Haven't drag raced too many times so have a question that I hope you all can help me out with.

Car is a 1990 C4 w/383 - est HP 450. Was at the drag strip Tuesday night in WI. RT was 2.032 - 1/8" mile 8.438 @ 86.22 and 1/4" mile time was 12.92 @ 112.55

Have 700R4 transmission with shift kit and 3200 stall torque converter. 3.73 gears. Nitto drag radials @22#'s.

Tires seemed to spin quit a bit - (didn't brake torque) - just gave it gas when light turned green.

Any suggestions on getting a lower 60' Time? - Thanks for any info

 

Nitto DRs need to be hotter than BFG .. when you do your burn out make sure you see white smoke.. (about 5 sec of spin) I think you are correct in NOT leaving at a higher RPM... try heating the tires more & lowering the air pressure to 18 lb

 

Thanks for the info - is 112 mph through the traps consistent with a 12.9 et or if I can hook better what type of et would be possible?

 

Try dropping your tire pressure 1 lb. at a time till you hook...you want as much pressure as possible and still hook...I run Nitto's as well and Nitto told me I could go down to 16 lbs. if I had to but no lower...I've never had to drop below 20 lbs. yet to hook...the good burnout is key with these DR's as JP said...

One thing you did not mention is which type of differential you have...I hope you have a D44 not a D36.. ...mph is an indication of the hp you are making...ET is a function of how well you put that power to the track...I have seen folks run high 12's at 105 mph...the key to lower ET's is your short time (60')...get that in the low 1.90's or 1.80's and watch your ET drop like crazy...remember, if you trap 112 @ 12.9 you will still trap 112, or darn close to it, no matter how much lower your ET is...

p.s. I just saw a post in another thread where a guy went 12.2 @ 112 mph...he had a 1.71 short time...

 

i ran my nittos at anywhere from 12-16 lbs depending on heat......a quick burnout and they hooked up great......you should see a dramatic improvement

 

I saw a box-stock ZZ502-equipped '76 run 12.03 @ 112 a few years ago (open-headers, 10" converter, THM400, 3.90s and 29" x 11" slicks ):
the more gear, converter, and traction you can throw at it, it'll 60' and ET better, with little difference in MPH, as the Funkmaster said earlier.

 

I had an old Chevelle that ran low 12.20s @ 111 mph. Our hp/lb is close (air conditioned DD, much heavier) based on the mph, but apparently my chassis and traction were better. I looks like you have a good 7 tenths you can gain in the ET without lifting the hood.

RACE ON!!!

 

Thanks for all the replys - Fuzzy Dice - Unfortunately I have a Dana 36 My brother-in-law also has a C4 - bought it with a 383 and was running low 12's hi 11's - he just added a procharger (changed heads, pistons, cam, etc) - and added Hoosier slicks - he also has a Dana 36 - hope mine lasts longer than his.

Happy 4th of July to all

 

procharger, slicks - who wants the odds on how short the life of the Dana 36's will be?

 

112 MPH is good for elevens if the car is geared properly and the suspension is setup right. In a vette, mid to low twelves is more realistic. Good luck, James

 

Happy 4th right back at ya!...best of luck with the diff...the better you hook the quicker you'll be swapping in a D44...I turned the spider gears in my D36 into chicklets with one good hook on street tires and that was with only 278 rwhp...your brother in law has no chance with his D36...

 

Once again - thanks for the replys - Mean LX - Any suggstions for suspension improvements? - Suspension is stock. Does the 3200 stall torque converter seem appropriate with 3:73 gears and 700R4 trans?

Race On -

 

In order to maximize your ET's you have to leave the line as hard as possible. 3.73 gears are not going to maximize you ET. You have to have a gear that puts you in the top of third gear (for an auto) through the traps. With 27" tires and a redline of 6400 RPM's you would want 4.56 gears. (just an example for 112 MPH trap speeds)
You also need to have maximum weight transfer to shock the rear tires that hard. You would want to put the battery in the rear, get adjustable shocks (QA1) and springs designed for drag racing. Your stall would also have to increase. If this is a track only car, these things aren't a problem. If it sees street duty often, and you don't want to compromise the cornering capabilites of the car, you will never see the true potential, ET wise, which corresponds to the power your car is making. Removing as much weight from the front end also aids in weight transfer.
In my mustang, I really didn't care about how quick it went around corners. So, I removed the front sway bar. It allows the front suspension to flex while removing 15-20 pounds off the front of the car. Skinnies up front can be worth as much as two tenths from less rolling resistance and less unsprung weight; also aiding in weight transfer.
I don't have much experince with the C-5's but, hopefully, once I get out of school will begin whittling away at my ET's. I guess it all depends on what you want out of your car. Good luck, James

 

Once again - Thanks for the info - Since this is mainly a street car, it sounds like some of the mods would take it out of this category.

Next time I go to the track, I'll try and lower the pressure in the tires, and try to get some weight off the car.

Everyone have a safe and happy 4th of July -