M5 1/4 question and video inside!

[FRENCH_CAMAROV6]

I've done my first 1/4 this week end.

I've got a manual transmission.

Here is my question:
at the end of the 1/4 I'm in third speed , 5300-5400 rpm

Is it better to shift before the 4th at 5100 ? (more power and more torque on 4000rpm with 4th than 3th and 5400prm) or leave the 3th?

(I've got 3.23 ratio)

My time (with my girfriend in the car, very bad launch, a lot a spinning)
60' : 2.413
1/8 10.188
1/4 : 15.788
RT : .626
78F

Here is the video, what do you think of it :
http://jerome.laurent6.free.fr/lurcy...d_macchris.avi

I can't avoid to spin on the track...but no problem on the street...

[ June 07, 2004, 10:26 AM: Message edited by: FRENCH_CAMAROV6 ]

[RallyRed 98]

wow, cool video! looks like you're just out racing in the middle of some farmer's field. :D

i've tried shifting into 4th and i usually end up trapping about 70 mph; when i leave the car in third i will trap about 71.

not sure what you're trapping but with a 10.18 i would guess about 67-68 mph. your 60' time is really hurting you... i would suggest dropping your rear tire pressure to about 19 or 20 psi and see if that helps. it also looks like your track isn't prepped very well; this is also hurting your traction.

tres bien, mon ami... c'est une video tres bonne. ;)

EDIT: sorry, my french skills don't even compare to your english

[ June 07, 2004, 06:18 PM: Message edited by: RallyRed 98 ]

[MustangEater8251]

On street tires, 19-20 psi is too low, will hurt your traction, you will want it more like 28ish.

That looks cool where you race, pavement looks kind of nice, better then my track [img]smile.gif[/img]

As for your car, stay in 3rd...


I have been told its better to stay in 3rd up to 95ish mph...

[FRENCH_CAMAROV6]

this is the lurcy levis' track
the only 1/4 track in france

Yes it's in the middle of nowhere, in the center of the France

My tire were 30 psi like everyday


et oui! ton français est excellent!

[ June 08, 2004, 04:39 AM: Message edited by: FRENCH_CAMAROV6 ]

[RallyRed 98]

Originally posted by MustangEater8251:
On street tires, 19-20 psi is too low, will hurt your traction, you will want it more like 28ish.

That looks cool where you race, pavement looks kind of nice, better then my track [img]smile.gif[/img]

As for your car, stay in 3rd...


I have been told its better to stay in 3rd up to 95ish mph...

hm, i know you've got 500 passes or whatever... but are you sure about 28 psi? i cut 2.4s with 28 psi and 2.1s with 19...

[Craig Griffis]

I stay in third and trap 92-93 mph. Any higher than that and you'll get close to rev limiter. You'll take more time shifting than you'll gain with horsepower. Do you have the MPH's?

[Dominic]

I stay in 3rd and run her to the rev limiter and shut down in 4th past the 1/4 mark. I don't let off until I'm sure I'm past the 1/4 mark. My time is in my sig.

Also, powershift, i.e. don't take your foot off the throttle and shift quickly and accurately. You won't hurt anything and your times should diminish down in the low 15s. Don't get discouraged [img]smile.gif[/img]

[Tru2Chevy]

Originally posted by RallyRed 98:
hm, i know you've got 500 passes or whatever... but are you sure about 28 psi? i cut 2.4s with 28 psi and 2.1s with 19...

The lower pressure may help you out on the launch, but will usually hurt you more on the top end due to greatly increased rolling resistance. Personally I wouldn't run average street performance tires less than 24 psi. Also make sure that you pump your fronts up to 50 psi or so while you are at the track. This reduces their rolling resistance.

- Justin

[mr_man]

I got worse traction with anything below 30 psi in my Formula.

Did you warm the tire's up before you raced? That should help some.

[ReodDai]

wish there was some place my car didn't have a problem spinning lol

[MustangEater8251]

Originally posted by RallyRed 98:
hm, i know you've got 500 passes or whatever... but are you sure about 28 psi? i cut 2.4s with 28 psi and 2.1s with 19...

some tires might be able to go a little lower but 19 seems kind of low...

if you lower steet tires too low, the middle of the tire will indent in and not touch the pavement. Racing slicks can do it because they have really weak sidewalls.

good ghetto way to tell... is put the tires at the pressure you like, go leave a patch of rubber somewhere.

If the outsides are darker then the middle, then the pressure is too low. If the center is dark, and the patch is much narrower then the tire then you are running too much pressure.