I have a 91 camaro Z-28 with the L98 in it. I have had it for a while and finaly took it to the track with some budys. After being on here for a while I was hoping to run like a 14.7. I havent done much but a air foil and removed the cats and put a three inch flowmaster exhaust on it. When I ran it I only ran a best of 15.2 with more constant runs in the 15.3's. Any ideas of why my car is so slow. It has 3.23 rear gears and I just put in a new 700r4 before I went to the track with billit servos. Could it be my injectors not flowing good enough or maybe my fuel pump. Thanks for any help.

 

Could be 100 different things. Post your timeslip and maybe we can help more. What was your mph, 60' time?

 

Ok here are a couple of my better ones.
60 foot time 2.154
1/8 mile 9.774 @70.31mph
1000 foot 12.796
1/4 mile 15.339@89.26

this was my best
60 2.109
1/8 9.724@70.32
1000 12.746
1/4 15.293@88.51

hope this helps

 

I would suspect tuning issues, when was the last time the plugs, plug wires, cap, rotor, and coil were changed? What is the timing set at? Fuel pressure ever been checked? Stuff like this can have a big impact. Your 60 foot isn't great but isn't too bad for street tires, so it looks like you're down on power and it wasn't driving/launch related. What RPM is your new tranny shifting at, if it's too high it will show you down? Start with the basics and get it in perfect tune, and then go from there. It's definitely too slow for a good running L98 car at a decent track.

It could also be the track actually. What track was this, what is the altitude there, what was the weather like etc? It's hard to compare times to those you see on the net since different conditions/tracks can make a HUGE difference... Race at a higher altitude track and then race at a sea level one and you can see a 1-2 second difference in times... I'm not up on Illinois, so I don't know what you're looking at for tracks/altitude there, maybe someone else can speak to the average times at this particular track... Or perhaps you know of some of the times for some of the other stock cars running there, were they also unusually slow as well?

And just to eliminate it since you mention going with friends, you were alone in the car during the runs right?

 

Since you are in DeKalb, I am guessing you ran at Byron.

I would second the tuning. Check the cap,rotor, timing,plugs and wires.

How many miles on the car? When was the last time the throttle body was cleaned and the TPS and IAC adjusted?

Maybe the TV cable is out of adjustment causing the trans to shift late or without enough pressure.

 

most certainly check timing, fuel pressure, etc. but a question, did you run it warmed up (i often see guys running them in the staging lanes, must be to slow them down).

 

Yeah i ran it at byron and i was alone it the car. The car had about 104,000 miles when i ran it. I did plugs bosch platnums and wires msd 8.5, and a fuel filter about 12,000 miles ago and I put a new distributer in about 5,000 miles ago along with a new cap and rotor. I have never checked the fuel pressure. My trans shifts at about 5 grand from first and about 5100 from second to third. There was only one other thirdgen runing when I was there and he had a 91 Z 5speed with a 305 and he was running high 14's. I've never adjusted the IAC and some one told me the speed desity cars had TPS the adjusted them selfs every time you start the car. Im not sure what altitude im at, im up by chicago if that helps. I've never done a fuel injection cleaning on it but was thinking of trying that. Thanks for your help this board is amazing. Any more insight would be really great.

 

Oohhh yeah I also had the car shut off in the staging lanes and i have a 170 degree thermostat and a hypertech fan switch in it.

 

Oohhh yeah I also had the car shut off in the staging lanes and i have a 170 degree thermostat and a hypertech fan switch in it.

 

Hmmmm....your 60ft times are not all that bad. It should still run in the, though.

I would try running some Redline fuel system cleaner through. You can get it at Pep Boys for $5.00.

I would double check the timing and try it at 10 degrees to see how the car likes that. I would also let the car cool down for at least an hour with a bag of ice on the plenum.

Try taking out your spare tire and jack, plus any other stuff that doesn't need to be in the car. Run with only a half tank of fuel.

