loose stall converters and dyno numbers
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loose stall converters and dyno numbers
i read this, what do you guys think?
http://www.converter.com/whatsnew_dynamometer.htm
THE TRUTH ABOUT DYNAMOMETER READINGS AND HIGH STALL TORQUE CONVERTERS
There is a misconception and a lot of misinformation about the poor vehicle performance numbers that are generated by testing a car with a high stall torque converter on a dynamometer. Most people that are not familiar with how a torque converter operates will automatically think that the torque converter is inefficient. This is totally false and the following facts are why you should not believe the dynamometer numbers while using an unlocked
high stall torque converter. All late model dynamometers have a software program that commands the loading and speed of the vehicle over a certain period of time while making a test pull. The software used in these dynamometers is setup to be used with a locked 1:1 connection between the engine and the rear wheels, such as using a standard shift transmission in 3rd gear or when an automatic transmission has the torque converter clutch
locked. When an unlocked high stall torque converter is used to make the pull and the dynamometer software has not been changed to allow for the fluid coupling differences the dynamometer readings will all be bogus. For instance, the low rpm torque readings will be high due to the torque multiplication of the torque converter being run in partial stall. Likewise,
the high rpm torque readings will be low due to the long period of time the dynamometer takes to allow the torque converter to transition from partial torque multiplication to a hydraulic locked condition. The only cure for this phenomenon is to rewrite the dynamometer software to prevent this from happening. Torque converters with a low STR or low stall are not as adversely affected by this phenomenon. The high rpm transition problems
never occur when the vehicle is being driven or raced normally. Therefore, worrying about what the dynamometer numbers are is a total waste of time. If your dynamometer operator refuses to alter the software to give correct readings then the only things you can do is (1.) lock the torque converter clutch and do the testing, (2.) use the readings you get with an unlocked torque converter as a baseline and continue to tune the car like normal
until you get the best numbers remembering these are just numbers and not the actual horsepower and torque or (3.) use a dynamometer shop that gives you the service you deserve for your hard earned money. The only really true test of the performance of a vehicle is to take it to the track and see what
ET and MPH the car will run.
kind of makes sense to me, any opinions
http://www.converter.com/whatsnew_dynamometer.htm
THE TRUTH ABOUT DYNAMOMETER READINGS AND HIGH STALL TORQUE CONVERTERS
There is a misconception and a lot of misinformation about the poor vehicle performance numbers that are generated by testing a car with a high stall torque converter on a dynamometer. Most people that are not familiar with how a torque converter operates will automatically think that the torque converter is inefficient. This is totally false and the following facts are why you should not believe the dynamometer numbers while using an unlocked
high stall torque converter. All late model dynamometers have a software program that commands the loading and speed of the vehicle over a certain period of time while making a test pull. The software used in these dynamometers is setup to be used with a locked 1:1 connection between the engine and the rear wheels, such as using a standard shift transmission in 3rd gear or when an automatic transmission has the torque converter clutch
locked. When an unlocked high stall torque converter is used to make the pull and the dynamometer software has not been changed to allow for the fluid coupling differences the dynamometer readings will all be bogus. For instance, the low rpm torque readings will be high due to the torque multiplication of the torque converter being run in partial stall. Likewise,
the high rpm torque readings will be low due to the long period of time the dynamometer takes to allow the torque converter to transition from partial torque multiplication to a hydraulic locked condition. The only cure for this phenomenon is to rewrite the dynamometer software to prevent this from happening. Torque converters with a low STR or low stall are not as adversely affected by this phenomenon. The high rpm transition problems
never occur when the vehicle is being driven or raced normally. Therefore, worrying about what the dynamometer numbers are is a total waste of time. If your dynamometer operator refuses to alter the software to give correct readings then the only things you can do is (1.) lock the torque converter clutch and do the testing, (2.) use the readings you get with an unlocked torque converter as a baseline and continue to tune the car like normal
until you get the best numbers remembering these are just numbers and not the actual horsepower and torque or (3.) use a dynamometer shop that gives you the service you deserve for your hard earned money. The only really true test of the performance of a vehicle is to take it to the track and see what
ET and MPH the car will run.
kind of makes sense to me, any opinions
Pull Over
Joined: Aug 2001
Posts: 924
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I wonder what standard tranny they are talking about that has a 1:1 3rd gear?
I haven't been to any dynos that can change the software to account for the converter before, I wonder what brand dyno they are referring to?
I haven't been to any dynos that can change the software to account for the converter before, I wonder what brand dyno they are referring to?
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"I'm in the 82nd Airborne and this is as far as the bastards are going!"
93 Cobra, R302 331,canfields,T-76,TKO......sold
87 Coupe, 466, Edelbrock heads,Vic jr,150 shot 10.41@129.5...sold
2006 Honda 450ER .....new toy
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"I'm in the 82nd Airborne and this is as far as the bastards are going!"
93 Cobra, R302 331,canfields,T-76,TKO......sold
87 Coupe, 466, Edelbrock heads,Vic jr,150 shot 10.41@129.5...sold
2006 Honda 450ER .....new toy
Do you own a Torch Red FRC and tremble every time you drive under I75 on Hwy 60 and look in your rearview mirror? If so you are suffering from what is known as Cobraphobia.
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Its probably a copout. They're just saying that to shift the focus to someone else.
I don't see why a chassis dyno company hasn't come up with a way to dyno cars with loose converters. I would think you could compare the rate of change in RPM between the engine and tire and calculate slippage that way and figure HP from there. That has bugged me for years.
I don't see why a chassis dyno company hasn't come up with a way to dyno cars with loose converters. I would think you could compare the rate of change in RPM between the engine and tire and calculate slippage that way and figure HP from there. That has bugged me for years.
