable fuel pressure regulator will give you a few hp and really help with bigger mods int he future. After that if you plan on going with heads, cam and intake in the future I'd recomend you look at getting a throttle body and mass air sensor. It'd be a good idea to get a set of sub frame connectors and control arms before you get into the high hp mods so you can actually put the power to the ground.

The list of mods is endless, you really need to get a good idea of where you want to go with it. ONce you know where you want to go you can ask specific questions to achieve youor goals. It's hard to recommend a tb or maf size if we don't know if you'll be running aftermarket heads cam or intake among other things. Anyway, I hope this helps, it's best to take it one area at a time and work toward a specific goal, saves you from buying the same parts several differen't times.

[ultraflo]

good points, I forgot about the suspension mods. But you have to realize that I tend to be the aforementioned (is that one word?) "buy parts twice, three times before getting it right type."

However, something that I have only purchased once (at this point, anyhow) is the Performance Distributors 130 amp alternator. Thought it would be a good idea for a big elec. fuel pump, elec. fan, elec. water pump, nitrous bottle heater, nitrous/fuel solenoids, you get the point...

I had good luck with the stock alternator with that smaller than stock pulley from march before I got stupid with all those mods...

Its a pretty heafty piece with a heafty price tag @ $285.00
Works great so far...

[ewalker302]

Thanks guys for the tips.

Here are my plans.

American thunder(flowmaster) or MAC cat back kit. I already have an h pipe-no cats. Or if you guys know of another company that makes a good cat back unit that I could compare prices to.
Anyone have any comparison data (price vs. quality vs. performance?)

I never plan to replace the heads, stock headers, or intake manifold.

A strut tower brace is as far as I am going with suspention mods.

I have decided against an underdrive pulley system, this is my daily driver, and dependibility means more than anything, I need my ac and my alternator for tunes.

As far as specific driving this car is driven everyday from hourlong Interstate trips, to country gravel roads, with a few stoplight drags along the way. (I cant resist kids in supras or hopped up civics revving their motors at me like they have a shot.)

So I guess my only other question is, with a wide open exhaust, cold air kit, k&n, and a well tuned stock system will I see worthwhile performance gains by upping the size of my TB and or MAF, EGR plate?

If so, what size should I go to for max gains or should I leave it alone (MAF, TB). I just want a little more bolt on power, I dont have plans for a street killer.

I wont be adding any other major components (headers, heads, manifolds)

However they car does have 100,000 miles, with these mods would replacing the fuel pump or any other fuel related comonents result in any gains?

Again, if anyone has any answers, advice, or other components i may have overlooked , thanks I do appreciate it.

My email is ewalker@peoplepc.com if anyone wants to go that route.

Thanks.

[89 Cobra LX]

I would finish off the exhaust first, but I would start with headers. I'm not sure why you're against aftermarket headers, but they are dollar for dollar one of the better mods that can be done to a stock 5.0 and they certainly won't hurt the motor. You're headers will ultimately take more advantage of the MAF and T-body you're going to add. And yes, the MAF and T-body should be upgraded. Don't go bigger than 65mm for the T-body on a stock 5.0.

For a point of reference, I added a 73mm MAF after I had all of the exhaust finished and there was a definate seat of the pants difference in perfomance... especially in the upper-rpms.

[Dark_5.0]

You will see absolutely no improvement with headers on a stock motor.

[ultraflo]

What about those Heddman torque step headers? They go from 1 1/2" into 1 5/8", have a firecone where the equal length tubes merge, ceramic coated...

If I were to buy some street headers, that would be my choice for a nearly stock, mildly modified setup. Anyone on the list have them or know anyone who runs them? I ran Dynomax equal length shorty's before getting long tubes, and I did not notice any seat-of-the-pants improvement when installed with stock, unported heads, etc. They were there when I was ready for them later down the road when my dad hogged out my E7's, and I bought a nitrous kit and mild cam/springs...

Back to your bolt on issue, my opinion has already been stated as far as the list of mods go... I don't believe you would have any problems running the pulleys as long as you run the overdrive pulley on the alternator, even with an elec. fan setup.

And if you plan on a t.b. and MAF without ever changing the intake or even carving around on it; well, that's up to you and only you -- it's your car afterall...

As far as your fuel system goes, a bigger in-tank pump, a clean filter, and an adj. pressure reg. are good mods... But if you plan on a MAF and t.b., might as well upgrade to some 24lb injectors.

The list of mods, and what order to do them in is ENDLESS!!
That is exactly what makes it so much fun

[Thad]

Since you're not upgrading the intake the bigger throttle body won't really do anything. What you could do is have the stock heads and intake port and polished then add a slightly bigger TB. this would give you some more umf than straight stock.
The reasoning behind not going with a bigger TB is that the engine won't breathe any different unless you change it some how. Either with porting or aftermarket heads.
The exhaust will help a bit but i would reccomend the aftermarket headers along with the cat back system. you run into the same effect with the breathing of the engine.
the most noticable power gains come from the opening up of your intake and heads.

Good Luck!
thad

[ewalker302]

Thanks again guys.

Heres what I am considering now.

Installing a cat bacs sys.

I want to get shorty,(stock length headers) any reccomendations (price vs. performance)? I have already installed the off road h pipe and want the headers to bolt right up.

But will the headers give me much improvement without modifying the stock intake manifold or heads?

After making these mods, will a 65 or 70mm MAf make much difference?

Thanks for your time and responses guys.
You are really helping me out.

[89 ATI]

I like the BBK shorties for the price. I felt that I lost some low end torque after I put them on a stock motor. You don't need T/B and mass air until you do the heads and intake.

[Thad]

I would start with the same brand of header that the h-pipe is. That would help ensure the fit-up.

exhaust normally gives anywhere between 5 hp-20hp depending on engine setup.

every little bit helps. A TB will help with restriction of air going in. but no real power gains. you should be fine with the stock TB since there's no plans for the intake or heads. if intake or head upgrade, porting or aftermarket, is to be done then the TB would be in order.

Good luck, and have fun!
thad