boosting issues

fisher72

fisher72

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recently had my car remapped the cars running 280bhp and about the same torque when they did the health check it came back with a faulty maf and actuator changed them and all seems well until it starts blowing the boost hose off the turbo fitted a boost gauge and in 6 gear pull the boost gauge goes right up and then the car hits limp mode set the actuator up with the 3 turns of preload i think i might have messed up any ideas cheers Paul forgot to mention no faults logged with vcd
 
I'm not an expert here but if they mapped it to 280/280 why did you need to change the parts after they mapped it instead of before?
surely you didn't set the actuator up properly and it is going to 30psi and popping off the hoses or going into limp mode, so the N75 is diverting the air to operate the actuator but it is jammed shut or similar.
 
i took the car away and fitted the parts then returned it the car was making 225bhp at first then they got it to 240 but said it was struggling to make the power i changed the actuator they got it to 260 but i fitted a cloe maf so took it away fitted a bosch maf and they reached 280bhp you could see the turbo intake sucking itself flat so i changed that but its blew the turbo hose of twice i am going to back the actuator all the way off and try again the n75 is new but ive got a spare i tried and still the same deleted the n249 aswell didnt think the car could make that kind of boost
 
fitting a new actuator may require map tweaks... the map may have been done to to weaker actuator and now that its 'stiffer' boost control is out the window...

If its a map thats genuinely setup for 280hp then thats a 'stage 2' so requires a minimum of FMIC/3" DP and for best results an 80mm TIP

Boost is spiking like that due to a combo of stiffer actuator and extra loading from being in 6th.... boost control needs a tweak to prevent the overshoot from the stiffer actuator

<tuffty/>
 
will take it back to the tuner its got a fmic oversized tip miltek with sports cat will get them to check it cheers tuffy
 
fisher72 said:
will take it back to the tuner its got a fmic oversized tip miltek with sports cat will get them to check it cheers tuffy
Click to expand...
Wound the actuator all the way off so no preload and it's still overboosting waiting for the tuner to get back to me
 
Reset the actuator a 3 full turns off preload changed the n75 back to the new one still the same I seen a post where they fitted a mbc so I've ordered a forge one and I'm going to set that to stop the boost spike spoke to the tuner and he said the map they did calls for 22 to 24 psi cheers paul
 
the map can't call for 24psi as the ECU can't see more than 22psi... there are ways to do it of course using open loop techniques but thats not the map calling for that boost more 'controlling' the overshoot...

If fixed duty (open loop) has been used then the map will definitely need tweaking to pull back the boost to deal with the actuator...

<tuffty/>
 
just red his reply its 22 psi tuffy going to do the manual boost controller until i can find out whats going on
 
what is the actual boost you are getting, have you joined a boost gauge on it, or logged the values (dont trust android torque pro)

maybe you are under the 22 psi - but another sensor is broken.
 
Put a boost gauge on it not logging any faults on vcds order a mbc so going to fit that to try and stop the over boosting
 
if you drive without the N75 plugged in does it still overboost? if it does an MBC will make no difference as all that does is what an N75 does but manually. so you set the spring and ball bearing to between ~15 and ~30 PSI but it still tries to operate the actuator and if that is the problem it will make no difference (are you sure you plumbed the N75 correctly to the actuator?)
 
An MBC plumbed in parallel to the N75 can be used to cap boost... its not ideal but was a why a few years back to get more than 22psi with a degree of control on big turbo stuff before open loop techniques were mastered...

Personally I wouldn't waste your money... pull the N75 electrically until the map has been sorted

<tuffty/>
 
im going to change the part numbers on the actuator that i have when ive done some reading the later actuators are plumbed in differently so thats the next port of call im sure ive got a c version and j version
 
what happens if the N75 is disconnected electrically?

can you photograph how you have set up the N75, TIP, charge-pipe and actuator?
 
If I disconnect it it runs at about 5 psi will take a picture and post it later cheers paul
 
Cheers
 

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well ~5 psi is correct for actuator pressure isn't it?

can't really see where all the pipes are going but the orientation looks correct.
 
Going to change the map sensor see what that does took the forge 007p off and put the standard one back on thought it might be not releasing the boost but know joy lol
 
With all this effort you are doing why not, Look to put a standard map back on?

I'm still confused - you had your car mapped to its maximum possible and then changed bits the tuner said were faulty.

You could read the map and back it up then put a standard bam map on to test?
 
The car didn't reach it's full potential till I had changed the bits it was at 225 then they identified the faults and I changed the faulty parts took it back and then the dynoed it to 280 bhp they told me the actuator was faulty the car wasn't holding boost and when I changed it I've got to much boost can I set a bleed valve into the actuator line till I control the boost spike cheers
 
Change the map. That's clearly your issue. It was mapped with a faulty actuator. Take the car back to the tuner, to fix the map they put on.

Or put back on the faulty actuator, until you can sort this out.

I think my stage 1 map which worked perfectly well on my S3 is causing my TT to over boost. I have made a tiny adjustment to the stock map and it's creating more power than a full stage 1 map was.
 
Last edited:
You could of course download the map from the ECU to review some of the settings in tunerpro.
 
