Transmission losses

Just wondered if anyone knows which parts of the R's transmission contributes most to the large losses these cars suffer between the flywheel & wheels? Mine was losing almost 100 bhp from 328.5 at the fly to the wheels figure which was more han most so I wondered if a transfer case in better nick could give me extra whp when I have my clutch done soon?

Sickly brakes can cause drag so can poor tyre pressure ..
All Showing as transmission loss

My brakes & tyre pressures were fine on the rolling road day but I thought I might be able to bolt on an extra 20 bhp if part of the Awd transmission was responsible for the losses as some cars only lost 75 bhp or so?

Mine was 286 atw and 330 atfw

Exactly Rob!

Maybe clutch slipping just a bit?

How do they measure it at the flywheel?

^ they don't, it done via maths & entering known value for vehicle or run down test on RR which calculates the drag.
I suspect operator error on RR or likes of low tyre pressures or slightly binding brakes.

Thanks, that's sort of what I thought, so the differences Marty and Rob are talking about between flywheel and wheels is just down to the operator putting in different numbers for the losses.
Nothing to worry about..

Are you taking it to Bobs rr day? You will be able to get a decent reading then I wouldnt worry too much!

It won't be back on the road for Bobs RR day but it might pay a visit to Southend if I get bigger injectors, a nistune & bigger turbo to go on in the future.

Mr B wrote:^ they don't, it done via maths & entering known value for vehicle or run down test on RR which calculates the drag.
I suspect operator error on RR or likes of low tyre pressures or slightly binding brakes.

exactly that ^^^^^

flywheel horsepower is a calculation based on software input from initially the dyno manufacturer then input supplied by the operator of the dyno on the day.
other factors also play a part such as the condition of rollers and other working parts of the dyno.

Something i did find out on the course we went on was that the figures can  lets say ''be cheated'' if the operator was that way inclined.
im not going to say how but there are ways of doing it to give a higher ''false'' reading at the fly

the true reading is power at the wheels so this is what people should really use in terms of how powerful their car is. The only reason people quote flywheel horsepower is because its the highest figure of the two so makes them feel like their car is more powerful than it really is, and if you ''as an operator'' give them a printout and say your cars made blah blah blah hp at fly then they feel better and go away with a bigger smile on their face. Bhp also sells cars so another reason!

Also interesting to know that many people think hub dyno's are more accurate, well that simply isnt the case!
A hub dyno neither gives an accurate reading at fly nor wheel horsepower as you still have transmission losses to hubs so flywheel hp is still an equasion.
Also due to the fact you have no wheels or rolling mass nor traction from rubber to road the wheel horsepower is also a guesstimate

Thats the reason i opted for the DD rollers as they give the most accurate reading possible at wheels due to the new design rollers which take over a day to machine each one of them which in turn gives the best traction possible from the tyres. This way the flywheel hp can be much easier calculated, and with mike who was one of the designers for dyno dynamics who now owns dyno developments he has taken all the ''not so good'' points from the dyno dynamics rollers and engineered what is now proving to be the most accurate rolling road possible in terms of flywheel calculated power and true wheel horsepower.

I will add its massive i just bought a sunny with a sr20 det ( pulsar) lump running 280 and belive me its a lot quicker than my pulsars and one i drove running 354 bhp

I bet 280bhp through just the fronts gets your full attention on boost. I just wondered if there was an area to look at on the R to reduce the loss.

only thing you can really do marty in order to reduce losses is

make sure clutch is in good order and handles given boost without slippage
check the 3 main diffs are fully operational and working as they should do
check all joints, mounts and bushes to make sure they are in good order
reduce unsprung weight of car
check tyre pressures, toe and other wheel alignments

Things like good clean oil in diffs as bob says weight ie light weight wheels etc every little helps. Carbon prop is something i will try one day

Smaller brakes

Or cut em in half like the yanks lol

Indy i got your message could be a lot of parts up for sale very soon i have all the bits you mentioned if i sell those ( not sure as some took ages to find) but you will get first refusal on them mate

Ok johnny cheers mate