Help...N75 Valve.....

[swadnod]

Hi,I have just purchased a 2000 X plate cupra turbo,I have just taken it into my local Seat/Vw tuning garage and they have informed me that I have the wrong N75 Valve fitted(valve that controls turbo waste gate)(fits in intake pipe by air flow meter)can anyone give me the correct Seat part no,so that I can go and get the correct/genuine part,this is my first Seat and my first post,please can you guys help,cheers Swadnod.

 

[CupraUK]

I don't think there is any such thing as a "wrong" N75 (assuming the car is running OK). Its personal preference, standards tend to be Ns and Cs. Some people fit a J and find it better. It depends on the car.

 

[CupraUK]

PS: Welcome!

 

[cordobabrendy]

standard is an F

 

[DPJ]

standard is an F

Wasn't sure here - isn't the car pre-VVT ?

 

[cordobabrendy]

they all ask for the same levels of boost tho?

 

[swadnod]

I have contacted the previous owner(hello scotty) and he has still got the original valve,which is an F,i am going to fit this as although my car is running great the Vw/Seat tuner I deal with recommends keeping the same N75 valve that was on the car when it was remapped(jabba).The tuner deals with fault codes/limp mode and running probs on this type of engine every day of the week and he does'nt rate the J valve that is fitted,no doubt people are going to post in now saying there car is running fine with a J valve fitted.cheers swadnod.

 

[cordobabrendy]

it will run with the j, mine did but its just not as driveable after a remap.

 

[swadnod]

just fitted the engines own F valve and its running great,cheers swadnod

 

[Dodson]

Always wanted advice on this subject.

I now have an idea of what the valve does but can someone explain what the benefit of an J valve is over the standard one?

Does the charcteristics of the turbo coming on boost change?

 

[cordobabrendy]

yea thats the main difference dodson, heres a graph of two different n75's running together to show you the difference on a rolling road
disregard the actual figures as they are low as the car hada couple of minor issues on the day but is a very good indicator of how the delivery differs. the higher figure is an n75c and lower figure is n75j, bear in mind this is on a remapped leon cupra and that on a standard cupra the gains are about the same for the J over the standard F. notice that the j comes in earlier but doesnt peak as high, on the standard engine the j is a better drive than the f but when getting stage 2'd the f valve needs to be back in or else you dont get the full use of boost.