I must be track retarded!

Ethereal Zer0 · Apr 19, 2004

Went to the track the other day...First run the last amber lights up and what happens?! MY FOOT SLIPPED OFF THE CLUTCH! lol ended up with a 4.6 60ft time! Atleast the car didn't die, was damn close though! Now here is my question...That run I trapped 97 something mph. After that I let some air out of my tires (was at 25psi after that) and ran a whopping 15.1 1/4 miles @ 92mph. Every run after that I ran about the same (eventually dropped the air pressure down to 20psi and gave her a rip) time but my trap speed continued to decline. Is it possible to lose trap speed from letting air out of the tires?! This was only my 2nd time to the track and I only got to run 4 times, the first time I went to the drags (left the tires alone at 40psi which I run on the street) I had a best of 14.7 @ 98.9mph. What happened?!

CivicEater · Apr 19, 2004

250 Rwhp and you only pulled high 14's ...I am thinking something else is wrong.

Ethereal Zer0 · Apr 19, 2004

CivicEater said:
250 Rwhp and you only pulled high 14's ...I am thinking something else is wrong.

SHHHHH!!!!! I know I can't drive worth crap!

Edit: btw, here is my dyno graph, how does my torque curve look? I have no idea how to read this damn thing!

VibrantRedGT · Apr 19, 2004

CivicEater said:
250 Rwhp and you only pulled high 14's ...I am thinking something else is wrong.

He's from the NW don't know the altitude though.

nmcgrawj · Apr 19, 2004

Hmmm what other mods do u have? 285hp (your 248rwhp plus 15% loss) seems like a lot for what u have listed. Aren't stock cobras at 240hp? Anyway...

Lowering your tire pressure is only supposed to give you more traction because of the larger tire patch contacting the ground. Unless you are losing traction, i wouldnlt lower it because i believe that if you lower it too much and you dont need it, it gives u a much larger contact patch which then means more rolling resistance which then slows you down.

Ever ride a bike that has over inflated tires and then a bike with underinflated tires? ITS MUCH easier on the over inflated to go faster and to stay fast.Just something to think about.....

Dont forget when thinkin about bikes though is that they dont worry about traction. We do, so we cant just pump our tires up all the way.

Rootus · Apr 19, 2004

VibrantRedGT said:
He's from the NW don't know the altitude though.

Yeah, NW tracks suck .

Dave

StangJonGT · Apr 19, 2004

nmcgrawj said:
Hmmm what other mods do u have? 285hp (your 248rwhp plus 15% loss) seems like a lot for what u have listed. Aren't stock cobras at 240hp? Anyway...

Lowering your tire pressure is only supposed to give you more traction because of the larger tire patch contacting the ground. Unless you are losing traction, i wouldnlt lower it because i believe that if you lower it too much and you dont need it, it gives u a much larger contact patch which then means more rolling resistance which then slows you down.

Ever ride a bike that has over inflated tires and then a bike with underinflated tires? ITS MUCH easier on the over inflated to go faster and to stay fast.Just something to think about.....

Dont forget when thinkin about bikes though is that they dont worry about traction. We do, so we cant just pump our tires up all the way.

You are exactly right about the underinflated tires. Unless traction is a problem, there is no need to deflate them. As for the HP rating, it is common knowledge that 5.0 Cobras are underrated from the factory. He could easily be laying down those numbers.

Jon

StangJonGT · Apr 19, 2004

Where in the NW are you? Usually we are pretty close to sea level, here in Seattle.

Jon

Ethereal Zer0 · Apr 19, 2004

The mods listed are the only mods currently installed. I raced at Pacific Raceways in Kent, I'm pretty sure its right near sea level. I noticed that my 60' times weren't much better with the lower tire pressure, lol figured it couldnt hurt too much to try it though I'm thinking that I will try 35psi next time I hit the track and see what happens.

Btw, thanks nmcgrawj that was a very good analogy!

Any other ideas to help me out? Thanks for all the help to those that posted, keep 'em coming!

mo_dingo · Apr 20, 2004

Post the following time slips. And please list everything the timeslip has! Also, please note any incidents related to each timeslip (i.e. took to long to get into a gear, long burnout, short burnout, etc)
One w/ lowest E/T
One w/ highest trap speed
One with best 60'

What RPM do you shift in each gear. 1-2, 2-3, (3-4??)

I plugged your torque curve into ZeroSignal's shift point calculator. According to it, 1-2 is 5700, 2-3 is 5600, 3-4 is 5500.

