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-   -   1/4 mile not making sense?? Help! (http://www.focusfanatics.com/forum/showthread.php?t=261727)

Kevin D 06-28-2011 10:06 AM

1/4 mile not making sense?? Help!
 
Had two runs yesterday. First was 15.82 @ 93.8mph. Second was 15.87 @ 92 MPH. I have 17's on my car with oversized tires. 215/50/17, so there off by 4% or so. All variables aside, if I switch back to the correct diameter of tire, shouldn't it drop bother numbers down? I guess I'm happy about the 92/93.8 mph, but not the time.
Short question, By changing to a small diameter (going back to original diamter), what gains/losses whould I see.
Thanks in advance!

alex62390 06-28-2011 10:17 AM

when decreasing the tires diameter, you should see a torque gain. Basically it would make your gear ratio lower. quicker acceleration but lower top speed. I do not know how much difference a 5% change in aspect ratio will make. 96mm vs 107mm pretty close.

Mike_Mac 06-28-2011 10:18 AM

it should lower your times, but we need more info then just et... i can't get traction for the life of me and can spin straight threw 1st gear.

also if the smaller tires have less grip you will probably run slower.0.1 sec off your 60ft is usually 02-0.3 off your et.

Kevin D 06-28-2011 10:22 AM

My new tires stick very well, but there a 50 series tire, not the correct 45 series. After all the things i've changed on the car, it still takes 15.8. This sucks. Someone has to know the best set up for a 1/4 mile run.

Mike_Mac 06-28-2011 10:25 AM

slicks.


whats the rest of the time slip?

i ran a 15.7 w/ a 2.43 60ft 87.6mph
ran a 16.8 w/ a 2.87 60ft 87.4mph

i have to take off like i would at a stop light or a just light up the tires and spin. put drag slicks or a radial and knock my 60ft's to 2.0 or less and ill probably net 14's

MustangCRZY302 06-28-2011 11:07 AM

what was your 60 ft times?

RyEnd 06-28-2011 11:08 AM

Dropping down to a 15" wheel would also help as it would decrease rotational mass.

1turbofocus 06-28-2011 11:22 AM

Quote:

Originally Posted by Kevin D (Post 3721792)
My new tires stick very well, but there a 50 series tire, not the correct 45 series. After all the things i've changed on the car, it still takes 15.8. This sucks. Someone has to know the best set up for a 1/4 mile run.

What all have you changed ?

Tom

Kevin D 06-28-2011 12:02 PM

2.47 0-60 foot.

Roushturboedzx3 06-28-2011 12:25 PM

OMG get that 60ft down and the ET will go down also.


Post the rest of the slip please


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