hey guys. new guy on the block. great forum you have here. wondering if you can help me out. my wife has a '88 L98. low milage vette. she has run as quick as 13.99 (once) but averages 14.10 on street tires.( we once tryed slicks but they just bogged the motor. we are looking to put the car into the 13's consistantly. the car has the following mods.
monza mufflers
underdrive crank pulley
hypertech chip
airfoil
tpis air filter.

i would like to perform the following. what are your comments?
remove maf screen
remove water pump disc
replace monza mufflers with straight pipe
cut air box ( how do I do this?)
bypass t/b coolant hose.
Also what are your thoughts on removing just the rear cat. and has anyone tryed to redirect air from the rad tunnel to the air box.
Any advise would be much abliged.

 

Hey guy ,
Your car is already out performing the manufacturer's expectations by close to a whole second . The slight mods that you are planning are not going to do much if anything. Time to get serious now. Start thinking drive train mod upgrades, or bolt on and enternal engine mods if you want to get more out of it !

 

Hey ,thanks for the quick responce. Heres the deal though. My wife is going to race it this summer at the local street car drags. The class she is going to play in is run as a 13.90 index (any quicker and you loose) so i really dont want to pic up much, just a tenth or so. Anyone tried the TPIS air box?

 

Keep the monzas! They are practically straight pipe with a little glasspack. A free flow cat will help maybe do it. Without doing internal mods. Long tube headers will give you about 18-20 rwhp. That may get you lower than 13.9 though. If no headers, a small gain will be seen by cutting out the pre-cats and welding straight pipe in their place.

The frisbee, or as you call it "water pump disc" removal is worth 10chp. I say do it and see where that gets you.

 

65Z01 (a member here) has an excellent recipe for getting the L98 (I assume it is) to be a solid 13 second contender. Maybe he will pipe in soon..

 

Just toss the frisbee from the front of the water pump pulley for a 10chp gain.

If you need another 8chp gain install cut back spark plugs.

How much fuel was in the tank when you ran those times?? A gallon of fuel weighs about 6lbs and each 100lbs is worth 10chp gain. Also the spare & jack are worth around 40lbs.

Each 10chp gain is worth 1mph in trap speed and should be worth .1 sec off your ET.

With the above tips you should be able to trim as much time off your ET as needed. You currently want to chop .2sec off your ET so that amounts to adding 20chp, losing 200lbs of some combo of the two.

Depending on weather you may need some additional power adders. The simplest of which is coolant temp. You could run a 180 deg T-stat with manual fan switch. The engine would run at stock temps, based on when the fan came on. When you needed a little boost you could bring on the fans and the heater to gain maybe 10chp, on demand.

Dropping into the 13.9s isn't going to be a problem. The real issue will be to ride the rail right on the edge of the index. Here you can use weight of fuel, coolant temp and even base timing to tweak power up/down depending on weather conditions.

I suggest you first toss the frisbee to get your best times solidly into the 13.9s and let her practice enough (with 1/2 tank of fuel) to get consistent runs. Then you will see how much power/weight you need to add/subtract.

 

a full second? what are u smoking?

 

what he said......

 

Thanx guys. What about the air box mods? Yes,no, maybe? And if yes, do you just cut the lid open around the vent openings.I've also thought about the spare and fuel.Would they not help out a street tire car (ballast).
Im not worried about being a little quick, I can always slow it down. I race an IHRA Super Rod car so we are very familiar with this type of racing, just never played with a TPI car. Great input guys. Thanx

 

The numbers he's running are right on for a stock car.

 

Listen to 65 Z01.

 

yes i know, i was commenting on the other post. i ran 14.2 stock, so i know.

 

well close enough, stock l 98 according to road and track for 1988 , says the car will only do a 14.7 I'm reading it right now, . . . .and i'm smoking my tires!

 

Are you running osca at TMP?.

 

I have an '89 six speed (engine specs are identical between 88 and 89). Way back when, I had a combination almost identical to what you are proposing. The only differences were that I have 1.6 rockers and I still had the frisbee and the TB coolant line installed -- probably about an even trade off.

In this trim, my car ran a best of 13.76@99.9 with a full tank of gas plus the spare. Sounds like this will put you right where you want to be.

 

Drag radials will do it with ease and you will be dead consistent. More power on street tires will make the ET minimum you are looking for, but you will also be erratic at 13.90 (over and under). Consistency is the name of the bracket game.

 

hey Red Rage we sure are? Are you familiar with the OSCA? I won the 10.90 class two years in a row with my old car.
Thanks for the info guys, but still curious as to the air box mods. Thought about drag radials just dont have any extra cash right now. It cost me about 10K a season to race my car so kind strapped for cash. the car is actually really consistant with the stock tires.

 

You can open the air filter lid by just cutting around the perimiter, leaving enough lip to hold the filter in place. This combined with a K&N filter should be worth 5-10chp....and if you are clever you could even build restrictor plates for the filter box to tweak power!

Don't worry about tossing weight hurting your hook on street tires. Remember that any added mass must be accelerated so that a slight reduction in traction is offset by having less inertia. Weight acts through the CG of the car so all added weight must be accelerated but only about 1/2 of the added weight acts on the rear wheels. Use weight transfer, correct inflation and good rubber to assure reliable hook, not weight.

If you stay in the 13.9s you should have no problem hooking up at the strip. Proper inflation, a little dry burnout and lining up in the tracks of slick tire cars will do fine. Never rely on balast for hook, balast just slows you down.

 

Yes, I ran 3 events last year in 12.90(got slaughtered by sloot) time is running out, I still have to try my slightly new combo to see if I'm going 11.90 or open comp. 13.90 would have been great to have 2 years ago. I was fairly consistant at 13.9x considering I was a track newbie(still am) running a six speed.

 

that sloot is quite a lad isnt he ! i had the blue vega wagon last year. this year i bought ou my bros share of our red flamed vega ( 8.90 ). stop bye and say hi.
mark