Torque converter lock up on dyno question
Torque converter lock up on dyno question What amount of HP should you see when the TC is locked on the dyno?
What does it mean if it gets a small amount of gain, say 10-15 HP, and conversley, what does it mean if you gain say, 20-25 or more HP??
Thanks..
What does it mean if it gets a small amount of gain, say 10-15 HP, and conversley, what does it mean if you gain say, 20-25 or more HP??
Thanks..
TECH Enthusiast
Joined: Sep 2004
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From: Omaha, NE
Good question. Like most answers, it depends. As an example, on a stock type converter you could see a 2-5% HP/TQ gain when locked. With an aftermarket, higher stall speed converter this percentage goes much higher, like in the 10% or more range.
What this means is that whenever you have slippage, you create heat and you lose effeciancy in the transfer of power from the input to the output of the converter. However, cars are often quicker because you get this HP loss back, plus more of it because this allows the engine to average more HP by riding the RPM range that produces the most of it. This also provides more TQ multiplication to the drive axles.
One thing that we notice on the dyno with unlocked TQ converters is how the temperature of the trans fluid affects slippage. The hotter the fluid the more slippage due to the fluid becoming more viscous. The higher the stall speed the more this fluid gets heated, thus it is very important that this temp be managed by a good trans cooler for consistant HP/TQ runs on the dyno and fast and consistant runs at the track. Hope this helps to answer your questions.
EJ
What this means is that whenever you have slippage, you create heat and you lose effeciancy in the transfer of power from the input to the output of the converter. However, cars are often quicker because you get this HP loss back, plus more of it because this allows the engine to average more HP by riding the RPM range that produces the most of it. This also provides more TQ multiplication to the drive axles.
One thing that we notice on the dyno with unlocked TQ converters is how the temperature of the trans fluid affects slippage. The hotter the fluid the more slippage due to the fluid becoming more viscous. The higher the stall speed the more this fluid gets heated, thus it is very important that this temp be managed by a good trans cooler for consistant HP/TQ runs on the dyno and fast and consistant runs at the track. Hope this helps to answer your questions.
EJ
Well when I dynoed my car I did both unlocked and locked. If you see a small hp gain between the converter being locked then that is a good thing. That just means that you have a very effiecent converter. I seen a 18hp difference between mine being locked and unlocked.... 355rwhp (unlocked) and 373rwhp (locked) that put my 3600 vig at 95% efficiency. Hope this helps
