LS1/A4 Techie opinions please
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 827
Likes: 2
From: Chandler AZ
LS1/A4 Techie opinions please
Please comment on my recent dyno pulls
http://forums.corvetteforum.com/zerothread?id=769352
http://forums.corvetteforum.com/zerothread?id=769352
Le Mans Master
Joined: Oct 2000
Posts: 6,504
Likes: 717
From: Sausalito CA
Re: LS1/A4 Techie opinions please (vettetax)
Yep that 5200 rpm drop I have seen before....and I also have it.
I've done two dynos two years apart.
To know avail have I found a resonable answer other than Torque Management.
The leads are: Knock Sensors, Weak Igintion Coil, lack of 95 octane fuel.
I am not a computer tuner expert and auto tap and the like have full grids showing air/fuel and timing ...everything. Those printouts could answer why the drop.
If moneys no object, I drive the car hard for awhile, blowing out the carbon and all on 95 octanne (race or airport) gas. Then re-dyno with this good gas and see what happens.
For one I would be very curious if you can pin point the reason for the drop and cure it!
Else, the dyno looks standard to me.
I've done two dynos two years apart.
To know avail have I found a resonable answer other than Torque Management.
The leads are: Knock Sensors, Weak Igintion Coil, lack of 95 octane fuel.
I am not a computer tuner expert and auto tap and the like have full grids showing air/fuel and timing ...everything. Those printouts could answer why the drop.
If moneys no object, I drive the car hard for awhile, blowing out the carbon and all on 95 octanne (race or airport) gas. Then re-dyno with this good gas and see what happens.
For one I would be very curious if you can pin point the reason for the drop and cure it!
Else, the dyno looks standard to me.
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 827
Likes: 2
From: Chandler AZ
Re: LS1/A4 Techie opinions please (Kenny94945)
Kenny, others are saying it's simply the A4 shifting from 3rd to 4th gear. If you exam the graphs closely, there are 3 significant dips in each curve. Makes sense if it's an automatic 4 speed....those can simply be the shift points thru the 4 gears.
Thanks for your thorough response :cheers: :cheers: :cheers:
Thanks for your thorough response :cheers: :cheers: :cheers:
Racer
Joined: Jul 2002
Posts: 267
Likes: 0
From: Minnetonka MN
Re: LS1/A4 Techie opinions please (vettetax)
I actually had the same dips on mine before installing the upgrades/tuning. It is not due to the car shifting, I can tell you that. EVERY dyno sheet I had before the heads/cam and upgraded tuning had that dip, even at different dyno shops. Car now at 415rwhp and NO dips on any dyno. I would doubt that the heads and cam had anything to do with this, so this leaves something in the factory tuning in the stock A4's that is causing the problem. That is unless there was some valve issue going on that was corrected with the upgraded heads.
You can take a look at the original dynos here:
http://ts.cranesystems.com/2002Corve...yno_number.htm
You can take a look at the original dynos here:
http://ts.cranesystems.com/2002Corve...yno_number.htm
