Flat spot at 5200rpm on 2.0T - Does yours do it?

[micky 32]

Any luck sorting your issues Carl?

[vRS Carl]

Nope

I give up with it now. My next step is K04 or an R36 Passat 

Carl

[micky 32]

So going leaner less fuel makes more power?? How does that work. I thought more fuel with more air make more power?

[Poverty]

So going leaner less fuel makes more power?? How does that work. I thought more fuel with more air make more power?

a better air to fuel ratio makes a more clean and efficient burn/explosion.

[micky 32]

So going leaner less fuel makes more power?? How does that work. I thought more fuel with more air make more power?

a better air to fuel ratio makes a more clean and efficient burn/explosion.

Did you try yours on F9 yet?

[Poverty]

Na mate, wont be running the car hard/adjusting settings till my vcds arrives so I can log at the same time.

Some more interesting data from a different member from SCN who also seems to have this flat spot on his revo stage 2 plus. Hoping jonny will have some more insight on the following.

I had previously posted a thread regarding my car cutting out with a low fuel/pressure, my local vag specialist Euro Performance, with great guidance from Kevin at REVO. Painstakely checked over data logging for a number of days:-

The possible issues intitially thought were

fuel filter blocked - checked and replaced pretty clogged

fuel pump faulty - removed and checked all looked fine cam follower replaced just as precaution

hpfp seizing - no markings on the internals and appeared to be working fine

They carried on data logging and eventually noticed that on acceleration, the fuel rail when reaching 130 bar fuel pressure. The fuel rail sensor was shutting down the car into limp mode or even stalling the car. It was established the that sensor was only capable of 130 bar of pressure and, on the logs once it requested 134 bar, the sensor would shut it down.

They then ordered a RS4 fuel rail sensor which is capable of 2.2 bar of pressure (I think), once fitted it allowed the required pressure to then be supplied.

[cuprak1]

Rs4 fuel rail sensor group buy anyone! 

[Poverty]

Rs4 fuel rail sensor group buy anyone! 

Thing im concerned about is though if the pump can only physically supply 130bar, and the car wants 134bar, then surely thats not good, and fitting a rs4 sensor is just masking a issue?

[david_phillips95]

Had the car out today with B7 T5 F9 and it wad running spot on - no flat spots through 3rd 4th and 5th  

I remember when the first day i got the car back from my Revo dealer, they had the settings at B8 T3 F6 (they set T3 as they werent sure what fue i ran). On the drive home i had flat spots in 4th and sometimes 5th so i had a read on here and seen that most people run and decided B9 T5 F6 so i gave this a try and still had flat spots...Ordered new NGK Iridium Plugs and and ran some STP Injector Cleaner in with a full tank of fuel. Ran the full tank of fuel with injector cleaner in it and filled up again (Vpower). The next day i was still gettting flat spots sometimes 3rd and more commonly 4th and 5th so the issue was not resolved.

I had really been racking my brain with this as i didnt have this issue running stage 1 software on B9 T5 F9, The only thing i could put it down to was running to higher boost and something was pulling back or giving in. From logs i had done on B9 T5 F6 i had seen the boost powering in early around 3k RPM @ 1.7bar and dying off higher up the rev range which i wasnt too happy with also the AFR was running a little rich.

After trying B7 T5 F9 i noticed a huge difference, smoother power delivery and felt overal better, logs showed the boost coming in at around 1.5 - 1.6 bar vs 1.7bar with B9, The boost through the rev range on B7 & B9 is very similar, the main difference is you arent getting a huge load of boost hitting in at 3k RPM. Running B7 brings the boost in less aggresively but sustains good levels of boost right till redline. Ran some checks on the AFR and its running leaner which im also happy about as it was too rich with F6.
So today i done some more logs, checked all my CF's for each cylinder and could see they were all around 0, as i run Vpower i decided to try T6 and do some more logs. The car feels sharper with T6 and im not seeing any CF's above 3 at peak RPM so all good there. Still running great with ZERO flat spots  
Im going to have a tinker around tommorow and try B8, im almost 100% sure that if i set B8 the flat spots are going to appear again, as i mentioned earlier the car was set at B8 by the Revo dealer and caused flat spots. If they do appear again then that settles it for me and i know its down to running to high a boost setting.
I will be attending a rolling road day on Sunday so will get the car on the rollers with B7 T6 F9 and see what it makes and get a look at the graphs.

Cheers Davie

[Poverty]

excellent findings there, excited to read about your findings on boost 8!

Really dont understand why revo are telling everyone to run Boost 9, timing 6 fuel 6? Id rather have more boost higher up the revs that more boost down low! So once me and one or two others change our settings and come up with the same result, its because of improperly setup cars!

[vRS Carl]

I tried boost 8 fuel 9 and timing 5,6&7. Also tried other fuelling ( 8 & 7 )

B7 T5 F9 seemed to give the best results according to the logs. Not saying that's the same for every car but for my car and it seems davies S3 B9 T6 or 7 and F6 definately isn't right.

Carl

[Poverty]

Its really weird as I removed all my mods once bar the stage 2 + map, and the flat spot was still there. I then changed the settings to boost 8, timing 5, fuel 9 and the flat spot was gone and drove really well, but I never gave it any thought as there were no other mods on the car. Need to try it with the mods.

[cuprak1]

trial and error my friend but if changing our settings doesnt work its back to the drawing board.. we can only try .. after 13 pages here and 8 on scn with still no answers what have we got to lose  !

[Poverty]

trial and error my friend but if changing our settings doesnt work its back to the drawing board.. we can only try .. after 13 pages here and 8 on scn with still no answers what have we got to lose  !

Our sanity

[cuprak1]

pov bring your SPS+ out on weekend so i can change my settings! lol im poor and only have the SPS switch :(