Martin-Hadland

iTrader: (2)

Not true!

rapidcossie

thats just cheating martin

xr2i-carl

so what did the m5 make then??? come on

rand

Marco, where can I get this done?

Cheers

xr2i-carl

????????????????? m5 ??????????????????

Billabong

I actually thought it might make a bit more than quoted, hence my guess. Not driven an M5, but I know which power delivery/unit I'd prefer to have, Euan

marco polo

iTrader: (1)

yes they did Rear VC's had 50Nm 2wd/4wd

the 4wd saff center diff has 25Nm

and the escort 4wd center VC has 50Nm

marco

marco polo

iTrader: (1)

well thats a good idea

marco

glancy2081

a can only wish my 4wd could turn to 2wd once moving

rapidcossie

A smoky old YB

dovboy

a cos on track is a bit like a rainbow smoke machine

BigErn

As far as Im aware you lose 40% power through 4x4 transmission from flywheel to road wheels. Not sure of 2wd losses.

Fiecos Dan

still wont be as fast, as the rolling resistance of the unused drive chain once switched.
But i guess an extra 15bhp should even it up.

xr2i-carl

so the new v10 m5 only made 444bhp as the flywheel?

Martin-Hadland

iTrader: (2)

Exactly what I said! You stated all VC's were 50nm, I said untrue. Read you reply

stevieturbo

There is no random number you can pluck from thin air, to guess what losses either might have.

And 40% would be HUGE !!!

Fagin

I dont care what your saying!!

rapidcossie

wheels

Lloyd

i doubt it would be even 15 bhp,the trans losses will be the same,as the rwd.because they are the only wheels connected to the engine.the skyline transfer unit is fluid controlled,not chain like a cos,so the only losses are the diff and shafts that run on bearings,and once moving the resistance to acceleration is very small.

marco polo

iTrader: (1)

i should have double checked what i wrote

marco polo

iTrader: (1)

Martin-Hadland

iTrader: (2)

Lloyd, you are both right and wrong! Indeed the drive to the front wheels IS fluid controlled but the system still has a chain exactly the same (but wider) as a 4x4 Cosworth. When no drive is being transmitted to the front the chain is freewheeling.

foreigneRS

finally there is a sensible and factual post about chassis dyno's from Gerry

Lloyd

i was nearly right then .lol

Turbosystems

iTrader: (5)

if we took out your engine and harnessed 550 red rum horses to your car would it do 190mph at brunters
what would be the et and terminal at santapod lol

The horses would be shod with road legal yokohama horse shoes

Lloyd

that would depend on how much nos you can get the horses to breath in. ps the engine is out if you want to try it,

Lloyd

ive just re-read this? its a bit cryptic but are you trying to tell me something?

svony

iTrader: (3)

I can't imagine the driveline loss to be more than 25% on a 4wd cossie. Last summer I dynoed my car (4x4 3dr replica) and the numbers were 258hp/284tq at the wheels, 4th gear pulls. With the percentage added for driveline loss that would put me almost exactly at the figure Karl quoted me for my setup when I got my chip from him.

At the rolling roads/dynos there in the UK who decides what the percentage loss is when setting up the machines to measure BHP? Is it a standard industry figure/formula or is it a random number applied by the individual operator? Whar gear are the runs usually made in?

Fiecos Dan

When i said drive chain, i meant transfere box, prop, diff, drive shafts.

Would be good to test the resistance, But that would mean modifie'n a RR so both roller are chain connected, so even when in 2wd mode, the fronts are being turn'd at same speed as the driven rear wheels, which this should show the rolling resistance drain on the power output.

pete mcrash

iTrader: (1)

.....mine has always been done in 4th

stevieturbo

From reading various forums, this can be a hot topic.... I think most do seem to use a random number.

We need to be using wheel figures here, same as the rest of the world. Thats what dynos measure in the first place.

As for the Skyline boxes....only the R32 box has true 2wd mode. The R33 and R34 always have some degree of drive to the front wheels, even when zero pressure is applied to the diff.

Lloyd

thats not true in my skyline box,its been on a 4wd dyno pack.and with the pressure turned off the front wheels have no drive.

Martin-Hadland

iTrader: (2)

Interesting statement can you explain further? Do you know R32 and 33 transfer boxes are the same?

stevieturbo

I was informed by a guy who works at RB abut the differences. He says the R33/34 centre diff can be modifed to give zero drive to the front wheels, same as R32.
But normally, R33 and R34 do still put some drive to the fronts at all times. I dont know how much though. He says its still ok for burnouts etc with a line lock though.

Initially I was searching for an R32 box, but ended up with an R33 as they are supposedly stronger, and generally better.

I also noticed on another forum, where the skyline guys actuallly have a manual pump, to ensure 4wd is engaged on the launch. The normal controller must be a little slow on the take up to engage 4wd. They have a additional hydraulic system via a handbrake style laver to pump the diff up.

Martin-Hadland

iTrader: (2)

He is wrong!

stevieturbo

He isnt the only person to have said similar.....

As I have no direct experience using one yet, I cant say. But I'd think someone that works on them for a living, might have an idea about them ??

Are you saying all of them are fully open then ?

Lloyd

your informant is wrong mate,the skyline 2wd to 4wd works via gyroscopes and accelerometers/decelerometers. ie it sets off in 2wd,the sensors signal the car is moving and then engages 4wd.you would be surprised how many skyline tuners i have spoken to who dont know how the system works.

Martin-Hadland

iTrader: (2)

I have stripped these centre diffs and know exactly how they work and with zero line pressure there is no drive to the front wheels. Maybe when fitted to the original vehicle there is some hyd pressure applied at all times but without that there is no drive.

As Lloyd mentioned above there are a great deal of people in the Skyline business that don’t completely understand how the system works .. Particularly the hyd valves etc, I know this because at the start of the project we were given some very bad advice by more than one tuner which resulted in damaged pump/valves.

xr2i-carl

sorted now tho martin?

stevieturbo

None of the above matters to me, as its not for a skyline.

The reasons you mention above, are why some of the skyline drag racers, have a manual pump, to engage 4wd before setting off on the 1/4, as the system can be lazy to engage 4wd, and hence lose traction off the line.

I simply asked how hydraulic pressure affected the diff and what was required to make full 4wd as per skyline car, and was it fully open when zero pressure was applied. I was told that only the R32 was fully 2wd.

And to fully engage 4wd requires circa 180-200psi.

I would be surprised if he is wrong, as he is one of the people who built Kieths car.
Perhaps there is a mis-communication somewhere...