[Dustin Bramell]

Originally Posted by Vyruz Reaper

how convenient for you

The truth tends to be that way.

EDIT: Shiv and I often think alike, and post at the same time.

[WilyB]

Truth shall make you free!

Thanks gents: The front roller vs rear roller might indeed explain the discrepancy between the real world (on the road) and the dyno at 3500, about peak torque on a 335.

As I stated several time, the V2 is of course working just fine, datalog confirms it, and by the seat of the pants, the car pulls strong and linear all the way to the red line.

I shall email your comments to Dave and, next pull, we shall tie the car to something more substantial.

[OpenFlash]

Originally Posted by WilyB

Truth shall make you free!

Thanks gents: The front roller vs rear roller might indeed explain the discrepancy between the real world (on the road) and the dyno at 3500, about peak torque on a 335.

As I stated several time, the V2 is of course working just fine, datalog confirms it, and by the seat of the pants, the car pulls strong and linear all the way to the red line.

I shall email your comments to Dave and, next pull, we shall tie the car to something more substantial.

Sure thing. For high torque 2wd cars, I usually tie the front of the car down as well (so it can't roll forward). Either that or really tighten the crap out of the rear straps. But at 175lbs, I can't muster up enough force to do that

Shiv

[Ryan(e92)]

High torque or not you should still tie the front down.

[OpenFlash]

Originally Posted by Ryan(e92)

High torque or not you should still tie the front down.

With Dyno Dynamics dynos, you really don't NEED to tie the front down. It's just how the dyno was designed and is one reason why it's so great to use. It's only when cars start to make enough power/torque to climb up on the front rollers (there are two per wheel), that additional securing is a good idea.

When dyno testing Evos, I don't bother tying down the front until its making over 400lb-ft of torque (GT30R turbo, race gas, 30psi of boost). But that torque is distributed evenly to both front and rear axles. With the case of the BMW, all the torque is going to only one axle!

Shiv

[WilyB]

I'd just like to add, Shiv, that I've been an early customer of your PROcede (#0039) and that for the past year I've been awed by your dedication to customer service on this forum and elsewhere and by the extent of your knowledge in our FI cars' tuning.

[WilyB]

Now, what about a PROcede for the '08 955TT?

[OpenFlash]

Originally Posted by WilyB

I'd just like to add, Shiv, that I've been an early customer of your PROcede (#0039) and that for the past year I've been awed by your dedication to customer service on this forum and elsewhere and by the extent of your knowledge in our FI cars' tuning.

aw shucks
thanks... shiv

[WilyB]

Originally Posted by shiv@vishnu

aw shucks
thanks... shiv

Wait till you read the post #29!

[OpenFlash]

Originally Posted by WilyB

Wait till you read the post #29!

what's a 955tt? nm... oh the suv! I'd have to drive on first!

shiv

[WilyB]

Sorry, a Porsche Cayenne Twin-Turbo.

PS: Looking for a guinea-pig Cayenne in the Bay Area.

[WilyB]

Originally Posted by shiv@vishnu

It also looks like your car is pulling off the rear rollers at peak torque. You can see this by a sudden bump in torque/boost at ~3500rpm. When this happens, the wheels are only spinning the front rollers and rear rollers are free-wheeling an no longer absorbing power. Then as torque falls, the car rolls back onto the rear roller and "catches".

Hi Shiv, here is the answer I got. I know you have the same dyno http://www.dyno.com.au/dyno/controller/customers so now I am a bit confused.

"The rear roller on this dyno free wheels. It is only to support the wheels when not doing a pull or during high traction low power steady state tuning. The traction system is designed so that the car actually pulls itself down and into the rollers.

Here is a video of a car making 500+ ft/lbs of torque. As you will note the rear tires come completely off of the rollers.

It is actually RECOMMENDED that the tires come of the rear rollers so that they can gain the MOST traction.

I will dyno your car with staps, without straps and totally tied down. I can tell you that nothing will change and your graphs will look the same."

[WilyB]

Bump!