The Begining of power

[SpikeD]

Hello to all. This being my first post, i only came to this site to get some general insite on what were asking to mod my 91 z28. But as i now know to truly get an idea i must ask all of you knowledgeable folks, so here goes. I am the proud owner of a 1991 Z28 with all the goodies an a wounerful 350 TPI, i wanna take this moddest 230 or so hp machine, an make a vulgar display of power for all to see. I wanna keep it fuel injected maybe go holly or linginfelter,but my question here is where should i start? when i got my car it was running hot an i checked the coolant an radiator to make sure all was good, i bought a 160 degree thermostat an a hpyertech chip an i dont hit 200 too often, other than that the car is stock. id like to know keeping my budget under $1000 for heads an maybe under 500 for headers what i should get any help would be greatly appericated, Thanks for you time.

[89IROC&RS]

well, with these cars, i suggest focusing on handling the power before you make it. namley addressing the cars known weak spots. Those being the chassis, rear end, and transmission. the first three mods i feel are nessesary to any third gen would be subframe connectors, a rebuilt performance rear differential, and a performance rebuild on the transmission. I had a B&M transkit installed in my 700R4 along with a corvette servo and a 2600rpm stall converter and its probly the best mod ive done so far. the rear end is known for being pretty weak, so pulling it out rebuilding it, and putting a stud girdle on it would be a great idea.

the next place to firm up the car would be suspension mods. strut tower braces, lower control arms, polyurethane bushings, and all that.

If you are looking to mod the engine first off, a great first move is to throw on a set of vortec heads with a SDPC tpi/vortec baseplate. youll also need an EGR kit thats welded into the exhaust manifolds, which would mean that you would also want to do headers at the same time as the other mods, has been prooven to make great power per dollar, those heads and intake are worth 55hp, and the headers are worth around 20 more. giving you somewhere around 300hp over the 230 from before. You can get a set of brand new heads, or hit up the junkyard and find a good pair for cheap. the baseplate is around 400 bucks, and the EGR kit is about 70 bucks, headers are around 300 bucks.

and by the way, welcome to the forum

[SpikeD]

iv got same Borg-Warner axel that the irocs came with, i think its 3.23, i love the posi. I thought it would be able to hold itself up for now. As for the tranny after 3rd gear im just kind cruisin on the highway even with my footdown. i seen the post you had describing your modded 700r4. it sounds really bad ass but you certianly put the money into it too, i was woundering how long it took befor you got to have it back on the road, an how much of a differance you noticed when accelerationg.

[SpikeD]

ok wow youll have to forgive me an my terrible spelling, somtimes i type to fast an ill leave out a letter here an there (what a good first impression)

[Morley]

For heads I would reccomend a set of Trickflow's (a tad over 1k) andfor headers you can't go wrong with SLP's (they will also be a tad over your $500 price). After that a Hot Cam upgrade or LPE 219 cam. Then on to induction, Either a converted LT1 manifold or Ported pleum, high flow runners and Accel/TPIS manifold. The bad news..the hypertec chip is useless. After those mods you will have to get a custom prom burned. You can either do it yourself OR contact Alvin here http://www.pcmforless.com/

[SpikeD]

I was talken to my buddy an hes a mechaninc. He brought up a good point thats just gonna prolong my driving an make this more machining work than i had thought about. my cars 14 years old an has 130,910.6 miles on it and mostly all ogiginal parts im gonna need to rebuild the block or atleaste have to wait to get different heads till after i make sure i can take it apart an not find anyhing wrong. if you have anything to add please speak your mind

[SpikeD]

theres one question thats been bothering me for a long time, car companys rate their cars by HP at the flywheel right? so doesnt that mean if my car made 245hp at the flywheel brand spanking new, then over the 14 years of it being driven an a 15% powerloss through the drive train wouldnt that make my actual HP close to only 200, i mean there 4 bangers an 6's that make that kinda power, so unless i go to a dyno ill never know that im maken true?

[89IROC&RS]

ok so youve got the 9 bolt rear end?? that would mean you have a 3.27 not a 3.23 gear. all the borg warner rears have gears that are a step above the factory ones, 2.77 to 2.73, 3.45 to 3.42 and so on and so forth.

oh and the modded 700R4 was the best mod i have done thus far. the increase in performance and throttle responce was intence. the shifts are extremely firm and actually caused me to accedentally downshift from drive to first gear one time. definatly worth the money invested.

[Morley]

Originally Posted by SpikeD

if my car made 245hp at the flywheel brand spanking new, then over the 14 years of it being driven an a 15% powerloss through the drive train wouldnt that make my actual HP close to only 200, i mean there 4 bangers an 6's that make that kinda power, so unless i go to a dyno ill never know that im maken true?

You are making 245HP at the flywheel, as long as everything is working properly, the miles on the engine don't really matter as long as things like compression, computer controls and emissions are functioning and correct.
Yes there are 4 & 6 cylinder engines making that level of HP...but a V8 has much more potential...the 4's & 6's are about maxed out (not counting S/C or turbo addons) at those power levels while the 350 doesn't get near its N/A max until about 400+ HP (and still be streetable).

[SpikeD]

thanks morley an 89iroc for all your advice so far, its great to know that people like you are out there to help the little guy. For starters i think im gonna get a more aggressive cam an a nice big set of headersthat willhopefully fit under the car. Any thoughts on a nice mean cam, an what does anybody have to say about a timing gear (maybe from edelbrock) to replace my timing chain, id like to get it for orginality over a true roller.

[Morley]

The timing gear set will cause problems, the noise it makes will be picked up by the knock sensor. A good timing chain set up is all you need (Cloyes).
Before doing the mods to your engine, have a compression test and leak down test done to check the integrity of your bottom end. If it all checks out a good cam to begin with is http://www.lingenfelter.com/Merchant...Category_Code=
BUT! When going with a larger cam you really need to convert your heads (or replace them) to use screw in rocker studs or have your studs "pinned". And you'll need to replace the pushrods and rocker arms (be sure to get narrow bodied self aligning)

[89IROC&RS]

well, replacing the timing chain is a good idea morley is correct that geared drives will trip the knock sensor. So a good ol doubble roller will work for ya just fine.

That would be the time to instal a new cam, however id say putting on a new set of heads would come first, or at the same time. A bigger cam might give you some performance, but the heads on the L98 are pretty low flow, so you wont see the best gains from the cam swap unless you upgrade the heads. But if you want to do the cam first, i suggest comp cams xtreme energy hydrolic roller cam for computer controlled vehicles. the lifts are less than alot of aftermarket cams but have alot more area under the curve for better low and mid range power. so youd get great power and better mileage than the really high lift cams. and your valvetrain would suffer less abuse.

[SpikeD]

theres a guy i know buzzing in my ear about his 95 camaro with the LT1, i already know hes got like 325hp but what other adviantages does he yeild over my TPI?

[Morley]

Originally Posted by SpikeD

theres a guy i know buzzing in my ear about his 95 camaro with the LT1, i already know hes got like 325hp but what other adviantages does he yeild over my TPI?

The LT1 has a short runner design, which means it will run higher RPM's, The TPI is a long runner design, it usually runs out of steam near 5k RPM BUT! and here's the kicker, it makes GOBS of low end torque which is what you need/want on the street.

[SpikeD]

wouldnt i need just to replace my baseplate(mainfold) an get the lt1 runner to help make that power, along with porting my heads or getting new ones, an some headers an a cam that we've already talked about, the tpi is nice but the way the pleunme runner have the tubes that bring the air in from the runner arent as good looken as the lt1 which dropes rightdown into the manifold.