Problems then on boost

[Mark0]

Hi, then pushing accelerator pedal to floor, under about 5000rpm or more it's like cutting fuel...
I don't really know how to explain, but maybe log and config file would help ? And maybe someone would find problems.
Log file: http://s000.tinyupload.com/index.php?file_id=24684735112253552142
Config: http://s000.tinyupload.com/index.php?file_id=08730326661466645577

[Leonhard]

You are reaching overboost fuelcut at 280kPa -> see Rev Limit/Overrun/Safety settings.
Boost control is working but it seems your hardware isn't following,
check your boost solenoid, wastegate actuator (spring settings/preload).

[Mark0]

You are reaching overboost fuelcut at 280kPa -> see Rev Limit/Overrun/Safety settings.
Boost control is working but it seems your hardware isn't following,
check your boost solenoid, wastegate actuator (spring settings/preload).

Well, wastegate actuators work as should, because engine was pulled out for clutch change and before putting back, checked them.
If you talking about overboost, using this solenoid: https://shop.vems.hu/catalog/high-capacity-port-boost-control-valve-p-171.html
Also, i have BOV with spring which tightened to very end. If you refering to my overboost the possible solution would be this...

I will give a shoot and see if it helps.
Only next month going to VEMS tuner who will make car run smoother, because previous user by himself adjusted settings and after my engine upgrades it doesn't run like it should.

Anyway, thanks for info.

[fphil]

Thanks for your log
@ 1.25:239 your coolant temp jumps from 90° to 72°. To you understand why?

[Leonhard]

I don't see a problem with your BOV, it seems to be closed (under boost pressure) as it should be.
If you already checked on the wastegate actuators, what is keeping them to open up for boost control?
I think, it's still worth to look around the boost solenoid.
If you don't mind, please tell us more about your 6-cylinder project 

[Mark0]

It's 2.7 bi-turbo engine, Audi S4, 2001.
All VEMS install was done by other car owner so basically i'm kind new in this.
And what about coolant temp? Why it drops?
Also noted that warmup turn on's. Does that mean i have bad sensor or what?

[Leonhard]

It's a fine engine, but very laborious . Most of the 2.7BiTurbo tuners stay with the original Bosch ME Motronic.
So this VEMS swap is quite rare and even more interesting to hear about.
The original Audi Boost solenoid (N75) controls both wastegate actuators simultaniously.
This boost solenoid (#078906283B) will work well with VEMS (use 42Hz for PWM period).
The Audi service training manual (SSP198) gives a lot of information about this engine, might be useful...

[Mark0]

Yeah, and it's expensive to maintain too :-D
Anyway, after work gonna check vac lines to turbo's. Maybe one of them just pop out but reaching first would mission one. Because i need go under car...
Pressure test would be great, but better look for it myself first.
Gonna provide more info after i find problem.

Quick update: taked vac line from boost solenoid and applied air with mouth and guess what, it goes freely to passenger side turbo underneath, so problem one way or another is solved, i gues...
About the project there will be more info and gonna post it if you wanna know more.

[Leonhard]

That's good to hear, there is progress in fault-finding

and sure, some more info please

Do you still use the original throttle valve?


here is a link to this Audi selfstudy-program:

http://www.ibiblio.org/tkan/audi/2.7Biturbo-SelfStudy.pdf

see page 22-28 for charging functions.

These SSPs always helped me a lot working with Audi engines.

[Mark0]

Thanks for link, but i have these files
About auto: Most of moding to engine was done by another owner (80%).
2.8 heads (not sure about intake and exhaust cams)
FMIC with pipes to match throttle body
Borg warner RS4 K04 turbo's
Exhaust manifolds also remaked to fit turbo's
Straight exhaust
RS4 fuel rails
RS4 fuel pump
RS4 intake manifold
W8 throttle body
RS4 throttle body y-pipe
Oil catch can
RS4 y-pipe
RS4 injectors (not realy sure about them...)
RS4 clutch
RS4 pressure plate with 15% more clamping force
RS4 transmission
MAC 35A-AAA-DDBA-1BA boost controler (also most of vacuum hoses removed, leaved only the needed one to control turbo's, brake booster and for boost gauge)
Adjustable fuel pressure (now it's about 6bar's)
Mafless

Well, everything else to match an RS4 power and a bit more.
Previous onwer claimed it's 500hp car, but for my opinion is ~400hp or maybe a little bigger. Then the VEMS will be configured properly, car will be runed on dyno to see how much exactly power it has.

[Leonhard]

RS4 step, nice setup.
I'm following up,
good luck!