Audi RS2

AVP · November 20, 2011, 08:38:06 PM

hmm
havent done a report.

i will now and post a link

AVP · November 20, 2011, 08:50:12 PM

here is the link

http://vems.hu/vemstune/bugreports/reports.php?cmd=view&key=IKGZiC

2 logs.

on the first you can see the flat spot between 5200-5500rpm

on the second log, where the run is at the very beggining,there is no flat spot and rpm vs time is linear

GintsK · November 20, 2011, 10:07:59 PM

I do not see where is disturbance in second log, but first one looks really weird. Especially if it comes not from rolling road test.
Similar shape seen when clutch starts to slip. But it is usually just once disturbance per WOT pull where torque reach maximum.
May be it comes from non-even logging frequency. If we look to SecL or Time line - it also looks not straight...

Gints

AVP · November 20, 2011, 10:19:52 PM

yes,that is what i said,
the second log looks much more normal than the first.

and i have 3 logs in total, 2 of them look like the first one.

i do not have any slip on the clutch either.

i do get a trigger error at the end of the rev range if you look as well on the logs, and once the trigger error comes in, i can see the rpm needle in my dash jumping around a bit.

im wondering if that has anything to do with it...

GintsK · November 20, 2011, 10:22:30 PM

So logs come from real road or dyno?

AVP · November 20, 2011, 10:24:56 PM

sorry,
real road.

first was slightly uphill and second was downhill on the opposite side of the road. but the amount of incline was minimal

AVP · November 24, 2011, 09:38:58 AM

i have had no responses from the report yet.

i plan to check the sensor and get a second one to test as well.

GintsK · November 24, 2011, 06:55:46 PM

May be it is because of disturbed time scale?
X-axis of log is samples, not time IMHO.
Very interesting!

AVP · November 25, 2011, 07:49:06 AM

admins say that there is no problem in the datalogging!!!

can this be wheel spin then?

as those areas of the graph are within the highest torque production (roughly) anyway, and put that with a slight uphill....? i dont know!

AVP · November 25, 2011, 07:54:27 AM

here is the run as i calculated the power with virtual dyno.

also here is the run on the second log where the time vs rpm is more linear, and it is a bit downhill

(disregard the red/blue lines, they are from another car)

So i cannot see how i can gain almost 50whp just by going from 1.87bar to 2bar overboost and holding the same boost at the redline.
Yes, its downhill and that will make a difference, but the issue is that on this run where the rpm vs time was nice, there are no ups and downs on the run!

GintsK · November 25, 2011, 08:30:42 AM

I think they are right. Simply VEMS can't send some part of sample with delay or with wrong rpms. As I wrote - very similar shape when clutch start to slip a little. I had such graphs more than once. But as a rule with one disturbance - at max torque. But yours seems more complex....

Of course dyno measurement will be off in case of wheel spin or clutch slip!

AVP · November 25, 2011, 10:30:18 AM

Sure. These are street measurements though, not dyno.
If we had knock control on vems I could say this is something to do with that.

I will check the sensor and make sure its ok, cause it is known that vems with some Audi flywheels seems to have trouble reading.

I still cannot believe that I can have as much as 500rpm off between my dash rpm and vems log. Something is definitely wrong.

AVP · November 26, 2011, 02:44:00 PM

I checked the sensor today, didn't seem to have any problems visually. I cleaned it and placed it back to its position

AVP · November 27, 2011, 03:33:56 PM

did some more logs today and new vemstune

seemed to log the rpm signal ok, so here is a result from my virtual dyno on a 4th gear pull, slight uphill

AVP · December 03, 2011, 05:50:36 PM

did a final change on the wastegate as the one that was on was only a loan. Car is behaving nicely.
Also changed the ECU for the water injection and everything is working properly again!

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Audi RS2