Stall TC GUYS Question about a Problem???
Thread Starter
Burning Brakes
Joined: Sep 1999
Posts: 1,247
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Stall TC GUYS Question about a Problem???
Lately at the track I have not been able to stall my Yank 3200 TC properly. After the burnout, and stage, I usually foot brake it up to 25-2600. Previously this was no problem, but lately as it comes up to 2000 the motor just starts to bog and the rpm will drop instead of going higher, no matter how much more throttle I give it. Actually more throttle makes the rpms drop. :confused: I spoke to a friend of mine Saturday who told me he had the same issue. Any thoughts on this would be appreciated.
Thanks,
Mike :flag
Thanks,
Mike :flag
Race Director
Joined: Oct 1999
Posts: 17,708
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From: Phila PA, Bonita Springs FL
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
Hi Mikie :seeya
I guess I'm that guy, and I have the same problem, only I can NEVER go over 2000 rpms...
My thought is tuning...
Not sure if this makes sense, but as you rev, you're giving more fuel to the engine, but since you're at a stand still, you're NOT giving it any more air, so either its way too rich, or the reving without increased air is messing up the A/F ratio..
I would think the sensors in the MAF unit would accomodate & adjust for this condition, but since we BOTH have the same problem, probably not...
I always wonder how some A4 cars can really tach it up at the line & we can't.
I am going for LS-1 Edit wideband O2 dyno tuning in August..
I guess I'll be able to know if tuning is the answer in Sept, but maybe someone in the know will chime in before...
Ellis
[Modified by indypace78, 8:50 PM 7/17/2003]
I guess I'm that guy, and I have the same problem, only I can NEVER go over 2000 rpms...
My thought is tuning...
Not sure if this makes sense, but as you rev, you're giving more fuel to the engine, but since you're at a stand still, you're NOT giving it any more air, so either its way too rich, or the reving without increased air is messing up the A/F ratio..
I would think the sensors in the MAF unit would accomodate & adjust for this condition, but since we BOTH have the same problem, probably not...
I always wonder how some A4 cars can really tach it up at the line & we can't.
I am going for LS-1 Edit wideband O2 dyno tuning in August..
I guess I'll be able to know if tuning is the answer in Sept, but maybe someone in the know will chime in before...
Ellis
[Modified by indypace78, 8:50 PM 7/17/2003]
Le Mans Master
Joined: Jan 2001
Posts: 5,786
Likes: 6
From: Lafayette Colorado
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
I just got done figuring out this problem. I upgraded my TC from a 3200 to 3800 and I was getting crappy results launching. I would get up to about 2300ish rpms, let off the brake and mash the gas and the car would only increase in rpms and mph slowly.
The fix was to increase the line pressure because of the higher stall converter. The other thing is that GM built in a feature with automatic transmissions using the OBD-II system. When both the brakes and gas are pressed together, the PCM will decrease torque so that the brake will hold and not let the car move forward. This is why you are only getting about 2000ish rpms.
To fix the problem, you need to reprogram the PCM. With LS1Edit; increase the Base Pressure vs Torque table and decrease the Brake Pressure vs Torque table. Both of these are in the Shift Firmness tab in the Transmission window. After I did this, I finally got to feel the full power of 3.90 gears and a Vig 3800 TC :D :eek: :hurray: :yesnod:
Keith
The fix was to increase the line pressure because of the higher stall converter. The other thing is that GM built in a feature with automatic transmissions using the OBD-II system. When both the brakes and gas are pressed together, the PCM will decrease torque so that the brake will hold and not let the car move forward. This is why you are only getting about 2000ish rpms.
To fix the problem, you need to reprogram the PCM. With LS1Edit; increase the Base Pressure vs Torque table and decrease the Brake Pressure vs Torque table. Both of these are in the Shift Firmness tab in the Transmission window. After I did this, I finally got to feel the full power of 3.90 gears and a Vig 3800 TC :D :eek: :hurray: :yesnod:
Keith
Race Director
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From: Phila PA, Bonita Springs FL
Re: Stall TC GUYS Question about a Problem??? (kromberg)
Hummmmmmmmmm
Everything you said seems to makes sense....
Can't wait to get my car to Julio at Cartek......! :smash: :cool:
[Modified by indypace78, 8:37 PM 7/18/2003]
Everything you said seems to makes sense....
Can't wait to get my car to Julio at Cartek......! :smash: :cool:
[Modified by indypace78, 8:37 PM 7/18/2003]
Thread Starter
Burning Brakes
Joined: Sep 1999
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Re: Stall TC GUYS Question about a Problem??? (kromberg)
Kromberg
Thanks bud, this does make sense :yesnod: I had a feeling that it was some how related to some ECM built-in "fail safe" item.
That's why I love this forum, it seems some one always has the answer. :)
Ellis
I am trying to get a hold of Dennis, as he has our LS1 edit, so I can program it as Kromberg suggested. I will let you know how it woirks out ASAP
Kromberg
Thanks again....Youdaman :smash: :cheers:
Mike :flag
Thanks bud, this does make sense :yesnod: I had a feeling that it was some how related to some ECM built-in "fail safe" item.
