dultanur
all promises, no action :)
when logging requested vs actual boost, how much would you say is normal, and how much is a boost leak?
what is acceptable boost loss?
- Thread starter dultanur
- Start date
Plot them on an Excel chart, requested v actual, it's the only way to really have a good look. Requested should meet actual through the mid-range:
I think this chart is bit too good, it's from a 210bhp SEAT Leon Cupra R.
But you get the idea. If it never meets requested you've defo got a problem somewhere.
I think this chart is bit too good, it's from a 210bhp SEAT Leon Cupra R.
But you get the idea. If it never meets requested you've defo got a problem somewhere.
dultanur
all promises, no action :)
ok. i guess my car has developed a problem, as it used to be just fine, now theres close to 0.1 bar loss...
what should i check? theres nothing obvious like hissing sounds and such...i haven't seviced my DV for 8000km, could that be it?
what should i check? theres nothing obvious like hissing sounds and such...i haven't seviced my DV for 8000km, could that be it?
dultanur said:
So you're failing to meet requested by 0.1bar? That's only 1.5psi, not exactly a lot...
Just check the obvious places really. Are you feeling down on power? Don't suppose you know what your g/s airflow was before the loss?
dultanur
all promises, no action :)
no power seems fine...
the wierd thing is, my MAF readings were a bit low even before i got the map, they are still low. right now i'm getting around 185g/s max. i got a new MAF from ebay but that was even worse, made the car go nuts. so back to the old one. i will try with a friends to see if it gets better.
there are some irregularities with my logs, i guess i'll have to make a serious log run in 4th gear through the rev range to get some solid results.
the wierd thing is, my MAF readings were a bit low even before i got the map, they are still low. right now i'm getting around 185g/s max. i got a new MAF from ebay but that was even worse, made the car go nuts. so back to the old one. i will try with a friends to see if it gets better.
there are some irregularities with my logs, i guess i'll have to make a serious log run in 4th gear through the rev range to get some solid results.
dultanur
all promises, no action :)
yeah i know, but usually i take logs on the highway when there are other cars around, so cant get to that speed un interrupted. i'll have to do a midnight run then 
eheh
my most recent logs are all going through the gears so maybe the boost doesn't have time to catch up properly.
ehehmy most recent logs are all going through the gears so maybe the boost doesn't have time to catch up properly.
dultanur
all promises, no action :)
Hi guys / girls. Im new to the whole S3 experience.
Picked up a very nice S3 last week. Car drives great.
Out of interest i did a plot tonight with my VAG.COM
Seem the be running slightly low on boost pressure.
What are your opinions on my graph?
I did the run in 4th 2000rpm to Red line. And have deducted atmospheric pressure from the boost to give the gauge pressure.
Not sure the torque figures from the ECU would be very accurate? i believe they are calculated from some 5 sensors around the engine ?
[URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"][URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"][URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"]
[/URL][/URL][/URL]
Picked up a very nice S3 last week. Car drives great.
Out of interest i did a plot tonight with my VAG.COM
Seem the be running slightly low on boost pressure.
What are your opinions on my graph?
I did the run in 4th 2000rpm to Red line. And have deducted atmospheric pressure from the boost to give the gauge pressure.
Not sure the torque figures from the ECU would be very accurate? i believe they are calculated from some 5 sensors around the engine ?
[URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"][URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"][URL="http://img399.imageshack.us/img399/4659/s3chartjpgzq3.jpg"]
[/URL][/URL][/URL]I think your MAF is shagged.
Very low g/s mass air flow and boost plot is all over the place.
Did you keep your foot down all the way through the revs or did you back off at (even slightly)?
I take it there are no fault codes?
Very low g/s mass air flow and boost plot is all over the place.
Did you keep your foot down all the way through the revs or did you back off at (even slightly)?
I take it there are no fault codes?
jm-baker said:
Hmm, 172 g/s is actually OK. I was just reading the scale wrong, i thought it looked more like 150.
