Stall speed converter???
- Thread starter porkipine
- Start date
05stroker
Never enough power guy!
What brand of stall is it and how do you like it on the street?
05stroker
Never enough power guy!
That's why I was asking. Should be nothing wrong with that stall for track time. Mine was a 3800 to start with but as I increased power it now flashes to 4400. I have a 4r70w though. I put a 3000 in my son's DD as we increase power I expect to will be in the 3500 range after the blower is on.
Wow that's way more than what was recommended for my car but we do have different blowers. M90, LTs, 4.10s, Detroit rocker cams, 28 tall DR's. PI and JDM both suggest 2800-3k stall. I love it, should have added it years ago.
Definitely need more stall speed for a centrifugal blower set-up when compared to a PD blower like you have.
If you still have the lock-up function, your mielage shouldn't be much different while cruising, or your tuner needs to put more thought on "when" your converter should be locked or unlocked imo. For example if your cruising down the highway on relatively flat ground, that converter should be locked and you should be experiencing the same efficiency/fuel mielage a standard trans car would see.
Five Oh Brian
Mustang Guru
Centri blowers need rpm's, and you want your stall converter to flash to just a few hundred rpm's below your peak torque. I'd recommend a stall speed in the high 4's (4,500 to 4,900 rpm's).
I should mention that my '07 GT had a Vortech V2 SQ supercharger. Non-intercooled, stock engine, stock exhaust, stock suspension, and just 393 rwhp, but ran 11.80's with 4.10 gears and a 5R55 automatic stalled to 4800 rpm's.
I should mention that my '07 GT had a Vortech V2 SQ supercharger. Non-intercooled, stock engine, stock exhaust, stock suspension, and just 393 rwhp, but ran 11.80's with 4.10 gears and a 5R55 automatic stalled to 4800 rpm's.
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I think it's crazy that your current 5.0 is running as quick with the stock air-box / paper filter as your old supercharged 3v.
A chassis dyno sheet would be a great source to decide on stall speed.
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Five Oh Brian
Mustang Guru
Agreed. And my '14 GT AT is actually quicker than my supercharged '07 GT AT was. The '14 runs 11.50's @ 117-118 while the '07 ran 11.80's @ 113-114 in the 1/4 mile. Even with the Vortech supercharger, my '07 only put down 393 rwhp, while the 5.0L puts down 435 rwhp. Both have 4.10 gears and roughly the same stall (4800 - 5000 rpm's). The stall converters are the magic in these cars.
+1. With Porkipine's car making peak torque at 5200 rpm's, and current mods supporting high rpm power, he would benefit from a converter that flashes to that rpm range to get the car into its powerband. I wouldn't put anything lower than a 4500 rpm stall in his car, and would actually go to 5000 rpm's. With proper traction, this combo should push Porkipine's car to low 11's @ 120+ in the 1/4 mile.
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Yeah listen to Five O. He really knows that setup. I was told because my blower makes so much torque down low a smaller stall would be better and i wouldn't lose all that low end torque I have.
Five Oh Brian
Mustang Guru
I've had plenty of stalled autos over the years, and I've asked lots of questions along the way to learn what I could. The internet and forums make it so much easier to trade information these days!
As you already have a 4300 rpm stall, I'd suggest getting some baselines with the current combo with a proper sticky tire. Then, if you're itchin' to go a little quicker, send out the stall converter to have it restalled higher. A lot of converter companies will do a free restall once. Then hit the track to see how much your ET's improve.
Thanks, Patrick. You're right on the money about the difference in blowers. It really comes down to building a combo that works in harmony. Your blower is a positive displacement blower which makes so much torque down low that you want to choose parts that work in that lower rpm power band. A big stall converter in your car would shoot the rpm's past the sweet spot that your blower works best in, so a converter in the 2500 to 3200 rpm range (like the 3K stall you have) makes a lot of sense for your car.
Porkipine's centrifugal blower doesn't make much boost at low rpm's, but should pull hard as boost increases at higher rpm's all the way up to redline. That means you want a converter that gets the motor into the higher rpm's instantly to hit the sweet spot of that blower, cams, exhaust, etc. I'm not sure what your shiftpoints are (6500 - 6800 rpm's?), but the higher you can tolerate, the more boost you'll make just before the shift. And, the cool thing about a big stall converter with a centrifugal blower is that on the upshift, you stay in the boost since the rpm's don't fall much. Guys with manual transmissions lose boost on an upshift (assuming they lift the throttle to make the shift). Makes the automatic cars quicker - all else held constant.
Can't wait to see some track #'s for your car, Porkipine! Keep us posted.
It looks like PI offers 1 free stall adjustment and their converters should be lock-up converters, so highway fuel economy should be find if your tune commands lock-up properly. Around town, fuel economy takes a hit since your seeing more rpm's before lock-up can happen.
As for wide open throttle (WOT), I had great success with my 5R55S trans in my '07 GT once my tuner changed the tune to command lock-up a half second after upshifts to pull harder (without unnecessary slippage) in each gear. 1st gear does not lock-up, nor would you want it to since you need the car at high rpm's to launch quicker from a dead stop.
The right converter, tuned correctly, is the biggest bang-for-the-buck in these cars after forced induction. I saw a 6 tenths of a second improvement in my 1/4 mile time in my '14 GT with the converter. It was similar in my '07 GT, although I don't have the exact # since I did a couple mods at the same time with that car.
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Five Oh Brian
Mustang Guru
Oh man, that sucks! Sorry to hear about the converter!
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