If you go close to the rev limiter (6250?) in each gear, you are shifting way too high.

Look at your torque curve. Concentrate on that. Horsepower is too deceiving.

See right at 4200 RPM's. The torque curve begins to fall flat on it's face. Now, the longer you stay in each gear (after 4200), the more torque you lose. Your acceleration rate is decreasing after 4200 RPM's.

But, because of gearing, you want to stay in the lowest gear until it becomes more "effeceint" to switch to a higher gear. 5500-5700 (as outlined above) is the threshold point for your torque curve. After that, you need to switch gears.

You have the better heads on your car (and more parts), and this allows you to shift later than I would. I shift 1-2 5200 & 2-3 5000. My torque curve falls flat on it's face at 3500 rpm's. And 5000-5200 is the threshold for my car.
Scott

mo_dingo · Apr 20, 2004

OH. Almost forgot.

93-95 Cobra motors are supposed to be underrated, aren't they? Never the less, he has the better heads/intake, so the mods he does translates into bigger power gains than we would achieve with out E7's and crappy intake mani.

My guess is your trap speed should net you low 14's. My guess is your 60' times are the problem. Or your shifting, if you shift to high.
Scott

Slow5.0 · Apr 20, 2004

Low tire pressure kill mph but you got better traction
Anyway I think 94-95 GT's are underated too , its more like 225-230HP not 215

95snoozer · Apr 20, 2004

Ethereal Zer0 said:
SHHHHH!!!!! I know I can't drive worth crap!

Edit: btw, here is my dyno graph, how does my torque curve look? I have no idea how to read this damn thing!

you make more power than I did on the dyno

Fast94Cobra · Apr 20, 2004

dont worry, 90% of us on the boards are track retarded. last time i ran a 13.9 @ 106 mph. 106 mph should be good enough for a 12 lol

Venom351R · Apr 20, 2004

Your TQ curve is fine and theres nothing wrong w/ your car, just that learning to drive at the track is alot diffrent then the street. Im in that learning process myself. Your 60" times will tell you alot as far as your traction. The first time I went I was running 92-94 MPH but w/ 2.4 and 2.6 60' times. Most people cant get good 60' times w/ out a set of DR's. Just pratice and get the thing to hook up and you will see your times drop.

moneypit94 · Apr 20, 2004

You will see this a lot... The better your 60' the lower your mph... This has a lot to do with traction and getting into your powerband faster. Also has to do with torque versus hp. You either slip and use mainly your hp, or you connect and use your torque. You waste too much time slipping to make up for it at the end of the track. IMO Torque is what wins races if you have can contain it.

At the track i go to it is dominated by big blocks... The really mild setups will run 11's easily and yet their trap speeds stay around 110... Lot of this is due to being torque monsters and getting off the line like crazy but not having the hp to pull them at the end.

Your average big block with just a head and intake/carb swap is like 250 rwhp but like 490 rwtq. Actually now that i think of it that is just a intake/carb swap.. (Guy was dynoing a 454 with stock heads with a duel carb setup right before i had dyno time)

Ethereal Zer0 · Apr 22, 2004

hmmmmm.........off to get some drag radials i suppose!

Nobody · Apr 22, 2004

Tyler, don't get too wigged out about it. I don't know of any 94-95 Stock long block Cobra that has cleared 13.99 N/A on street tires. My first run at PR was 14.8 @ 96mph. That was with just about the same mods you have. I raced a bone stock 95 Cobra twice in the same day and he couldn't break into the 14's. I won't blame it all on the track, but when all the people we know around here never did it (Will, Noong, Eric, Me, You) maybe there is something about the NW. Maybe we all just suck because Viperos is knocking on the door with his stock long block GT.

CManT1914 · Apr 22, 2004

Seth5.0 said:
Low tire pressure kill mph but you got better traction
Anyway I think 94-95 GT's are underated too , its more like 225-230HP not 215

That's what I'm screaming! My car is surprisingly fast for stock. So either the 94-95's were underrated, or I have a "freak" car.

Zero Signal · Apr 22, 2004

Have you calculated your shift points out? According to the torque curve you posted up there, you should be shifting at 6000 rpm.

To be more exact:
1st to 2nd: 6200 rpm
2nd to 3rd: 6000 rpm
3rd to 4th: 5800 rpm
4th to 5th: 6000 rpm

I must be track retarded!

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