Best High Stall for Light Throttle
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TECH Apprentice
Joined: Apr 2012
Posts: 333
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From: New Zealand
Best High Stall for Light Throttle I've seareched but few touch on this subject.... so here goes 
I'm currently running a Slingshot 2800 behind my 550hp LS1 that really only stalls around 2600 but at light throttle the engine will slip about an extra 500rpm to move out on light throttle, more on a hill, as I have 3.07:1 rear gears. Because the exhaust is fairly loud the slip is quite noticable around town. On the flat it will of course idle forward no problem.
I'm thinking of getting another converter with a lock up that can handle WOT at up to 700rwhp.
I don't want any more slip than I've got however! It feels loose as it is until I step on it.
So what converters are you guys running that could get more stall and be no looser than what I have and handle lock up at WOT?
Was thinking PC Vigilante 3200 with triple disck lock up - but have heard they are not as tight at light throttle as some. Can handle 500rpm slip - but 1000rpm would be a joke around town.
Cheers
I'm currently running a Slingshot 2800 behind my 550hp LS1 that really only stalls around 2600 but at light throttle the engine will slip about an extra 500rpm to move out on light throttle, more on a hill, as I have 3.07:1 rear gears. Because the exhaust is fairly loud the slip is quite noticable around town. On the flat it will of course idle forward no problem.
I'm thinking of getting another converter with a lock up that can handle WOT at up to 700rwhp.
I don't want any more slip than I've got however! It feels loose as it is until I step on it.
So what converters are you guys running that could get more stall and be no looser than what I have and handle lock up at WOT?
Was thinking PC Vigilante 3200 with triple disck lock up - but have heard they are not as tight at light throttle as some. Can handle 500rpm slip - but 1000rpm would be a joke around town.
Cheers
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Joined: Aug 2010
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From: Ann Arbor, MI
I have a 525(?)HP LS2 with an aggressive cam (231/239 duration, .617/.624 lift, 113 LSA). I suspect you have something similar. I have set the lockup relatively high at 55 mph; anything lower and the engine/car will chug noticeable because the cam is not smooth under 1800 rpm. Others have reported similar chugging and "solved" it by also increasing their lockup speed.
I ran a Yank 3600 which I read is tighter than most around town (and conversely not as quick at the track). I don't have hills to deal with.
Considering that a triple disk is around $1000, I would suggest changing to a 3.42 or even 3.73 which will make your existing converter feel much tighter and make the car perform better at only a slight reduction in gas mileage.
I ran a Yank 3600 which I read is tighter than most around town (and conversely not as quick at the track). I don't have hills to deal with.
Considering that a triple disk is around $1000, I would suggest changing to a 3.42 or even 3.73 which will make your existing converter feel much tighter and make the car perform better at only a slight reduction in gas mileage.
Thread Starter
TECH Apprentice
Joined: Apr 2012
Posts: 333
Likes: 4
From: New Zealand
Thread Starter
TECH Apprentice
Joined: Apr 2012
Posts: 333
Likes: 4
From: New Zealand
I have a 525(?)HP LS2 with an aggressive cam (231/239 duration, .617/.624 lift, 113 LSA). I suspect you have something similar. I have set the lockup relatively high at 55 mph; anything lower and the engine/car will chug noticeable because the cam is not smooth under 1800 rpm. Others have reported similar chugging and "solved" it by also increasing their lockup speed.
I ran a Yank 3600 which I read is tighter than most around town (and conversely not as quick at the track). I don't have hills to deal with.
Considering that a triple disk is around $1000, I would suggest changing to a 3.42 or even 3.73 which will make your existing converter feel much tighter and make the car perform better at only a slight reduction in gas mileage.
I ran a Yank 3600 which I read is tighter than most around town (and conversely not as quick at the track). I don't have hills to deal with.
Considering that a triple disk is around $1000, I would suggest changing to a 3.42 or even 3.73 which will make your existing converter feel much tighter and make the car perform better at only a slight reduction in gas mileage.
Last edited by Bazman; May 2, 2013 at 06:04 PM.
The lower the STR, the less pedal you will need to move
and the lower the light-throttle RPM rise will be. You also
would see torque multiplication continue to higher RPMs.
This (low STR) is not too popular though; I had to spec
mine custom.
and the lower the light-throttle RPM rise will be. You also
would see torque multiplication continue to higher RPMs.
This (low STR) is not too popular though; I had to spec
mine custom.
Thread Starter
TECH Apprentice
Joined: Apr 2012
Posts: 333
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From: New Zealand
My understanding is that a high STR only helps for the 1st second anyway as it dissolves once the car rolls out??
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Right, STR is not just the raw torque multiplication
at stall, it also is the "slope" of how that multiplication
rolls off with RPM. A high STR hits hard and fades early
to 1:1; a low STR hits softer but multiplies further out.
With a 3500/2.0 I am seeing multiplication past 5000RPM
as evidenced by an uphill pull where I WOT-locked the
converter midway, and could see the acceleration fall
back.
Yank used to have some converter dyno curves in
their tech section that illustrate this (though I'm sure
there is variation by build / design, to the STR's relation
to efficiency, coupling-slope and so on).
at stall, it also is the "slope" of how that multiplication
rolls off with RPM. A high STR hits hard and fades early
to 1:1; a low STR hits softer but multiplies further out.
With a 3500/2.0 I am seeing multiplication past 5000RPM
as evidenced by an uphill pull where I WOT-locked the
converter midway, and could see the acceleration fall
back.
Yank used to have some converter dyno curves in
their tech section that illustrate this (though I'm sure
there is variation by build / design, to the STR's relation
to efficiency, coupling-slope and so on).
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TECH Apprentice
Joined: Apr 2012
Posts: 333
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From: New Zealand
Right, STR is not just the raw torque multiplication
at stall, it also is the "slope" of how that multiplication
rolls off with RPM. A high STR hits hard and fades early
to 1:1; a low STR hits softer but multiplies further out.
With a 3500/2.0 I am seeing multiplication past 5000RPM
as evidenced by an uphill pull where I WOT-locked the
converter midway, and could see the acceleration fall
back.
Yank used to have some converter dyno curves in
their tech section that illustrate this (though I'm sure
there is variation by build / design, to the STR's relation
to efficiency, coupling-slope and so on).
at stall, it also is the "slope" of how that multiplication
rolls off with RPM. A high STR hits hard and fades early
to 1:1; a low STR hits softer but multiplies further out.
With a 3500/2.0 I am seeing multiplication past 5000RPM
as evidenced by an uphill pull where I WOT-locked the
converter midway, and could see the acceleration fall
back.
Yank used to have some converter dyno curves in
their tech section that illustrate this (though I'm sure
there is variation by build / design, to the STR's relation
to efficiency, coupling-slope and so on).
So if I read that right - a big hit STR might be popular but is only any good for burn outs or on slicks? Then I'd far rather have the more efficient lower STR that gives more under the curve, has less slip at light throttle, and will still stall at the rpm you want at WOT.
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