tsbbzm

I would like to get my stock 91', L-98, 250HP, up to around 275 or 300HP.
What would be the easiest and cheapest modifications to the L-98 to get the most HP gains?
Thanks,

rocco16

Cam; most for the least.



Larry
code5coupe

__________
Often wrong, never in doubt....

SCCA VETTE

Nos!

comp

exhaust and chip ?

GIJoe

The stock HP should be 245rwhp I believe.

back when mine was bone stock, I had a K&N and gutted catand I dynoed it at 265rwhp. That's the one and only time it's ever been dynoed

I am sure I am pushing over 300HP now, and then over 400 with spray.

Nitrous = cheapest HP gains of any mod.
$1200 should get you setup with 150HP with the tap of a switch with all extra safety gear. $600ish gets you the base kit, but the extras are worth it (purge, bottle heater, gauges, etc)

Aardwolf

A cam is not that easy or cheap though. You should replace the lifters, witch cost a lot. Springs would be needed. That can be a can of worms.

Under drive pulleys (steel is pretty cheap)
NOS (there is a bunch of cost in this, then refilling the bottle to!)
No cats (free but putting a high flow back in is best)
Muffler elim (very low cost)
roller tip rockers 1.6 and springs (could come in under $100)

Umm, I don't know what else. Not that much is easy or cheap. Porting the intake is cheap but it's a lot of work.

BADDUCK

If you have a frisbee on the waterpump pulley toss it, 10 free HP.
Dual outlet Magnaflow OEM style mufflers $220 pair, 10 HP.
High flow Cat bolt on type with air tube $149, 5 HP
March aluminum under drive pulleys #4425 $136 5-8 HP.

Gain 30 CHP all bolt on $505 = $16.83 per CHP!

BADDUCK

Sorry

BADDUCK

Triple post

Shimy86

Are you a do it yourselfer or taking to a shop? do it yourself ...I'd say K&N filter, cut out filter lid, remove screens in MAF, replace stock mufflers with high flow and you should be about 275 for less than $400. Take it to a shop and the options open up dramatically but so will cost.

Nice looking car!!

silverja

Excellent suggestion ....

You can visit this link for some low cost ways to boost your C4's power:

http://corvettebuyers.com/c4vettes/performance.htm

I was lucky enough to inherit this information concerning many inexpensive modifications to boost C4 horsepower. Give them a look and best of luck.

DaleD

I'm not a racer or an expert, but here's my plans for my 87, (not all this year).

Magnaflow catback - on order, total job $600.
Cut air filter lid, K&N - not a lot of gain, but reusable filter is good. ~$30
LT1 intake modded for L98 - part is $200 or $400, depending on if you buy complete, or have yours modded.
Once exhaust and intake are done, get a good programmable chip, and have it custom programmed for my car. $200.

Last performance mod I want to do is a beefed up torque converter, 2400 stall maybe.

I figure that will get my 240hp L98 up to about 290hp. The tranny mod would help the seat dyno!

Once that is done, it will be all about looks for me. Like I said, I'm not a racer, I just like having a car that is capable.

Oh, and here's Vader's site. He gives his own experience with mods that do and don't work.
http://temp.corvetteforum.net/c4/vader86/

Aardwolf

Very dated info. on that site. The HP claim is laughable. Interesting reading though.

tsbbzm

What is this "frisbee" your talking about, do you mean replace waterpump pully?

BADDUCK

It is the damper which is bolted to the front of the waterpump pulley on later L98's. It is secured by 4 bolts. I took mine off and used washers when I put the bolts back in so the bolts wouldn't bottom out.

Aardwolf

Same here! That didn't take long at all.

Shimy86

my 86 dosent have one??

BADDUCK

Nope

Demonic85

that the L98 intake manifold absolutely sucks, but there are many different solutions and none of them are cheap.

I know a lot of people dont want to tear into the engine, but cylinder heads can make a lot more power as well. Of course its not cheap as it will generally cost anywhere from $1200 to over $2000 but they are an absolute must if your going for big power.

vader86

Cheap is relative.

My website has some overall strategies, but getting from 245-250chp to 300chp is not all that hard. The question is whether you can do some yourself, and what you want to live with in terms of noise. Verts dont resonate quite like coupes, but it could be too loud for you.

Exhaust is the best thing to start with. You can get 25-30rwhp from doing just a full exhaust (you make about ~210rwhp or so now). That could run about $1000 or so.

1.6RR's always are nice, 10-15hp or so, at around $250 for the parts.

Then the intake, which will have to be totally redone and not just one piece. Manifolds cost about $350-450 (depends greatly on who and where, but theyre all about the same) and runners are also pretty expensive. Port the plenum and you could see gains similar to what the exhaust would give you, at around the same prices though.