I just put on my new slicks and wheels, and went to the track today. My best ET prior to adding slicks was 12.2XX. Today (on the bottle, 150 shot) my best time was a 12.5XX. I was expecting about a low 11 with the spray and slicks. Bottle pressure was low due to temp, but not that low.(about 650-700), Teperature today was about 50 degrees, so I thought what a great oppertunity to lay down a good number.

The Car boggs off the line very very bad. The second half of the quarter it pulls like a freight train. but out of the hole it feels like I am towing a freight train!

On previous trips to the track I experienced tire spin and eventually the car would hook and go, today, I could barely do a burnout. (I have line lock so A burn out was possible) but just nailing the throttle there was nothing. Yes I did have the traction controll off, I tried in competitive mode and with out comp mode, no difference. The oil pres was good the temp was good, all the guages were right where they were supposed to be. The car seems to drive OK and acceleration from about 35 MPH seems to be unaffected.

I need help! I'd hate to have to go to the dealer. I wrench on all my cars myself, and now I have no idea where to look.

 

Auto or 6 speed?

 

I had that problem in my T/A... It was a problem with how HARD I was launching the car... On street tires I could launch at 3k rpm with no bog, but spinning... On DR's I had to launch at about 4k to avoid bog...

And that was on that crappy fbody 10 bolt, in an M6. :X!

 

Auto, I can't leave at any higher rpm. I have a stock converter, and I am hitting the stall of the converter now. It left harder in the past, I don't know why it is acting like this now??????????

 

well this is a dumb question but have you tried launching your auto like a manual and dropping it into 1. It almost sounds as if your launching from 2nd gear? If that is the case you might have either a torque converter issue or tranny issue or possible electrical connection going to either one. Iam no expert in transmissions on these cars. Hopefully someone will chime in. I just try to approach these things logically and with good common sense.

Good luck and keep us up to date on your find.
-X-

 

I've manualy shifted the car in the past (just for amusement), but first gear is first gear no matter where you put the shift lever. Starting from a stop it makes no difference.

Thanks, keep throwing ideas out. You never know when the right one will come up.

 

I should just be able to turn off the traction controll, mash the loud pedal, and smoke the hides and haul as.......Oops. (shouldn't say haul a**)

 

just sounds to me then, that 1 of 2 different things are happening.

1. You have a really really sticky tire that is hooking up nicely and causing you to feel like your bogging. (Check tire pressures and try adjusting to remove some of the squishiness in the tire) Low pressures obviously will hook you up better and cause less wheel spin but will also absorb a lot of your energy (causing somewhat a bogging feeling)
2. Just not enough power, you need more power if your going to stay with these new slicks you got. To roast them up the way you want, either your going to have to get a better torque converter, change the gearing to lower it, go 4:10's if draging the 1/4, or do something to the motor to generate more power. Or if you have the cash do all of these.

I would think that fooling with the tire pressures might help dial in the new slicks better, but feel your not probably going to get the results your looking for. But hey its free.

Going to a new torque converter will definitely help your launch and roasting the tires. I think this is your weak spot now. Sounds like you went to a new super sticky slick and your stock stall converter just aint cutting it anymore. Once you do get a new stall converter, adjust the shift points and hardness through either a programmer or a tuner, that too will help a lot.

The gears, I forget if you mentioned what your auto had, if its the 2:59's then there is no wonder why your bogging, but even if you have something in the 3:s range, a set of 4:10's for what your doing I have heard will make you feel like you have 100 extra HP.

Good Luck
-X-

 

Seems like your tires may be a bit too soft and your converter is too weak. Put more air in the tires to help dial them in better, and get a steeper stall converter. One more thing, how much power is your car making without the nitros? Maybe the slicks are killing your launch because your not making enough power down low to get them going without bogging too much. If you have a relatively stock engine, making minimal power, slicks will hurt you more than they help you.

 

Just a thought---with the DR's you are pulling so much harder off the line that the engine may be detonating--Do you have any way to check and see if you have any knock retard ??--If so it may be pulling out so much timing--especially with the spray-that it's bogging--

 

How can I check the timming? I know old school with a timming light, and I own an adjustable timming light. But there is no distributor to turn????

Oh well, I might run like crap, but i looked good doing it
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I honestly appreciate all the help here.

1. where can I buy gears/rear used for the best price?
2. What spec converter should I look for? I still want to street drive the car regularly so i dont want to sloppy of a converter, and the motor is basically stock (bolt ons) and bottle.
3. how to check spark timing retard?
I didn't even consider that as an option. The car seemed to drive fine. I could not hear any spark knock. Of course with the helmet on and loud exhaust in the next lane, it would be tough anyhow.

 

What axle ratio 2.73 or 3.15?? Someone mentioned 2.59, but this was never an option for the C5.. A 2.73 rear would possibly bog with slicks

 

Do you have any DTCs that are current??

BC

 

If you have stock gears you either have 2:73's or 3:15's.
A popular drag racing/street gear is 3:42's. with a 3600 stall convertor.

ECS has gears & can also install same day.

Did we ever meet at Cecil ?

Jay

 

I take it you have not had hardend outputs shafts installed in your differential. If not, eventually, you will not drive your car home from the strip.

 

If you have 2.73s with stock converter that is part of your problem.

Send me a PM with what you have done to your car and we can help with suggestions.

Bob

 

Lots of input here but the one that deserves the most focus is the one that points you toward something going on with the engine. If you were lighting up the wienies with street tires and running 12.2's, tire spin was costing you some E.T. Strapping on slicks should have meant running 12.2's at the worst. That you lost 3 tenths says something isn't making power. Are you on spray at the green or do you launch for 30 feet or so and then toggle it on? Someone that knows a lot about NOS jump in here and comment on optimum turn on point when using NOS.

If you're following conventional wisdom on hitting the spray, think back and see if there is anything else that changed or you are doing different.

And back up the thread was what I think was a suggestion to bring up rpm's in neutral and slam tranny into first gear. Two things argue against that.

1. Unless it has changed, NHRA rules (maybe all the sanctioning bodies) don't allow this, because
2. It's a good way to grenade the converter/tranny and dump lots of transmission fluid on the track.

On the other hand, it may be a way to get that high stall converter 'cuz neutral starts are going to eventually break something.

Charlie

 

"Neutral drops" is what you are refering to. That was fun with mom's car when we were 16 years old but not today. I think what he was refering to was just starting the launch in 1'st gear rather than drive.

Before the slicks, I was launching without the bottle, and flipping the arming swithch as I passed the tree. I am using a WOT (wide open throttle switch) so with the system armed when I hit WOT the nitrous sprays (with the fuel).

This weekend, when I launched, because i was using the slicks, I launched with the nitrous armed. So when the pedal hit the floor I was all in. I honestly expected to launch hard because without the slicks it spun. now adding the bottle I thought that would compensate for the slicks.

Like I said earlier, it pulls hard at the top, just not out of the hole.

Thanks again for all the suggestions

 

A rear end swap could get a little expensive. most of the 98 corvettes came with the 2.73 rear end. Im in the process of putting a 4000 stall on my 98. with the stock rear I would suggest nothing smaller than that if u are looking for the best results.