[s-cars] 1/4 miles and clutches

[Keith Maddock]

All this talk of 1/4 miles times and launches, I thought I'd share my OneLap experience.

We had two 1/4 mile drags in OneLap... I managed to botch both of em..
Run 1: 14.936   (sorry no trap speed)
Hmm can't find the time for Run 2 , but it was pretty similar maybe .1 or .2 sec faster.

This was before Mark and I found that a much better launch can be had by holding the parking brake pretty tight, revving up to about 3500-4000 rpm, slowly letting out the clutch to put some load on the engine to get the boost up, then releasing the parking break, and gradually letting the clutch out.  The key was to keep the RPM's and the boost up!  Needless to say this procedure has two drawbacks:
1) Hard to time for a 1/4 launch  (easy for a OneLap style launch where your time starts when you pass the light-beam trigger 5 feet after your start line...)
2) Pretty hard on the clutch...

Anyone have a better launch / clutch torture procedure?

For comparison, some interesting OneLap 1/4 times:
(remember lots of these drivers had never done a 1/4 drag before)
Lister Vette: 11.255
Viper ACR: 11.833     (one lap winner)
Supra TT: 12.193     (definately far from stock)
996TT: 12.346     (stock i think..)
Plymouth Valiant: 12.507
Z06 Vette: 12.914    (stock i think..)
V8 280z: 13.166     (go datsun!)
Renntech C32 AMG: 13.362    (~400hp)
Shogun: 13.651     (Festiva with rear moutned supercharged SHO engine)
M5: 13.821     (supercharged)
APR modd'd S4tt: 14.161     (supposedly ~310-320 hp)
Stock S4tt: 14.262
MTM modd'd S4tt: 14.567    (supposedly ~360 hp)
jag S Type R: 14.488    (stock)

Keith "Car-less in Koblenz" Maddock
93 S4 with goodies, but 7000 miles away


****************************************************************
Keith Maddock, TRW Automotive,  Koblenz, Germany
Slip Control Systems, Systems Design, Traction Control
+49 (0)261/ 895 2474     -    -    keith.maddock at trw.com

>>> "Jack Gagnon" <bullitt at cybertours.com> 21-Aug-02 04:13:12 >>>

Yea Paul is right

How about this
Me

Run 1 :20.423 at 64.90 (yup that is 20 seconds).
Run 2: 18.065 at 81.44
Run 3: 21.401 at 65.11(limp mode again)

Pretty pathetic huh! I am used to running 12.8's@ 110 with my 89 mustang

other lane

Run 1 :12.828 at 104.76 1.8 60' (60's GM muscle car)
Run 2: 13.619 at 100.98 2.0 60' ( Ford Lighting Pickup)
Run 3: 14.365 at 100.46 2.3 60' (BMW M3)


Explanation/Excuses

1.	I just swapped out my tiny undersized puny TAP injectors with stock
injectors and did not disable the Rising rate FPR resulting in way rich
conditions.

2.	The ECU detected an overboost condition (Code 224)and I hit the fuel cut
out in 1st gear. the remainder of the run was in low boost limp mode.  Runs
1& 3 I hit the fuel cut out, Run 2 Was sputtering from the rich condition
and I short shifted to keep the damn thing from going into limp mode again.

3.	I was Fr#$#@n HOT! 97deg and 10 minutes of heat soak prior to each run.

I have since corrected my overboost problem (bad MAF sensor connection) and
removed the rising rate FPR and everything is running fine now.  I did a few
0-60 runs with the g-tech and was able to get a 5.9 without a miss so I am
ready to race again!  I even managed to get a bit of clutch smell while
trying to perfect my launch.  It appears that dropping the clutch at much
over 3500 rpm results in enough engine power to get no bog, but the damn car
is so heavy that the clutch slips.  Even though the times really sucked I
learned that my car needed some TLC and the trip was worth it.  I think I
will try again soon.


92 S4
K& N Cone filter
KKK small 26/Garrett T04 turbo
Sport intercooler
Piper cams
Ported heads
RS2 EM
3" exhaust
Lehmann stage 3 chip
3 bar sensor
Big reds
Koni's
245/40 17's

What do you think it will run?

Jack G


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