[ksfrogman]

'06 E90 330i 6MT

Dyno Comparisons (HP gained, lost, and reclaimed)

Stock, Style 162 (18x8.5) wheels, max of 3 runs (6-17-06):

211.93 wHP, 193.20 ft-lbs

Stock, 19x10 wheels, max of 3 runs (7-31-06):

210.37 wHP, 192.75 ft-lbs, humidity ~33%

GruppeM, 19x10 wheels, max of 3 runs (7-31-06):

215.87 wHP, 200.20 ft-lbs, humidity ~33%

GruppeM, 19x10 wheels, Dinan large throttle body, max of 3 runs (11-17-06):

206.88 wHP, 197.50 ft-lbs, humidity ~50%
Time to 6800 rpm (4th gear) in secs = 16 seconds

GruppeM, 19x10 wheels, Dinan large throttle body, 3.64 open performance diff, max of 3 runs (11-17-06):

214.81 wHP, 200.38 ft-lbs, humidity ~50%
Time to 6800 rpm (4th gear) in secs = 12 seconds

Notes:

1) Will post dynos later this evening
2) Spoke with Long Beach BMW S.A. re: installation of large throttle body
3) Spoke with Steve Dinan re: large throttle body
4) Will replace unit with new Dinan throttle body, and bench test existing one.
5) Will post interesting white paper re: Dyno testing.

[ksfrogman]

Today's before and after comparison with installation of 3.64 open performance differential (stock = 3.15)

[StewtheBassman]

That's the kind of stuff i like to see, thanks froggie!! Very interesting how the hp dropped with the throttle body!

[ksfrogman]

Sucky early AM dyno today with Dinan throttle body (3 runs shown here):


Dyno after performance differential added (3 runs shown here):

[ksfrogman]

White Paper:

Dynamometer Testing and the Modern BMW Engine
by: Steve Dinan

Click here to read paper.

A number of variables come into play when dyno testing, even on the same day--e.g., temperature sensors, fuel adaptations, run conditions, etc.

In theory, we doubt the larger bore would result in a loss of HP under ideal run conditions. It is possible the throttle body flap is not opening completely?! Dinan will bench test my existing throttle body.

[mosport70]

Frog

Thanks for the excellent post.

Did I miss your post on the new diff ????
Where did you get it? How does the car feel on the street?

[arcrox]

Very interesting...thanks once again for doing the community a service.

[just4kickz]

haha yess... good thread

[///Matt]

Michael,

I've learned that the 325 Step diff is a 3.73. Why didn't you go with this one? I think I may end up switching my 3.64 to 3.73.

And what does open performance diff mean? I thought you just took a stock diff from a 330i step?

Matt

[ksfrogman]

Originally Posted by ///Matt

Michael,

I've learned that the 325 Step diff is a 3.73. Why didn't you go with this one? I think I may end up switching my 3.64 to 3.73.

And what does open performance diff mean? I thought you just took a stock diff from a 330i step?

Matt

Yes, I've known that for awhile.

Going from 3.15 to 3.64 is a 15% change, and 500 rpm difference at speed. The shorter the gearing, the more the shifting. The 3.64 seemed the best compromise, since this car is my daily commuter and I had to consider what my engine speed would at freeway cruising speed (65-85 mph). I didn't want to be cruising at 90 mph above 4000 rpm.

If we had solid lifters and a redline of 8000 rpm, then it might make sense to numerically higher on the differential gearing.

You might recall this gearing worksheet I used to plug in my individual values.

[ksfrogman]

Originally Posted by mosport70

Frog

Thanks for the excellent post.

Did I miss your post on the new diff ????
Where did you get it? How does the car feel on the street?

When you get on it, the tach noticeably goes from idle to redline more easily and quickly. Yet, it still seems to be very practical for normal driving. I'm not having to work it that hard to drive around town.

[///Matt]

Michael, you didn't answer my other question...

What makes your diff an Open Performance??

[ksfrogman]

Originally Posted by ///Matt

Michael, you didn't answer my other question...

What makes your diff an Open Performance??

An open or standard differential, unlike a locking one, allows wheel speed variance between two wheels on the same axle.

The adjective "performance" is attached to it by vendors who promote this as a means to enhance performance in manual transmission cars. Yet, the 3.64 open diff is the 330i's standard steptronic diff, and the 3.73 the 325i's standard step diff (as you know).

By the way, you might want to do some calculations going from 3.64 to 3.73. I'm not sure if you'll really notice a dramatic difference.

[uhaulball]

what is the differential on a 330xi?

[ksfrogman]

Originally Posted by uhaulball

what is the differential on a 330xi?

330xi:
3.64 in the steptronic
3.23 in the manual

325xi:
3.91 in the steptronic
3.38 in the manual

330i:
3.64 in the steptronic
3.15 in the manual

325i:
3.73 in the steptronic
3.23 in the manual

[///Matt]

WOWZA. 3.91 in the 325xi step, huh??

[StewtheBassman]

Now I know why my 325xi is such a party animal!!! It wasn't the Carbon filter after all LOL!!! And I still get great gas mileage!

[Chesmu]

Hey Froggy,

How did you get your differential changed?

[uhaulball]

so if i got the differential of the 325xi, my shifts would be more aggressive; better throttle response?

[SuperSport]

frogman, good info Is there anyway to correct for the speedo calibration ??

[///Matt]

Uhaul, you are correct, but I don't know if the 325xi diff will WORK with your car, because it might be differently designed, with awd....

[uhaulball]

Originally Posted by ///Matt

Uhaul, you are correct, but I don't know if the 325xi diff will WORK with your car, because it might be differently designed, with awd....

i have a 330xi though