:yesnod: :yesnod:

 

with those mods, you should be at least 100mph, probably 102.

any exhaust shop can do a backpressure test to determine if any of the 3 cats are clogged. I had that done trying to find why I was down on power. My cats were fine.

check your base timing, it should be 6* BTDC. don't forget to unplug the tan wire by the firewall, it'll keep the computer from changing the timing on you. This was my problem. I had the car at the Pontiac dealership I used to work at and told them to set the timing. I went through days of crap, then decided to check it myself. It was set at 6* ATDC. Last time I took my car there.

when was the last time you did a tune up? You should change cap, rotor, wires, spark plugs. I also changed the module in the dist. I got an Accel part from AutoZone (or Advance, I can never remember)

You may also want to invest in scanning software. If you have a laptop, you'lll need a cable ~$90 and software, ~$FREE on up. I'm using the AKM cable and TTS Datamaster. I'm only just getting started using the scans, but it gives a wealth of information. Go to the C4 scan and tune section and read the FAQ. There is a good FAQ at thirdgen.org, too.

You'll also want to check your fuel pressure. I picked up a guage at the local autoparts store. Checked fuel pressure at idle then taped the guage to the window and went for a drive. You should probably change the fuel filter, if you haven't all ready.

You can also check for a bad fuel injector using a Volt/Ohm Meter. The resistance across all the injectors should be similar and somewhere around 17 or 16. (that's a guess from my poor memory)


[Modified by Raistlin, 5:31 PM 3/20/2003]

 

13.5 at 105.xx mph with a 2.09 60 foot. 1990 coupe,6 speed, street tires, true duals, no cats, shorty headers, muffler elims, afpr, free mods, cut lid with KN, accell base, air foil, air pump eliminator kit.

 

Mods in Sig.
11.4 motor only.
mid 10's "on the bottle" :steering:

 

Remove the pre converter.......the best and cheapest, You can do!

 

1st time for me...14.6 @ 95.2. and thats at 3300 ft :(

 

I first started with a cat back exhaust from Flowmaster, with a Walker Y-Pipe and Random Tech Cat as my first mod on my '86 Auto. Then I changed my rear gears from 2.59 to 3.73's. This was my first mistake though and I will be removing them at a later date. Waaaaaay too much gear!! :crazy: But hey they were free. :)
Next list of mods were K&N, 160 Stat, Open air lid, Air foil, SVO 24lb injectors, Accel 8.8mm wires, chip, walbro fuel pump, Ported Plenum, AS&M runners, Ported Base, Air Pump Eliminator kit & March Pulleys.

My track results were very poor because I found out my Throttle Body was not working properly and opening LESS than half way. :eek: I never made a pass with the TB fixed and could only run a best of 14.01 & 96 MPH. :( :cry

But since then I fixed this and bought a set of Lingenfelter Headers, a SLP Converter and a NX nitrous kit with all the saftey features! :cool: :cheers:
IT NEVER ENDS!! :lol: :cheers:

Good luck!

 

thanx for all the input guys!

It never ceases to amaze me how knowledgable everyone on this forum is.

I love you guys! :hurray:

I think my first step will be to have an exhaust shop do the backpressure test. Then I'll go replace the spark wires and fuel filter. There's a good chance those parts are 13 years old.

 

14.3 @ 95 Bone stock. Out of 28 roadtests from magazines that I have collected, the average for a Factory Stock L98 Corvette is 14.5 @ 95.
The Quickest was 13.90 and the slowest was 15.20.


[Modified by DarthD, 6:16 PM 3/21/2003]

 

I ran a 14.7 bone stock.

I called two exhaust shops, and both of them told me that there is no backpressure test.

Myabe I'll just take a broomhandle to the cat and see what happens.

 

With mods listed on this site ~> www.cardomain.com/id/timspeed
I've ran a 13.6@100 with a 1.85 60' on my regular 275/40 Potenza RE730's. When I was at the track last time, I had my timing up at like 8º BTDC. I'm gonna change it back to 6º BTDC and try it again, then maybe put it at 10º and see..I just am really looking to get a 13 flat out of this combo...

 

i watched the guy at Meineke do the pressure test on my car. It's pretty straight foward. they just stick a pressure sensor in the exhaust before and after the cats and measure the difference. Maybe the shops you called didn't have the equipment.

Checking the throttle body for full opening is a good idea. I was trying to figure out why I wasn't getting full TPS voltage on my scans. I replaced the TPS, and still no full voltage. I finally noticed the throttle gear was hitting a worm clamp :bb

 

Stock: 13.89 @ 98.17
Now: 12.89 @ 109.66 out of tune and <cringe> 2.2 60' times. Lots more to go! :cheers:

 

I may have found en explanation for my bad quarter mile times. Yesterday I got into the car to go to work, and the power brakes weren't working. So instead of going to work, I took it over to the dealership. After inspecting it, they told me the reason for the brakes' failure was that my intake manifolds were so clogged with carbon that the brakes weren't getting any air. I didnt even know the brakes were attached to the intake manifolds! Anyway, they cleaned out my TPI, and now the car's running smoother than ever. So maybe next time I go to the track my times will improve.

:) :chevy

 

stock i ran a 14.31@98.6MPH with a crappy 2.21 6o foot.

had i got the 60 down to 2.00, i would of been a 14.00 or so.

 

Your brake booster is connected to a vaccuum fitting on your intake manifold. If the became carbon polluted (I honestly can't really picture that) then your brakes would get no vaccuum assist.