You can buy an MPPS lead from eBay for about £14, which will download the map. If it reads the file correctly you can view it in tunerpro to see if they have put down some crazy high load values of 220 across the board because it was mapped with a hole in it.
 
if i was to do a data log on vcds how would i do it and what would i be looking for sorry to be a pain cheers paul
 
fisher72 said:
The car didn't reach it's full potential till I had changed the bits it was at 225 then they identified the faults and I changed the faulty parts took it back and then the dynoed it to 280 bhp they told me the actuator was faulty the car wasn't holding boost and when I changed it I've got to much boost can I set a bleed valve into the actuator line till I control the boost spike cheers
Click to expand...
280bhp (if real) then how is it the actuator is'nt workign properly... Not holding boost you say but what is it holding at 5500-6000rpm?
 
Didn't say it wasn't holding boost its over boosting I've ordered a mpps lead like Stuart said I'm not an expert I've had my car mapped on dyno dynamics rollers and given a print out with the 3 different tunning times on the rollers starting art 225 then 255 then 280 I can only go off what they say so o don't know if it's real I've come on here to ask your opinion not to be made out to be a liar my s3 as got all the modifications to be stage 2 which it should be
 
fisher72 said:
Didn't say it wasn't holding boost its over boosting I've ordered a mpps lead like Stuart said I'm not an expert I've had my car mapped on dyno dynamics rollers and given a print out with the 3 different tunning times on the rollers starting art 225 then 255 then 280 I can only go off what they say so o don't know if it's real I've come on here to ask your opinion not to be made out to be a liar my s3 as got all the modifications to be stage 2 which it should be
Click to expand...
you need to calm the f*ck down kiddo.......
I've not said or called you a liar - ***
read the words WRITTEN... by YOU!!!!!


.....and then the dynoed it to 280 bhp they told me the actuator was faulty the car wasn't holding boost
Click to expand...
<<<< These are what YOU typed ***....
 
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I think the point is that your tuner managed to get 280bhp from your car with a faulty actuator then advised you changed the faulty actuator and now it's over boosting, but if he managed to get 280bhp with a fault then what are the actual figures now, it was leaking and now it's not.

These standard S3s struggle with fuel delivery to safely produce much more than 270, when you run out of fuel you can only add air which generates heat and encourages detonation.

As a beginner myself, I would invest in a KKL lead and MPPS lead and download the software, onto a laptop. These leads although are another cost are not a new sensor or whatever as a shot in the dark, but can start communicating with the car to see what it thinks is going on.

Pretty sure Bill was querying the accuracy of the 280 as he has dyno'd hundreds if not thousands of 1.8T setups from 150 - 650bhp.
 
Stuart B said:
I think the point is that your tuner managed to get 280bhp from your car with a faulty actuator then advised you changed the faulty actuator and now it's over boosting, but if he managed to get 280bhp with a fault then what are the actual figures now, it was leaking and now it's not.

These standard S3s struggle with fuel delivery to safely produce much more than 270, when you run out of fuel you can only add air which generates heat and encourages detonation.

As a beginner myself, I would invest in a KKL lead and MPPS lead and download the software, onto a laptop. These leads although are another cost are not a new sensor or whatever as a shot in the dark, but can start communicating with the car to see what it thinks is going on.

Pretty sure Bill was querying the accuracy of the 280 as he has dyno'd hundreds if not thousands of 1.8T setups from 150 - 650bhp.
Click to expand...
if you read my post he identified the faulty actuator i took the car away fitted the new actuator the dynod the car once more
 
Stuart B said:
I think the point is that your tuner managed to get 280bhp from your car with a faulty actuator then advised you changed the faulty actuator and now it's over boosting, but if he managed to get 280bhp with a fault then what are the actual figures now, it was leaking and now it's not.

These standard S3s struggle with fuel delivery to safely produce much more than 270, when you run out of fuel you can only add air which generates heat and encourages detonation.

As a beginner myself, I would invest in a KKL lead and MPPS lead and download the software, onto a laptop. These leads although are another cost are not a new sensor or whatever as a shot in the dark, but can start communicating with the car to see what it thinks is going on.

Pretty sure Bill was querying the accuracy of the 280 as he has dyno'd hundreds if not thousands of 1.8T setups from 150 - 650bhp.
Click to expand...

aye, (if) the 280bhp was realistic, and the mapper was chasing more boost up top, then in my experience the 280bhp is max its likely to be giving regardless of actuator fitted, as >5500rpm or more the compressor wheel is flat out of flow and boost pressure WILL always fall away. A healhty std 5psi actuator'd k04 will hold 1.2bar to 6500rpm as a reference. Hence asking the simple question previously what boost was it doing.... etc etc.. blah blah, I've lost the will to type more......................................
 
if i disconnect the n75 it runs 5 psi ive put 3 turns of preload on the actuator if i run it up through the gears it gets 24 psi and then tails off in 6 if i plant my foot at 50 mph it sends the boost gauge off the boost gauge and puts it into soft limp would a faulty map sensor cause this also what would i look for on vcds to log the boost thanks badger 5
 
Something not right there at all... what actuator did you get? whats it rated at?

<tuffty/>
 
fisher72 said:
just bought a standard replacement of ebay
Click to expand...
Huummm... therein lays the problem... no guarantee thats its any good dude tbh...

Sounds to me that there is not much movement in the actuator or its sticking... the fact it does 5-6psi suggests its capable of of the lower pressure but for it to hit 26+ psi then settle suggests a mechanical issue to me...

<tuffty/>
 
thrown the old one out which one the you suggest tuffy is there anyway of controlling the boost whilst i source one the mcb ive ordered is a 3 way one which i think is useless cheers paul
 
this thread has become like kite string after it was thrown in the boot of a car with a wild cat, and driven to the other end of the country.

#gaslighted
 
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