best converter for high hp turbo car with 4l80
01-20-2009, 09:16 PM
#1
best converter for high hp turbo car with 4l80 i have ran a couple of diferent precision converters with high hp. 600-1050rwhp. they were ok and didn't die or anything like that but not what i would call a good turbo converter even after a couple of restalls. one was too tight even after having it loosend up twice. the other was rated at 3400 but stalled to 5400, to be fair we never gave them a chance to tighten up the one that went to 5400rpm, we were having too much fun with the car
. i would bet our peek tq on this car was in the 4800rpm range but that is just a guess since we never got to see the meat of our tq.
point is... after talking to several guys in the same hp range that had tried precision, even with multiple restalls they could not get a converter that was loose enough to get the boost going and at the same time tight enough to not blow thru the tq. 3 local guys all went to ultimate converts after trying more than one precision and each of them picked up a ton of top end while still geting the high stall they wanted off the line. one guy with a supra went from a best of 150mph to 158mph with just a converter swap. all 3 of these guys were running t400's
i talked to ultimate today. they were less than excited to do anything with a 4l80 and tried to push us toward a t400. maybe that is good advice but we want overdrive and lock up even though we are 90% race and 10% street.
next was coen. i have to think they can make a well set up turbo converter but i havn't seen the praise like i did with ultimate. they only sell a single dick lock up and say do not lock it up at wot.
next was circle D., chris had come interesting info and you guys have probably seen his post. said the 9.5" is too small(loose) for what we want and the 10.5" is too big(tight). sugested their 10.25" unit with the billet housing and tripple lock up disk. he dared us to lock it up at wot and try and hurt it. thing is i dont have any reason to think they can do better than precision hiting a decently high stall speed while holding the tq up top but once we hit 3rd and lock it up that wouldn't matter.
last company and the one i am tempted to go with would be precision again. kind of go with what you know. haven't talked to them but it would probably have to be a 5disk 9.5", i suspect it would stall pleanty high and get us off the line great. then 2nd gear would go by quick but never get to see the meat of our tq. then shortly after hitting 3rd we would lock it up. only problem here is 2nd gear would be less than ideal since i suspect our rpms would drop on the 1-2 shift from 6200 down to maybe 5500 while our peek tq will be well under that.
i know, long post, just looking for any info anyone might have to share. exact set up will be ~408ci 6 bolt heads, maxed out twin sc61's, spray off the line for now, maybe a brake/2 step later, 3200lbs, 28" tire, 350gear(for now).
. i would bet our peek tq on this car was in the 4800rpm range but that is just a guess since we never got to see the meat of our tq.point is... after talking to several guys in the same hp range that had tried precision, even with multiple restalls they could not get a converter that was loose enough to get the boost going and at the same time tight enough to not blow thru the tq. 3 local guys all went to ultimate converts after trying more than one precision and each of them picked up a ton of top end while still geting the high stall they wanted off the line. one guy with a supra went from a best of 150mph to 158mph with just a converter swap. all 3 of these guys were running t400's
i talked to ultimate today. they were less than excited to do anything with a 4l80 and tried to push us toward a t400. maybe that is good advice but we want overdrive and lock up even though we are 90% race and 10% street.
next was coen. i have to think they can make a well set up turbo converter but i havn't seen the praise like i did with ultimate. they only sell a single dick lock up and say do not lock it up at wot.
next was circle D., chris had come interesting info and you guys have probably seen his post. said the 9.5" is too small(loose) for what we want and the 10.5" is too big(tight). sugested their 10.25" unit with the billet housing and tripple lock up disk. he dared us to lock it up at wot and try and hurt it
. thing is i dont have any reason to think they can do better than precision hiting a decently high stall speed while holding the tq up top but once we hit 3rd and lock it up that wouldn't matter.last company and the one i am tempted to go with would be precision again. kind of go with what you know. haven't talked to them but it would probably have to be a 5disk 9.5", i suspect it would stall pleanty high and get us off the line great. then 2nd gear would go by quick but never get to see the meat of our tq. then shortly after hitting 3rd we would lock it up. only problem here is 2nd gear would be less than ideal since i suspect our rpms would drop on the 1-2 shift from 6200 down to maybe 5500 while our peek tq will be well under that.
i know, long post, just looking for any info anyone might have to share. exact set up will be ~408ci 6 bolt heads, maxed out twin sc61's, spray off the line for now, maybe a brake/2 step later, 3200lbs, 28" tire, 350gear(for now).
