Vag com boost log graph

borachris · Oct 26, 2009

Hi guys, i'm new to logging with vag com so go easy if non of this makes sense lol.

http://vaglog.vag-technique.fr/users/borachris/chris_boost.CSV_26-10-2009_15-57-09.png

Is it ok that the Actual boost is higher than the specified?

My thinking was that if its getting more boost than its asking for it won't be putting enough fuel in for the air its getting?

Right or wrong?

Curious Chris · Oct 26, 2009

Too much air is never a problem. And then I can read the time stamp on the bottom but it is inherent in the boost system that you first overshoot and then it adjusts down to the target if you hold the pedal down long enough.

fenwick458 · Oct 26, 2009

thats not the "true" value of boost the the ECU is requesting. by default VAG COM can only read upto 2600mbar for specified boost, to get the true values shown you need to do something with the software and remove the limiter.

same goes for if you install a 4 bar MAP sensor, VAG COM only shows upto 2983.5mbar but the ECU can reud upto 4000mbar!

borachris · Oct 27, 2009

Ah I see, Cheers for that Stu, I thought it was odd that it hit 2600 and flat lined so perfectly!

im570rm · Oct 27, 2009

imo the actuator has a bad adjustment.What duty cycle do you have @ 4000 rpm?

aRd · Oct 28, 2009

im570rm,

here's Chris raw data from channel 011

http://www.4shared.com/file/144301038/a8455080/chris_boost_graph.html

im570rm · Oct 28, 2009

the duty cycle is fine,it's not that,now it can be a lot of reasons,put the stock tune back and log it again.

borachris · Oct 28, 2009

Cheers for posting that data up Ray.

im570rm said:
the duty cycle is fine,it's not that,now it can be a lot of reasons,put the stock tune back and log it again.

Thanks, What do you think is the problem and what effect is it having?

It will be the weekend before I can try log my stock tune.

im570rm · Oct 28, 2009

could be a lot of resons:bad software,broken turbo,rusty actuator,broken n75,etc .I guess is something wrong with the actuator or vnt system anyway if you look on the log the duty cycle goes up & down a few times and it should go up all the time ,so i can only guess that the actuator is rusty or the vanes are blocked from time to time.

aRd · Oct 28, 2009

im570rm, the turbo on Chris car is hybrid 1756, only done a few weeks ago.

could it be the actuator is setup incorrectly ?

im570rm · Oct 29, 2009

nop,the adjustment is right however there are a few variations under 2500 rpm which can be explained with a lot of reasons look in my previous post

borachris · Oct 29, 2009

im570rm said:
nop,the adjustment is right however there are a few variations under 2500 rpm which can be explained with a lot of reasons look in my previous post

Thanks for the advice my friend

The turbo was freshly re-built only 3 or 4 weeks ago so hopefully thats not the problem

I'll try a new N75 at the weekend and also do a few logs with my old tune and see if it makes a difference.

I'll post up the results asap.

aRd · Oct 30, 2009

borachris said:
Thanks for the advice my friend

The turbo was freshly re-built only 3 or 4 weeks ago so hopefully thats not the problem

I'll try a new N75 at the weekend and also do a few logs with my old tune and see if it makes a difference.

I'll post up the results asap.

N75 waiting for you at mine !

Rub87 · Oct 30, 2009

It just overshoots a little, requested boost will be around 1.8 bar I guess, kwp data isn't adjusted so req only shows up to 2600mbar, don't worry, a little better N75 values could make the boost curve look a bit nicer.. but it looks like it's goign well

fenwick458 · Oct 30, 2009

Rub87 said:
It just overshoots a little, requested boost will be around 1.8 bar I guess, kwp data isn't adjusted so req only shows up to 2600mbar, don't worry, a little better N75 values could make the boost curve look a bit nicer.. but it looks like it's goign well

anymore info on how to adjust the KWP data to show above 2600mbar rub?
i'm going to my mapper tomorrow and if i knew a little more about it then maybe i could try and explain it to them and they can do it for me!

borachris · Oct 30, 2009

Rub87 said:
It just overshoots a little, requested boost will be around 1.8 bar I guess, kwp data isn't adjusted so req only shows up to 2600mbar, don't worry, a little better N75 values could make the boost curve look a bit nicer.. but it looks like it's goign well

I'll have a play about with it at the weekend

aRd · Oct 30, 2009

Rub87 said:
It just overshoots a little, requested boost will be around 1.8 bar I guess, kwp data isn't adjusted so req only shows up to 2600mbar, don't worry, a little better N75 values could make the boost curve look a bit nicer.. but it looks like it's goign well

I think the map Chris is running has boost set to 1.725 bar in the map.

Rub87 · Oct 30, 2009

just had a look at the file, it's askin 2795mbar, seems I wasn''t too far off

also judging from the file I can say it's not perfectly smokefree in transient zone, and that N75 values are quite good for this setup oem wise, only open vanes a bit earlier and/or request a little less boost pre 2000rpm =)

borachris · Oct 30, 2009

Rub87 said:
just had a look at the file, it's askin 2795mbar, seems I wasn''t too far off

also judging from the file I can say it's not perfectly smokefree in transient zone, and that N75 values are quite good for this setup oem wise, only open vanes a bit earlier and/or request a little less boost pre 2000rpm =)

Yes I get that you know your stuff

lol

When you say not smokefree in the transient zone what do you mean? It does smoke a little now and then but not all of the time?

So do you think I should try and adjust anything or leave the it alone?

Rub87 · Oct 30, 2009

transient I mean the moments the turbo is going from no ot low boost till it reached it's requested boost

borachris · Oct 30, 2009

Rub87 said:
transient I mean the moments the turbo is going from no ot low boost till it reached it's requested boost

Yeah sometimes when I first put my foot down I get a little smoke but it cleans up pretty much straight away.

Do you think I need to adjust anything on the turbo?

Rub87 · Oct 30, 2009

nope I think turbo is fine as it is!

Vag com boost log graph

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