N75 change..does it effect your map..?

[s4woody]

most guys on here that have had there car mapped have then at some point replaced there N75 valve with a new standard (S4) or RS2 type..or even played with the adjuster screw..
now are all standard (new) N75 valves set to the same/spec-boost rate or will the map need tweaking to bring it back to the same state of map that you paid for..

[S4TAN]

most guys on here that have had there car mapped have then at some point replaced there N75 valve with a new standard (S4) or RS2 type..or even played with the adjuster screw..

WHAT? Who'd do a thing like that??!! Perish the thought!

I think we've had this debate before woody - new N75's come from the factory all set at the same solenoid rate (as near as dammit within manufacturing tolerances can allow i think) - so if you're replacing like for like (i.e. S4 valve for S4 valve) then I doubt the re-map you bought from your tuna has to be tweaked.

[s4woody]

but valves do wear and springs if any inside do get weak..

I doubt the re-map you bought from your tuna has to be tweaked.

your theory sounds fishy to me..

[Ads4]

the re-map you bought from your tuna .

Nice

[grizz]

The n75 will over time not preform as well as a new one , i fitted a new one on the 6 and found 9bhp !!! I would recommend fitting a new one before you get a car remapped..

[S4TAN]

but valves do wear and springs if any inside do get weak..

True - I went along the same thought process as this and replaced mine very soon after finding out what it did ... in my garage I have about 5 N75s - all in various states of "tweakedness" - the one on my car is for an RS2 ...

your theory sounds fishy to me..

Groan!

The n75 will over time not preform as well as a new one , i fitted a new one on the 6 and found 9bhp !!! I would recommend fitting a new one before you get a car remapped..

Agreed - my comment about them being the same was referring to ones that come out of the factory all being the same (within manufacturing tolerances) - if you've got an old one on the car (say been there for several years, or since build) then yes - i'd certainly replace it pre-remap.

[s4woody]

pre-remap maybe..but if grizz found 9bhp on a dyno just by replacing his N75 then how much would an S4/RS4 find or even lose..my point i suppose is how big a part does the N75 valve play in mapping a car..should they be replaced as part of the health check or before mapping a car even if the car has a clean bill of health..

[CliveH]

That's a very good point Simon. I would say "yes", just to be safe and for the cost involved.

[S4TAN]

should they be replaced as part of the health check or before mapping a car even if the car has a clean bill of health..

Yep - think you're right woody ... same goes for N249s (a solenoid valve too) ... for those that don't bypass them.

A new N249 and N75 is around £65-£70 for the pair - gotta be worth doing.

[s4woody]

i,ll look at priceing a little map kit..new N249'N75 and a pair of 710n's..

[AdamS4]

Simon, what price can you doing just the N249 and N75 ?

[GrahamS4]

The n75 will over time not preform as well as a new one , i fitted a new one on the 6 and found 9bhp !!! I would recommend fitting a new one before you get a car remapped..

What do you think causes the deterioration - age or use?

Very low mileage '98 car, you can hear my cogs turning I am sure.

[S4TAN]

Probably use over age Graham - parts deteriorate/wear I guess and aren't as sharp as they were when new - especially considereing that the N75 is a solenoid valve that opens and closes continuously at varying rates according to the ECU requested boost signals.