Well, I finally had a chance to make some timed 1/4 mile runs last night, and was suprised that they weren't faster. I've got the Abt Chip, custom exhaust, etc... and my best 1/4 mile was 14.168. I'm sure most of the reason for this was the part behind the steering wheel.


For my launch I was revving to 4-5K, and then slipping (not dropping) the clutch quickly. I shifted at 6500 in each gear, and let it run to red line in 3rd at the finish. (A few times I shifted to 4th at 6500, and got about .1 sec slower). The time slip info is posted below. If anyone has any ideas on how to improve them, I'd love to hear 'em!
(BTW, my other times were 14.429, 14.397, 14.336, and 14.260 - in order - so at least I was getting better!)

R/T 1.232 (ouch!)
60' - 2.024
330 - 5.915
1/8 - 9.130
MPH (1/8) - 77.45
1000 - 11.860
1/4 - 14.168
MPH - 98.66

ps - 6 spd transmission

 

Not wanting to possibly put myself (or my warranty) in jeopardy here, so I will be somewhat vague.(but still helpful I hope)
Launching the 2.7T 6 spd is hard to do. I've made a few "hard" runs on the car, but the majority of them have been "soft" runs. It's gotten to the point that I can estimate my et from the moment I've launched and I see the 60' time come up on the board.
First, let me begin with the launch. I ran my best times launching at 3800-4000rpm with quick slip of the clutch. I got absolutely no bog on those launches. I simply held the revs steady, and on the last yellow stuffed the accelerator while feeding in the clutch. If you feel the "two-stage" engagement (or bog) you didn't do it correctly. With my stock tires, I was able to chirp the fronts on these launches. I was able to pull a 2.01 60ft. time, pretty consistently. (I have no idea where my timeslips are now, but Ming 2.7T has scans of them for sure). Your 60' time is good, so it looks like you've got the launch part correct.
Next is shifting. I never powershift. I always release the throttle fully and engage the clutch as you normally would. But, I am an extremely fast shifter. I shift so fast when running hard that the car usually never gets that "fall on the face" feeling that you get when you clutch quickly when accelerating hard. How much of a difference does your shifting make in the 1/4? I don't know, but people often ask me if my car is a manual or not. I've got to believe that the faster you shift, the higher the engine rpms (and also boost) will be in the next gear, which should trim some time off your ET. I shift at 6500-6700 from 1-2, and I run 3rd through the traps (just about 6800).

What surprises me is the fact that your MPH numbers seem a little low for the mods that you have. I've run 94-95.9xx mph on my 14.4-14.5 passes bone stock. Did you let your car cool off before you ran? I always let the car cool for about 1/2 hour before running (with the hood up). The cooler the better, so long as the oil temp is still off the cold mark.

Now, I know that I can run 14.5's with ease, by doing as I described above. I did try one or two "hard" runs. For the hard runs, I did as I did above except for the launch. I launched at 5xxx and gave the same quick slip of the clutch. I pulled off a sub 2.0 60 ft. time (it was a 1.8xx) and the car was really hauling until I missed the shift to 3rd gear. Even though I had missed the shift,(one of those bad, missed the shift and couldn't find it ones) my timeslip was very good. It was a 14.58 @ 94.03 mph. That would've been a 14.2-14.1 for sure. I never mentioned that timeslip because I ashamed to mention that I missed a shift.

I would keep doing what you're doing on the launch, and practice your shifting. Maybe that will keep the turbos "on the boil" and take another .1-.2 off your et. Try to run under 1/2 tank if you can, and also, before going to the track the next time, get yourself 1/2 tank of 100 octane unleaded 2-3 days before. That should make a difference.

 

Best time Car & Driver could get for A6 4.2 was 14.9, Lexus GS430 was 14.5 and 540i was 14.3. You would have beat them all.

 

I was hoping to break into the 13's. I also blew a shift to 3rd (badly) on my 14.3 run, so that one could have done it, too. I had a bunch of extra weight in the car (besides me...), too. Golf clubs, spare tire, 3/4 tank of gas.

I'll try it with 100 octane and less weight next time, too.

 

Reducing weight can have a big effect on times. Less weight and a cool day will bring on the 13's.

 

1)practice your launch. Get 60' time down. That is what will put you in the 13's
2)take out spare or anything else you can
3)use 100+ octane fuel.
4)better intake. (more flow)
5)run on a cool day 60 degrees or less.

Probably all the stuff you already know but thought I would mention.

 

Your 60' time should be below 1.90. For an S4, people shoot for a 1.80. With the stock chip in my S4, I had a 2.02' 60' time once (2500rpm slip clutch launch) and ran a 14.39, so your ET seems just right for that launch, with more weight and more horsepower. A 1.85 60' time probably would have gotten you a 13.87 or so...

 

BTW - Temp was around 55-60

 

By shifting at 6500 you are giving up a bit of mechanical advantage. Try to time the 1-2 shift so that it is at 7000 RPM (7100 is new max in chipped ECUs).

2-3 should be done at about 6700 RPM, and in theory 3-4 should be at 5600 RPM. In practice, the time lost by shifting into 4th probably negates any added mechanical advantage, as the shift occurs very close to the end of the 1/4 mile.

The graph below will give you an idea of how the gearing impacts power at the wheels. Note that this graph was done for an APR chip, but I would not expect a great difference in a chart based on an ABT dyno run.<ul><li><a href="https://forums.audiworld.com/s4/msgs/371339.phtml">Graph of wheel torque in each gear</a></li></ul>

 

<ul><li><a href="https://forums.audiworld.com/s4/msgs/314792.phtml">Shift point discussion</a></li></ul>