Boosting problem

mikey_b

Active Member
May 18, 2008
322
0
Manchester
hi im running a manual boost controler since fitting it ive had a problem its set to run at 12-14 psi but after driving it for 20mins or so when i give it some it starts to under boost at 6-8 psi!!! any one got a clue???
 

mikey_b

Active Member
May 18, 2008
322
0
Manchester
to be honnest i havent got vag com i need to get it but dont know where from and how much!

when i dnt give it beans and drive normal for a few mins its back to running at 12 psi then dose the same again!!!
 

Ronin225

Active Member
Jan 17, 2008
4,652
22
Worcester
Some sort of leak maybe temperature related?
How many original OEM hoses are still used? or are most uprated?
Turbo outlet pipe maybe
 

mikey_b

Active Member
May 18, 2008
322
0
Manchester
all intercooler ones are uprated just the one from the turbo that goes behind engine to the side and pancake pipe are stock...
 

Ronin225

Active Member
Jan 17, 2008
4,652
22
Worcester
The redish colour one of the turbo is the outlet pipe.
It is made of a different material but might be worth checking over
 

wild willy

Full Member
Aug 4, 2003
2,323
0
Wales
The mbc is causing part throttle limp mode. Basically the mbc is allowing the turbo to boost earlier than the n75 valve would have allowed. Under hard acceleration all is good but on part throttle you can hit limp simply because your making more boost than the map requests. (map is set to limp if deviation exceeds 2psi between requested and delivered).
The only way to make more reliable power is as follows.

1. replace 6psi actuator with a Forge unit and uprate to a 10psi spring.
2. Increase the boost requests of the map with lemmingwinks, vtune, sp3 etc.
3.Increase fueling with the above software.
4.Connect your boost controller in parallel with the n75 valve. This will prevent any part throttle limp and allow the mbc to keep the turbo spikes to within 1.6bar.

set mbc to operate @ 1.2 bar.

you should hold 1.3 bar to the red line which will be a huge kick, by keeping the spike in check should reduce strain on the stock turbo.
 
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