That's why I love this forum, it seems some one always has the answer. :)
Ellis
I am trying to get a hold of Dennis, as he has our LS1 edit, so I can program it as Kromberg suggested. I will let you know how it woirks out ASAP
Kromberg
Thanks again....Youdaman :smash: :cheers:
Mike :flag
Safety Car
Joined: Aug 2000
Posts: 4,154
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From: Murphy TX
Cruise-In II Veteran
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
Previously this was no problem, but lately...
If you have a stock PCM (I didn't think you did... :confused: ) I think you're just seeing the effects of abuse mode. Keith, can you confirm whether or not the abuse mode stuff controls whether or not the Brake P v T table is used or otherwise comment on the relationship between them?
[Modified by ToplessTexan, 8:45 AM 7/19/2003]
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Race Director
Joined: Oct 1999
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From: Phila PA, Bonita Springs FL
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
Let me know how it works ASAP!!! 215-416-0186
Is this something most tuners already know, or should we be specifically mentioning these items get done?
Is this something most tuners already know, or should we be specifically mentioning these items get done?
Thread Starter
Burning Brakes
Joined: Sep 1999
Posts: 1,247
Likes: 0
Re: Stall TC GUYS Question about a Problem??? (ToplessTexan)
Previously this was no problem, but lately...
Hmmm... Are you saying that the behavior has changed with the car in the same configuration or that the behavior has changed as a result of changing configurations?
If you have a stock PCM (I didn't think you did... :confused: ) I think you're just seeing the effects of abuse mode. Keith, can you confirm whether or not the abuse mode stuff controls whether or not the Brake P v T table is used or otherwise comment on the relationship between them?
[Modified by ToplessTexan, 8:45 AM 7/19/2003]
Hmmm... Are you saying that the behavior has changed with the car in the same configuration or that the behavior has changed as a result of changing configurations?
If you have a stock PCM (I didn't think you did... :confused: ) I think you're just seeing the effects of abuse mode. Keith, can you confirm whether or not the abuse mode stuff controls whether or not the Brake P v T table is used or otherwise comment on the relationship between them?
[Modified by ToplessTexan, 8:45 AM 7/19/2003]
When I first installed this TC it was not a problem. It just got progressively worse :confused: I have stock tuning but a few items changed with LS1 Edit, such as shift points and TM deleted. What are your thoughts on this?
Thanks,
Mike
Racer
Joined: Mar 2002
Posts: 488
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Re: Stall TC GUYS Question about a Problem??? (wallstAL)
I am sooo going to try this when I get home.
On a stock TC I cant do burnouts at the track without going into the water box (even on stock tires) and even then I can only do them for a few seconds before the PCM starts reducing power and I can't spin anymore. I already took out TQ managment completely and made it so it can't check for abuse mode so I know that is not the problem.
On a stock TC I cant do burnouts at the track without going into the water box (even on stock tires) and even then I can only do them for a few seconds before the PCM starts reducing power and I can't spin anymore. I already took out TQ managment completely and made it so it can't check for abuse mode so I know that is not the problem.
Safety Car
Joined: Aug 2000
Posts: 4,154
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From: Murphy TX
Cruise-In II Veteran
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
When I first installed this TC it was not a problem. It just got progressively worse :confused: I have stock tuning but a few items changed with LS1 Edit, such as shift points and TM deleted. What are your thoughts on this?
Safety Car
Joined: Aug 2000
Posts: 4,154
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From: Murphy TX
Cruise-In II Veteran
Re: Stall TC GUYS Question about a Problem??? (indypace78)
Can this "abuse mode" be eliminated?
Or do making theses adjustments just greatly reduce it?
Or do making theses adjustments just greatly reduce it?
[Modified by ToplessTexan, 6:27 PM 7/19/2003]
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From: Phila PA, Bonita Springs FL
Re: Stall TC GUYS Question about a Problem??? (ToplessTexan)
kromberg...
I see you made you made this post. http://forums.corvetteforum.com/zerothread?id=600888
Did you suddenly become educated in LS-1 Edit, or did a tuner do the adjustments as you describe above? Great job & thanks if it works..
I see you made you made this post. http://forums.corvetteforum.com/zerothread?id=600888
Did you suddenly become educated in LS-1 Edit, or did a tuner do the adjustments as you describe above? Great job & thanks if it works..
Pro
Joined: Mar 1999
Posts: 535
Likes: 1
From: GA
Re: Stall TC GUYS Question about a Problem??? (kromberg)
With LS1Edit; increase the Base Pressure vs Torque table and decrease the Brake Pressure vs Torque table. Both of these are in the Shift Firmness tab in the Transmission window.
Thanks.
Le Mans Master
Joined: Nov 2000
Posts: 7,294
Likes: 1
From: Coral Springs Florida
Re: Stall TC GUYS Question about a Problem??? (Mikie C)
For best results on a launch use a "flash stall" at the track..NOT a brake stall.. :nono: I was of the thinking that a higher brake stall at 2800-3000 would put me in the "power range" at launch as well but actually my best 60' times and best E.T.'s are a result of a flash stall engagment.. I now only load the engine to about 1300-1500 and smash the gas on the third yellow..!!
BTW , I have a YANK SS3800 and 3.73's....It works!! Try it.. :yesnod:
BTW , I have a YANK SS3800 and 3.73's....It works!! Try it.. :yesnod: