Pressure Tesitng Intake Hoses

[S2central.net]

Yes Glen - I also prefer to do this with a big old bung in the pipe before it enters the IM as then you know it should be absolutely air tight when pressurising from the MAF... and yes the stock hose can balloon a little under pressure - the accordion hose is designed to suck of course and resist being narrowed under vacuum.


Paul

[Dr H]

I tried it tonight from the MAF and couldn't get any pressure in it -well only 4.5 psi according to the gauge :mad:

I'll try bunging the pipe at the IM and do it again. Where abouts do I bung it? The end of the IC pipe before it goes into the black metal tube or the end of the black metal tube at the throttle body or ????

The MAF plug *looks* dead clean but I'll give it a go as you suggest you never know. Why brake cleaner? Can I use anything else?

Cheers

Leigh

[S2central.net]

Best at the throttle body but its easier to disconnect the pipe just before the metal section so you can pressurise everything from the MAF inlet thru the turbo, hoses, intercooler and O-ring.

Paul

[Doug_RS2]

So which part of the breather system coming off the intake pressurises the cam cover? So so we can block that and get higher than 15psi?

[S2central.net]

Well if you don't block the hose where it enters the pressure pipe onwards to the throttle body, then air will sneak past the butterfly plate on its idle stop and flow past whatever inlet valves happen to be open. Then it will of course eventually squeeze its way past the piston rings and start to pressurise the crankcase which breathes along with the camshaft housing.

Of course, I could be talking pants on this, cos the full mysteries of the PCV system on the S2 still elude me as I haven't taken it apart yet.

There is a connection from the MAF hose into the crankcase breather system, which I assume only passes air at vacuum because of the check valve in the system - but I could be wrong. It could be that the pressure in the MAF hose allows the crankcase to be pressurised directly.

To be 100% sure, simply block the vent in the MAF hose which attaches to the breather system and test again (with the pressure pipe blocked also).

Paul

[Dr H]

Did all this tonight. Got it up to 15-20psi a few times but it loses pressure pretty quick. Down to about 10 psi in say 10-15 secs?
No obvious leaks that I can hear.

Went for a spin with a mate who kept a close eye on the boost and even up a pretty steep hill on WOT boost drops back almost instantly it has reached peak.

Also I cleaned the MAF connections but seems to be the same. I'll remove the plugs again in another 100miles or so and see if they are sooted up again.

Car still doesn't *feel* right. My mate said that he noticed a sort of flat spot a couple of times from the passenger seat. It's really difficult to describe. What I need is another car for a side by side test.

Hopefully get to see Paul J tomorrow and borrow his MAF for a quick spin.

Maybe I'm just going mad??? :wacked:

Leigh