Help with 60'

[BLWN32V]

I went to a local 1/8th mile track a couple weeks ago trying to figure out my car. First time at the track with me driving. It was in street trim as far as the wheels and tires and also the tune. I ran 305/30/18 Mickey Thompson Dr's @16psi and pulled consistent high 1.5x 60' times best of 1.56. I was footbraking at about 2k rpms.

Last weekend I went to Mason Dixon to make some full passes with my drag wheels/tires and race tune. My best 60' of the day was a 1.58, my last pass. I was consistently in the 1.6's all morning. I'm running 26X11.5 M/T ET Streets with 16psi...tubeless. The car didn't seem to really spin or bog though. I left on the footbrake @2k rpm. I have a trans brake but, it doesn't hold past 2800 rpm since I upped the line pressure in the trans. I didnt even try it.

I would think the lighter weight and more aggressive tune alone would have helped me get out of the hole a little quicker. The tires I thought would make a little difference too???

 

[SPRAYED DAILY]

I know it's lower than what some people like running but my best results with slicks on the cobra was with 12psi. It would dead hook, it did feel a bit floaty on the top end but it wasn't too bad.


What rear and suspension is in the car.

 

[BLWN32V]

I know it's lower than what some people like running but my best results with slicks on the cobra was with 12psi. It would dead hook, it did feel a bit floaty on the top end but it wasn't too bad.


What rear and suspension is in the car.

SRA, Moser 31 Spline Axles w/Eaton Posi/3.73 Gears
Solid bushings
Baseline Upper Control arms
Baseline Lower Control arms
Baseline welded anti roll bar
KYB AGX shocks...I tried settings from 4 through 6 but saw no difference.
Rear Coilovers

Tubular K member, 175lb coilovers, strange struts

 

[IronTerp]

Heck, my best success with ET Streets was 11 to 11.5 psi.

 

[BLWN32V]

Heck, my best success with ET Streets was 11 to 11.5 psi.

wow, ok I guess I will try to lower the pressure. I guess I do remember a couple years ago runnin around 11psi in my slicks with my GT.

 

[SPRAYED DAILY]

Suspension looks good. What's your pinion angle at?

 

[BLWN32V]

Suspension looks good. What's your pinion angle at?

Not sure honestly. I lowered the car when I put the coilovers on to make it look pimp with my 18's lol. I heard -2 to -4 degrees is where you want it, does that sound right to you?

 

[04yellowcobra]

wow ... need a lot more information!!

First the basics:
crank/trans centerline to driveshaft centerline angle?
driveshaft centerline to pinion centerline angle?
front strut travel from at rest (at raceweight/racetrim) to full extension (this does not mean the tire off the ground but when the strut itself stops moving).
How much preload is in the ARB?

More complex items:
Where is the instant center and what is the anti-squat percentage?
What is the weight bias of the car? Is the left to right weight bias within 5%?

I assume with your statements about leaving on the footbrake you have an auto. Is the stall converter setup properly for the weight and power level of the car?

You state rear coilovers? What spring rate and are they stock location or relocated? How are you adjusting the ride height/Instant center/antisquat percentage?

How old are the slicks? How many passes on your car? How many passes on someone elses car (if so what kind of power did that car make)? Are the tires spinning on the rims?

What kind of RPM are you turning out the back door with a 26" and 3.73s? My main suggestion would be to move to a 28" tall (the sidewall stiff or soft will depend on how your car transfers the weight).

Do you have any video or pictures of the car leaving?

Thats all for now. If its easier you can call me and I can try to clear up some of this for you. Let me know if thats what you want to do?

 

[SPRAYED DAILY]

Yeah def talk to Jason,

my car responded good to -1.5

 

[04yellowcobra]

One more question:

Are you running the baseline relocation uppers or stock point to point?

 

[BLWN32V]

wow ... need a lot more information!!

First the basics:
crank/trans centerline to driveshaft centerline angle?
driveshaft centerline to pinion centerline angle?
front strut travel from at rest (at raceweight/racetrim) to full extension (this does not mean the tire off the ground but when the strut itself stops moving).
How much preload is in the ARB?

More complex items:
Where is the instant center and what is the anti-squat percentage?
What is the weight bias of the car? Is the left to right weight bias within 5%?

I assume with your statements about leaving on the footbrake you have an auto. Is the stall converter setup properly for the weight and power level of the car?

You state rear coilovers? What spring rate and are they stock location or relocated? How are you adjusting the ride height/Instant center/antisquat percentage?

How old are the slicks? How many passes on your car? How many passes on someone elses car (if so what kind of power did that car make)? Are the tires spinning on the rims?

What kind of RPM are you turning out the back door with a 26" and 3.73s? My main suggestion would be to move to a 28" tall (the sidewall stiff or soft will depend on how your car transfers the weight).

Do you have any video or pictures of the car leaving?

Thats all for now. If its easier you can call me and I can try to clear up some of this for you. Let me know if thats what you want to do?

I know what you are referring to mostly...It is mostly a street car and I do not have all that info. I just wanted to see if I could get some basic simple answers. Guess it isn't that simple :dw:

Thanks for the input, I guess I need to take the car and get it scaled and have all the angles and all that stuff looked at.

 

[04yellowcobra]

If you want it to work you have to get right down to the nity grity. If not ... well ... you better watch your back for eaton powered cars that have done some homework

 

[IronTerp]

Josh, in all likelyhood, since you've hit a 1.56 with drag radials, you should be able to hit consistent low 1.5's and maybe high 1.4's if you get your slick specifics locked in, your launch dynamics fine tuned a bit, and your shock/strut settings maximized for proper front to rear weight distribution. Jason's approach is very advanced and is designed to get every last 1/100th of a second out of your 60' time. Most SRA fellas don't go into that kind of detail.

 

[BLWN32V]

I'd really like to get in the 1.4's with this car without any more weight reduction and utilizing the same parts. I know it can be done! Thanks guys, I will look into everything and I'm sure I'll be making some adjustments.

 

[Derek@Amazon]

you have any video of the car? hard to say what you need to do with out seeing what its already doing

 

[Snakesvt04]

you should be in the 1.40 with a different tire. try the the 28's. the tires you are using have no side wall, plus you have to much power for 305/30/18.... that like beeing on ice. i ran that tire for a year

 

[Derek@Amazon]

you should be in the 1.40 with a different tire. try the the 28's. the tires you are using have no side wall, plus you have to much power for 305/30/18.... that like beeing on ice. i ran that tire for a year

yea just noticed that hes on a 26" tire

throw a 28x10.50 on it or a 275/60 radial. you need the sidewall

 

[BLWN32V]

here's a vid my gf took that day...
[nomedia="http://www.youtube.com/watch?v=q_WpNr4FGNA"]YouTube- 10.76 pass 2004 Cobra[/nomedia]

 

[Derek@Amazon]

hard to see in the video but it looks like you need to slow up the front a little bit cuz it looks to be unloading the rear a bit when it fully stretches the front out.

this was off the foot brake right?

 

[04yellowcobra]

Not enough RPM out of the hole. The chassis isn't doing anything because it doesn't have to. Increase the launch RPM and other things may start showing up.