Jet Jockey/A4 Pilot

Just came back from the drag strip. I ran multiple 1/4 miles runs tonight, ten to be exact and once again the car pulled through without putting up a fuss.

First thing I'm going to say is that the
<b>G-Tech Pro</b> is <b>dead accurate</b>. I have full confidence that if I test with it again the numbers will be reliable. Mind you going to the track for $5.00 CAD, yes guys that's
$3.50 US for as many runs as you want with a time slip for every run now that is very cheap and fun.

<b>Track and weather Conditions:</b>

Compared to when I tested with the G-Tech Pro it was warmer, around 10 F warmer tonight and it was windy, maybe 10 mph winds that were cross wind to a bit headwind. I don't know how much the wind would have affected the times tonight.

Again tonight as the other night the times were very consistent. On my first ever run I Fvcked up big time, I got a 2.562 for the 60', 9.865 for the 1/8 and a 15.092 for the 1/4 @ 91.374 mph. Like I said lets forget this run please.

The other runs were in the 14.2s to 14.5s and all 60' times were between 1.9 to 2.06 seconds!
The 1/8 of a mile came in between 9.01 to 9.2 seconds and the speeds were between 97.2 and 98.1 mph. All the speeds are somewhat slower by up to 3.5 mph when compared to the G-Tech Pro runs.

In one of my best runs these were the numbers;

60' at 1.943 seconds, 1/8 at 9.012 seconds and the 1/4 mile at 14.22 seconds with a speed of 98.123 mph.

My best run of the night was as follows;

60' at 1.872 seconds, 1/8 at 8.971 seconds and the 1/4 mile at 14.16 second with a speed of <b>94.216 mph</b>, WTF!
The 14.16 seconds is only 2/100th off the G-tech Pro Time of the other night at 14.14 seconds.

<b>Observations and questions</b>

During most launches if not all, I got lots of four wheel spin. Would this partially explain the poor 1.8 to 2.1 60' times?
If so, how much faster could the 1/4 mile times have been if I got a good 60' time? What is a good 60' time?

In my best run I got a 14.16 time but a really low speed of 94.216 mph, how can that be? That is almost 7 mph less than what was recorded with the G-Tech Pro (the other night) and 4 mph slower than my second best run tonight. Mind you I did miss shift a gear, could that explain it?

The fact that it was 10 F warmer tonight, could that have affected the times? Also what about a small headwind?

Finally I ran against some WRXs and I beat them except for one that was modified and he beat me by 2/10th. I also ran against someone I know with a modified and much lighter B5 A4 with a PES Stage 3 with a T28 set up. He beat me but not by much either, about 1/10th. To be fair he says is clutch is finished and he could/would not dump it on the launches. He was also faster then me in speed at the end of the 1/4 mile. I could really hear his turbo kick in when he was coming up behind me.

In any case if someone with drag strip experience can explain to me these points I would appreciate it.

TIA,

Mike

YnotS4

Less wheel spin equals lower 60 ft time plus lower trap speed. More wheel spin has the opposite effect. Without the missed gear this would have been your best run given the 60ft time.

Weather will alter your et as well go back on a night when it is cooler by 10-20 degrees you will see.

Wind also will alter times tail wind is the best.

Play around with your shift points and remember what you did on your 1.8 sec 60ft time. Sounds like the car can run a high 13.

I'm no experst but I hope that helps

ESFO

Boy. $3.50 to run... I pay $13.00!

Anyway, to answer your questions... Your 60' time of 1.87 is very good. If you can duplicate or repeat that, you're doing well. Your car, being lighter than mine, should be able to 60' in about 1.80 seconds or a little quicker. That's a realistic goal.

On your best run you apparently missed a gear at or near the 1/8 mile because your 1/8 time didn't follow the off the line advantage shown in your 60' time. That 0.071 advantage should have carried through, all things being equal. What your runs show so well is that, your 60' time means EVERYTHING. You can screw up in your driving after that, to some extent, and still ET pretty well. But to get back to the issue, your missed shift is the reason your mph lowered. Nothing else. Getting good traction will simply allow you to get the most out of the available power. It will not slow you down.