Boost leak then? Initial spike of pressure that it can't sustain. Check all the hoses between the inlet manifold and the turbo outlet, plus hoses to the N75 and DV.
Could be the DV.
Whip it off, use a biro to push up the piston and cover the top (narrow) vac connection with your thumb and see if the piston stays in place. Releasing your thumb should see the piston snap back in to place. If it doesn't stay in place with your thumb their then the rubber diaphragm is split. They are £22 from Audi.
Whip it off, use a biro to push up the piston and cover the top (narrow) vac connection with your thumb and see if the piston stays in place. Releasing your thumb should see the piston snap back in to place. If it doesn't stay in place with your thumb their then the rubber diaphragm is split. They are £22 from Audi.
dultanur
all promises, no action :)
jm, there seems to be something wrong (Doh!)
paul heres my boost plot. i did it in 6th gear (!) thats why the max rpm is a bit low. same day my MAF readings again came in at 185 max. tomorrow i'll borrow a brand new MAF and try that.
paul heres my boost plot. i did it in 6th gear (!) thats why the max rpm is a bit low. same day my MAF readings again came in at 185 max. tomorrow i'll borrow a brand new MAF and try that.
dultanur
all promises, no action :)
the new MAf also gave low readings so i guess theres a problem.
heres another boost graph:
http://imageshack.us
they both have the same features; actual boost is low until about 4300rpm, then they both track normally...whats the problem ?!??!
can it be the N75?
heres another boost graph:
http://imageshack.us
they both have the same features; actual boost is low until about 4300rpm, then they both track normally...whats the problem ?!??!
can it be the N75?
dultanur
all promises, no action :)
not much. i feel the same, but the cars top speed is not good, actually about what it was std. i'm buying a new MAF from bosch, in the hopes that the low MAF reading is the cause, but somehow i think it isn't.
the boost graphs i took when std. were perfect.
how do i log N75 duty cycle and what would i be looking for?
the boost graphs i took when std. were perfect.
how do i log N75 duty cycle and what would i be looking for?
can't remember which block it is, but it's called '% duty cycle'. log it and then we'll worry about whether it's right or not
are you getting a misfire or hesitancy? 1.5bar of boost is being requested and met, it doesn't look to bad from that point of view.
what about logging timing pull (cf's). If it's not making top end then the ECU may be pulling the timing. Maybe one of the Lambda probes is ******?
are you getting a misfire or hesitancy? 1.5bar of boost is being requested and met, it doesn't look to bad from that point of view.
what about logging timing pull (cf's). If it's not making top end then the ECU may be pulling the timing. Maybe one of the Lambda probes is ******?
dultanur
all promises, no action :)
nope timing is fine. no misfire or hesitancy, i had some hesitation with the MAF from ebay but that one was reaaly ******, also threw up a fault code. now i'm back to my original.
i guess if it was a leak it would show all across the rev range...i dunno.
i'll get an N75 duty cycle log, the new MAF and check these again.
BTW, the requested boost seems to me to be falling too quickly, i'm getting less than 1 bar at 6000rpm...is this normal? but since its requested boost, i guess thats what the map is requesting so shouldn't be a problem.
i guess if it was a leak it would show all across the rev range...i dunno.
i'll get an N75 duty cycle log, the new MAF and check these again.
BTW, the requested boost seems to me to be falling too quickly, i'm getting less than 1 bar at 6000rpm...is this normal? but since its requested boost, i guess thats what the map is requesting so shouldn't be a problem.
dultanur
all promises, no action :)
dultanur
all promises, no action :)
right thanks.
and ummm...what am i looking for?
i guess it should read 100% until catching up with requested boost, then something lower?
and ummm...what am i looking for?
i guess it should read 100% until catching up with requested boost, then something lower?
Just did a run with a new DV.
