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

 

The psi sounds about right, as well as the burnout. If the tires were brand new then that may explain the slight spinning you had. Once there heat cycled they will be better, also track prep may be some of the problem.

Randy

 

A lot of hitters use QTP tires. I like the 27" diameter with my combo.

 

Ive run mine as low as 10 but that ws a really bad track... I have always found a little longer burn out helps when the tire is new. Hold that burn out about 2-3 sec longer and it may help. After about 2-3 trips to the track they will hook much better.

You can go lower on pressure if you have tubes and screws. If not then I wouldnt go any lower than that 13-14 psi range.

 

Brian, per my Hoosier rep no tubes. I know what the tires say but they run better with no tubes. I ran tubes last season but never again. Just adds weight and harder to fix if you run over something and get a flat. The tires do hold air from week to week without the tubes.

 

really? hmmm, I'll have to try my next set without tubes. I'm not breaking them down just to take em out

 

Yep I'm tubeless as per the Hoosier web page.

Thanks for the words guys. And yes this was the first outing for these tires.

 

Well, in the past 4 yrs the car has never had anything but slicks mounted track or street, off the top of my head 1 set of 28x10 hoosier full slicks, 2 sets of M/T 29.5x9 full slicks with tubes (never run tubes again PITA and slows ya down since they're sooo heavy) and Hoosier QTP 26x11.5" 3 sets, 27x11.5" 3 sets, and 13 sets of the 28x11.5'. Since we're talking a larger tire 27"+ I will focus on what I've found out.

When I was foot braking and weighed 3420lbs I found optimium psi on a 7" rim to be 13-14psi. The QTP's do require a longer burnout due to the medium compound they use to wrok effectively...alot more than the M/T full slicks liked, but funny enough I got more passes out of my Hoosiers than the M/T with the shorter burnouts. ANY new set of stickies I found takes at least 3-4 good burnouts and full passes before they "break in" and start running real consistant. I always took care of break in by just flogging it on the street so that was never a problem except a few times in a rush to get to the track. ALSO, do not expect great consistant traction at a T&T event, very few if any tracks put too much time/energy/materials into track prep due to number of typical street cars that show up and destroy the starting line anyways with all the sand and dirt they drag up. Traction/Test and Tune typically do not go together in the same sentence at any track I've ever run.

Once I changed the entire drivetrain and added weight to the car due to beefier parts, to stay on the green side of the light I had to run 10psi and have been running 10 psi ever since. I'm sure it would pick up some ET by going back up in psi if the tires would hold the track since your not losing time due to tires wadding up, but I dont care about fast ET...just consistant ET.

FWIW I had one race weekend that my lights were garbage at a new track, could'nt figure it out. Got home and found my tire guage had become miscalibrated by 3psi so all day I was running at 7psi. Still got the win for the day and car handled just fine at the big end, but lights were terrible. Also need to add these tires have never had tubes in them ever, and I do have the rim screws installed since even with bead glue I was rotating the tires approx 1" per pass.

So for all practical purposes you can run'em down to 7psi safely from experience, but you need to adjust pressure to what the car and the driver wants/needs. On the S-10 which also uses Hoosier QTP but 31x16.5's I ran them tubless at 5psi when we were having troubles, but have since bumped them upto 8psi. The lower the psi the more squirrely it gets on the big end.

 

IHI thanks for the input.

 

I just made the switch from 26" QTP to the 27's. I ran 14 PSI this weekend and hooked as consistantly as an M6 car will hook. I had run my 26" ers down to 10 PSI without problems. I have to run tubes because I use rim screws. The M6 hits so hard that it will spin the tire about 2" on the rim every launch without screws. I hate the tubes and screws but you gotta do what you gotta do.

Steve

 

I notice yesterday that at 12.5 psi I turned them about 3/4-1" total on 7 passes.

 

Depending on how heavy your car is, the only thing I can see "making" you run tubes is the fact your a stick car and a small tire so you probably are benefitting from the extra layer of rubber/stiffness the tube is providing. But make no mistake-tubes are definately an option and not required even with rims screws if you dont drill through the bead of the tire LOL.

Has'nt ever been a tube installed inside any of my Hoosiers ever and never will be, slows ya down and PITA trying to balance. Rims have been screwed for years to prevent rim spinning. Driven on the hwy and raced on the weekends, never a problem with anything-not even losing air.

 

I ran my 28x11.5-15 QTP's with rim screws and without tubes - no problem.

 

You laugh at drilling through the beads but I run Centerline rims and the standard Moroso Rim Screws are too long and go clear through the bead of QTP's and it really makes a mess of things. Like I said I hate tubes and screws I guess the rim thickness on my centerlines is thinner than most rims

Steve

 

I dont know if I'll be able to go back to no tubes. The rim has been modified to take the tube. I dont think I can get a valve stem in it anymore. I might be stuck with tubes for now. But I do plan on going to a full slick in the near future.