Dyno Gearing

[Xany]

interesting they did the dyno in 3rd gear....4th is 1:1....3rd would give a different reading for sure.

[camerondownunder88]

^^^^ I'm with Xany 3rd would give lower readings by far.

 

Also a 5K has 48KW stock so mmm I think Mr dyno man is out of calibration..lol

 

But GL with sale and also if it is the earlier head has it been shaved to run on dished pistons? Or does it run the lower compression great for a SC or turbo setup?

 

Cameron

[Medicine_Man]

interesting they did the dyno in 3rd gear....4th is 1:1....3rd would give a different reading for sure.

 

Pretty sure all dyno dynamics dynos run shootout mode in 3rd gear to keep the variables the same..

[Gavatron]

interesting they did the dyno in 3rd gear....4th is 1:1....3rd would give a different reading for sure.

^^^^ I'm with Xany 3rd would give lower readings by far.

 

Also a 5K has 48KW stock so mmm I think Mr dyno man is out of calibration..lol

They do the run in 3rd because doing it in 4th would take way to long to rev out and the dyno can only go so fast. The gearing is compensated for by the software. Have seen consecutive runs of the same car on the same dyno but set to 3rd gear then 4th. Reading differed by only 2kW.

 

I don't know why a stock 5K having 48kW at the FLYWHEEL has to do with this. But meh.

Edited September 26, 2007 by Gavatron

[Azza666]

^^^^ I'm with Xany 3rd would give lower readings by far.

 

Also a 5K has 48KW stock so mmm I think Mr dyno man is out of calibration..lol

 

But GL with sale and also if it is the earlier head has it been shaved to run on dished pistons? Or does it run the lower compression great for a SC or turbo setup?

 

Cameron

 

I'm with gavetron y would it give a diferent reading even in 1st. a dyno just simulates the road, it puts load on your engine and depending on how easily your engine caries that load is how it calculates horsepower

 

if your driving along in 2nd does your car have les horsepower than in 4th? no its got exactly the same amount of power unless mabbee the air tempratuer and pressure change then it will differ slightly

[Xany]

I'm with gavetron y would it give a diferent reading even in 1st. a dyno just simulates the road, it puts load on your engine and depending on how easily your engine caries that load is how it calculates horsepower

 

if your driving along in 2nd does your car have les horsepower than in 4th? no its got exactly the same amount of power unless mabbee the air tempratuer and pressure change then it will differ slightly

 

 

You should probably do some more reading on how a dyno works then.....and how the readings can be affected by the gearing.

 

Eg:

Gearing: a chassis dyno is susceptible to gearing bias. Recorded power can be affected on a dyno graph by simply running the test car in too low or too high a gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars. In a 1:1 ratio, the two gears that make up a gear set are the same size. When one is larger than the other, either in a lower gear than 1:1 or a higher gear than 1:1, there are frictional losses that translates to less power put to the wheels. Also, too high of a gear that causes the test car to go to a top speed far greater than the available fan cooling capacity will produce invalid results.

[Hiro Protagonist]

When I went to the Toymods Dyno Day at the start of the year (run on a Dyno Dymanics dyno in shootout mode at SAS), they tended to do all the 4-cylinder engines in 3rd gear, and all the others in 4th. No idea why, but they did