Installing atmospheric dump valve,

[shinny]

So the Rev3+ don't run rich with a leaky bov?

Can't see why it should... unless the vac line from the plenum to the BOV is leaking.

[Woody928]

Slight hijack here, my apologies. but on rev3+ tubbys (I have a rev4) are the aftermarket bovs better for the car?

the rev3+ engines meter air via the MAP sensor which is plumbed into the intake manifold after the throttle body, as opposed to the rev1/2 engines using the AFM that is on the induction kit before the turbo's compressor. A BOV venting to atmosphere dumps air from between the turbo and the throttle, meaning the air metering on rev3+ engines are unaffected because the BOV is dumping unmetered air. However on the earlier engines the air is metered by the AFM before it is dumped, meaning the ECU thinks MUCH more air is going into the engine that actually is, meaning it shoves loads of fuel into the cylinders and causes a majorly rich situation, hence potential bogging down and temporary lack of power immediately after a dump.

Thanks mate, quite interesting to know how it works, sounds like there's not really much point though unless you get a new one and want that that whoosh noise.

Depends if the aftermarket one is in better condition than your stock one! I've just found out mine isn't!
HM

[MRturboTom]

I had more popping, banging and flames on my rev3 turbo than I've ever had on my rev 1&2 turbos.
Had several afm turbo cars all with vent to atmosphere and never an issue. The recirculated air will still be rich for a moment so makes little odds.
If the car is running rough or bogging down its not the dumped air but usually a leak on the vacuum side much like a single piston and/or diaphragm type bov

[dan2k5]

We have had another play with it tonight and unfortunately are no further forward. The vacuum pipe from the bov is now attached to the intake manifold but it still won't boost. It dumps just fine but no performance, actually feels slower than old engine. Anyone have any ideas?

[GazRev1Tubby]

Do you have a decent boost gauge fitted?

If not, that's your first job. See what it's doing

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[dan2k5]

Hi Gaz, no not as yet. Will get him to fit one. Would temperature have anything to do with restricting the turbo? Theres still air trapped in the system as when we went for a drive the gauge started going down as we were moving.

[GazRev1Tubby]

Did you pour the coolant in slowly when you bled it? If you pour it in too quickly, you'll trap air in the system and make it much harder to bleed.

Literally just trickle it in, from a measuring jug.

If its running the stock setup, boost will be limited on a cold engine, you shouldn't be any where near boost until properly up to temp. At least 10 minutes of driving until you try and boost. The coolant gauge is not an indication of a warm engine, the oil takes twice as long to get to operating temperature.

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[jimGTS]

A gauge that drops is usually sign of a stick open thermostat.

As said, any drop in temp, will also lower oil temps.
If ecu isn't seeing the temp it wants it will disable the stock boost controller and limit your boost.

[dan2k5]

Cheers guys, and yeah we did pour it in slow to try and avoid trapping air in but the gauge is still playing up. Will get him to buy a thermostat to eliminate that possibility.

[MRturboTom]

Cheers guys, and yeah we did pour it in slow to try and avoid trapping air in but the gauge is still playing up. Will get him to buy a thermostat to eliminate that possibility.

Buy a genuine part. You'll need the rubber seal too.
The little valve in it is to be fitted at the top!

[GazRev1Tubby]

The jiggle valve in the stat has to align with the notch on the thermostat housing, check the bgb as that will show you what I mean

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[dan2k5]

Quick update on this, we fitted a boost gauge tonight but its constantly stuck at 0 which doesn't look promising. Dump valve is still dumping loud but theres no boost at all on it. He has not bought a thermo yet.

[MRturboTom]

Is it plumbed in correctly as 0 is just atmosphericpressure.
Should idle about -0.7

[dan2k5]

As far as I can see yes, i plumbed a t piece in between the turbo pressure sensor and the white filter.