How do I find my converters STR (stall torque ratio)
#1
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Must have been a year and a half ago I purchased my competition TCI 3600 from ws6stor.com and for some reason its in my head that I have a 2.7 STR but I wanted to find out for sure.
In the past for my LT1 I purchased a super street fighter TCI 3500 and it seemed to have hit harder off the line. I believe that one to have a 2.5 STR and when I would let off it would sqeak the serpentine belt (may not have anything to do with the converter but did'nt do it before the install)
Both cars were/are bolt on cars with headers and such. No aftermarket heads/cam. I know for a fact the LS1 has quite a bit more power (duh) but the LT1 60 ft I could get 1.70 - 1.72 consistantly, with the LS1 I can barely get 1.75s dead hooking. Was wondering if the str was the difference or if I was something else.
BTW: I looked on a few speedshop sites and Vigilante doesnt seem to release info on STR.
In the past for my LT1 I purchased a super street fighter TCI 3500 and it seemed to have hit harder off the line. I believe that one to have a 2.5 STR and when I would let off it would sqeak the serpentine belt (may not have anything to do with the converter but did'nt do it before the install)
Both cars were/are bolt on cars with headers and such. No aftermarket heads/cam. I know for a fact the LS1 has quite a bit more power (duh) but the LT1 60 ft I could get 1.70 - 1.72 consistantly, with the LS1 I can barely get 1.75s dead hooking. Was wondering if the str was the difference or if I was something else.
BTW: I looked on a few speedshop sites and Vigilante doesnt seem to release info on STR.
#3
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Originally Posted by SCREAMIN
Must have been a year and a half ago I purchased my competition TCI 3600 from ws6stor.com and for some reason its in my head that I have a 2.7 STR but I wanted to find out for sure.
BTW: I looked on a few speedshop sites and Vigilante doesnt seem to release info on STR.
BTW: I looked on a few speedshop sites and Vigilante doesnt seem to release info on STR.
1. Better call TCI, see if they even Dyno their units???
2. http://www.converter.com/torqueratio.htm
Quote from the linky: "In our tests we have never seen an STR over 2.55."
this is what they told me on the phone also, 2.55 is the STR on the Vig.
#4
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It occurs to me that we have a pretty similair mod list but you have ls6 intake and a 3.42 gears inside a 12 bolt. With my off the shelf SSF3500 (2.5 STR) I pull consistent 1.70-1.72 60's on normal weather days. In cool air I hit 1.65-1.69 60's. Even on hot and humid days I still hit 1.75-1.78 60's.
This is all dead hooking on M/T street radials and at 900 feet above sea level BTW. So if that's what I hit on 3.23's and a 2.5 STR then I can't see how your STR could be 2.7 when you're hitting worse 60's and with better gears. In fact, I wouldn't be surprised if your converter has a 2.2 STR based on your results.
But the only way to know for sure is to remove it from the vehicle and have it tested by someone with the proper equipment. I know Yank can verify STR's. I'm not sure about TCI but you could always call them and ask Kevin. Personally I would just pull it out and sell it. Then you can replace it with a Yank SS4000 that has a 2.6 STR
This is all dead hooking on M/T street radials and at 900 feet above sea level BTW. So if that's what I hit on 3.23's and a 2.5 STR then I can't see how your STR could be 2.7 when you're hitting worse 60's and with better gears. In fact, I wouldn't be surprised if your converter has a 2.2 STR based on your results.
But the only way to know for sure is to remove it from the vehicle and have it tested by someone with the proper equipment. I know Yank can verify STR's. I'm not sure about TCI but you could always call them and ask Kevin. Personally I would just pull it out and sell it. Then you can replace it with a Yank SS4000 that has a 2.6 STR
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#5
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Apply a set amount of torque (or HP) to the input side of the converter, while on a converter dyno. On the output side of the converter, hold the (trans) input shaft with a suitable brake. Monitor your input torque value, your output torque value, as well as input (engine) RPM. When input RPM reaches the rated stall speed, record the input/output torque values. Divide the output torque by the input torque, this gives you the STR. No other way of doing it.
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