how to get more performance?

[skyjack]

i have a 1991 z28 with l98 code motor ,was wondering if anybody had any ideas to modify this motor for more horse power? thx im a rookie to this

[Rally Sport]

CAI, exhaust.. you talking about taking it apart or what?

[skyjack]

manifold headers ?

[Genopsyde]

Vortech Supercharger, headers, hi-flow cat, 3" cat-back system, transgo shift kit, 3.73 gears, cam upgrade, prom chip...etc.

[92zcamaroperson]

if you go to www.thirdgen.org and sort through the technical articles you'll find a more in depth and basic description of what you could do to you car as well as much more.

[89IROC&RS]

*grin* man that is a kid in a candy store question, i could write like ten pages on this, give me some limits, how much power do you want, what kinda gas mileage, what is the car used for, and most importantly, how much do you have to spend.

[philly rs]

i was just gonna say that damn iroc.... ill quote brian earl speldner....do u have deep pockets?? if u have 10 grand u can make a 10 sec car...if not then for just a few grand we can at least get u off 2 a good start

[tcfco2005]

i know its an old post but i need to know what he wanted to know.My engine is a 91z28 l98 tpi
i want decent gas milage and want to run a 12 or 13 at the track.The car is a daily driver so i need it to be dependable...im rebuilding the whole engine so any parts internaly that will help ill take opinions on.
thanks

[92zcamaroperson]

Your not gonna get the best of mileage anyway you look at it. Something like a paxton supercharger and high quality internal parts with a mild cam and port and polish of your heads, aluminum rockers, heavier springs.....If you go nuts your gonna kill your mileage. Vortec heads do wonders for these engines as well. And arent to expensive. Dont know where to find the intake manifold though. Anybody got a link? See I too am trying to find the perfect balance between gas mileage and performance. Its gotta be possible....Example. A friend of mine has a 96 corvette with an LT4. Sweet motor. 375 hp. He can get 31 mpg highway. If I could get that mileage even with premium it would all balance out.

[supervisor1886]

VIAGRA my friend!!!

[tcfco2005]

who makes good internal engine parts...how is Sealed Power?

[Link85x]

Originally Posted by 92zcamaroperson

Your not gonna get the best of mileage anyway you look at it. Something like a paxton supercharger and high quality internal parts with a mild cam and port and polish of your heads, aluminum rockers, heavier springs.....If you go nuts your gonna kill your mileage. Vortec heads do wonders for these engines as well. And arent to expensive. Dont know where to find the intake manifold though. Anybody got a link? See I too am trying to find the perfect balance between gas mileage and performance. Its gotta be possible....Example. A friend of mine has a 96 corvette with an LT4. Sweet motor. 375 hp. He can get 31 mpg highway. If I could get that mileage even with premium it would all balance out.

http://www.sdpc2000.com/catalog/1460...-Baseplate.htm
There's your link dude!

[89IROC&RS]

actually 12s or 13s with the L98 and the auto is actually pretty easy. youve got the ten bolt rear end im assuming so find a fourth gen torsen with 3.23 gears. you dont want any deeper than that for this project. get yourself the vortec tpi conversion kit. an accel superram intake wouldnt hurt but isnt nessesary. an aftermarket cam is gonna be nessesary, but you dont need to go overboard. keep the lift below .500 inch. like somewhere in the neighborhood of .470 inches. a set of headers, and a catback system. and a rebuild on the tranny with high performance internals, and a shift kit. along with a 2400 stall lockup converter will give you great performance, with reasonable highway and around town mileage. youll also want a high power aftermarket capasitive discharge ignition system and aftermarket high voltage coil. im partial to the crane cams HI-6 fireball system myself.

the gears for instance, most people think that 2.77 gears will be the best mileage, well on the highway maybe, but you have alot of mechancial work to overcome for acceleration (why bonnoville cars with 2.33 gears need pusher trucks) so you wind up pressing the gas down and using alot of gass just to get moving. the 3.23 gears will make acceleration much easier using less fuel, which will actually increase around town gas mileage, and will only up the highway rpms by around 300rpms. which shouldnt hurt it too much. My IROC in a very sad state of repair with 2.77 gears got an average 23mpg on the highway, with a shitty cam, stock manifolds an low flowing stock heads.

the benifit of the vortec heads is combustion efficiency, they make more power from a given ammount of fuel, meaning you can back off the gas more for the same acceleration. meaning you get better gas mileage. also you can up the compression with the vortec heads to around 9.5:1 or 9.6:1 and still run 87 octain gas. ive heard of people running 10:1 but im not gonna throw a guarantee on it. the benifit to this is that higher compression engines are far more effiecent, making better use of the combustion pressures. again meaning you get more bang for a given ammount of fuel with less waisted energy, meaning you get more power, and better gas mileage.

I wouldnt up to a 1000cfm throttle body or anything, or run a supercharger, because both of those push more air into the engine, which will use more fuel, which will hurt fuel econimy.

with those mods, you should be running at least in the 13's and maybe high 12s, and will easily best 20mpg on the highway, maybe as high as 25mpg. (hell my girl got a best of 26mpg on the way home, remember the average 23mpg includes most of the drive which was done at around 70mph with shots up to 110mph and also over the mountains where the air is thinner and it was harder for the car to run. and that was stock and badley in disrepair.)

hell if you want to get really crazy, pull that engine out and tear it to peices, coat every metal on metal surface with anti friction coatings, and coat the piston crown, valve faces, combustion chamber, and exhaust port with thermal reflective coatings.

the key to power and fuel economy is not to cram more air and fuel into the engine, but to make more power with the fuel and air you already have in the engine. anything you can do to make that happen, that means fighting friction, better combustion, and letting the engine get its job done without working to hard. will make you a very happy person

[Link85x]

Hey 89, can you use the Holley Stealth Ram with the vortec heads?

[89IROC&RS]

i dont believe so, check with holley