NEW guy-L98
Burning Brakes
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
Assuming that it's "all original"..with 114K on the thing the First place to point the wrenches is the heads. The valve job is shot, the springs are tired and the guides worn out. Start there or anything else you do to it will be compromised by the valve/head problems.
In Fl. I'll wager that the trans has already had a rebuild - at Least one. Assuming an automatic here... The Dana 36 rear is going to be worn pretty badly also - it'll be not just Gears but a complete diff rebuild. A taller ratio will help though - and will also push the rpm's up/gas mileage down on the highway.
The L-98 is a low rpm torquer - the party is over at about 4500 (it ain't no Ford motor..). Be careful with Too much gear in it, you Want to hold the tach down where the good torque numbers are.
Drive it for awhile before tearing into it - Then decide what it "needs" to make you happy. Like has already been said - you'll probably be busy enough fixing Other stuff anyhow
In Fl. I'll wager that the trans has already had a rebuild - at Least one. Assuming an automatic here... The Dana 36 rear is going to be worn pretty badly also - it'll be not just Gears but a complete diff rebuild. A taller ratio will help though - and will also push the rpm's up/gas mileage down on the highway.
The L-98 is a low rpm torquer - the party is over at about 4500 (it ain't no Ford motor..). Be careful with Too much gear in it, you Want to hold the tach down where the good torque numbers are.
Drive it for awhile before tearing into it - Then decide what it "needs" to make you happy. Like has already been said - you'll probably be busy enough fixing Other stuff anyhow
Burning Brakes
Joined: Oct 2004
Posts: 898
Likes: 1
From: Pearland Texas
You need to save your money for now, alot of problems will creep up for the car soon.
Give it 6 months before you start doing anything, at least. You need to get to know the car and figure out what you like and dislike about it.
Best money you can spend right now is on a Helm Shop Manual, helminc.com.
Give it 6 months before you start doing anything, at least. You need to get to know the car and figure out what you like and dislike about it.
Best money you can spend right now is on a Helm Shop Manual, helminc.com.
It's your money, my car had 16K on it when I got it and I've had it for 5 years and I'm always fixing something minor, it never ends !
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Try a good tune-up first....
First thing you should consider is completing a comprehensive tune-up. I have attached a WORD file with the specifications for a complete L98 tune-up. Once you have completed all the tasks on the tune-up spec sheet, you can proceed with desired modifications.
Here are the results you can expect on a stock L98 from various engine modifications. This information is from VADER's website which has a lot of pretty good stuff on it:
Corvette L98 Modifications & Expected Results:
(Track Times from a 1989 L98 car)
Bone Stock -> 13.87@98.60 MPH (60 degs , 2.0 60')
With Crank Pulley -> 13.74@99.56 MPH (60 degs , 2.0 60')
With drag radial tires, TB Bypass , K&N , Air Foil , Cut Lid
-> 13.34@102.20 MPH (40 degs,1.85 60' )
With Air Pump Elimination , 12" GM Convertor , Ported MAF ,160 stat
-> 13.16@102.04 (65 degs , 1.76 60')
With TPIS catback ->12.85 @104.90 (45 degs , 1.74 60')
With Accel lower Manifold ->12.96 @105.18 (45 degs, 1.79 60')
With AS&M runners ->12.81 @107.09 (65 degs, 1.73 60')
With Hooker headers he made 271rwhp and 345rwtq.
Good luck! AND Welcome to the Forum
Here are the results you can expect on a stock L98 from various engine modifications. This information is from VADER's website which has a lot of pretty good stuff on it:
Corvette L98 Modifications & Expected Results:
(Track Times from a 1989 L98 car)
Bone Stock -> 13.87@98.60 MPH (60 degs , 2.0 60')
With Crank Pulley -> 13.74@99.56 MPH (60 degs , 2.0 60')
With drag radial tires, TB Bypass , K&N , Air Foil , Cut Lid
-> 13.34@102.20 MPH (40 degs,1.85 60' )
With Air Pump Elimination , 12" GM Convertor , Ported MAF ,160 stat
-> 13.16@102.04 (65 degs , 1.76 60')
With TPIS catback ->12.85 @104.90 (45 degs , 1.74 60')
With Accel lower Manifold ->12.96 @105.18 (45 degs, 1.79 60')
With AS&M runners ->12.81 @107.09 (65 degs, 1.73 60')
With Hooker headers he made 271rwhp and 345rwtq.
Good luck! AND Welcome to the Forum
Advanced
Joined: Dec 2006
Posts: 97
Likes: 0
From: PA
have to agree with waiting a few months to see what problems come up and address them there. Anyway, go with headers first before you do anything if this isn't included with GIJoes exhaust.
only do gears if it's an auto. Gears on the 4 speed are pointless due to the low peak hp on the tpi.
only do gears if it's an auto. Gears on the 4 speed are pointless due to the low peak hp on the tpi.
Racer
Joined: Mar 2007
Posts: 306
Likes: 0
From: New Hampshire
Everyone states the same, Pitch the airfoil but if you look at the throttle body in a reasonable manner you will see the stock body has a flat area around the ports. The air foil removes the restriction causing air flow to enter the throttle body with less restriction.
Years ago, people took out the chock plate for better flow for the same reason. I say, for the price, get the air foil. Yes, I did buy one and although I don't have a dyno, I think it does help.
Years ago, people took out the chock plate for better flow for the same reason. I say, for the price, get the air foil. Yes, I did buy one and although I don't have a dyno, I think it does help.
