MPI Twin Owners, Come in!
- Thread starter SIKDMAX
- Start date
Just curious; what torque converter have you found to be the best for the Twin Turbo set up? What is the optimal stall and coupling for running twins? This might have a Dumb A$$ card to it as well. But thought I would ask.... Also if you are saying that the twins are pushing 45-55psi boost and not running head studs etc, does this mean GM made some adjustments, to handle this boost pressure.
MCRAT stated earlier that at around 45psi the truck is not tractible. Is this with the twins... or can you explain this more.. not quite understanding what is meant by this.
MCRAT stated earlier that at around 45psi the truck is not tractible. Is this with the twins... or can you explain this more.. not quite understanding what is meant by this.
Generally twin converters run a little tighter... compared to a converter for a BIG single. IMO really its preferecne and truck use. Call Mike L if you need a twin converter he has a little experience...
Pat is gloating and excited
(I would be as well) about traction at 45 lbs of boost, he has potentle for another 60 lbs of boost, yet he is traction limited at 45... he can't "hook it up" wheelspin.
I'm no expert by any means but I have some experience with twin turbos. As far as stall speed, I don't think there is any one answer. The twin sets that run a stock charger as the primary or small charger can run with a lower stall speed than a custom set for high horsepower. Whatever it takes to light the turbos. The precision in my 07 daily driver tow truck stalls at about 2100. It works fine and drives very nice. The TC in the race truck will be much higher to get the turbo to spool. This pretty simple minded and probably obvioius to most, but the traction issue in Casper is more a product of the HP and torque that Pat is making at 45lb of boost in that truck. You can make 50+ lbs of boost with a smaller hp truck and not have a traction issue. Boost under 50 lbs or so with a stock motors running stock injectors and a single CP should not be a problem. Should being the operative word. Every truck is different.
on that "other site" there is a thread about Sun Coast TCs and it said
"GM-1059-3D
Approx. brake stall is 2000 RPM
Ideal converter for twins or quick spool turbos. Our 1059-3D converter will brake stall about 2000 RPM and couples nicely at wide open speeds. When your shifts are at 2000-2500 cruising you get about a 500 RPM drop with the 1059. This converter has two limits, it requires a minimum tune of 220HP and quick spool turbo."
has any one ran this TC yet? would it be good got the BIG twin kit from MPI
"GM-1059-3D
Approx. brake stall is 2000 RPM
Ideal converter for twins or quick spool turbos. Our 1059-3D converter will brake stall about 2000 RPM and couples nicely at wide open speeds. When your shifts are at 2000-2500 cruising you get about a 500 RPM drop with the 1059. This converter has two limits, it requires a minimum tune of 220HP and quick spool turbo."
has any one ran this TC yet? would it be good got the BIG twin kit from MPI
My experience with TC's:
The trouble is getting past 2000rpm when staging. It's dependant on tuning more than charger.
For racing, no converter on the market will stall at less than 3000 when you get past the 2000rpm barrier. But some are "tighter" than others. For engines with good power at 2500 (Tune Only to 2.6" charger) a tight converter is quicker, like the Suncoast 1057. But when you go up to 3.0" and larger, looser is going to be quicker.
For twins using the stock charger, a SC 1057 will most likely be the quickest choice, since they can make good power down low. But if they are "big twins", I'd start with a looser converter. Casper runs a Mike L. converter and it spools well with a 3.2" charger (1.5x sixties) and has no problem with the PPE Bonneville twins (3.0+3.6").
The trouble is getting past 2000rpm when staging. It's dependant on tuning more than charger.
For racing, no converter on the market will stall at less than 3000 when you get past the 2000rpm barrier. But some are "tighter" than others. For engines with good power at 2500 (Tune Only to 2.6" charger) a tight converter is quicker, like the Suncoast 1057. But when you go up to 3.0" and larger, looser is going to be quicker.
