Converter Efficiency
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From: Victoria, TX
Converter Efficiency Posted this in the Dyno section but not getting much response.
Here's the deal, got my car dynoed for the first time the other day, I was very pleased with the locked numbers, but unlocked there was a much bigger loss than I was expecting.
Locked: 345 rwhp / 353 rwtq
Unlocked: 323 rwhp / 339 rwtq
323/345 = 93, is this my efficiency, or is it on the tq side (works out to 96)? I just thought the 22 hp drop was pretty big.
Thanks,
Craig
Here's the deal, got my car dynoed for the first time the other day, I was very pleased with the locked numbers, but unlocked there was a much bigger loss than I was expecting.
Locked: 345 rwhp / 353 rwtq
Unlocked: 323 rwhp / 339 rwtq
323/345 = 93, is this my efficiency, or is it on the tq side (works out to 96)? I just thought the 22 hp drop was pretty big.
Thanks,
Craig
Well honestly compared to mine 327hp locked and 283 unlocked! 
Im having my converter redone after that! Jason at MTI ran it on the dyno a few times comparing both. Looks like a bum converter so having Precision go ahead and restall it and fix it. He said from what I understand looks like you should loose around 20hp give or take just depends on how loose the converter is or efficeint it is. Maybe someone will correct me and Ill learn something.
Im having my converter redone after that! Jason at MTI ran it on the dyno a few times comparing both. Looks like a bum converter so having Precision go ahead and restall it and fix it. He said from what I understand looks like you should loose around 20hp give or take just depends on how loose the converter is or efficeint it is. Maybe someone will correct me and Ill learn something. 22 Hp is a pretty sizable loss for a 3500 stall on bolt-ons. Is it a tight feeling converter? They tend to be lower efficency.
I assume these were Back-to-back dyno runs.
I lost 13 hp with YTP 4200.
I assume these were Back-to-back dyno runs.
I lost 13 hp with YTP 4200.
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From: Victoria, TX
Yeah, these were on back to back runs. It's a TCI SSF converter. I can't really compare how tight it is to any other aftermarket converter because it's the only one I've had. Maybe I'll contact TCI.
Craig
Craig
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From: Victoria, TX
Well, I spoke with Kevin at TCI. He said it sounds like the converter is slipping a little bit more than it should be. He said they would look at it if I wanted, but 5-10 hp isn't worth dropping the trans again to me. He also said it will get more efficient the higher the rpms go, so after a new cam it should be better. FYI unlocked/locked does not equal efficiency. Kevin said it is a pretty good estimation, but not the right way to figure it.
I wouldn't bother either for 5 hp.
The most common ways to look at efficency are locked/unlocked and rpm slippage (engine rpm vs output shaft rpm). They are pretty measurable for the common man.
I like locked to unlocked because I'm more interested in power to the rear wheels.
BTW, What did Kevin suggest?
The most common ways to look at efficency are locked/unlocked and rpm slippage (engine rpm vs output shaft rpm). They are pretty measurable for the common man.
I like locked to unlocked because I'm more interested in power to the rear wheels.
BTW, What did Kevin suggest?
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Originally Posted by calongo_SS
Well, I spoke with Kevin at TCI. He said it sounds like the converter is slipping a little bit more than it should be. He said they would look at it if I wanted, but 5-10 hp isn't worth dropping the trans again to me. He also said it will get more efficient the higher the rpms go, so after a new cam it should be better. FYI unlocked/locked does not equal efficiency. Kevin said it is a pretty good estimation, but not the right way to figure it.
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From: Victoria, TX
Originally Posted by Ragtop 99
My bad, I meant what did Kevin suggest for how to measure efficency?
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Joined: Nov 2001
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From: Troy, AL
23 RWHP is what my TCI 3500 lost unlocked. That didn't bother me at all considering that it trapped 113.5 MPH with an internally stock engine at 3550 lbs with stock gears. I wouldn't worry about it if it works well at the track. 
