AWD Question

[zweetdreamz]

I want to get the car dynoed. The closest awd dyno is a couple hours away. Do you think that since the awd is computer controlled I could pull a fuse or what not to take it to a fwd dyno? whatcha think

 

[jersey_emt]

I wouldn't dare chance anything like that..... (ugh)

 

[Aricjm15]

the differential is computer controlled. Just the torque bias, not weather its on or off.

 

[zweetdreamz]

Im not gonna be dumb that's why I asked a question. and if the awd was disabled what would be dumb about it

 

[35ounce]

not flaming you, but even if you could disable the awd, what good would it be dynoing just two wheels??

 

[Aricjm15]

not flaming you, but even if you could disable the awd, what good would it be dynoing just two wheels??

if you want to tune the car it would be usefull, and if you were looking just to get an idea of how much power you are putting down.

besides isnt the diff controlled by the main ECU? So if you pulled the fuse the car wouldn't even run.

 

[Kooldino]

if you want to tune the car it would be usefull, and if you were looking just to get an idea of how much power you are putting down.

besides isnt the diff controlled by the main ECU? So if you pulled the fuse the car wouldn't even run.

In Subarus, you can pull a fuse and it will run as 2wd.

 

[Aricjm15]

In Subarus, you can pull a fuse and it will run as 2wd.

i worked at a subie dealer and never heard that. Most subways dont have a computer controlled diff either. Is that just with the STI?

 

[35ounce]

but when would you ever be putting down power to just two wheels? hardly... so yea it's nice to see what kind of power you're putting out, but majority of the time the four wheels are being driven so i don't necessarily see the point of tuning based on a two wheel dyno

 

[Aricjm15]

but when would you ever be putting down power to just two wheels? hardly... so yea it's nice to see what kind of power you're putting out, but majority of the time the four wheels are being driven so i don't necessarily see the point of tuning based on a two wheel dyno

when tuning the car it does not matter if all 4 wheels being driven, the engine just needs to be under load. Not like it matters at the moment as there is not really any computer out there that can tune the MS6 due to the direct injection.

 

[BlkZoomZoom]

Power is always transferred to the driveshaft back to the haldex unit. That is why the transfer case is water-cooled.

Technically if you pull the e-brake up to the first notch it disables the Haldex unit.
This "disconnects" the rear wheels power. I have tried it on the street, and it does turn the MS6 into a wheel hopping torque steer monster. The driveshaft will still spin but the power never gets to the rear-end.

You "should" be able to dyno it simply by pulling the e-brake up.

 

[35ounce]

whoops, yea i didn't mean to say what's the point of "tuning" based on two wheels (i'm still slightly under the influence from last night)... i meant to say that i didn't see the point of measuring the power through just two wheels cuz of drivetrain losses when power is put out through the four wheels.

but then again, this is my first awd car so there is a good chance that i have no idea what the hell i'm talking about (nuts)

 

[mazdaowner123]

Like previously mentioned, a lot of people tune scoobies and evos on 2wd dynos. My guess is it's just because awd dynos are harder to find.

 

[zweetdreamz]

awd dynos are harder to find. I just want a base hp even thought it's not to all wheels it gives me a starting point. Its kinda like a scale. If you use the same scale everytime you will always see the changes from the first time you weighed it. So if i dynoed the front wheels and say i got 220 fwhp and then i added an intake and i dynoed at 225 fwhp i would know how much i gained. Make since?