01-20-2009, 11:11 PM
#4
Turbo combos are difficult to make a converter for.
The Buick GN crowd has been messing with this for years, they have a little V6 that is essentially a slug until it spools up, so making a converter that will let it spool but not be loose under power is tricky.
PTC in Alabama has been doing great things and has EXCELLENT efficiency numbers on these types of combos, so I would suggest giving them a call at least.
Your combo is a bit different because you have a little more power before the boost comes on.
I know a friend of mine (converter builder, Mike Ridings) was messing with a TT V8 combo recently that was blowing through the 9.5" so they went to a 10" to fix it and that solved the probem. It was a big power deal, 1600 HP IIRC. You might look him up too since he's been playing with the turbo stuff.
I wouldn't expect ANY builder to hit the stall on the first try on a turbo combo, just to be fair to all of them, but I would try to deal with a company that has plenty of turbo experience.
Why it matters for the converter what trans is behind it I'm not sure... Obviously the lockup/non lockup of a 4L80 vs 400 and different drive hubs for different splines, but a 10" converter with a certain fin angle, stator config should be the same more or less.
We were using an Edge 9.5" in a TH400 behind a 700 HP 496 BBC on a customers car and went to a 4L80 and had Andre build a converter for the 80 to match and he hit it dead on. So must not be too much difference.
Good luck.
The Buick GN crowd has been messing with this for years, they have a little V6 that is essentially a slug until it spools up, so making a converter that will let it spool but not be loose under power is tricky.
PTC in Alabama has been doing great things and has EXCELLENT efficiency numbers on these types of combos, so I would suggest giving them a call at least.
Your combo is a bit different because you have a little more power before the boost comes on.
I know a friend of mine (converter builder, Mike Ridings) was messing with a TT V8 combo recently that was blowing through the 9.5" so they went to a 10" to fix it and that solved the probem. It was a big power deal, 1600 HP IIRC. You might look him up too since he's been playing with the turbo stuff.
I wouldn't expect ANY builder to hit the stall on the first try on a turbo combo, just to be fair to all of them, but I would try to deal with a company that has plenty of turbo experience.
Why it matters for the converter what trans is behind it I'm not sure... Obviously the lockup/non lockup of a 4L80 vs 400 and different drive hubs for different splines, but a 10" converter with a certain fin angle, stator config should be the same more or less.
We were using an Edge 9.5" in a TH400 behind a 700 HP 496 BBC on a customers car and went to a 4L80 and had Andre build a converter for the 80 to match and he hit it dead on. So must not be too much difference.
Good luck.
01-21-2009, 06:05 AM
#5
Trakday has a Fast Turbo Car.You Should PM him and ask him How we helped him!!!
I would also side with Vinney at ultimate on the 400 but we can build a 265 for the 4L80E you have as well. Heres a link to our turbo converters
http://www.fticonverters.com/convert...EPOWERWELD.jpg
Greg
I would also side with Vinney at ultimate on the 400 but we can build a 265 for the 4L80E you have as well. Heres a link to our turbo converters
http://www.fticonverters.com/convert...EPOWERWELD.jpg
Greg
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FTI COMPETITION CONVERTERS AND TRANSMISSIONS
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FTI Converter build sheet
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01-21-2009, 07:02 PM
#11
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Hunter02SS had good luck with PTC. Mightymouse seems to be happy with his Yank. CircleD has excellent customer service and seems confident they can give you want you want. I would look into those 3 for sure.
01-22-2009, 07:01 AM
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good choice! Chris at circle D is a great converter guy!!!
If the truck is full weight, I think the 10" (258) will still be a tad to slippery unlocked, but with chris' multi-disc option (which is killer by the way) kind of negates the whole loose converter thing.
Jakeshoe, give me a call when you can.
Mike.
01-23-2009, 06:48 AM
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02-01-2009, 01:14 AM
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I purchased the yank pt 3400 but on the dyno its more like 5400 my app is supercharged engine is about 1100- 1200 .Due to the high stall my tuner now tells me we need to put a manual for better control over tuning would this be corect .
Last edited by hawkls7; 02-01-2009 at 01:45 AM.