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Author Topic: Has anybody actually replaced the n75 boost controller on their mk5 GTI?  (Read 1851 times)

Offline Cohibastevie

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So I had my car mapped on Friday.

Performance gains were phenomenal and it’s like driving a different car. However (as had been seemingly reported many times by other users on this forum) I’m getting insane boost pressures (30+ psi) when doing pulls and when I hit 4000 rpm in third or 4th going up a hill the over boost protection is kicking in and the car going into limp mode with the whole thing resetting itself when the ignition turned off and on again yada yada.

Been scouring the forums the last few days and most signs point to checking DV, MAP and N75 boost controller.

A revision G dv with GFB went in on the car with new MAP sensor just a week ago, all been running well so confident I can rule them out.

That leaves the n75 boost controller - I can find no videos anywhere of somebody replacing one of these on their mk5 GTI, there’s a few out there for a4s but those engines are mounted longitudinal. It’s not the process of replacing that I’m questioning, it seems a piece of piss.

However…

Access to it seems downright hellish to work on, a to get the torx bolts holding it in out, and b to get it crimp style hose clamps back on there just seems no room at all to operate.

Is removing wheel arch liner the “voila” moment leaving me enough space to tackle this job?

I don’t have vcds or access to it btw so I can’t confirm if the n75 is the problem or not.

Anyway in advance I thank you all for your sage advice!

Offline Cohibastevie

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Re: Has anybody actually replaced the n75 boost controller on their mk5 GTI?
« Reply #1 on: September 17, 2024, 05:46:20 am »
 :happy2:Anybody?

Thanks lol

Offline mjmallia

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Re: Has anybody actually replaced the n75 boost controller on their mk5 GTI?
« Reply #2 on: September 17, 2024, 09:29:43 am »
Replaced mine about a week ago now. 

Drivers wheel liner needs to be removed and the car on jacks.  Access is tight but possible......I had to remove the entire IC pipe from the turbo to improve that access further.

The hardest part was getting the original one time use hose clamps off.
« Last Edit: September 27, 2024, 12:22:39 pm by mjmallia »
Mike

South Coast

S3 8L ---- Golf Mk4 GT TDI ---- Lupo GTI ----  A4 B6 Sline ---- Golf Mk5 GTI

Offline JettaJ

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Re: Has anybody actually replaced the n75 boost controller on their mk5 GTI?
« Reply #3 on: October 08, 2024, 10:33:42 pm »
Replaced mine about a week ago now. 

Drivers wheel liner needs to be removed and the car on jacks.  Access is tight but possible......I had to remove the entire IC pipe from the turbo to improve that access further.

The hardest part was getting the original one time use hose clamps off.

I did the same about a month ago, liner was fine I got a valve with new hoses so I just cut the old ones and pulled the valve out then got in there with the needle nose.
71 standard beetle 1800cc - currently in pieces
91 GTI 16v - cannibalized for Jetta and sold
97 Jetta GT converted to ABA 16v - sold
2007 - GTI current source of hair loss