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which engine mods?

9

90coupe

Guest
Just did complete tuneup etc. on my newly purchased 90 Coupe. Looks and runs super, now for more power!! I read in my fuel injection manual that this is a speed density system rather than mass air which means the computer can't compensate for better breathing etc. Any one have any suggestions on what my best course of action on the L98 is? I thought about a valve grind/port job, exhaust system, and 1.6 roller rockers. What do I need to do to make these impact the power?

Ron
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
I think the first mod that people do is the K&N with the lid cut open.

Are you going to do headers? A lot of people also do the exhaust because for the money and ease of work, you really do hear results. When I put my Flowmaster catback system on, it really felt much better.

One of our members Rich just did the roller rockers, check out that thread. He wrote quite a good thread on the work but I don't think he's driven much since.

Good luck!
 
9

90coupe

Guest
engine mods

Thanks for the reply. I've heard that even something simple liking cutting open the front of the air filter housing (and giving the engine more air) can cause a lousy idle and since the speed density can't compensate it serves no benefit. I don't know. Anyone out there have any experience or expertise?

Thanks!!

90coupe
 
Joined
Jun 20, 2002
Messages
2,509
Location
Tallahassee, FL
Corvette
none right now :(
The car will still compensate for the extra air, it just doesn't do it as quickly as a car with MAF... Definitely cut open the air box lid... Roller rockers will help, exhaust for sure... Make sure you do your research before you make the mods though... Something like 1.6 rockers will increase HP, at the sacrifice of low end torque... If torque is what you like about your engine, make sure your mods are picked accordingly
 
L

LarryBible

Guest
Don't forget the airfoil, and underdrive pulley added to the other items. An aftermarket, honeycomb catalyitic converter flows much better than the original.

My '88 has never been opened up, but the mods add up. The car is quick. It has: K&N, underdrive pulley, airfoil, good wires, high flow cat and Dyno-Max mufflers. I have thought about the rockers, but I don't want roller tips, and I'm not sure if aluminum roller rockers will fit under the valve covers.

I expect that I will not do anything with the rockers until rebuild time, at which it will get a 3 3/4" stroke and a cam that will take advantage of the roller lifters.

Good luck,
 
S

sothpaw

Guest
coolant bypass first

I recommend this one for you first. It is dirt cheap (like 2 bucks if you do it yourself)
and it got me .2 s or so in the 1/4 mi.

I also have a speed density set up, so I can say for sure that the bypass worked well and
also opening up the airbox (I put on an SLP claw for maximum effect) helps. Roller rockers
also helped me, maybe .2-.3 s for them.

Exhaust will help you a lot, especially on the L98. That is my next move.
 

rdgfx3

Well-known member
Joined
Jul 25, 2001
Messages
202
Location
Rowlett,TX.
Corvette
2008 Silver Coupe
Could you go into detail about the coolant bypass?:confused

I have a 90 coupe and the speed density setup has discouraged me from making a lot of mods.It seems I wouldn't receive any benefit due to the speed density config.:cry

Lemme know if I'm wrong.:w
 

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