Problems at the track with A6
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 34
Likes: 0
From: Houston Texas
Problems at the track with A6
My car usually consistently runs 11.4-11.3 @ around 125 with about a 1.9 60 ft. with 18" MT drag radials. I have a 6 lb. Procharger, Kook's LT's, Kook's Hi-flo cats and Corsa touring. I also have a wide-body kit. The work and tune was done by MTI in Houston. The car has 7500 miles and about 5500 miles on the car since the work and tune.
The problem was. . .I went to the track on Friday night. Swaped from my 19's to my 18" drag radials and proceed to make my passes. First pass I ran a 12.3 @ 89 and got out of it at the 1000 ft line. I ran in "S" mode with AH on and TC off. The car ran strong till about 5000 rpm, but the car didn't seem to want to shift. It was like the computer wasn't telling it to shift in time. It would bang-out on the rev limiter and i'd peddle it and the car would finally shift. I'd get back in it and it would do the same thing for 3rd gear. I made 4 more passes and it did the same thing each time.
The only thing I could think of is, last week I bought new tires (345/30/19's) that seem to be considerably taller than my 315/30/18 DR's. Before, I was running 325/30/19 run-flats, but never had a problem with the car not wanting to shift.
Anyone have any idea why the car would act that way?
The problem was. . .I went to the track on Friday night. Swaped from my 19's to my 18" drag radials and proceed to make my passes. First pass I ran a 12.3 @ 89 and got out of it at the 1000 ft line. I ran in "S" mode with AH on and TC off. The car ran strong till about 5000 rpm, but the car didn't seem to want to shift. It was like the computer wasn't telling it to shift in time. It would bang-out on the rev limiter and i'd peddle it and the car would finally shift. I'd get back in it and it would do the same thing for 3rd gear. I made 4 more passes and it did the same thing each time.
The only thing I could think of is, last week I bought new tires (345/30/19's) that seem to be considerably taller than my 315/30/18 DR's. Before, I was running 325/30/19 run-flats, but never had a problem with the car not wanting to shift.
Anyone have any idea why the car would act that way?
Drifting
Joined: Dec 2002
Posts: 1,613
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If you are sure you were not in paddle mode the best thing would be to bring your HPtuners with you to the track and tweek your shift points.
But the taller tire should shift sooner??? anyway
Lower the shift mph by 1 mph (for the 1-2) then tweek the shift rpm to your liking there are 4 or 8 tables I would make them all the same.
But the taller tire should shift sooner??? anyway
Lower the shift mph by 1 mph (for the 1-2) then tweek the shift rpm to your liking there are 4 or 8 tables I would make them all the same.
Last edited by SoldSyclone; May 12, 2008 at 12:47 PM.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
If you are sure you were not in paddle mode the best thing would be to bring your HPtuners with you to the track and tweek your shift points.
But the taller tire should shift sooner??? anyway
Lower the shift mph by 1 mph (for the 1-2) then tweek the shift rpm to your liking there are 4 or 8 tables I would make them all the same.
But the taller tire should shift sooner??? anyway
Lower the shift mph by 1 mph (for the 1-2) then tweek the shift rpm to your liking there are 4 or 8 tables I would make them all the same.
Drifting
Joined: Dec 2002
Posts: 1,613
Likes: 0
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 34
Likes: 0
From: Houston Texas
Thanks guys. I beleive my tuner uses LS Edit and not HP Tuners. I'll just take my car back in and see if they can fix it. The funny thing is. . .the car has shifted fine in the past and nothing has changed.
Drifting
Joined: Dec 2002
Posts: 1,613
Likes: 0
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
I'll be in Vegas in September, thought about running there, but I'm only there during the week, not the weekend.
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 34
Likes: 0
From: Houston Texas
Well. . .as I mention in the original post, I was running 325/30/19's run flats on the street and last week bought some 345/30/19 Nitto Invos that are a little taller. I thought perhaps the computer was confused when I put the DR's on, which are 315/30/18, which are much shorter.
The car didn't seem to mind going from the 325/30/19's to the DR's, so I didn't figure it would make a difference with the 345's.
The car didn't seem to mind going from the 325/30/19's to the DR's, so I didn't figure it would make a difference with the 345's.
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Race Director
Joined: Mar 2005
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From: Austin Texas
Computer (Active Handling) was confused. Front to rear rotation speeds are too great with the 18" Drag radials
Stock rear = 84.35" circumference.
325/30/19 = 83.78", 0.68% smaller.
345/30/19 = 85.26", 1.07% larger.
315/30/18 = 79.92", 5.26% smaller.
The computer may have been applying the brakes to try balance the F to R tire speeds. Maybe try a smaller front tire with the drag radials?
Stock rear = 84.35" circumference.
325/30/19 = 83.78", 0.68% smaller.
345/30/19 = 85.26", 1.07% larger.
315/30/18 = 79.92", 5.26% smaller.
The computer may have been applying the brakes to try balance the F to R tire speeds. Maybe try a smaller front tire with the drag radials?