traction and tires

[robsbird]

:lol: :lol: 8) 8) discuss the tire that has worked best for you. I have a 68 roadrunner 542ci about 900 hp 4 link 3200 lb w/o driver 1.34 60 6.teens 1/8. but I don,t think my car hooks its best. I have 32/16/15 MT s/ wall med compound. have adjusted a million settings and nothing really changes much. The car does ok but I think something is not just right. Its a foot brake 5000 8" convertor. big lift and duration roller. rob

[BEAST477]

I don't think your times are too bad for 3400 lbs and foot braking.JMO

[robsbird]

:arrow:beast It seems like I have to much tire spin, it does ok I just think it should do better. occasionally It will whellie the front about 3 or 4 inch and I have about 11 inch (8 inch lift) I guess. maby of front suspension travel. I also footbrake and im thinking about going to a transbrake. I read that a 4 link works best by shocking the susp. but if changing tires would do it that would be better.

[Harbone]

get the transbrake and you will be more than happy! all that horsepower with that setup and you will get the results you want.

[chevynovaman]

IF YOUR FOOT BRAKING NOW AND SPINNING, TRANS-BRAKE IS GOING TO BE PUSHING WAY MORE RPMS THAN FOOT BRAKING.. MY CAR IS 485 HP 3000 LB NOVA AND RUNS 1.50'S 60' AND LOW 7.0 EIGHTHS. FOOT BRAKING.. IS IT A POSSIBILLITY THAT YOUR CONVERTER IS TO BIG AND YOUR THROWING ALL YOUR 900 HP AND TQ OUT THE WINDOW BECAUSE YOUR BYPASSING ALL YOUR TORQUE RANGE. YOU COULD TRY TO RUN A HIGHER GEAR RATIO TO USE MORE TORQUE.. THAT SHOULD RUN WAY FASTER THAN THAT... BEST OF LUCK ON YOUR TRACTION

[robsbird]

:D thanks harbone and nova , I bought this car rolling and built the motor I had the trans built useing tci trans parts, the last part I bought was the converter. I gave tci all the info, complete engine info, tire size gear ratio etc. and this is the convertor they suggested. but I might try another one. I read that a 4 link works best with a shocking like a clutch or trans brake. I'm going to try a heavier spring rate to get more rear suspension seperation. :idea:

[RM1]

robsbird,sounds like you should check the fash on your converter to see where it stalls at or go to a trans break.I race a 2600#monza w/driver with a mild 400+hp355,th350 with 4500 stall converter,4.56 rear 33-15-15 d5 goodyear@6#air,ladder bar set in the center hole.I leave at 3500 on a 2step my 60ft's are 1.430 and 1/8 6.86@ 98mph and 10.96 1/4@ 120mph RM1, check out my profile

[robsbird]

:? rm1 define flash; when I stage, the car will push the front tire at about 3000 rpm I use the brake 4 wh disc. shift at 6800. Icalled tci and gave them this same info and they said they could not improve on the converter. is flash the rpm that moves the car or ??. thanks rob

[chrisr]

To see what your converter will flash, don't push the rpm's until the car is trying to move. Stall at a lower rpm then when you leave see what the rpm's FLASH to. If you are footbraking to the point that the car is trying to push past the brakes then you are allready on the converter therefore it can not flash. Try starting out about 2000 or so and then leave and see what rpm you come up to. I hope I explained that good enough.

[us7race]

Do you have any starting line video?
That was we can see what is happening.
Transbrake launches usually help traction.

[dparker]

If you have a manuel valve body in your trans, you can put your car in 3rd or high gear and stall your converter usually you can hold your car to 90% of your total stall because of the gearing difference. The difference between the rpm you can stall in first gear and your total stall is what is considered your flash stall. As for a four link, I dont think they hit any harder than a ladder bar, they do give you more adjustment and mostly allow you to take out how hard your car hits. A footbrake car seems to transfer weight alittle slower so your car need to transfer weight easier than a transbrake car. Your car will probably leave better with a transbrake for that reason.JMO

[RM1]

robsbird,the other racers have explained it real good I would ad a couple things to help one is drive your car in the pits around 2000rpm in low gear and smash the gas and see where the tack goes before the car moves this is your flash,if staging to high you've loaded the chassie and with out some flash it wont transfer the wight.If go to a trans break you control the launch and rule of thum is you want be 1000 or 1500rpm less than or advertised setting.

[robsbird]

:shock: 8) ok , now what is the best way to use flash. and thanks rob

[RM1]

rob,start at a idle point around 1350 in grear just so the car rows a little w/no break,when you stage the car casses will not be loaded then bring the r's up to 18 to 2000rpm.Stage shallow just flicker the 2nd bulb this will give you that little exter room to launch.If you stay low on the idle it will take more gas to get to 1350rpm and it will loaded the casses.When see the last yellow mash the gas the flash should go to were the convertor stalls, and launchs the car with all the weight transfer. Your cam is big so it might not idle at 1350 so just play with it. RM1

[robsbird]

:lol: thanks rm1 ill try that next saturday on the 28 I can,t go this week I just traded for some fiberglass door and fenders. wan,t ot put those on this week and ill let you know what happens. rob