torque converter

zby67

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Nov 15, 2010
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ok i was reading around and for an auto trans the stock stall for the torque converter is 400. now lets say i bump it up to 800 or 1000? (no higher then 800 if i stay N/A) and how much torque would be gained? N/A engine (K&N air intake)? turbo engine (with 57 trim CT-26 turbo)?
 

Devin LeBlanc

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umm, yeah, no... huh? That didn't make any since..

Service manual says the stall speed for N/A's are 2200 rpm, and for Turbo models 2500 rpm.

My stock Torque converter stalled about 1900 before starting to spin the tires. I had mine re done and now stalls at 2500 rpm.

You won't gain any torque from it.. That is just the stall speed.
 

IJ.

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You do actually pick up some torque with a High Stall, a TC is a torque multiplier, it only multiplies while there's a difference in speeds across it ie: Slip, once it hydraulically "locks" you pretty much back to 1:1.

My 7M with stock stall speed even with 500+ rwhp was a SLUG off the line, fitted a 2800 Histall and the car was transformed and stupid fast from a dig.
 

zby67

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IJ.;1731982 said:
You do actually pick up some torque with a High Stall, a TC is a torque multiplier, it only multiplies while there's a difference in speeds across it ie: Slip, once it hydraulically "locks" you pretty much back to 1:1.

My 7M with stock stall speed even with 500+ rwhp was a SLUG off the line, fitted a 2800 Histall and the car was transformed and stupid fast from a dig.

ok so i was wrong on the stock stall speed.

what would happen if you put a highstall on a stock engine?
 

IJ.

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zby67;1732135 said:
ok so i was wrong on the stock stall speed.

what would happen if you put a highstall on a stock engine?

Ummm the car would be less of a slug on launches, think of it as slipping a clutch on a manual car to get the RPM's up where the engine is making good power as opposed to a granny start.
 

zby67

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IJ.;1732269 said:
Ummm the car would be less of a slug on launches, think of it as slipping a clutch on a manual car to get the RPM's up where the engine is making good power as opposed to a granny start.

so even with out a turbo high stall speed the better?
 

Nick M

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IJ.;1731982 said:
My 7M with stock stall speed even with 500+ rwhp was a SLUG off the line, fitted a 2800 Histall and the car was transformed and stupid fast from a dig.

The book says 2500, and I haven't seen it. Mine is also about 1900. That will cut about 2.667 60' with a turbo that comes in about 2500, and is pulling hard at 3500.
 

IJ.

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Nick M;1733132 said:
The book says 2500, and I haven't seen it. Mine is also about 1900. That will cut about 2.667 60' with a turbo that comes in about 2500, and is pulling hard at 3500.

Thinking the book is talking about a "flash stall" and not a hard stall on the brakes Nick, ie: Stab the throttle and it'll go to 2500 for a split second but does pull back to 1900ish when fully loaded, flashing my 2800's give me closer to 3500 but it takes a good set of tires to hook up this way as it shock loads the chassis, I could break the 7m loose at just about any speed up to 60mph if I did this with TRAC off.
 

Nick M

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Toyota claims 2500 if you put your foot on the floor with the brakes applied. Mine won't. It will crawl over 2000 and slowly rise after the flash. I always get off the throttle after it reaches the stall. I don't have a large cooler installed yet. Shame on me.
 

Devin LeBlanc

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With the stock stall I was cutting 1.8 60 ft's E-brake pulled full and hard on the brakes. It would go to about 2800 and I would launch. Now I have a "loosened" converter that I can launch at about 3500 which gets me well into the power range. 1.6 60ft's all day long with the MT Slicks
 

IJ.

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Nick M;1733159 said:
Toyota claims 2500 if you put your foot on the floor with the brakes applied. Mine won't. It will crawl over 2000 and slowly rise after the flash. I always get off the throttle after it reaches the stall. I don't have a large cooler installed yet. Shame on me.

Same same, mine would try to drive away doing this with the stock convertor, I played around with Launch Control in the MoTeC with the HighStall and there was no way in hell I could hold it on the brakes as the vaccum in the boosted bled off the car just drove away.
 

zby67

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How do you test the stall? If i puch it say from a stop sign right befor 2k rpms (1700-1800 rpms) is when i gain power and i clime in speed faster. Now with a stick ether w87 or R154 how would do this or does a stick have a torqu coverter? I dont know much about sticks. And barrly know how to drive one.
 

SupraCorwin

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With a stick your left foot is the torque converter, press in the clutch and rev the engine to desired rpm range then let go.
Manual transmissions use a flywheel and clutch instead of a TC.
 

Nick M

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SupraCorwin;1733556 said:
With a stick your left foot is the torque converter, press in the clutch and rev the engine to desired rpm range then let go.
Manual transmissions use a flywheel and clutch instead of a TC.

Not really. A torque converter mulitplies engine torque. A manual trans does not. The converter has a built in stall speed from the design, but it also reacts to the input torque. The more torque it is fed, the more the you get out of it. A properly built auto will whip a manual with the same gear ratios every time. Properly built means it has performance in mind, not comfort.
 

SupraCorwin

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Nick M;1733645 said:
Not really. A torque converter mulitplies engine torque. A manual trans does not. The converter has a built in stall speed from the design, but it also reacts to the input torque. The more torque it is fed, the more the you get out of it. A properly built auto will whip a manual with the same gear ratios every time. Properly built means it has performance in mind, not comfort.

I was only giving that example to Zby67 for a manual tranny's relation to stall speeds... Obviously a auto has many more differences then a manual.