Remove driveshaft to run on 2 wheel drive dyno?!

[Crazy_pilot]

There's a new dyno being installed in town, so I asked on the local forum if it could do AWD cars. The response I got was to remove the driveshaft and run the car.

Uhhhhhh....what? Does this work? Would the car survive? It's not something that fills me with warm fuzzy feelings.

The second statement was that the operator might install a set of dummy rollers to allow AWD cars to do pulls. Is that the typical AWD dyno arrangement, that only one set of rollers applies resistance and takes measurements, and the other just allows the wheels to spin? Doesn't add up to me, with transmissions that can vary torque from front to rear there would be some power lost to those unmeasured dummy rollers.

[bheinen74]

this sounds like fail. what about placing fuse into fwd holder slot of fusebox... would hate for the fuse to fry though, that would send the car off to outer space.

[svxfiles]

Originally Posted by Crazy_pilot

There's a new dyno being installed in town, so I asked on the local forum if it could do AWD cars. The response I got was to remove the driveshaft and run the car.

Uhhhhhh....what? Does this work? Would the car survive? It's not something that fills me with warm fuzzy feelings.

The second statement was that the operator might install a set of dummy rollers to allow AWD cars to do pulls. Is that the typical AWD dyno arrangement, that only one set of rollers applies resistance and takes measurements, and the other just allows the wheels to spin? Doesn't add up to me, with transmissions that can vary torque from front to rear there would be some power lost to those unmeasured dummy rollers.

NO!
On a dyno pull you are running full throttle.
If your driveshaft is disconnected, and drag is introduced to the front wheels only, the power will find the path of least resistance and smoke the clutch pack.
Don't do it.

[Crazy_pilot]

Originally Posted by svxfiles

NO!
On a dyno pull you are running full throttle.
If your driveshaft is disconnected, and drag is introduced to the front wheels only, the power will find the path of least resistance and smoke the clutch pack.
Don't do it.

That's pretty much what I figured. Why the hell someone would think that the proper way to dyno an AWD car I don't know.

[svxfiles]

Originally Posted by Crazy_pilot

That's pretty much what I figured. Why the hell someone would think that the proper way to dyno an AWD car I don't know.

If it had a solid lock up of some kind it would be fine.
But then it would be a 4wd, rather than AWD.

[Blacky]

There are 4 wheel dynos. My brothers friend has one at his shop near Toronto and does a lot of work with racing Subarus, mainly WRX I would imagine.