This is vexing me....

[Jason]

if you have a car, for arguments sake rear engined rear wheel drive.... you put it on the rollers and it produces 200hp @the wheels..

you then take it away and put another identical engine in it powering the front wheels, making it 4wd..

.. if you put it on the rollers (4wd r/r) then it would still have 200hp @ the wheels.......

this seems very strange to me... :confused:

[RADS_S13]

:confused:
wouldn't that give 400BHP as you would be measuring all four wheels :confused:

[Rob-S13]

200 @ front wheels + 200 @back wheels = 400 Total :nod:

else you just confused me to! :annoyed:

[Jason]

no, because it dosent accumulate like that, you got same power over more driven wheels... seems strange does it not? ??? ?

[ATrull]

depends on who is calculating your bhp

they increase the number to give you a flywheel figure, by a 17% for rwd and around 25% for 4wd, I believe.

[Sideways Danny]

you'd lose power at the wheels, 4wd has MASSIVE transmission loses

[Sideways Danny]

depends on who is calculating your bhp

they increase the number to give you a flywheel figure, by a 17% for rwd and around 25% for 4wd, I believe.

I've seen upto 35% losses on a 4wd

[ATrull]

I've seen upto 35% losses on a 4wd


mmm - that is massive.

[2 Black Lines]

I've seen upto 35% losses on a 4wd

But in this situation it has 4 driven wheels - therefore transmission losses are less/ same/more?? the difference is when you drive on the road/track then the extra capacity takes effect and the car is faster, (cue an anorak with the equation that escapes me for the mo!

[Rob-S13]

but its not 4wd

technically,

you have 2 engines and 2 drive trains

seperate, so the power losses are equivalent to a 2wd set up

but for each set of wheels! :thumbs:

so you have a engine running front wheels thats 200bhp @ wheels

& you have a engine running rear wheels thats 200bhp @ wheels

so no more losses anywhere coz both them figures are messureed seperatly

400BHP

[Infinity]

you'd lose power at the wheels, 4wd has MASSIVE transmission loses

Ah, but he never said anything about a 4wd drivetrain. He said and engine at the back and an engine at the front. Surely there is a difference here as the car was originally RWD. You are are therefore making the car 4wd, but not if you see what I mean.

Disclaimer: I'm not an engineer, so I may be taking out of my arse!

EDIT: Beaten to it!

Jut

[Rob-S13]

EDIT: Beaten to it!

:nod: :thumbs:

[Jason]

so, if this was done, would it show the same power figure on the rollers?? obvoiusly it would be a lot quicker, its just that the hp figures would read the same???

[Sibbers]

I think if you have two engines driving 2 wheels each on their own drive train then you'd have around 200hp at the wheels but with twice the torque as was given in the first post example.

[Rob-S13]

i think i see what you getting at,

you put the car on 4wd rolling road

whats the out come!

i would still say 400bhp,

coz the machines gona work out the power been put through each set of rollers

and the car would be putting 200bhp though each set!

but i don't know what else the machine will do coz i not sure how the properly work


to get a 100% accurate figure you need to measure the front and rear seperately and then add this power together!

[Sibbers]

actually yeah I agree with rob, 4wd rolling roads do add the power together don't they? so yeah 400hp unless the engines and wheels share the same transmission in which case apply a 30% loss

[Infinity]

Dubsport quote power on one of their cars seprately:

ENGINES: Front- 2782cc VR6 from Mk3 Golf, Rear 2861cc VR6 from Corrado. Custom Scorpion stainless exhaust, single silencer for front engine, triple silencers for rear engine. Power 174bhp (front), 190bhp (rear).

TRANSMISSION: Standard Mk3 Golf cable-change gearboxes front and rear, custom gearshift link mechanism.

Now obviously that isn't @ the hubs power... You could say that what you're suggesting is a 400bhp car with 200bhp at the front and 200bhp at the rear.

Oh bugger, now I've just confused myself :confused:

Jut

[Rob-S13]

is this final now?

my brain hurts :wack:

[Sideways Danny]

bugger, i read it wrong, (well actually i read it right but thought i'd read it wrong) :wack:

Yeah twin engine would double the at wheel HP, Ian Birchs twin engined golf did it

[Infinity]

Yeah twin engine would double the at wheel HP, Ian Birchs twin engined golf did it

Sorted :thumbs:

Jut

[2 Black Lines]

Lets say car1 (rwd with 200bhp) weighs 1100kg = 181 bhp/ton

car 2 (all wd x2 engines) with 200=200 and a weight of say 1250 kg = 320Bhp/ton.

Now if I can count, 4wd and that power, interesting.

[Grim]

if you have a car, for arguments sake rear engined rear wheel drive.... you put it on the rollers and it produces 200hp @the wheels..

you then take it away and put another identical engine in it powering the front wheels, making it 4wd..

.. if you put it on the rollers (4wd r/r) then it would still have 200hp @ the wheels.......

this seems very strange to me... :confused:

i think you boys have sorted yourself out, but if you put a 200sx on a 4wheel roller, it would show as 0bhp front + 200bhp rear.
put in another engine and drive train to the fronts and it would show as 200+200