Drag Racing Tech - Hoosier QTP help
AL SS590 M6
04-27-2006, 08:28 AM
Hoosier QTPs help with setup PLEASE
Any of you guys that are running Hoosier Quick Time Pro DOT.
I just switched from 26-11.5x16 ET streets on factory rims to 27-11.5x15 QTPs on 15x8 Weld Pro Stars and boy are these tires different.
Went to the track last night for the first time with this combo and chased my butt all night. I started out with 15 psi cold and spun like I was on street tires. Dropped to 15 warm, a little better. Then 14 warm, a little better. At 13.5 warm it almost dead hooked but not quite.
Car is a heads/cam LS1 Formula at 3450 lbs with a big converter and 4.11 gears.
So here are my questions:
1. Is this pressure near normal for these tires?
2. How much lower can I safely go?
3. How much burnout do I need to get these sticky? I do my burnout in 2nd gear and it'll spin loose for about 2.5-3 seconds then the revs start to drag down, are they ready then? Or do I need to power thru that slight bog for a few more seconds?
I had the ET streets all figured out now I need some help from you guys with experience with this tire.
thanks in advance
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Slow Z28
04-27-2006, 11:55 AM
i'm doing about 6-7 second burnouts on a fall day(mid 60's)
i never have droppd the pressure lower than 17psi. my car with the full suspension and the QA1's, 382 All bore, TH350, will dead hook at that PSi. but it's just playing with the suspension at that point.
blkchevyz
04-27-2006, 12:09 PM
mine do there best around 10-12 psi
carrsls1_camaro
04-27-2006, 02:43 PM
First thing is I have ran those tires as low as 8psi hot and never had a problem but they will rotate on the rim a very little amount (maybe 1/4") but when you run the tire pressure low it can hurt your MPH on the top end. I would rather run 12-13 psi hot and make the susp. work than no susp. and 8-10 psi. What does your susp. consist of? I would think a TA and LCA would make a world of difference. As far as the burn out goes I try to start in first let it get a few R's up shift into second and as soon as it starts to bog the motor let off the brake/linelock and power into the throttle and let the tire hook itself coming out of the water box.
AL SS590 M6
04-28-2006, 12:05 AM
. What does your susp. consist of? I would think a TA and LCA would make a world of difference. As far as the burn out goes I try to start in first let it get a few R's up shift into second and as soon as it starts to bog the motor let off the brake/linelock and power into the throttle and let the tire hook itself coming out of the water box.
Spohn body mount rod end TA, Spohn double adjustable rod end LCAs with relocation brackets, QA 1 all around, QA 1 springs up front, air bag in right rear spring, 1" solid CM sway bar in rear, PA tubular K and A arms.
I've hooked to a 1.48 60' on 26" ET streets but I felt that I was going thru the traps a little to high in the rpm band so I went with these 27" Hoosiers. Just trying to figure them out. Sounds like the 12-13 hot will get me there.
carrsls1_camaro
04-28-2006, 07:31 AM
WOW that car is deffinetly suspened. I would try the lower air pressure and run with that for now and if it is still having traction issues then start to adjust pinion angle and preload on the right rear a little more.
AL SS590 M6
04-28-2006, 07:46 AM
WOW that car is deffinetly suspened. I would try the lower air pressure and run with that for now and if it is still having traction issues then start to adjust pinion angle and preload on the right rear a little more.
Yeah pinion angle is set at -2 and i'm at 7 rr and 6 lr with the QA1s with ~17psi in the air bag. Car leaves nice and straight.
carrsls1_camaro
04-28-2006, 07:50 AM
Yea if the air pressure thing doesn't do it I would look for a new track cause that one won't hook your car ever if that doesn't work.lol
Slow Z28
04-28-2006, 09:41 AM
Just for clarifying purposes for my car, I have pretty much the same setup with the rod end LCA's and PHR, Spohn long torque arm relocated off the tranny, and a wolfe rear sway bar.
At 17-18psi it'll dead hook mid 1.4's off a footbrake. I just need to get rid of this little hesitation on launch with some tuning.
i'm at -2* pinion angle. 2 on both front shocks, and 5 for both rears. With the wolfe sway bar, no need to set one side stiffer.
AL SS590 M6
04-28-2006, 11:18 AM
Just for clarifying purposes for my car, I have pretty much the same setup with the rod end LCA's and PHR, Spohn long torque arm relocated off the tranny, and a wolfe rear sway bar.
At 17-18psi it'll dead hook mid 1.4's off a footbrake. I just need to get rid of this little hesitation on launch with some tuning.
i'm at -2* pinion angle. 2 on both front shocks, and 5 for both rears. With the wolfe sway bar, no need to set one side stiffer.
What width wheels do you have?? 10"??
I have mine on 8" rims and after 2 passes at 17.5psi hot you could see that the tires were only hitting on the middle 5 or 6" and I blew them away like street radials.
After I dropped them to 15psi hot and made 2 more passes the outside and inside 1/2" still wasn't touching but the traction improved some.
At 14 psi they finally showed that they were contacting all the way across the tire but still didn't dead hook.
Maybe the 8" rims suck the sidewall in too much?? But that's the recommended rim for the tire according to Hoosiers web page.:confused:
If they'll work at 13psi then that's what I'll run.
Slow Z28
04-28-2006, 01:55 PM
i have 15x10 w/ 7.5" BS
So that could be part of it. Obviously the higher pressure you could keep 'em at without spinning is what you want them at. Plus they've been alot more stable at the top end compared to the 11-12psi ET drags i used to run
The Juggernaut
04-28-2006, 03:08 PM
I ran my QTP's at 11.0-11.5 hot. Dead hooked 7k clutch dumps cam only(400rwhp)
AL SS590 M6
04-30-2006, 08:22 AM
Thanks for all the help guys. I went to a club track rental yesterday and hooked from 1.53 to 1.63 with no track prep at 12.5 psi so on a race day we should be able to get it to hook.