28 replies to this topic

[ToM 2012]

jez must of done something to make it abit quicker lol 

[Tamworthbay]

I'm pretty sure that power is per driven wheel. assuming the diff is not differentiating.

If that was per wheel the combined BHP would be more than its producing at the flywheel. Something funny with those stats though... But If it drives well now who cares?

[ToM 2012]

 

I'm pretty sure that power is per driven wheel. assuming the diff is not differentiating.

I can't see a standard (???) 998 having 48.4 bhp

 

and working on that theory the last time my standard 998 with a pea shooter exhaust had 29.5 bhp at the wheels....

 

 

Its not just the gearbox were power is lost though, it's everything that transmits the power to the wheels, including the bearings, brakes, tyres, tyre pressures and even the tracking.  

 

its 44.8 do you meen? i cant see 48.4 on the sheet

[Tamworthbay]

I'm pretty sure that power is per driven wheel. assuming the diff is not differentiating.

I can't see a standard (???) 998 having 48.4 bhp
 
and working on that theory the last time my standard 998 with a pea shooter exhaust had 29.5 bhp at the wheels....
 
 
Its not just the gearbox were power is lost though, it's everything that transmits the power to the wheels, including the bearings, brakes, tyres, tyre pressures and even the tracking.

its 44.8 do you meen? i cant see 48.4 on the sheet

2x24.2 =48.4

I think that is where it comes from- the idea that the figure is per wheel. I don't think that is the case for reason I said above.

[ToM 2012]

ahh right. sorry new to this its my first time. im sure they wouldnt lie? 

[1984mini25]

 

 

 

I'm pretty sure that power is per driven wheel. assuming the diff is not differentiating.

I can't see a standard (???) 998 having 48.4 bhp
 
and working on that theory the last time my standard 998 with a pea shooter exhaust had 29.5 bhp at the wheels....
 
 
Its not just the gearbox were power is lost though, it's everything that transmits the power to the wheels, including the bearings, brakes, tyres, tyre pressures and even the tracking.

its 44.8 do you meen? i cant see 48.4 on the sheet

2x24.2 =48.4

I think that is where it comes from- the idea that the figure is per wheel. I don't think that is the case for reason I said above.

 

and also it would mean that a 29 year old standard 998 with standard cast manifold and pea shooter exhaust with 29.5 at the wheels, would in theory have 59bhp lol

 

but at the end of the day it's not all about how much power, its how well it drives afterwards.

[Tamworthbay]

I'm pretty sure that power is per driven wheel. assuming the diff is not differentiating.

I can't see a standard (???) 998 having 48.4 bhp
 
and working on that theory the last time my standard 998 with a pea shooter exhaust had 29.5 bhp at the wheels....
 
 
Its not just the gearbox were power is lost though, it's everything that transmits the power to the wheels, including the bearings, brakes, tyres, tyre pressures and even the tracking.

its 44.8 do you meen? i cant see 48.4 on the sheet

2x24.2 =48.4
I think that is where it comes from- the idea that the figure is per wheel. I don't think that is the case for reason I said above.

and also it would mean that a 29 year old standard 998 with standard cast manifold and pea shooter exhaust with 29.5 at the wheels, would in theory have 59bhp lol
 
but at the end of the day it's not all about how much power, *********its how well it drives afterwards.*********

There is an echo in here ^^^^^^^^^^^^^

[ToM 2012]

aslong as it doesnt drink the fuel it will be ok for me. 

[A-Cell]

The BHP is measured at the wheels on the rolling road dynamometer, in this case the car was developing 24.2 Maximum HP.

Then a coast down measurement is made or the drag, this takes into account all of the forces required transmission, bearings, tyres, brakes rubbing etc, in this case the 20.6

This is added to the HP measured at the wheels to give the HP at the flywheel - 44.8 total.

This is then corrected for ambient conditions, temp , pressure to give the corrected BHP at the flywheel.

[cradley-heathen]

i am aware that all the running gear, brakes, tyres etc is also responsible for the drag that is measured, but i rebuilt the front hubs myself and sorted the brakes and can confirm the car rolls very easily.

 

the only thing i can think of is that he may have used the brakes to slow the rollers on the run down (i have seen this done a few times now, saves sitting there waiting for it to stop) doing that would create extra drag and throw the readings out.

 

if he thought you would be more interested in how it runs rather than a print out, its perfectly possible he could have done this.

 

either way, it went up the hill to colley gate the other week when i drove it back from mot, if it pulls better than that now then there cant be much up with it.

[A-Cell]

If he added to the coast down drag by applying brakes then this would increase the drag HP which would give a bigger calculated HP at the flywheel!

[cradley-heathen]

If he added to the coast down drag by applying brakes then this would increase the drag HP which would give a bigger calculated HP at the flywheel!

 i suspected i may have had that wrong, never mind!

 

(hangs head in shame lol)

[ianclark1275]

 

If he added to the coast down drag by applying brakes then this would increase the drag HP which would give a bigger calculated HP at the flywheel!

 i suspected i may have had that wrong, never mind!

 

(hangs head in shame lol)

 

 

one of the reasons the mini metro had ball bearing wheel bearings, not tapered, was to reduce the rolling losses and make the old A series look more efficient !

[A-Cell]

The Metro also had the A+ and a better CdA and was more economic - HLE 99 mpg!