[s-cars] Dragstrip day

[Evan Levine]

Sounds to be like the main problem is just the clutch. When you see the
fastest speed on the worst launch it's most likely because the worst launch
was the easiest on the clutch. My car has similar issues at the strip and I
know it's the clutch for sure. My best times are with a slow launch -
otherwise it just slips all the way down the strip.
 Evan


 On 9/27/05, Mesa Cycles <info at mesacycles.com> wrote:
>
>
> > ------------------------------
> >
> > Message: 9
> > Date: Mon, 26 Sep 2005 20:53:55 EDT
> > From: Djdawson2 at aol.com
> > Subject: [s-cars] Dragstrip day
> > To: s-car-list at audifans.com
> > Message-ID: <8e.30917426.3069f223 at aol.com>
> > Content-Type: text/plain; charset="US-ASCII"
> >
> > Well...
> > Finally got the car to the dragstrip. I had my newly installed 928 MAF.
> > Temps were 81-85 degrees by my dash display, and the dragstrip is at
> 2700ft.
> > The runs were made with pump Chevron 91 octane gas.
> >
> > The results were less than pleasing... but I have to pass them along as
> data
> > points, or I'd be a cheater.
> >
> > 4 runs... 13.13 @ 106.48, 13.23 @ 100.85, 13.19 @ 103.10 and 13.20 @
> 100.81.
> >
> > I don't believe I can draw many useful conclusions yet, as the 928 MAF
> isn't
> > adjusted properly. The car refused to pull hard in 3rd gear, and
> somehow,
> > the early run times (60ft, 330ft, and 1/8 mile) had NO effect on the
> overall
> > time.
> >
> > My best 60ft time was 1.805 sec. My worst launch resulted in a 2.244 sec
> > 60ft. Ironically, the run with the 2.244 60ft was my quickest and
> fastest
> > run,
> > when it took me nearly .5 seconds longer to complete the first 60ft.
> What?
> > Why?
> >
> > I discovered A/F ratios were pushing into the mid 13s in 3rd gear. As
> soon
> > as this would happen, the timing would back off. I never had a run where
> the
> > engine would pull hard in all gears. Very frustrating, and no way to
> adjust
> > at the track. From my dyno experience, I know the engine tends to make
> its
> > best power when the A/Fs are in the high 10s when under full boost and
> WOT.
> > Improvement is certainly available here.
> >
> > Next, the clutch. The Centerforce isn't up to the task. You can't launch
> > aggressively, or it will go into an uncontrolled slip. Gotta do
> something
> > about this if I'm going to see good dragstrip results. Other cars that
> were
> > making it to 106mph were recording mid 12s on the ET.
> >
> > Finally, the gear ratios. Quandry here... 3rd gear at 8500rpm still
> won't
> > get you to the end of the track. However, shifting into 4th is done so
> late
> > that it becomes a penalty. As a result, my best time and speed (13.13 @
> > 106.48) was achieved by running 3rd gear to 8500rpm, pushing in the
> clutch
> > and
> > coasting through the trap.
> >
> > So, back to the dyno. Need to get that MAF dialed in. I will dyno and
> tune
> > the engine this weekend to get it running right. And then I'll be back
> to
> > the strip on Oct 8th for another try.
> >
> > All wasn't lost, however. When you can run next to a new Z06 (I think
> was
> > the designation) at still beat him by 4 or 5 carlengths in a heavy 4
> door
> > sedan... you still feel pretty good, and generate a lot of curiosity in
> the
> > pits.
> > Stay tuned.
> > Dave
> >
> >
> > ------------------------------
> >
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> >
> >
> > End of S-CAR-List Digest, Vol 23, Issue 95
>
>
> Dave,
> What are you running for a turbo and software?
> Russ Murphy
> > ******************************************
>
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