Only did it in 3rd gear, 2000 - red line. Shorter road!!
The boost is topping about 0.75 Barg @ 3120rpm.
I also logged the N75 :
61% @ 0.75 Barg inlet @ 3120rpm
69% @ 0.73 Barg inlet @ 5760rpm
Graph: [URL="http://img338.imageshack.us/img338/676/s3withforgeat4.jpg"]
[/URL]
What do you guys think? N75 seem's low to me, what could cause this?
This was a basic run, ideally i want to plot it in 4th again. Possibly later!
Cheers
Only did it in 3rd gear, 2000 - red line. Shorter road!!
The boost is topping about 0.75 Barg @ 3120rpm.
I also logged the N75 :
61% @ 0.75 Barg inlet @ 3120rpm
69% @ 0.73 Barg inlet @ 5760rpm
Graph: [URL="http://img338.imageshack.us/img338/676/s3withforgeat4.jpg"]
[/URL]What do you guys think? N75 seem's low to me, what could cause this?
This was a basic run, ideally i want to plot it in 4th again. Possibly later!
Cheers
dultanur
all promises, no action :)
hmm...still think you have a leak...
theres still too much difference between commanded and actual boost, and your max. boost is at a very high rpm IIRC, my boost used to peak around 2500rpm...
about the N75, i have no idea but it seems to me that the N75 should keep seeing 100% until it gets the boost right...isn't that logical?
just to clarify, you're logging block 115 and 114 right?
theres still too much difference between commanded and actual boost, and your max. boost is at a very high rpm IIRC, my boost used to peak around 2500rpm...
about the N75, i have no idea but it seems to me that the N75 should keep seeing 100% until it gets the boost right...isn't that logical?
just to clarify, you're logging block 115 and 114 right?
dultanur said:
Shouldn't close the wastegate more than 95% IIRC, just a safety thing from the ECU (again).
All being healthy you should be able meet requested boost at ~90% Duty Cycle.
It's not a boost leak, if it was a leak that big you'd have a fault code. It *looks* like the N75 is ******. You're not meeting requested boost because the wastegate is wide open (probably).
dultanur
all promises, no action :)
i took some boost and N75 logs today.
i dont know how yours is, but my cars block 114 shows 4 "%load" data,i have no idea what the first 3 are but the 4th seems to be N75 duty cycle... here are the graphs.
http://imageshack.us
http://img78.imageshack.us/img78/189/99995433if8.jpg
as you can see the N75 seems to spike to 95% than immediately falls to around 80% for the rest of the rev range. i still think my boost is peaking a bit high in the rev range.i checked my DV today and it works fine, no leakage. will be fitting a new bosch MAF sensor tomorrow and see if it changes anything. will post again.
i dont know how yours is, but my cars block 114 shows 4 "%load" data,i have no idea what the first 3 are but the 4th seems to be N75 duty cycle... here are the graphs.
http://imageshack.us
http://img78.imageshack.us/img78/189/99995433if8.jpg
as you can see the N75 seems to spike to 95% than immediately falls to around 80% for the rest of the rev range. i still think my boost is peaking a bit high in the rev range.i checked my DV today and it works fine, no leakage. will be fitting a new bosch MAF sensor tomorrow and see if it changes anything. will post again.
Well, i just did a 4th gear plot, and for the 1st time all seems fine !!!
Not sure what has changed since the last plots, only thing i can think of is when i was playing about trying to pressure test the system, i did remove a few hoses, so maybe one of the joints was bad etc.
But im happy for now!
[URL="http://img249.imageshack.us/img249/5113/s3withforgeokmf0.jpg"]
[/URL]
Not sure what has changed since the last plots, only thing i can think of is when i was playing about trying to pressure test the system, i did remove a few hoses, so maybe one of the joints was bad etc.
But im happy for now!
[URL="http://img249.imageshack.us/img249/5113/s3withforgeokmf0.jpg"]
[/URL]
