Pixlix

Vehicle : 2011 A6 Grand Sport

Last Friday weather was pretty good here in south texas so I decided to get the dark stars on and head out to the local race track , previous best has been a 11.005 @125.6 with 1.59 60ft

New best 10.905 @ 126.2 with 1.54 60ft

Car felt pretty good however I still need to get my transmission tune checked out because as soon as it takes off the line it sounds like it downshifts and looses some momentum

Mods are : TSP 235/239 cam,
1 7/8 long tubes , 3" x pipe , 3" borla stinger exhaust off z06, Underdrive pulley, Vararam cold air, Yank 3600, tune and dark stars with 28" Hoosier race slicks , stock unmilled heads other than BTR valve springs
And stock 2:73 rearend

SteveDoten@ARH

nice results!! Is the 28" tire best with the 2.73's?

who tuned the car?

Pixlix

Yes 2:73s with a 28" tire, Wally from Auto Adrenaline in stafford, TX tuned it

dicky

Nice time! For some reason it seems like its almost impossible to cross that 11.00 for some of us, I tried for about a 1.5 years before i finally did myself. The trans problem you're having, does it actually feel like it downshifts of does it just sound like it?

You should see if you can borrow a set of 26" tires to try, they might work a little better for you. The 26" would give it a bit more of a gear advantage unless it will cause you to shift right before the finish.

congrats
dicky

Plaincoupe

Congrat on the new best! my car does the same when i launch it an i cant figure it out.....

Pixlix

I can feel it come up and squat again, I'll try and get the video link ,you can actually see the car doing the double squat , It even does it launching on 1 with the paddle , can't figure it out

As far As 26" I'm Gona really look into them for n/a runs , I use 28" because every now and then I spray it off the line

Pixlix

It's gone 10.504@ 130 with 100 shot off the line before , doesn't work as well because it hits the rev between shifts

dicky

Ok the 28 make since then, I'm getting ready to do nitrous myself so I'm having to move up to 28s too. I think i know what you're talking about with the trans, mine used to the something like that.

Back before I finally got a good trans rebuild mine would launch off the line real hard like usual but at 19 mph (i have 3.42 gears and 26" tires) it felt like i got rear ended by a mack truck. At 19 mph it felt like a really hard down shift hard enough to break my tires loose a little and causing me to hit the rev limiter on most runs. After the 1-2 shift the rest of the run was perfect but the 1-2 shift with the odd 1st gear thing caused my times to be pretty unpredictable. The car drove around town fine, so i just kept assuming it was something in the tune or my drag radials were shot. I finally got tired of it and took it over to century transmission for a rebuild.

Mike at century pulled it apart and found some gear that was busted at the base and that was the only thing we could figure was causing the odd launch. I can't remember what he called that gear but he replaced it did the full rebuild (i skipped on the output shaft) and i haven't had a problem at all since, its been going for over 3.5 years now. Now my car is pretty consistent at the track.

Do you have that nitrous on an RPM window switch?
just curious because like I said earlier, I'm about to do a nitrous setup also.

Just looked up the part, it was one of the clutch packs.

Pixlix

Damn I would really hope it's not my transmission , got the car bone stock with 14 k miles , mine doesn't feel violent in that little downshift deal , feels more like letting off and flooring
It again, the way my nitrous solenoid gets activated is with a micro switch at the bottom of the gas pedal, it's a cold fusion ring kit, I have a lingenfelter timing box and the nitrous wired together so they both power up at the same time

Pixlix

But I think imma have to get rid of the box , I was under the impression that if it shifts on motor it's Gona shift on nitrous and I was only going to have to mess with timing , I was wrong tho , it hits the rev between shifts with nitrous , the bigger the shot the more it hits. , need a different tranny tune so it would defeat the purpose of running without switching tunes

Slamdcoop0428

Congrats on hitting the 10's!! It's a great feeling. I just hit the 10's with my cam only ls3 m6 a few weeks ago

GARY2004Z06

OP- Congrats on the 10 second N/A pass.

GARY2004Z06

To anyone considering tire size, it should be based on trap speed, rpm, and gearing. There are plenty on tires that will work on a decently prepped track which are approximately 26".

CI GS

As long as you have the 6L80 trans, I think you're going to have to tune the shift points differently for nitrous vs. N/A runs. I battled the same thing with my 08 Sierra Denali for months. From what I understand (and I'm no expert), the problem is that the TCM uses input power along with programmed shift RPM and shift speeds to shift, and the added power causes it to shift higher, thereby causing it to hit the rev limiter. For example, on my truck, once I had it tuned that it shifted at say, 6600RPM on an N/A run, the minute I made a nitrous pass with the same tune, it would hit the limiter at 7000RPM and refused to shift, especially in higher gears. At first, after I figured out what the problem was (by dangerously upping the rev limit to 7200) I used a window switch to shut the N2O down at like 6500, so that when it shifted it would be off the nitrous, but I didn't like how it slowed down on each shift, although that seemed to work okay. We subsequently just retuned it with lower shift speeds on days I went to the track, since I ran in almost all the time on Nitrous, and that worked too.
Best bet is to talk to someone like subfloor on here who is an expert on these A6 transmissions. He can sort you out.
The kicking down problem that you have sounds like that may be something you need to take care of first though.
Good luck and keep knocking down those ETs!

Plaincoupe

Subfloor is the man with these transmissions, I am having the same issue with the launch, he advised me to add an 1/2 quart of fliud 1st, then if that didn't do it raise the 1-2 shift pressure. So imma give it a try, but I have to be at the track so it can hook to test out the tips he gave. if weather permits.

Plaincoupe

you can hear the off an on power on the launch

C6David

I was having the same exact problem with mine with a ss4000. Talked to a very knowledgable guy about it and that had that problem for 3 years before he figured it out. I was doing mid 1.5s and running 11.2s at the time. Said to raise the line pressure and add a quart of fluid. So thats what i did. Hit the track 2 weeks later and did a 10.88 1.49 60' Then did a 10.78 1.46 60' No more hopping or diving. It just takes off and plants down.

C6David

Congrats on the 10 sec pass too!

Plaincoupe

Awsome! Thanks for sharing, really appreciate that! I cant wait to hit the track again hopefully I can get my 10 sec pass!!

Pixlix

That's exactly what my car does plaincoupe!! I am most defenetly Gona add extra oil
First and have my tuner look over the shifts , hopefully it can lower my times also like c6david , thank you as
Soon as I get some new results or findings I'll
Post them up