My friend down in Florida had a '92 Z28 L98 and it ran a 14.66@98 with only a flowmaster muffler, K&N's, and an airfoil. I'm sure with some more practice with the car and the fact that I busted the trans mount didn't help. It probably would have gone 14.40's.

I live only an hour from you. If you want to ever swing by, I will be happy to take a look at the car for you. I can also do porting of your plenum for a small fee too.

Also check out: ww.mfba.org (The Midwest F-Body Association)

 

Hey Formula8 thanks for the tips. I just got my car out from hybernation from the winter and have a few more modes i've done over the winter. But I would'nt mind maybe driving to were u live so u could see what my cars like. But the real reason I would like to come there is to check out your car and meet another thirdgen'er. I dont really know any thirdgen guys around here and your car seems pretty decked out. I already knocked the walls in front of the egr holes in the upper plenum out this winter. I got k&n air filters and made the home made ram air out of the fog light openings. I also put 4.10 gears in and got a performance resorce chip and put that in. These are my winter modes so I dont know what it will run know I have to wait till byron opens on the 5th of april to see. Im getting ready to do a pressureised fuel injection cleaning on it in the next week because of the advice i've got from this post and check the fuel pressure. Do any of u think I should change the plugs again they probly have 15,000 miles on them. Thanks again for all the help from this board, you guys are great.

 

I think I may have found your problem: 4.10 gears.

That is a pretty tall gear for a 700R4/L98 car. First rear in the 700R4 is really tall. Your car is using up all the torque running through the first 2 gears. It runs out of steam by the 3rd gear, therefore hurting your E/T's.

You might want to go down to a 3.45 ratio. You can find 10bolt rears really cheap ready to bolt in and sell yours to make up the difference.

Hey, swing by anytime!! I am always here! My car should be running in the next few weeks. Just waiting on someback ordred parts to arrive from Summit.

 

it looks like them numbers were done with a 3.23 gear. a 4.10 gear in an L98 still isn't that bad as it's only going to cross around 5k or less which is his shift point area.

 

4.10s are wayyyyyyyyy to steep for a tuned port car, 3.27s are really good, 3.45s with an auto are pushin it unless u have some mods that increase the power band to like 5500

 

The numbers from my time slips are are with the 3.23 gears in it. The modes I listed were all done over the winter and dont have any time slips from them. I will have some new time slips with the modes I listed on the the 5th of april. I post them once I get them.

 

4.10 gear is never too steep for any n/a engine. remember it's not revving it hard, it's just making use of all 3 gears not using first, second and just into third. even with the 4.10's he's not likely to see over 5k in third through the traps.

 

Why did you add more 'mods' to a car that you already knew wasn't running right. 89mph for a SD L98 is WAY off what it shoudl be running.

Now what is the problem with it. I dunno, it's not my car. Just wanted to point out you're always better off getting what you have working right before you add more on top of it.

 

I did the mods over the winter before I was a member of this board or even knew about this board. I didnt know that my car was slow for a SD L98. All I knew was my car was slow. Once I got on this board and started looking around I noticed that my car was slow compared to other ones on this boarded. I dont know anyone else with a thirdgen so I had no one to compare my car with before this board. So now that i've done what i've done I cant go back and take every thing off. Im just looking for some place to start looking for a problem. My car runs great dosent miss or hesitate. I was driveing it 175 mile round trips last year when it was my daily driver with the 3.23's and it got 20 MPG so I didnt think there was any thing wrong with it.

 

Your problem could be as simple as a little knock retard or dirty injectors. Could be as bad as a slipping tranny eating an undue amount of power. Or partially clogged cats. Or if that was your only time at the track, maybe even a strong headwind or a low pressure zone.

Hard to diagnose a problem like "why is my car slow" over the net. From where we are, it could be anything. hell, you say you put a dizzy in it last year, did you set the timing right? Etc. Could be anything.