Goin' to the track......need some opinions

Cobra912

Active Member

May 1, 2005

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Jun 24, 2009

#1

• Jun 24, 2009

• #1

Need some advice. I ran my car last year two times at the local 1/4 mile.

I ran a 12.87 @ 111 on street tires with my 331. Second time out I ran a 12.24 @ 113 on a set of older goodyear slicks on 10 holes.

What I was wondering was this................what would you recommend for psi in the slicks? I ran 14-15 last year which seemed to hook up great but I had what I thought was quite a bit of shimmy at 113 mph. I was a little worried. They are balanced but I 'am only running a sway bar on the rear and skinnies up front.

Second how much gas do you run in your tank? I know lighter is better but with the light rear ended foxbody, would it be better to run at half or more for better weight transfer?


BTW thanks to everybody who voted for me for the FOTM.

 

NoSloCoupes

"I would do anything for a FREE muffler"

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Mar 4, 2000

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stangnet.cardomain.com

Jun 24, 2009

#2

• Jun 24, 2009

• #2

I try anwhere from 10-13psi cold(burnout will add additional 1-2psi). Last outing on the stiff sidewall MT slicks at 13psi i netted my best 60' of 1.41 leaving at 5500rpm. Usually a 1/4 tank also. If a stick, do burnout in 2nd gear and keep the rpms up as not to burn the clutch.

Just play with the pressures and check them before each run, make sure both sides are even of course.

 

G

GTOreturns

Well-Known Member

Oct 1, 2003

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West Coast Best Coast

Jun 24, 2009

#3

• Jun 24, 2009

• #3

iF IT HOOKED WELL WITH 14-15 PSI THEN YOULL RUN THE SAME THIS YEAR. tHE SHIMMY CAN BE ANY NUMBER OF THINGS. Just 2 off the top of my head would be d.s. or front wheel balancing. Or both! (Sorry for the cap locks)
Get it below an 1/8 of a tank. Then add 1 gallon of racing fuel to it while at the track. Then you can even bump the timing a bit!

 

rbonella

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Dec 15, 2008

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Jun 24, 2009

#4

• Jun 24, 2009

• #4

When it comes to running with your slicks, do what I did back when I didn't know what I was doing, (still learning today) I tried a 28x10 M/T slick @ 20 psi (on 10 holes), ran it, noted my 60 ft and 1/4et & mph. Dropped psi to 18, lowered my 60 ft, and 1/4et, mph increased. I was running stock everything w/4:10's and no swaybar up front. Eventually figured 16 psi was working out the best for my car. Try and experiment with different pressures.
Fuel level and weight transfer...lighter will always be faster, but I get what your saying. I always used to keep my subwoofer box in my coupe for that same reason, and it was a pain to get it out!! On that note, I would always fine tune your traction issues with as little fuel as possible b/c lighter is always faster but this is only what I experienced, there might be better insight to come. Good Luck!

 

Cobra912

Active Member

May 1, 2005

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Jun 24, 2009

#5

• Jun 24, 2009

• #5

The car does not shimmy with the street tires on my draglites. Also I forgot to mention I/m now running a Paxton 1220SL blower with all the applicable upgrades. The car is a beast!

What I'm also wondering is this...........What RPM should I leave at? I have factory control arms and torque boxes!

 

Cobra912

Active Member

May 1, 2005

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Jun 24, 2009

#6

• Jun 24, 2009

• #6

NoSlo90 said:

I try anwhere from 10-13psi cold(burnout will add additional 1-2psi). Last outing on the stiff sidewall MT slicks at 13psi i netted my best 60' of 1.41 leaving at 5500rpm. Usually a 1/4 tank also. If a stick, do burnout in 2nd gear and keep the rpms up as not to burn the clutch.

Just play with the pressures and check them before each run, make sure both sides are even of course.

Click to expand...

I learned that the hard way. I tried it in first gear and ground it out trying to shift into second!

 

G

GTOreturns

Well-Known Member

Oct 1, 2003

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West Coast Best Coast

Jun 24, 2009

#7

• Jun 24, 2009

• #7

Your on borrowed time my friend. Get some torque box reinforcements! I bought a set from SN parts section.

 

Cobra912

Active Member

May 1, 2005

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Jun 24, 2009

#8

• Jun 24, 2009

• #8

I'm worried about it. I bought a set of uppers and am looking for a set of lowers and when I buy them I was going to get the wild rides reinforcement kit.

 

blackened88lx

Active Member

Aug 9, 2006

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Jun 26, 2009

#9

• Jun 26, 2009

• #9

What were your 60ft times before with the slicks? There's no reason you should be running more than 12psi in a set of slicks. A full tank will definitely help it hook. Is this "shimmy" more of a sway side to side in the rear end?? Bias ply slicks move around quite a bit. It will almost feel like the car is going sideways a little bit.

DO NOT even think about going to the track with slicks again until you strengthen your torque boxes. Trust me, you don't want to fix them after they're ****ed up.

 

25thmustang

Mustang Master

Sep 5, 2003

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Montgomery, NY

Jun 26, 2009

#10

• Jun 26, 2009

• #10

The shimmy up top is most likely the sidewall of the tire and nothing to worry about. Just get used to it. Imagine doing it at 135 mph?

I run anywhere from 10-15 psi depending what the car/track/driver likes. That is all just guessing, same with launch RPM. Start with higher pressure, 14-15. If it spins, drop it down a psi. Launching seems to be the best at 5000-5200 for my car, but that means nothing, as every car is different.