im going to putting a stall in my lifted 2500hd before i do my cam. what stall speed is everyone running? do i need to upgrade the tranny cooler? any info is appreciated thanks
I know im thread digging here but Great response. I was actually looking for a new torque converter as mine has started making some horrendous noise when i stumblef across this old post on google. After reading it i think ill go with a 3000-3200 stall.Dont let the grammar NAzi's get you down. Stall can be either a noun or a verb. I installed a higher rpm stall converter. Noun I stalled up the TC. Verb.
You want to install a TC with a higher stall speed, which probably has a smaller turbine in it if you go with a quality aftermarket unit.
In the Vortec 305/350 you can use an S-10 V6 TC and behind a Voirtec 350 I get 2700-2800 stall speed with the rear tires stationary, trans in gear, throttle on the floor.
The 5.3/6.0 that has a 60e/65e/70e trans begind them can benefit from a TC from a Trailblazer that has an inline 6 cylinder in it. Guys report 2300-2800 rpm stall speeds with this TC.
Since you have the 4l80e, you are very limited in regards to such swapping of stock TC's, but all is not lost. For a while there were indeed vans that were equipped with the Vortec 4.3 V6 and 4l80e transmissions. Attaining the TC from such a vehicle will give you some extra stall speed while retaining the efficient STR(stall torque ratio).
If you really want some fun stoplight fun I suggest you go with an aftermarket TC, but these raent cheap. You dont need a multidisk clutch setup. Those are only of interest if you are locking the TC at WOT with big power. Let it be known that the 4l80e does lock its TCC at WOT in 2nd gear with throttles above 87.5%. 60e trucks dont lock at WOT til over 75mph in 3rd gear.
Staying with a single clutch will help to save some money.
Yank, Precision Industries, and I would give Circle D a try($775 for either a 245mm(9-3/4")3000-4400 or a 258mm(10-1/4") 2500-3500 rpm of stall speed.
I assume since you have a truck that has the 80e that you are driving a 3/4 HD truck with the LQ4 engine rated at [email protected]/360 lb/[email protected]
Maximum acceleration from a torque converter is attained when the exact stall speed occurs at peak engine torque. That way the engien has to accelerate from peak torque to peak hp. But for daily driving it is suggested that the TC stall speed be under the torque peak. Because of thisw I suggest a torque converter with a stall speed of 3400-3800rpm.
The proper TC will be one of the biggest bang for buck modifications you can make to your truck(even with the high cost of the 80e/85e TC's). It made a big difference in my truck and the Vortec 350(L31) is much different than the much better power at upper rpm LQ4 GEN 3 engine. I have better out of the hole launches, as well as much better acceleration recovery after WOT shifts (lower my shift extension by 400rpm) as well as improving 2nd gear and 3rd gear roll ons. With a GEN 3 engine, the gains from a higher stalling TC would be even greater due to its higher powerbands than the earlier GEN 1E Vortec engines.
A high stall TC installed in a TBI engined truck could actually have its acceleration hindered as the stall speed of the TC could be past its torque peak. SOme TBI engines had torque peaks of 1800rpm, so a 2800rpms tall speed may not work out so well.
Ever notice how your engine at WOT tends to seem much more powerful above 3500 rpm than when below? Thats because the GEN 3 engines need those revs to get the power numbers they do.
A higher stalling TC will allow your engine to get past the lower revs and into the meat of its torque and power band MUCH quicker. The good thing is that since all these modern auto transmissions have TCC's(torque converter clutches) if you jhave a TC stall speed of 3500rpm, your cruise revs arent going to be 3500rpm like they would with the older th350/400transmissions.
When you are at light throttle when cruising the TCC will lock bringing your transmission inpout shaft speeds down to whatever your engine rpm is(or pretty close depends on the PWM-pulsewidth modulation setup of your truck).
The biggest problems with a higher stalling TC heat production occurs when towing, as this causes the TC to stall more(if TCC is unlocked) and towing itself can induce TCC unlocking which allows the TC to stall higher which causes increased temps. A simple WOT blast down the 1/4 mile doesnt warrant a cooler, but towing a trailer up a hill certainly does. Temps can be in the 700º range coming right off the fins in certain hi-po situations. Your HD truck will have the stock trans fluid cooler in rad cooler as well as probably having the stock auxillary cooler. A higher stalling TC can be akin to feathering the clutch in a manaul trans equipped vehiclesp a dirtbike, it allows for better acceleration, but also creates more heat.
One possible problem might be if you like rock crawling, a really high TC stall speed can sometimes make wheel motion vs. throttle input touchy. But I have no personal experience in this.
If I were you, and was having a TC installed, I would run a 3500-3800 stall speed if you tow little and want a really fun truck out of the hole, and doing roll ons.
If you tow heavy, I suggest a lower stall speed 3000-3500rpm.
Any cam you install will probably decrease the low rpm torque production of your engine, this will cause your TC to stall at a lower rpm. If you are going agressive on the cam, you will want to go higher rpm stall speeds than I suggested. Towing heavy with tall tires/low TC stall speed and an agressive cam is looking for trouble though. Engines lugging because they are experiencing high loads while under their torque band kills economy and is hard on parts.
Baseline rule for stall is 500 RPM above the camshaft rating. If the cam has a "2,500 to 6,500" RPM range a 3,000 stall would be close. The other variables would include vehicle weight, engine size etc.I know im thread digging here but Great response. I was actually looking for a new torque converter as mine has started making some horrendous noise when i stumblef across this old post on google. After reading it i think ill go with a 3000-3200 stall.
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