Initial mods for a stock 89
Thread Starter
Instructor
Joined: May 2002
Posts: 127
Likes: 0
From: Syracuse NY
Initial mods for a stock 89
Could anyone help me out with an initial mod upgrade for a stock 89 with 65k miles. I don't want to go crazy yet, just want an affordable way to add horsepower, other than K+N air filter and such. :chevy
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Initial mods for a stock 89 (Raskell5)
Check out the mods list on my site; I'm sending you some '90 L98 mods results data.
BTW, you might consider an SLP ram/cold air intake instead of a K&N and cut lid as the kit comes with a stock size K&N, which makes it very reasonable cost wise.
BTW, you might consider an SLP ram/cold air intake instead of a K&N and cut lid as the kit comes with a stock size K&N, which makes it very reasonable cost wise.
Instructor
Joined: Apr 2002
Posts: 243
Likes: 0
From: Hockessin DE
Re: Initial mods for a stock 89 (Raskell5)
with nothing more than a K&N with an opened stock lid, an adjustable fuel pressure regulator, and a catback exhaust system, i was able to go 13.44 at 102.51mph. this was done with 20psi in the rear tires, 6* base timing, fuel pressure set at 48 psi, and a excellent launch on street tires. i would really recommend you get exhaust first, as the factory system is very restrictive
Le Mans Master
Joined: Mar 2002
Posts: 5,300
Likes: 3
From: Mississauga, Ontario Corvettes were built to be driven...not trailered
St Jude Donor '07-'08-'09
Re: Initial mods for a stock 89 (Raskell5)
Underdrive pulley's always give you a good bang for your buck... :cheers:
Team Owner
Joined: Sep 2001
Posts: 62,099
Likes: 1,724
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Initial mods for a stock 89 (Raskell5)
I dont like the Underdrive pulleys, but you should definitely go with whatever 65Z01 sent you, he knows alot about L98s.
Drifting
Joined: Jul 2000
Posts: 1,661
Likes: 4
From: Phoenix, Arizona
Re: Initial mods for a stock 89 (Raskell5)
I think that Gordon Killebrew has done presentations (i.e., Carlisle) where he said the most performance increase for the buck on an L98 Corvette is to replace the front y-pipe with one that eliminates the precats. Subsequently, replacing the stock cat with a high flow cat should make a signfiicant additional improvement. Good luck.
Instructor
Joined: Apr 2002
Posts: 243
Likes: 0
From: Hockessin DE
Re: Initial mods for a stock 89 (NavyVet)
this mod is what i want to do next, but with all the bad reviews about the quality of the MAD front ypipe (they seem to be the only company that makes a replacement one without the precats), im hesitating to get one. i guess ill have to find a independant shop with the skill to custom make one
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Burning Brakes
Joined: Apr 2002
Posts: 755
Likes: 0
From: Patterson CA
Re: Initial mods for a stock 89 (NavyVet)
I think that Gordon Killebrew has done presentations (i.e., Carlisle) where he said the most performance increase for the buck on an L98 Corvette is to replace the front y-pipe with one that eliminates the precats. Subsequently, replacing the stock cat with a high flow cat should make a signfiicant additional improvement. Good luck.
Now I just gotta figure out how to fool the SMOG inspector :lol:
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Initial mods for a stock 89 (tpivette89)
tpivette89, if you're not too far from Trenton, NJ give Denny at Mufflex a call. He did all my exhaust mods, including the custom front Y-pipe, in about 3hrs for a great price.
Le Mans Master
Joined: Jul 2001
Posts: 8,182
Likes: 3
From: Santa Maria, CA
Re: Initial mods for a stock 89 (Raskell5)
all the free mods first.
Then I vote for allowing that L98 to breathe better. No need to sink lots of money into a fancy aftermarket exhaust set-up. A killer system can be fabbed up very affordably by a competent shop. The MAD catless front Y true dual system mentioned above IS a great kit and cheap to boot if doing your own work.
Also another vote for 6* on the timing.
maybe lighten the car a little; remove spare tire and jack.
IMHO, the AFPR can wait till ya get some serious mods. Not really necessary to add more fuel to an already rich running motor.
Then I vote for allowing that L98 to breathe better. No need to sink lots of money into a fancy aftermarket exhaust set-up. A killer system can be fabbed up very affordably by a competent shop. The MAD catless front Y true dual system mentioned above IS a great kit and cheap to boot if doing your own work.
Also another vote for 6* on the timing.
maybe lighten the car a little; remove spare tire and jack.
IMHO, the AFPR can wait till ya get some serious mods. Not really necessary to add more fuel to an already rich running motor.
