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      11-05-2009, 03:39 PM   #1
Jim E.
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Drives: 99 M3, 11 X5d, 16 F31
Join Date: Mar 2009
Location: US

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Thumbs up 335d - VAC Motorsports Diesel Power Module for the US cars

So I finally broke down and had the VAC Motorsports Diesel Control Module installed and dyno'ed.

I was skeptical when I called VAC and told them that I would do it if they put my car on the dyno and did before and after runs. Aaron and Steve were nice guys and very accommodating. In fact, Aaron told me if I did not like the results I didn't have to buy it.

I also told him that I highly doubted their hp gain figure on their site but would be happy with a 15% increase across the board.

The results are attached.

Basically my peak wheel torque is around 450 ft-lbs @ ~1600 rpm's and fairly flat down to 425 wheel torque @ 2400 rpm's. 450 wheel torque is around 520 ft-lbs at the crank assuming around a 16% loss factor. I really don't know what the loss factor is for an automatic tranny but heard it can range from 15% to 25%. Anyone have any insight on this?

In terms of wheel hp the base peak was 225 hp @ 4K (~260 hp) and jumped to nearly 260 hp at the same rpm. (~300 hp crank)

Notice how the hp stayed up in the upper 4K rpm.

Overall when tooling around town the car feels the same. When you hit it then it jumped into another category from the stock setup. I'm still getting used to it so I think it might be a bit premature to give a full seat of the pants description. But it definitely put a smile on my face!

Note, according to Steve at VAC, they can reprogram this module for more gains but have it set to the most conservative setting until they get more feedback. He said it's as easy as unplugging the module, sending it to them and getting it back.

As a reference point, BMW's figures at the crank are: 265hp @ 4200 rpm and 425ft-lbs @ 1750-2250 rpm.

Dyno runs were on Dynapacks. Runs were made in fifth gear and the dynapacks were adjusted to about a 2.45 rear ratio (.87 x 2.81). Ambient temp was around 58-60 degrees F. Water temp was around 190 degrees F.

Attached Images
File Type: pdf 335d Hp and TRQ.pdf (332.4 KB, 577 views)

Last edited by Jim E.; 11-05-2009 at 07:28 PM.