20 HP and 24 lbs torque with fuel,air,timing possible?

[KRAM36]

Originally Posted by The Radium King

um ... i said 100 hp/litre. ie, divide horsepower by engine displacement. pretty standard way to state the efficacy of your engine. your 318 hp / 3.2 litres is 100 horsepower per litre. porsche could barely get that with race engines of the 996 era, and pretty much couldn't with the m96. 55 hp out of the 3.2 puts you at 307 hp; the 3.4L 996 only made 304 hp, so i doubt you'll be able to get there with .2 less litres.

How can a chassis dyno machine know the drive train loss on a car? I started a thread to find the drive train loss through a Tiptronic trans Boxster.

Curious about HP loss through the drivetrain.

Only person to give out any real numbers was Jake Raby, but it was for manual cars.

Originally Posted by Jake Raby

I have two engine dynes and a chassis dyno all within 50' of each other. We can pull an developmental engine off the engine dyno and install it into the car the same day, then test it on the chassis dyno. I see 18-22% losses generally from a manual car.

Pay zero attention to the factory power rating, often times they are posted in DIN and not SAE anyway.

So if Jake Raby is seeing a 4% swing on manuals, how is a chassis dyno machine going to know how to accurately calculate drive train loss?

Can you answer that for me? What's the drive train loss on a Tip trans car?

[The Radium King]

Originally Posted by KRAM36

How can a chassis dyno machine know the drive train loss on a car?

you can add a correction factor into a dyno; someone could have easily modified those dyno results with a 1.15 or 1.2 correction factor so that it was reading high. as was previously stated, the only real information you can get from a dyno is change in hp, not absolute numbers. and in all the tuning i have seen of boxsters, i have yet to see anyone bolt on a 50 hp increase. i have seen people brag of 300 hp, but no 50 hp increase. that's why everyone always wants before and after numbers, because absolute numbers mean nothing when it comes to dynos.

[Jake Raby]

So if Jake Raby is seeing a 4% swing on manuals, how is a chassis dyno machine going to know how to accurately calculate drive train loss?

The dynos that show flywheel HP gathered at the rear wheels have always been a joke to me. The drivetrain losses are calculated through a wizard thats no where near accurate for the drivetrain of a Porsche. On top of that, the ones I've seen before allow the user to put what ever figure they want in for a drivetrain loss and the software moves the curve. Its a real good way to cheat.

Numbers gathered at the rear wheels should always be just that. They should not be converted to some wild guess drivetrain loss correction.

If you want flywheel HP numbers, gain those from an engine dyno.

The quickest way to slow a car down is to use a dyno to gather the wrong data, for the wrong reasons.