Went and took care of my baseline dyno today.... so now its time to start playing around.
The TQ was swinging around and was wondering if anyone has seen this before. The car ran fine on the dyno...
The lower pull was sport button off....

 

Hi,
What do you mean by torque swinging?

I was interested that you actually saw a different power reading without sport button. I thought sport button only changed the throttle ratio map (no data here, just opinion.. maybe it changes more!).

I ran my car up as standard and didn't experience the 'messy' torque graph you are describing but we dont run the rollers on an acceleration test, we run it on a loaded test where it is set to hold each 500rpm increment and stabilised readings are taken.

Regards,
Steven_RW

 

if you look at the picture I posted it shows the TQ swinging around a lot through out the dyno pull.
this was just a dyno on rollers with a 4th gear pull from about 2500 rpm
the sport button adds about 3 psi of boast and more aggressive timing curve.
I see 15 psi with sport button off
18 psi with sport button on

 

my 03/2012 all4 with N18 engine, the sport button makes no difference in boost or HP/Torque

now, if i had a rennsport tune, the sport button would "activate" the tune and there would be a difference, but stock, sport button makes no difference

what year/model is your car? are you sure it has stock ECU, not tuned?

 

There is a smoothing setting on the dyno software, I think that might need to be changed, I can not see it on your photo as its too small.

 

The chart posted is too low resolution to really see, but typically that sort of torque moment is associated with a poorly placed tach signal. e.g a recording error.

 

I will look into doing a better post of the picture. The tool bar does not seam to give you much help to install pics with size options.

good idea on checking the tach connection --

Im starting to put parts on it so before I put the exhaust on im going to do another dyno run just to see if anything changes after a few normal aftermarkets are thrown at it

 

Interesting.

My standard 2007 Mcs ran .8bar (11.76psi) up to 6,000 rpm and .7bar (10.29psi) at 6,500.

These are 'held' boost figures, IE when the car is loaded up at 2,000 - 3,000 - 4,000rpm and so on, not a spike figure which is next to irrelevant.

My 'mapped' car now runs 1bar (14.7psi) up to 6,000rpm and .9bar (13.3psi) at 6,500rpm.

I don't understand why everyone is seeing so much more boost but not as much power as me (potential assumption in there), especially with their 'standard' cars.

Is there really that much variability?

Regards,
Steven

 

How are you getting your boast numbers ?
Scan Gauge calculates the boast number .
I have a gauge I tapped in on my inlet tube.

 

Hi,

I was using an OBD code reader. I have access to the cheaper versions and proper BMW spec readers as my father runs a company selling them and has done for xx years.

I don't as yet, have a dedicated boost gauge in the car and just use what the cars sensors see.

Have you put them back to back to test if they both read the same?

Regards,
Steven_RW

 

How can you make any conclusions with such a sh1tty plot from the dyno operator? For God's sake turn on data smoothing!

 

Well I used my scan gauge at first and it was slow due to the fact it has to calculate to give you a boast reading. Also it did not have good repeatablity. That's why I put the boast gauge on

Well Kountryboy I will get right on that and hit the "smooth data button"

 

The best way to post pictures is to hyperlink to a picture hosting site. Then it will display the full size.

 

Thanks for the heads up to post pictures.

 

What kind of car did you dyno?