Powerloss through drivetrain.
Thread Starter
Scooby Senior
iTrader: (1)
Joined: Nov 2000
Posts: 9,708
Likes: 73
From: Wildberg, Germany/Reading, UK
Powerloss through drivetrain.
Hi, had my MY00 on a RR for the first time on saturday and was basically not very impressed with the results.
Apparently I have 205.3 ps at the wheels and 103.3ps power loss through the drive train.
Is this normal?
it seems a bit high at 33% powerloss.
Any advice or comments gratefully received.
Apparently I have 205.3 ps at the wheels and 103.3ps power loss through the drive train.
Is this normal?
it seems a bit high at 33% powerloss.
Any advice or comments gratefully received.
Thread Starter
Scooby Senior
iTrader: (1)
Joined: Nov 2000
Posts: 9,708
Likes: 73
From: Wildberg, Germany/Reading, UK
That is what I thought, I was expecting more at the wheels.
I have 312.1 at the fly and 205.3 at the wheels.
Any ideas where abouts in the drive train these ponies might be escaping???
I have 312.1 at the fly and 205.3 at the wheels.
Any ideas where abouts in the drive train these ponies might be escaping???
Scooby Senior
Joined: Jan 2003
Posts: 3,638
Likes: 229
From: Friedrichshafen Germany/Preston UK
It could be the additional back preasure created by those flames coming out of your exhaust 
I also logged 70bhp losses on the same RR as Wurzel, but my power was a more respectable 323PS
I also logged 70bhp losses on the same RR as Wurzel, but my power was a more respectable 323PS
Scooby Regular
Joined: Jul 2002
Posts: 9,173
Likes: 0
From: Under your bonnet
Perhaps your tyrez were flat.
Or you had mud and snows on....
My six speed and sticky tyres loses 150bhp on the dyno,
100bhp is average.
I think I had 80 odd loss when I was at lower power lower speed and on assemetricos.
Andy
Or you had mud and snows on....
My six speed and sticky tyres loses 150bhp on the dyno,
100bhp is average.
I think I had 80 odd loss when I was at lower power lower speed and on assemetricos.
Andy
Scooby Regular
Joined: Feb 2005
Posts: 492
Likes: 34
From: Oxfordshire
I would treat the power quoted loss with a pinch of salt. 100bhp = 75kW. That's a lot of heat to get rid of from a transmission system on a RR.
I believe the RR motors the rollers and measures the power required to drive the wheels at the test speed. This measurement may include all the losses in the the RR as well. I would hope not but can't be sure.
The other point of increased loss is between the tyres and the rollers. RR rollers are quite small diameter so deflect the tyre more than a road does. This requires power to overcome it. The speed of the tyres generates air movement so they can dissapate the heat quite well. The tyres still get hot though. Tyre pressures and tyre design can all affest this.
RR's are excelent tools but are best used as comparators for setting up an engine. That way you can see if a change alters power output and by how much. The actual power figures should be treated with caution.
I believe the RR motors the rollers and measures the power required to drive the wheels at the test speed. This measurement may include all the losses in the the RR as well. I would hope not but can't be sure.
The other point of increased loss is between the tyres and the rollers. RR rollers are quite small diameter so deflect the tyre more than a road does. This requires power to overcome it. The speed of the tyres generates air movement so they can dissapate the heat quite well. The tyres still get hot though. Tyre pressures and tyre design can all affest this.
RR's are excelent tools but are best used as comparators for setting up an engine. That way you can see if a change alters power output and by how much. The actual power figures should be treated with caution.
Thread
Thread Starter
Forum
Replies
Last Post