So I have to respectfully disagree with the previous post. I've raced (in other vehicles) on street tires, drag radials and slicks. I've always seen an increase in mph with each upgrade in tire stick. Think about it... A car that sits at the line spinning is making poor use of it's available power. It is, in effect, shortening the available room it has to get up to speed before the end of the quarter mile. Tire spin is almost always bad. In our cars I'm not so sure about that. Not spinning in our cars usually means that you're bogging. You're not giving it enough gas to get into the engine's sweet spot for your run. So some wheelspin is ok... a loud chirp or hard screeeech. In a rear wheel drive car, wheel spin is always bad because it's too difficult to feather the throttle to get the wheelspin under control and the longer it takes to use full throttle, the more wasted your run is. Not applicable in our case. We can't make the tires spin enough to hurt us. Just keep the throttle down, it'll hook in about .10 seconds.

A crosswind may have some effect, but I would never shy away from running because of it... unless it's moving the car around. A slight crosswind won't hurt you to any discernable degree. A headwind, almost regardless of how strong, will have an effect on your mph in particular. Because I don't know which way the wind will be blowing on the track before I get to the track, if the wind is strong, I won't even go. I won't go to the track unless I feel conditions are ideal. No use in running if I'm not going to be running in conditions that will allow me to see my best.

Temperature will definitely effect your runs. Humidity and barometric pressure also effect your engine's ability to make power. Case in point: The last time I ran my car, I went to the track on what I thought was a perfect night. Humidity was about 61%, barometer around 31 and temp about 80. I figured that as the night went on temps would lower and it would be all good. Well, the track is an hour and 45 minutes away, south and towards the shore. Conditions there were very different. And as the night went on it got worse. Temp stayed in the low 80's and the humidity rose with every mile I drove toward the track. I got there and the best I could do was a 13.81 @ 100.4. That's about .43 seconds slower than my best and 3 mph slower. But the turbo cars were suffering too. One guy in a WRX STI could only manage a 14.02 @ 99mph(his best on a previous night was 13.3 @ 105) and a guy in a seriously modified Neon SRT4 could only manage a 14.0 (his claimed best was 13.2 previously).

(Edited)
I should mention that before this night I would never have imagined that air quality, unless you're talking about 100 degrees + 100% humidity vs. 40degrees + 40% humidity, could have this much affect on a car. Given the conditions, I would have expected 2 tenths and 2 mph reduction. What I forgot to mention is that on that night my ESP kept coming on although I had it turned off. The light was on in the dash to show that the system is off, but when I shifted, full throttle, it would have the same reaction as if the ESP is on, cutting power. It did it in each gear. Full throttle power shifting yields very linear acceleration, no bucking or hesitations between gears. The ESP coming in just took that advantage away from me. I believe that that's the main reason I didn't run well, but it certainly doesn't explain why all these other guys were running slower. That's an air quality issue. But 8 tenths is more than I can swallow for the SRT4 guy.

Go back on a cool night and watch your turbo go crazy....

Happy Wednesday!

Jet Jockey/A4 Pilot

Thank you to both of you.

SlykmrS4

How were you launching? Dumping the clutch?

Jet Jockey/A4 Pilot

But the ESP is not really the culprit I'm worried about, but the <b>EDL</b>. Even with the ESP switched <b>OFF</b> the EDL is still active until 50 mph. Now this system will slow you down at the start, so goes the theory from the B5 S4 crowd. So I basically pulled the ABS and EDL fuse out to make sure no electronic system interfered.

Strange thing is I got a lot of wheel spin last night (EDL <b>disabled</b>) and none the other night(EDL <b>enabled</b>). I'm starting to wonder if it was the launch pad's lack of grip compared to the road where I did the G-Tech Pro runs or is it maybe the fact that the EDL was disabled that I got too much wheel spin. I will have to go back to that same road and test out that theory.

All I can tell you was that my head seemed to snap back more the other night under the initial full acceleration. Last night just did not feel the same.

Jet Jockey/A4 Pilot

And feathering the clutch out while going on the upswing to 6000 RPM to be on boost.

ESFO

an abnormality. I need to take it in for service. What's EDL?

It sounds like you were getting more wheelspin than I initially imagined. Some tracks are particularly slippery. The track I go to is known for being very sticky. The lanes are in constant use, and they prep the track with a traction compound.

Jet Jockey/A4 Pilot

All VWs and Audis have it. On the Quattros like our cars it is active until 50 mph (80 Kph). On the FWD versions it is active only at lower speeds.

Basically EDL uses ABS logic in reverse to apply braking to a wheel that is spinning thus transferring power/torque to the opposite side for better traction. It is a poor mans limited slip diff.. The problem is that is fine for regular driving but bad for performance driving, especially in racing applications. The only way to disable EDL is to pull the fuse for the ABS or ESP.

ESFO

Thanks. I learned something new today!