For twins using the stock charger, a SC 1057 will most likely be the quickest choice, since they can make good power down low. But if they are "big twins", I'd start with a looser converter. Casper runs a Mike L. converter and it spools well with a 3.2" charger (1.5x sixties) and has no problem with the PPE Bonneville twins (3.0+3.6").
Casper has tested/run at least 7 different converters. To be honest, Mike knows more about what trans parts are in Casper than I do anymore.
i would think a general rule of thumb would be to just choose the converter off the small chargers size and what the truck is being used for , wether twinned or not i dont think it would come into play , i wouldnt think the big one would light till after most converters would stall out anyways , but have never driven a twinned truck so this is just theory ?
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A looser converter is the safest direction in which to error. If you can't spool, you can't ET no matter what. Launching a big charger truck at 2000rpm is going to cost you between .5 to 1.0 seconds. One second delay in building boost after the launch is huge.
Oh, the "traction impaired" thingy.
Once you cross over about 700hp, street testing becomes pointless. As soon as the charger(s) light, the tires spin and boost falls.
Once you cross over about 700hp, street testing becomes pointless. As soon as the charger(s) light, the tires spin and boost falls.
The 1057 in my truck has no stall that I've found, too loose IMO on my truck. I really like the 1054 for the standard set of MPI twins.
Nathan and I tested a converter that stalled right at 2200 with his set of twins on his LMM. Felt very good and launched very hard. It is back at the manufacture getting loosened up a hair.
Nathan and I tested a converter that stalled right at 2200 with his set of twins on his LMM. Felt very good and launched very hard. It is back at the manufacture getting loosened up a hair.
Odd. The 1057 is the tightest I've tested so far. Because I was running a big single, we had to go looser to run high altitude tracks.
So far, at sea level, I haven't found a converter that won't drive through brakes no matter how big the charger is, so the stall can't be measured. Wendy will launch at 2500 rpm with the 1057 and take off in a hurry, so will Blue. Casper launches at 3000 with the looser converter when I feel lucky. With the 1057 it couldn't get up to 2500 before taking off without me.
When we did comparison converter testing, I unlocked the converter for the full 1/4 mile pass. Right after launching (2100?), the RPM went up to ~3200+ IIRC and stayed there, no matter which converter we used.
Most likely my 1057 has loosened up quite a bit during 2 busy seasons of racing. I've had it over 2600rpm easily on a 1st gear launch and over 3200rpm on 2nd gear launch without pushing through. Now my truck would never launch well up there, but it'll go there.
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I know my truck will walk through the brakes @ 1800 with stock converter and Stealth 2 box only.....
this came from nathan on dp , the big kit is on his truck being driven and has started testing shouldnt be long no boys
Quote Idaho CTD
"Well the testing didn't go as planned. I had to fix a coolant leak. Then I took it out and drove it. I don't know why but the tune in my truck has no low end fueling. It comes on strong above 22-2400rpms but wont make more than 7-800* egt's below that. When it did come on it made about 45-46psi and 1100-1150* egt's at 110mph. I run 60% over injectors and 1900ms of pulse width. Tomorrow I'll get Rob to figure out what is wrong with the tune and do some more testing. One good thing is that the oil pressure stays in 40-45psi range once the rpm's are above about 1000. I didn't have time to get a DP gauge in today with the coolant leak but I will tomorrow before testing. With EGT's that low I doubt the drive pressure is very high."
Quote Idaho CTD
"Well the testing didn't go as planned. I had to fix a coolant leak. Then I took it out and drove it. I don't know why but the tune in my truck has no low end fueling. It comes on strong above 22-2400rpms but wont make more than 7-800* egt's below that. When it did come on it made about 45-46psi and 1100-1150* egt's at 110mph. I run 60% over injectors and 1900ms of pulse width. Tomorrow I'll get Rob to figure out what is wrong with the tune and do some more testing. One good thing is that the oil pressure stays in 40-45psi range once the rpm's are above about 1000. I didn't have time to get a DP gauge in today with the coolant leak but I will tomorrow before testing. With EGT's that low I doubt the drive pressure is very high."