problems dont walk alone...

[kirvis]

well when i fitted the N75 i looked at the thread with fitting instructions. so im pretty sure i fitted it ok.
ok going to do it now. wish me luck

[s2_bo]

No no no, The BOV woant effect it at all! as it doesn't do anything different when the engine is under load then a normal diverter valve... The only time you will notice a diffrenct is just after gear change but its not that bad.
This sounds like way to big a power cut to be anything to do with the ECU having to adapt mixture due to the calculated air being dump to atmosphere.

Just for reference, I have had BOVs on all my s2s and RS2 at some point and its never ever coursed something as bad as this.


Also if the N75 had lost a hose at worst you would only see .4bar boost. (1.4 bar on the digi gauge) as it would be not diverting pressure to the lower part of the wastegate and therefore the gate would open at spring pressure... Unless its the one going back to the maf hose, if thats off the you will be sucking in uncalculated air but such a small amount woant have such a big effect either...


Lets get facts right here before we send Kirvis on a mission to undo things that dont need to be changed...

[prj]

well just like i mentioned i changed N75 to solve the problem, as it was the same with the standard one
ill take the BOV off and let you know is there any changes

I doubt there will be... the BOV just totally screws up your mixture on gearchange...

Are you really really sure the N75 is connected correctly? Search this forum for "Boost control essentials" by Paul, read that document, and make 100% sure you have connected everything exactly as needed.

As I said, if you have 1 bar boost at part throttle, you have no boost control! Check that the wastegate can open... make sure the spring is not completely screwed down.

[kirvis]

+1, check that too.
But even if that solves the problem, get rid of the BOV... it still floods engine on every gearchange.

well just like i mentioned i changed N75 to solve the problem, as it was the same with the standard one
ill take the BOV off and let you know is there any changes

[prj]

Maybe a hose came off the N75? Or its connected wrong.

+1, check that too.
But even if that solves the problem, get rid of the BOV... it still floods engine on every gearchange.

[newsh]

Maybe a hose came off the N75? Or its connected wrong.

[kirvis]

In standard form there is no BOV.
There is a bypass. Big difference.

Also check your wastegate, is the nut overtightened? Is there a different spring?
From what you described it sounds like you have no boost control at all.

going to have my breakfast and will check it

[prj]

ok ill put the standard bov back on. so u recon it should change straight away?

In standard form there is no BOV.
There is a bypass. Big difference.

Also check your wastegate, is the nut overtightened? Is there a different spring?
From what you described it sounds like you have no boost control at all.

[kirvis]

ok ill put the standard bov back on. so u recon it should change straight away?

[prj]

uhu... "OK"...
With a BOV you flood your engine every single time you let off the throttle.

What you are describing sounds like boost cut. Put a stock WG spring into your wastegate, or "unscrew" it, it's obviously not a 0.4 bar spring in there, if you have 1 bar of boost at part throttle.

Take that BOV and throw it into the garbage bin and buy a proper metal bypass.
If you like that annoying BOV sound, then get a cone filter and you will also hear that sound with a bypass.

Until you do all that, stop complaining

P.S.
It's possible the ECU can't handle your "upgraded" N75 either. Why would you even "upgrade" it? Stock one worked fine for me at like 2 bar boost.
I don't think that's very likely though, because the N75 is a very simple device and you can indeed swap many of them...

[kirvis]

but i was using this bov for about a year and it was ok before

[prj]

???????

The BOV that you have, you are venting the excess air into the atmosphere, and not circulating it back after the MAF?

If you do that, it explains everything.

[kirvis]

???????

[prj]

You have a BOV?
And you are venting the air to atmosphere?

[kirvis]

its all standard apart from forge BOV , and Upgraded N75