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Easy way to work out a more sensible torque fig from the crazy 'derived' dyno results

Not_An_Abba_Fan

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I gauge "power" by seat of the pants and driveability, not a dyno. A dyno is a tuning tool. I don't take much notice of power figures.

An example is at our drag strip here in WA, a car that had 400+ rwhp 5.7L LS1 had its arse handed to it on a plate by a Falcon with little more than extractors and an exhaust. He would have been lucky to be pushing 250 rwhp. It was all gearing and tyre choice that smoked the Commodore. It was an NA BA sedan. It was an XR6, but non turbo.
 

vyseriesII

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I gauge "power" by seat of the pants and driveability, not a dyno. A dyno is a tuning tool. I don't take much notice of power figures.

An example is at our drag strip here in WA, a car that had 400+ rwhp 5.7L LS1 had its arse handed to it on a plate by a Falcon with little more than extractors and an exhaust. He would have been lucky to be pushing 250 rwhp. It was all gearing and tyre choice that smoked the Commodore. It was an NA BA sedan. It was an XR6, but non turbo.
Sounds like the dude in the 5.7l is a terrible driver or got a shocking start. HAHA :p

Seat of the pants is always a good test though. Bitumen dyno FTW

There are still a lot of factors when it comes to the strip, driver ability etc. But def a better way to judge some ones power.

We need Mythbusters to do a controlled test on a few different cars and there happy dyno sheets lmao.

The thing that shits me about dyno's is all it takes is a wanker operator, he can inflate the figure to look like he's actually done something good or just to please a customer.
 
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4wheelinls1

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It actually is derived engine torque and measured wheel torque. Forgetting losses the engine torque is a calculation based on roller rpm vs engine rpm. If the roller is doing 1/2 engine speed then the torque measured at the wheels is double. Derived engine torque comes from this and requires and accurate tacho signal be fed to the dyno. People get carried away with 1:1, considering the final drive is not 1:1 and the ratio or the tyre circumference to the roller circumference is not 1:1 is does not matter so much what gear is chosen, having said that a lower roller speed will mean less frictional loss and generally higher readings as will a loosely tied car that does not have to turn the weighty rear rollers show more measured power.
 

lowrider636

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Gday guys im new here to the forum ,Was wondering if anybody could help me Translating my torque figure .My Diff ratio is 3.45 and the tune was done in fourth gear ..Its a 6 speed manual ..There is a dyno printout in my garage ..I don't know how to post a pic in this thread ..cheers guys
 

Not_An_Abba_Fan

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Translating torque how? Torque is torque. That is your figure. 4th gear is 1:1 ratio on a 6 speed.
 

ari666

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FWIW, good way to see if the dyno is a fraud is to check that HP and TQ [email protected] they should ALWAYS cross over at that point.

if you have a 1000nm reading and a 280hp reading and they dont intersect and cross over at 5252rpm, then something is amiss and its usually as NAAF said:

theyre pulling in the wrong gear.



in more ways than 1
 

MANX SS

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Can anyone tell me roughly what 522rwhp would be at the flywheel?
 
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