was just wondering, i was just havin a look at the rr results for the scoobies and was quite shocked about the transmission loss! i mean some peeps are gettin 250bhp but only 149 at the wheels! is this due to 4wd! i drive a cliosport 172CUP at the mo lookin for a scooby and at my last rr my results were 187bhp at flywheel and 157bhp at the wheels! i know my care isnt as quick as a scooby! so whats the go! im sure youll explain it and ill feel stupid but i need to know!

Thanks
Dan

 

Not sure how much is due to the 4WD, but it does use alot of power.
Cheers.
Ian.

 

Yep - it's quite shocking! 3 diffs instead of one. That's why Scoobies always get whooped by M3s etc on top end

 

Rolling roads have a double contact patch for each tyre and often the car is strapped down onto it. For this reason the losses are inflated. At over 200 BHP I think the losses are more than made up for by the traction and the power out of corners especially if it is wet or a rough road.

If the losses were as high as rolling roads typically suggest the acceleration figures would be far worse.

You can't compare a standard Scooby to an M3. You can a modified one though. My Scooby will do 50-80 in a similar time that it takes an E46 M3 to do 60-80 It does help weighing 335kg less and more power at the wheels than they have at the flywheel - AWD losses don't matter then

[Edited by john banks - 3/18/2003 5:46:23 PM]

 

Just get an RA 195bhp at the wheels in standard (ish) trim .

 

Yeah you've gotta remember that rolling-roading a FWD car is optimistic cos the rear wheels dont have to turn at all whereas they're still going to contribute to losses like the 4WD although not as much cos they're not driven.

 

Thanks for the comments guys!

 

I never believed it would make such a difference.

My 944 Turbo (250bhp) weighs in at 1400kg but in 3rd and 4th gears the difference in performance is vastly improved compared to my old MY01 with full decat (est 245 bhp).

I would think a similar weight 4WD car, would need at least 10% more power to be able to stay with 2WD car once moving.

[Edited by davyboy - 19/03/2003 11:19:26]

 

Dan what mods have you got on the cup, i have just bought the wife one to try keep her out of the scoob, quick little car in standard trim

 

The driveline loss is calculated during a vehicle deceleration. You are driving the diffs backwards (in terms of torque input) and they don`t like that - much more loss than when torque driving through them the `correct` way.

 

IIRC 4WD loses 22-25%, RWD 17% & FWD 15%

DazW

 

s600hby its standard. been done on 2 diff rr's with only a 4bhp diff. dont ask why, cos we cant work it out either, the week before a cup was on the rollers and pushed 172.5bhp exeactly!

 

Just been looking at your Dyno charts and have had exactley same reaction as Dan.

http://dyno.scoobynet.co.uk/indexps.htm

I know it's good for corners and wet roads blah blah, but those are big losses!

My standard C230K has 166.8BHP at the wheels (measured at G-Force Aylesbury) and I am suprissed at the amount of modded Scoobies around that mark.

Not saying anything about it, just adding my results here (my charts not allowed in your other cars secion as G-Force not on your list). I have got all interested in Rolling Roads lately and transmission losses etc. My car is manual and I laugh at my Automatic Mercedes Club associates because they have big losses too.



[Edited by GrahamC230K - 8/22/2003 8:41:48 PM]

 

whats the kerbweight of a C230 ?

 

1345KG. Not so lardy eh?

 

Thats pretty good for a merc I thought they were all well over 1500kgs.

 

I got 318bhp at the flywheel and 287 at the wheels,only 31 lost through the transmission.STI7 PPP + a few other bits hehe

 

Thats the best 4wd transmission figure I have seen 9%. Not saying its wrong but I would get it RR somewhere else to to confirm it.

[Edited by chrisp - 8/26/2003 11:21:39 AM]

 

Chrisp,had it done twice at different places and the first time was 41bhp loss.

 

Something's wrong me thinks!

We have gone from one extreme to another in this thread!

 

forget the losses and get em in the corners

 

I thought the CUP at Castle combe last week was well cool. Driver was ragging it round pretty quickly.

On a seperate note I have followed my other half in her 172 loads of times and the power difference is there to see. However it is still a nippy car round the ring roads