Max boost launch on MT DR 275/60/15 ?

[Drewster]

Can any one do high boost launches on MT DRs? Whats the secret?
I can make 12psi boost on the foot brake but the MT DRs 275/60/15 cant hold it and get blown away. They seem to stick at about 7-8 psi launch max.
18-20 psi in tire gets same result.
Am I asking too much of a DR?
Times and other info is in my Signature

 

[Rafs-T-Type]

What kind of PSI you running? Have you tried adjusting that? How was the track prep? Was it a TNT where everyone was blowing there tires off, or were others making good short times?

 

[Drewster]

It was a TnT during a Bracket race event. Lots of cars with slicks. Both me and another TR driver with MT DRs was only able to launch with 7-8psi boost. But that’s was about it. Similar for other nights.
He runs mid 6s, and I high 6s in the 1/8.
The slick cars had no problem.


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[Mr.Spool]

The slick cars had no problem.

the radials cars cannot be shocked like a slick.high boost launches arent going to happen on a 255 radial

 

[Mr.Spool]

Am I asking too much of a DR?

its the way your asking

 

[Drewster]

no matter how I asked, wouldn't stick much over 5psi. Will try MT Pros next round

 

[Mr.Spool]

no matter how I asked, wouldn't stick much over 5psi. Will try MT Pros next round

It's the sidewall and how your applying the power.

 

[Pronto]

I would remove the air bags with the HR bar.

 

[GnJoe87]

This video is somewhat helpful if you want to learn what a drag radial setup needs to perform.

 

[Drewster]

Thank You!

 

[Drewster]

I tried with no air bag pressure but had some rubbing on a hard hit, so running 5psi at the moment

 

[Pronto]

255 shouldn't rub anywhere with the right wheel offset. I had them on stock t rims with plenty of room.

 

[Jerryl]

I have had great experience with the instant center adjustment from H&R. On a well prepped track and 255's, the car launched 10-12 psi, no spinning.
Should be better now that the exhaust leaks are fixed and the converter is right.

HR rear suspension setup

Just wondering, what is the best way to set up a rear suspension. I have an HR anti-roll bar, adjustable upper, and 1/4 degree lowers. Car does not hook up on DR'S. Should I be adjusting the bar? It's at the base adjustment. Would love to use my trans brake. BTW Installing comp adjustable front...

turbobuick.com

 

[Chuck Leeper]

Monroe shocks are not what I'd use to dial in the suspension.
I'd look at a double adjustable shock for all 4 corners.

 

[ITSAV6]

Local guy to me does 1.4x on MT 275/60 off trans brake at 10-12# He has the weld on rear bar and pulls both front tires about knee high I thing he has 90/10 and 50/50 shocks. I can do mid 1.6 on 255's launching @2800@0# with ATR rear bar and IROC front bar and stock shocks.

 

[bison]

My test car runs high 1.4’s on the street with 120lbs of ballast with the 275 pro. If you can’t get this tire to work on a prepped surface something is seriously wrong. Rpm and ramp are what matters. It will usually take most of it by 1.2 seconds on the street. Launch usually 3-4psi. Rpm 3600-3700ish.


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[Chuck Leeper]

and IROC front bar and stock shocks.

Have you tried a pass with the ft bar unhooked?

 

[Jerryl]

If any of you watch Street Outlaws, I would like to encourage some thoughts;

-Same size tires (10.5' tires)
-Often lighter cars that what we have
-Much more power overall (1800-3200 peak?)
-Still hooking hard on a unprepped surface with 2 water burn-outs
-Let's ask ourselves how?

So, IMHO;
-It's likely not the tire size that is the problem
-Nor the power we are trying to put down
-But the combination of everything.

 

[bison]

If any of you watch Street Outlaws, I would like to encourage some thoughts;

-Same size tires (10.5' tires)
-Often lighter cars that what we have
-Much more power overall (1800-3200 peak?)
-Still hooking hard on a unprepped surface with 2 water burn-outs
-Let's ask ourselves how?

So, IMHO;
-It's likely not the tire size that is the problem
-Nor the power we are trying to put down
-But the combination of everything.

Those cars are scaled way back in power and the cars are ballasted. Most have big tires too. Small tire is a death sentence for that kind of racing.


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[Jerryl]

Those cars are scaled way back in power and the cars are ballasted. Most have big tires too. Small tire is a death sentence for that kind of racing.


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Agree.
On last night's episode, there were running on small tires (10.5×29) and still hooking enough to pull the front wheels though. So they are likely launching with decent power. Weight placement makes a big difference, but JJ also briefly mentioned Instant center on one episode. Those guys have it down to a science!