n75 valve differences?

[jasongtr]

From what i have read some hold boost a little longer, some help to offer smoother power delivery, non of which i know if its true, but as there are some clued up people on here i thought id ask.

My car is an S3 AMK code, N249 removed (well still plugged in) milltek exhaust and decat, currently forge TIP, forge diverter, S2k induction.

Just wondering if one would be better than the other, or stick to what the car should of come with, but thats not always the best or we wouldn't be modifying cars at all really.

cheers

 

[<tuffty/>]

the J valve is laggier in response and can create boost spikes.. this was a 'tuning method' used back in the day on AGU's with K03's to get a little more out of them as the ECU's are too dumb to care and the K03 can only produce max boost for a millisecond anyway... using these on later ME7 based ECU's however can cause limp mode as the ECU has more protection routines at its disposal.. if it detects an overboost situation it will drop into limp

Further to that the resultant boost spike is not the best scenario in the world and can potentially lead to rod failure under certain conditions...

That said... the J valves can be mapped to be less spikey but then that defeats to object as good boost control can be had with decent custom mapping and the std N75 valve...

In summary... its not worth fitting

<tuffty/>

 

[jasongtr]

you must be psychic mate, i was only asking as a car i am breaking has a brand new N75 fitted and i happens to be a J type. Not that there was anything wrong with mine, i scanned it yesterday and a cam sensor came up, could be an old problem so I've cleared the codes and will rescan after a week or so to see what comes back (dont drive it often at the moment)

Need to get a B5 TIP and a remap i think, be nice to have a little more oomph