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Author
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Topic: Launching ABOVE stall rpm?
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 01:08 PM
   
Can you do it with a trans brake? I always thought that you couldn't launch above the stall rpm of the converter, but now I am being told that you can. These automatics are so confusing! 
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 01:27 PM
NO,The max engine speed on the t-brake is the stall rpm.  SteveW
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 01:39 PM
quote:
Originally posted by steve'66:
NO,The max engine speed on the t-brake is the stall rpm. SteveW
So if you had a 2500 stall, that would be the highest you could launch, right?
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 01:58 PM
You could set the two step higher, but then why bother using a two step. Your confusion may be because some car's foot brakes aren't good enough to hold the car back to the converter's real stall speed. Like a t-brake can. SteveW
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 02:06 PM
quote:
Originally posted by steve'66:
You could set the two step higher, but then why bother using a two step. Your confusion may be because some car's foot brakes aren't good enough to hold the car back to the converter's real stall speed. Like a t-brake can. SteveW
The reason I ask is because I have gotten a recommendation from 2 converter companies saying that a 2500 stall is what I would need. And since I am used to launching the 5 speed at 5500, 2500 seems like bog city to me. 
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 02:58 PM
Yeah,I think your car will be a pig with a 2500 stall converter.  SteveW
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kid vishus
Gearhead Posts: 4538
From: middle of NC
Registered: Oct 2000
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posted 08-22-2002 06:48 PM
quote:
Originally posted by steve'66:
Yeah,I think your car will be a pig with a 2500 stall converter. SteveW
I agree with Steve. that's way too tight of a convertor. I would have guessed more around 4000, unless it's street driven alot, then I ouwld still say at least 3000-3200. I would definatley call someone else and see what they say. Maybe the motor needs more cam and that is confusing the tech people.
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 06:49 PM
quote:
Originally posted by kid vishus:
I agree with Steve. that's way too tight of a convertor. I would have guessed more around 4000, unless it's street driven alot, then I ouwld still say at least 3000-3200. I would definatley call someone else and see what they say. Maybe the motor needs more cam and that is confusing the tech people.
It's driven to and from the track; that's all the street it sees.
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 08:00 PM
4,000 stall YES  Next time you call them don't mention the street and see what they say. SteveW
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Rustang
Gearhead Posts: 471
From: Clarion PA
Registered: Nov 2000
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posted 08-22-2002 09:46 PM
Some things to consider:
Don't forget that a torque converter can produce over 2 times engine torque at stall.
What stall speed you choose will really depend on what rpm maximum torque happens with your engine. You want stall to occur just slightly below or at max torque for best performance. If your motor makes max torque at 2700, then 2500 stall might be good. My guess is, however, like the other guys, that a hot street 289 will probably have max torque around 3500.
My experience is make sure the converter mfg. builds a converter tailored to your combo, and not simply pull their "standard" item off the shelf and sell it to you. Chances are you won't be happy. ------------------
'68 mustang 351 clevor- 10.92@124
'67 Stang, 351W -11.18@118
'69 351C Torino-14.90@100
'78 Pickup 351W-15.56@88
'79 Pickup 460 ET=??
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 09:51 PM
Russ,His dyno sheet said max torque about 4200 if I remember an earlier post correctly. So you agree with us. The wrong converter is what gives automatics a "bad rap". SteveW
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 10:00 PM
quote:
Originally posted by steve'66:
Russ,His dyno sheet said max torque about 4200 if I remember an earlier post correctly. So you agree with us. The wrong converter is what gives automatics a "bad rap". SteveW
You're very close; it was 4100. But the weird thing was the horsepwoer really struggled from 5200-6200; only gaining like 12 hp in that band. I don't know if it's the 1 1/2 primaries on teh tri-y's, or the Pertronix, or what, but that ain't right, either!
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 10:08 PM
You've GOT to get rid of those why-try headers! A cheap set of Headmans ($100) will let it breath up top! SteveW
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65_289
Gearhead Posts: 761
From:
Registered: Jul 2001
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posted 08-22-2002 10:36 PM
quote:
Originally posted by steve'66:
You've GOT to get rid of those why-try headers! A cheap set of Headmans ($100) will let it breath up top! SteveW
I was thinking of Super Comps for my birthday in October........
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steve'66
Gearhead Posts: 6522
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-22-2002 11:45 PM
SuperComps are even better.  SteveW
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