Dynapack/hub dyno

[Gumball]

Hi

Took my w212 e63 and mates w204 c63 to be power run on the hub dyno.

Both cars mapped by DMS.

C63 went on, wheels off at the rear, hubs connected. 386bhp at 5k. Run again. Same. Working out the increase from 3k to 5k we easily assumed over 500bhp would be achieved assuming no issues occurred in this space.

Called DMS and they said the Merc's don't like being run on hub dyno and that happens often.

So he's expecting 530bhp and me say 700bhp but abandoned the sesssion.

Anyone else heard of this happening? Any views?

 

[John Laidlaw]

Sorry, who is DMS?

 

[daveenty]

Sorry, who is DMS?

DMS Automotive I should imagine John. Don't know anything about them really so can't comment.

Never heard that a MB isn't a suitable candidate for a hub dyno, though mine's always set up on a rolling road. I do know that a few of the SLK guys have used hub type machines, though they seem more popular in the US than over here.

 

[Gumball]

Reading my post again it could be suggestive of anything DMS map related. That's not the intention. I've had a C63 saloon mapped by them that put down 537bhp/510lbft and the E feels wild.

Just can't get my head around what could be stopping the car thinking all is good. Gearing related I'm sure

Chris

 

[John Laidlaw]

DMS Automotive I should imagine John. Don't know anything about them really so can't comment.

Never heard that a MB isn't a suitable candidate for a hub dyno, though mine's always set up on a rolling road. I do know that a few of the SLK guys have used hub type machines, though they seem more popular in the US than over here.

Thanks Dave...maybe the OP needs to get onto a rolling road for comparison- I see on their site they have one...

 

[turbopete]

possibly traction control not been switched fully off, limiting the power available at the hubs?

in all honesty it shouldn't make a difference to the reading whether its on a hub dyno or a rolling road, all things being equal. its the transmission that causes a power 'loss' between what is quoted at an engine (at the flywheel) and the direct dyno readings. most decent dynos compensate for that.