Log review / sanity check.

[joneze93tsi]

Background,

Been driving the Stage2 B8 for a month, and as expected the B7 feels much slower than I remember.[>_<]
I'm back to daily driving the B7, and decided to do some logging tonight as I haven't checked her in a year or more..
Just looking to confirm this is usual for a stage2+ car, it seems the requested boost would be higher?

Decided to do a 3rd gear log w/ the usual APR suggestions, but narrowed it down to the usual suspects. (rpm/ boost / n75 ect.)

CLICK HERE FOR ENTIRE CSV LOG OF THIS RUN (http://www.columbusht.com/filtered2.csv)

Mods: APR Stage2+ Fresh follower maybe 1500miles ago, cam in excellent shape. Car is in excellent shape mechanically.
Boost logs seem to indicate there is no boost leak, rail pressure is a steady 130 bar, no misfires ect.

It seems my boost is tapering way faster than I remember, from 19psi peak just before 3k to 12psi by 4, and only 11psi by 5k.

WG Duty cycle is only 50-60% for most of the run, is the ECU pulling back boost for some reason ?


http://www.columbusht.com/3rdgear.jpg

[joneze93tsi]

Looking at several other boost plots/ logs posted for stage2 cars, it seems that their requested boost through the mid-range stays around 15-16psi.
Any reason the tune would request less boost over time?

Someone just tell me it's normal so I can move on with my day...[:D]

[CorneliusRox]

So the wastegate is made to lower boost (super simplification), so when it says 'wastegate-duty cycle', I think that is when the wastegate is releasing the most air (which makes sense since it would be spiking right where it says 94). Rail pressure looks great. I dont know why it would taper like that. Your AFR looks good too. Pretty lean, then right around spool up it richens up a bit and gets slightly richer as it goes on (duno if that is how the tune is written at the end, normally they stay pretty constant). I would maybe see if the wastegate needs adjusting.

When pulling the plug from the N75, does it just throw a CEL and remain closed or does it try to compensate with the ECU? If it just throws a CEL and stays closed, you could try unplugging it to see if your wastegate is the real issue.

[joneze93tsi]

Is saw the thread with the wastegate adjustment(s) being made.

Those guys usually couldn't hit 19psi anymore, were only hitting 15psi ect and had general sluggishness.
I am hitting the peak, and following the requested boost down (as can be seen by 50-60% Duty cycle).

I guess my quandary is with why the tune is tapering the boost so aggressively. Most other logs seem to try and drag at least 15-16 PSI through the core of the powerband.
This aggressively stats driving downward (per ecu request).

[joneze93tsi]

So the wastegate is made to lower boost (super simplification), so when it says 'wastegate-duty cycle', I think that is when the wastegate is releasing the most air (which makes sense since it would be spiking right where it says 94). Rail pressure looks great. I dont know why it would taper like that. Your AFR looks good too. Pretty lean, then right around spool up it richens up a bit and gets slightly richer as it goes on (duno if that is how the tune is written at the end, normally they stay pretty constant). I would maybe see if the wastegate needs adjusting.

When pulling the plug from the N75, does it just throw a CEL and remain closed or does it try to compensate with the ECU? If it just throws a CEL and stays closed, you could try unplugging it to see if your wastegate is the real issue.

You are correct, the higher the WG duty cycle, the harder it is pushing the turbo. But it sure does drop aggressively after the spike, which is the part I can't figure out.
I could see there being a boost leak if the WG duty cycle was high, as was requested boost. But I found no boost leaks, got a fresh piston DV & PCV ect. She's sealed tight!

[Existentialist]

I logged my Stage II+ today to compare. This is at about 50f ambient, 3rd gear, APR Stage II+ 93 file, ER SMIC, 034 HFC, AWE HPFP, Milltek cat-back, other small things. One thing I noticed in my logs was that my rail pressure maxed out at 110 Bar, so I may have something else wrong making these results not directly comparable to yours.

Raw Data (http://dl.dropbox.com/u/45470490/LOG-20111115.CSV)

http://dl.dropbox.com/u/45470490/Boost.PNG

[CorneliusRox]

I logged my Stage II+ today to compare. This is at about 50f ambient, 3rd gear, APR Stage II+ 93 file, ER SMIC, 034 HFC, AWE HPFP, Milltek cat-back, other small things. One thing I noticed in my logs was that my rail pressure maxed out at 110 Bar, so I may have something else wrong making these results not directly comparable to yours.


You probably have a PRV that cracks at 110BAR. Get a bigger one and you might notice less fuel cuts ;-)

[Existentialist]

You probably have a PRV that cracks at 110BAR. Get a bigger one and you might notice less fuel cuts ;-)

The specified pressure remains constant at 110 bar. Am I understand correctly that the ECU isn't even requesting over 110 bar?

http://dl.dropbox.com/u/45470490/Fuel.PNG

[wootwoot]

Is there a thread that shows how to do datalogs and make charts like this? I did some datalogging this morning but I'm not sure how to graph it out so nicely.