power loss

[red reading]

And one last thing, horsepower is only a calculation of revs over torque, both mine and danny fenels car make 435lbft of torque (both at 1.85 ish bar boost on differant turbos), mine is just made lower down the rev range than df's hence why my hp is lower, my old car (gt3071r) was making 420hp/420lbft but it was a narrower powerband due to the power tailing off at the top end, the next turbo i used (gt2876r ish) made 413/370 at less boost but that had a wider power band but less torque? all these figures are on the same dyno with conditions near the same

 

[red reading]

I know about the Rotating mass from the wheels. But did not know it affected the loss so much. i have saved almost 20kg in weight with my new rims in total so ill see what the Difference is.

energy saved from spinning the wheels will transmit as power to the ground..........just not as much as you think because ultimately your torque figure is the same, hp is a efficiancy rating in reality of the engine, torque is the turning force (thats what you feel when the car comes on boost)

 

[skiddusmarkus]

prop is rotational losses (would'nt show on the dyno as it will be so smaller gain)
tyres are frictional losses (the dyno would calculate the differance, so you will not get any gain)
engine mounts will help with response not losses to the wheels,

and if you look at the top of the page i have listed transmission things you could do

I don't get what you mean about the prop Danny, isn't it taking extra power to turn a heavier prop so reducing PAW?Same for driveshafts?

I think I get what you mean about the tyres though, guess smaller wheels will also help as not only lighter wheels but lighter tyres assuming a low profile.

 

[PobodY]

The diameter of a prop is pretty small thus the difference it makes is negligable compared to the road wheels?

You may have noticed that cars set-up for low rolling resistance have really skinny tyres; less contact with the road means less resistance (thus less loss)... but it's not great for traction for acceleration and/or braking.

 

[Thor]

Mine was 507 hp at 12% loss = 453 whp but that was with OS giken TS2B and now i have fitted the Sachs race clutch (4,8kg lighter than OS Giken). I don´t know how much it is different because the weight loss at the flywheel is...

 

[red reading]

george has got it, diamiter is the key as well as weight.....inertia basically the further from the center the weight is the harder it is to accelerate

The diameter of a prop is pretty small thus the difference it makes is negligable compared to the road wheels?

You may have noticed that cars set-up for low rolling resistance have really skinny tyres; less contact with the road means less resistance (thus less loss)... but it's not great for traction for acceleration and/or braking.

 

[skiddusmarkus]

OK, I see.I was just looking at it from a weight point of view and the fact that you supposedly accelerate faster with carbon ones, but I guess once its actually turning then the difference is minimal.

 

[skiddusmarkus]

After this mapping session, car made 394bhp @ fly, 312bhp @ wheels so a lot more transmission loss.It does now have the PAR box back on which is lower ratio whatever difference that would make.

 

[PobodY]

How did they measure the wheel and fly values to give you those figures? That equates to 20%, which is the bang in the middle of guestimate range that Danny suggested in the first place rather than a quantified loss... plus it seems just a little too round and neat, but that could be pure luck.

 

[skiddusmarkus]

Same rollers as Danny both times Po-Surrey RR, so assume they use the same way most do of seeing what the rundown power loss is and deducting it from the flywheel.So either a blip the 1st time on, or the gearbox made a difference.

Edit, add it on to make the flywheel power, not deduct.

 

[campbellju]

Mine was 507 hp at 12% loss = 453 whp but that was with OS giken TS2B and now i have fitted the Sachs race clutch (4,8kg lighter than OS Giken). I don´t know how much it is different because the weight loss at the flywheel is...

I never realised you were only using a 12% loss figure. That is very prudent. If we use the 25% (20% loss) that every one else seems to be using then that equate to 566hp!

Is the 12% correct because if it is then 566hp is pretty good

 

[Thor]

fine that you've noticed it james

if my calculation is correct, than it is the real result!

But how is the different with a lighter flywheel???

 

[PobodY]

How are they measuring the flywheel power if it's a rolling road? Surely you measure the power at the wheels and back-calculate the flywheel power; only an engine dyno could measure the true flywheel power? - Or is that what you meant with the edit (and it's actually a 25% loss because I got it round the wrong way)?

If they're measuring the run-down to estimate the loss, that makes sense.

 

[campbellju]

But how is the different with a lighter flywheel???

1% maybe but not 10%

 

[Thor]

Ah ok but the different is only too see at the torque i mean...