N75 Question

[S4TAN]

Would like to ask a question, or 2, or 3.... (and clear up any ambiguity on the N75 for an eedjit such as myself):

What are the possible effects of tweaking the screw on the N75 solenoid valve AFTER a car has had one of your custom re-maps? Can doing this decrease the performance gained by running one of your maps? Conversely, can doing this produce any additional performance given by the custom map? If yes to either question, which way do you turn the screw? And by how much? Etc etc....

Can doing this be a really BAD THING TO DO?

Also - how is boost affected by turning the screw (a) clockwise and (b) anti-clockwise?

Apologies for the questions (and i know i've raised the subject before) but this topic still intrigues me, and I'd much appreciate some expert input...

Hope you can oblige with the answers....thanks in advance.

[dodgydave]

Okay,

I did a lot of N75 tweaking and my advice is DON'T DO IT!!! There is a fine line between a bit more boost and jamming the plunger hence no boost. There is no point in doing this if you had a custom remap as this will throw it onf the boost curve and end up in positive deviatio errors!! To tweak this way you need to do MAP clamping, which will then send the wrong boost signal to the ECU!


SO DON'T DO IT!!! Get a remap from MRC and that'll give you the best performance for your setup!!

[S4TAN]

Ummmm....that's why i asked the question dave: I already have an MRC custom re-map and purely out of interest want to know the effects of tweaking N75 after having the map. i.e. how does doing this affect Mihneas map - and other questions like how much does his map utilise the setting on the N75....

Really would like S2_Tuner to answer these please!!!

[MarkB]

Give him a call then?

It's a control loop. will make no difference until you go beyond a point that the valve is able to control back to. IMO

[S4TAN]

could do but thought I'd do it via the forum for everyone elses benefit in case they had ever wondered the same thing

Would like to know if it can have any effect on the timing - from what (little) i understand tweaking anti-clockwise causes less turbo lag(?) - could this then cause the ecu to <beep> timing? I'm way out of my depth here (as I'm sure is blatantly obvious) so just wanted to get Mihnea's 2c worth - after all he wrote the map and is the expert!!!!

[MarkB]

so just wanted to get Mihnea's 2c worth - after all he wrote the map and is the expert!!!!

True. Hopefully he will comment, he's been on here this morning...

If the boost ramped up too quickly and over shot this could push the engine into detination and the knock sensors will pull the timing back.

It would be nice to lay this one to rest with a true expert opinion

PS I'll keep quiet now...

[S4TAN]

It would be nice to lay this one to rest with a true expert opinion

nail on the head!

[CliveH]

It would be nice to lay this one to rest with a true expert opinion

I agree, lets see what the expert says...but Jules, I think it's a REALLY EVIL thing to do...

[S4TAN]

groan.........

[S4TAN]

Hey Mihnea - pm'd you on this - but to no avail! Any chance you could post an answer to this an put it to bed? - after all it is a question related to your custom maps!!

[Doug_S2]

you get more boost than is requested by the ecu by changing the valves response to a frequency - you might get more than requested throwing a code, you cqan run more boost than is safe - the ko3 turbos can run higher boost but they are likely to go pop.

[S2tuner]

Totally agreed with Doug, sorry Julian, haven't had lots of time last week for forums unfortunately...

[DavidT]

Hey Mihnea - pm'd you on this - but to no avail! Any chance you could post an answer to this an put it to bed? - after all it is a question related to your custom maps!!

Please remember that MRC are in business to make money and therefore not obliged to share their knowledge or experience beyond a certain level on forums.

[shineydave]

so if the N75 was to be changed due to a fault would the car require remaping again?

[Doug_S2]

in some cases - yes.