Dyno Sheet
[Edited on 2-3-2004 by Craig Torrens]
!!!!!!!!
is that rear wheel or flywheel??
At the wheels.
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Thanks Craig, I was just about to ask you if you had it yet.
I must say that looks like a Honda torque curve...........very flat:thumb:thumb
Andrew Grace
AMG beat you all :P
where has the dyno sheet gone??
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gotta bigga one
I will try again................ yes its bigger but it fuzzy :cry
So what does craig's slip look like?
Doesn't show up on my puter screen 
Deja vu. I have a headache.:cry
You will lose power through the gearbox. If the engine had 200hp at the flywheel it would not have the same at the rear wheels.
Even motorcycles experience HP loss through their drivetrain and they one of the most efficient. Around 5% for chain and sprockets.
All gearboxes reduce HP.
Just need to look at all the work that Dyno Dynamics have done testing hundreds of engine/trans so that their chassis dynos can provide a calculated
back to the flywheel figure if desired.
Even the direct drive of a Top Fueler looses HP through the clutch.
Work on about 15% loss, so 121@wheels = 140@the fly...
Think about that 80 weight oil being squeezed outta teeth, theres a reason it gets hot... friction
Lots of expert opinions and all constructive,it still comes down to diff ratios working threw Gboxes and tyres.Percentage Hp for rear engines is 5%
to10% this info comes from Goodman Race Engines ,gives us somthing to think about when doing Dyno runs to Track runs.JVLRacing[/size]
[Edited on 30-6-2004 by gayanne]
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Any spec on the Pobjoy donk or are we liven a dream?
As for loosing power through the trans...Gene Berg told me 15 years ago that you can expect around 15% loss, minimum.
My little 1776 made a best quarter of 14.8 and no special trans ratios....
So what can I expect for HP.
Never dyno'd it, may have to some day!
Keep in mind my engine is now over 10 years old!
[Edited on 30-6-2004 by humpty]
Simon may be perth should have a vw dyno day ??
I know Myaree Dyno tune have dyno days from time to time. Everyone turns up, big blocks to cosworths....Be nice to see a certain red Notch there!, Maybe my bug too!
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humpty, first we need to know what the car weighed.
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Not trying to start a shit fight, but is it possible to have a look at the specs on a Pobjoy ? Cam ? compression ? etc... or do you have to sign a
confidentiality agreement or something before buying one??
Ive picked up little tidbits of info, looking for some substance !!!
Me to Adrian!!
These Dynamic Dyno's do they take into account horsepower sapping high altitude??
Craig P.:bounce
RE: gearbox losses.
as others have said, use 15% as a minimum.
Most dyno operators will use about 17%. This is right for most modern vehicles, and mainly front wheel drives. FWD cars has efficient gearboxes as
each gearset is parallel to the next.
VW's are older designs, and has a ring and pinion, which is not very efficient. Kombi gearboxes are less efficent than beetle gearboxes. VW
gearbox'es seem to be losing somewhere between 20 and 25%.
It the helical gears that suck the power. The helix angle forces some of the torque to be transmitted, and some of it to be wasted in a thrust force.
This is why race cars use striaght cut gears in their gearboxes. They don't have the inefficency problems of helical gears.
Motorcycles almost always use straight cut gears, that is why they are much more efficient.
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