Still got a ****** Boost Leak

[Lee]

Log lambda throughout the rev range to see what is going on. It may throw up something dodgy.

I have a Forge DV006 which would not hold more than 1 bar boost the 'right' way around. Reversing it allowed more boost to be 'held' probably due to poor piston sealing. Other who have reversed a good aftermarket DV have experienced surging. Stiffer spring have also caused this effect on some vehicles.

Lee

PS mine runs 1.4 bar which tails off at high revs but I noticed the other day that in 4th, 5th and 6th from low revs that it would peak at 1.55 bar.....Mik, I think I still have overboost enabled! Explains why it is now a bit of a rocketship (on a k24) and I suspect it must be close to 300bhp by the type of cars that I annialate without trying too hard recently.

[Doug_RS2]

It is not going to harm anything turning the diverter round so you might as well try it.

If you disconnect the electrical connector to the WGFV and see what boost you are running you will see if that is near enough standard. I think you sadi a while ago that it used to be superchipped (maybe I'm wrong) so it could easily be set wrong.

@Lee - what was the valve you had to replace at Gregs dads garage - on the breather system? (I don't have it so I don't know what it does!) Maybe worth checking that?

[S2central.net]

Errr Doug - reversing the original Bosch valve is a nice way of reducing max boost as it allows pressure to push back on twee spring in the stock valve.

The correct position for Bosch valve is that the control port points to the MAF hose. This means that boost pressure actually works with the spring to keep the valve shut (on boost). When lifting off - the pressure in turbo pipe reduces and manifold pressure turns to vacuum momentarily afterwards - then the TBV is opened to allow recirculation of remaining pressure in the boost pipe.

[S2central.net]

Log lambda throughout the rev range to see what is going on. It may throw up something dodgy.

I have a Forge DV006 which would not hold more than 1 bar boost the 'right' way around. Reversing it allowed more boost to be 'held' probably due to poor piston sealing. Other who have reversed a good aftermarket DV have experienced surging. Stiffer spring have also caused this effect on some vehicles.

Lee

PS mine runs 1.4 bar which tails off at high revs but I noticed the other day that in 4th, 5th and 6th from low revs that it would peak at 1.55 bar.....Mik, I think I still have overboost enabled! Explains why it is now a bit of a rocketship (on a k24) and I suspect it must be close to 300bhp by the type of cars that I annialate without trying too hard recently.

Maybe your WG spring is a tad too tight ! Dunno how long a K24 would take that abuse - guess it depends how long it holds 1.55bar - it turns into a heat pump pretty quickly !

[Doug_RS2]

Errr Doug - reversing the original Bosch valve is a nice way of reducing max boost as it allows pressure to push back on twee spring in the stock valve.

OK - didn't know that - is Leigh's diverter the correct way around then?

[Dr H]

OK - didn't know that - is Leigh's diverter the correct way around then?

Good question! The leg with the small plastic raised bit on the side of it (hope you understand this) is going into the MAF hose. That's they way round the one I removed was. Right or wrong

PS - @Doug, posted you the lambda today - sorry its taken me so long

[Lee]

@Lee - what was the valve you had to replace at Gregs dads garage - on the breather system? (I don't have it so I don't know what it does!) Maybe worth checking that?

That is meant to be a one way valve in the oil breather system. Someone blew though it equally easy in both directions on the new one so I am not convinced that it does squat! Next time it will be a piece of copper pipe to replace that part. It should have a diaphragm inside but the new one did not show this..

[Doug_RS2]

Eh? Does the vacuum hose stick out sideways or vertical?

[Lee]

Maybe your WG spring is a tad too tight ! Dunno how long a K24 would take that abuse - guess it depends how long it holds 1.55bar - it turns into a heat pump pretty quickly !

Works for me! I know that the K24 goes grossly inefficient at these levels but mine doesn't spend much time there to be honest. I am mostly over 5k rpm when I get into 4, 5 or 6 (ie 7k shifts). I only noticed recently when pulling high load from low revs in high gears whilst trying out out new prototype boost guage...I was a bit surprised but now I know what engine regime to avoid. Before you ask, our prototype guage has been calibrated against a reference guage which cos a few hundred pounds to calibrate a few months ago so I know it is spot on.

[Dr H]

Eh? Does the vacuum hose stick out sideways or vertical?

Yeah sticks out sideways. Much easier way of describing it

[Lee]

Eh? Does the vacuum hose stick out sideways or vertical?

My DV has the wee vac hose vertical. This is the wrong way around, right?

[Doug_RS2]

Sideways is standard.

Lee - I have mine the wrong way round as well - you get some chatter on gear changes with teh metal piston.

[newsh]

On my homefried 3B it'll go to 23lbs (1.58 Bar) for a few seconds if I floor it at just over 3k before dropping back to 20lbs (1.4) I don't know if it holds this all the way to redline cos I never take it there, or maybe I've forgotten... Anyway It drops off a bit at higher revs.. Anyway, I just spend most of my time flooring it at just over 3k cos its fun..
If I floor it at low rpms, it just goes up to 20lbs and stays there..

Except it'll all be different soon with the RS2 parts, (mmmm boooost....

[Lee]

No chatter for me. It opens and closes...job done. This orientation works for me in my current state of tune. More power might need more than one valve to elimintate valve 'bounce' on closing.

[newsh]

That's with the standard spring screwed down about 12mm? With a ur spring in it its mental, but Mihnea said I had to take it out to avoid blowing up the turbo.. Also it made the clutch slip.