Stage 2+ poor figures...Adi

William McGougan

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Hi all, went to ecotune in Glasgow today to have my APR stage 2+ software fitted, it came out with 335bhp 365ftplb

It's loosing boost and at top end not holding, has a revision G Nov which has been checked by them and they checked for boost leaks and the system was air tight

They checked fueling, ignition, timing etc everything is spot on its just the boost pressure is dropping and not as it should be

They have said potential actuator faulty

Anyone have any insight if there is anything else to look at? As it's a big job and costly to do actuator

Mods list is:
Airtec cooler
Lova hpfp
RS4 valve
RFD
Milltek sports cat/downpipe
Milltek Catback non res
Ramair oversized induction kit
NGK -1 plugs
Red R8 coils
Forge Turbo muffler delete
 
I’m assuming they checked the ecu for faults ? It could be a faulty sensor which is trimming boost.

Actuators aren’t common to failing but it could easily be your issue at that is what holds the boost whilst squeezing the loud pedal.

If I were you I’d take a trip to Rtech as they are scrupulous when it comes to fault finding
 
Yeah they data logged all fuel trims boost levels ignition timing etc, scanned for codes and only code was a cooling fan intermittent fault which I knew of (they are stuck on permanent when engine is on) I would go to r-tech however they are 5 hours away from me being in Scotland
 
Your other option I to buy a GFB DV+ . I have this DV on my stage 2+ and I made 370bhp - 420ftlbs


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Yeah I have one but was advised to remove it from the car by ecotune prior to mapping, really don't know what to do here, other than stick a new turbo/actuator on and hope it fixes it
 
Can you log requested and actual boost, along with requested and actual fuel rail pressures?
 
Yeah ecotune done that and showed me the graph with boost line requested then actual boost line and that's where the actual boost is not reaching requested boost, fuelling they also data logged and is perfect along with timing etc, they said eithe actuator or boost leak but there is no leak, is there any chance it could be N75 valve? When logging it's going to 93% on VCDS
 
I forgot to mention there is actually a fault code of which ecotune told me and i also scanned it, P0299
Boost Pressure Regulation P0299 - 002 - Control Range Not Reached - Intermittent

possible causes are boost leaks- system is fine and air tight
actuator ???
maybe N75 but i would be guessing at that ???
 
Clean your N75.

it’s like a toggle switch for air, use a 12V battery to toggle it and see if it is holding vacuum in both positions

they do get mucky so don’t fully close or open so cleaning helps for certain
 
Yeah I have had a few people suggest N75, I will just replace it then that will certainly eliminate that issue if it is that valve, thank you, hopefully this cures my issue and I can get full power

please don’t waste your money, it takes 2 minutes to test with a vacuum gauge pump (even the ones uses to bleed brakes will do the job).


And cleaning is also just as simple
 

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Ok, so am I checking to make sure no air suction from other end?


It’s just a 1 input 2 output valve. So all it does is divert the vacuum between 2 ports depending if it is energised or not .

Remove it, take it inside and you just need any 12V source and a a vacuum gauge

1)
- without it energised
-pump vacuum on and see if it reaches like 500mmHg
see if it will hold for about 2 seconds or instantly drop to zero

2)
-move the vacuum to the other position
-energise with 12V (there is no polarity to worry about)
-Pump to reach 500mmHg
see if it will hold for about 2 seconds or instantly drop to zero

This will confirm if the solenoid fully sealing in position positions
 
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It's odd that it's only at high rpm, that's usually where the boost is lower - a boost leak would show up at 3-4k rpm where it peaks. Is your turbo OK - what's your mileage? Fuel pump cam follower replaced? Fuel filter replaced?
 
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It's odd that it's only at high rpm, that's usually where the boost is lower - a boost leak would show up at 3-4k rpm where it peaks. Is your turbo OK - what's your mileage? Fuel pump cam follower replaced? Fuel filter replaced?

It is not making requested boost pressure across almost all the range, ecotune have said they believe it to be a faulty actuator after they done all the checks and data logs, 72000miles cam follower done recent, fuel filter done 1 week ago prior to tune along with a full service, all genuine parts I never buy cheap, all boost hoses tight and no leaks present, system was pressure tested to 30 psi and was air tight, I think it must be N75 related or actuator has went soft, as sometimes the boost does surge then back off

Turbo sounds and feels mechanically ok, very little movement on turbo bearings when inlet pipe removed to inspect, actuator feels solid on turbo no play on the rod/arm at turbo

I fitted a boost gauge tonight, so for apr stage 2+ v3.4 file

Peaked at 20 psi but dropped down to 15psi within a second or two this happened for 1,2,3& 4th gears, for 5th and 6th it held around 18-20 psi

I believe those are low pressures for stage 2+ i should be seeing around 1.5-1.8bar (22-26psi) and holding those pressures to redline.

Another note, it had a stage 1 map and pulled 307 bhp it only seems to be after stage 2+ i have the issues relating to boost and the p0299 boost code which again makes me think actuator is weak or faulty N75
 
If you don’t have any vacuum gauge

Without replacing parts, clean the N75 and see if you have improvement.

1) fill it with fairy liquid (not brake cleaner as it will eat the ABS) and actuate on and off 50 times just need 2 wires and connected to your 12V battery.

blow the rest out with your mouth, and using the 12v to open the other position and blow the last bit out

Then do the same test of driving and tell us if the boost pressure has changed or holding higher boost for a bit longer


Basically if the N75 isn’t fully sealing/seating it could be saturating your vacuum supply (including the reserve) therefore making the actuator retract whilst as the duty cycle to demand more boost actually increases, since it is not maintaining or meeting the demanded vacuum to get the desired opening of the actuator
 
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I don't have a vacuum gauge I was going to try source one, I got a new N75 priced from work it's costing £38 for a genuine part, I am going to replace it and hopefully see an improvement, if not onto the actuator, thank you for your very informative help it's been great, and certainly educated me some more on these cars, I will give an update on Friday once the part arrives in from Audi and see if it helped
 
The map won’t hold pressures, it will spike and then drop down as you approach redline.

I’m occasionally seeing 30psi in 3rd and 4th but it’s typically 28’ish. I too have a weak actuator and I’m loosing boost early. Refitting an Audi Dv (replacing the junk DV+) have a small increase but it won’t fix an actuator issue.
 
Have you got the latest PCV on it as the early ones fail with random running issues.
 
The map won’t hold pressures, it will spike and then drop down as you approach redline.

I’m occasionally seeing 30psi in 3rd and 4th but it’s typically 28’ish. I too have a weak actuator and I’m loosing boost early. Refitting an Audi Dv (replacing the junk DV+) have a small increase but it won’t fix an actuator issue.

Yeah I assumed so, that's the way most maps run, however if you are seeing peaks of 30psi but typically 28 then there is a substantial loss of boost for me, I have a revision G bov on and it's fine
 
N75 replacement done, it does run smoother however still lack of.power and boost, so sadly its going to be the actuator wondering wither to send turbo away to get reconditioned whilst it's off anyway
 

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