Pressure testing

[Virdee Autos]

Used the pressure tester for the first time today, after fitting a hose, so thought I'd give it a go.

One thing that struck me, and I have searched for this high and low on here, but have not seen any constructive answer is, at what rate should the pressure drop?

I went up to around 12-15psi, but nothing more, as that is what I had read on here.

Couldn't hear no leaks, but pressure obviously dropped over time. Was just wondering what is a good target to adhere to.

Thanks in advance

[jimbo1234567]

about 10psi virdee, then listen for the hissing

[mikeyquattro]

15psi. Took approx 20 secs to drop to 5 psi iirc

[Blue_Thunder]

And how much pressure is lost through the PCV breather? I'm sure when i've tested mine in the past not much at all came out, but when doing it last weekend I had to hold my thumb over the PCV breather pipe in order to allow the system to hold pressure.

[Virdee Autos]

I'm guessing you mean by the PCV, the oil breather on the LHS.

If so, then I had a bung which came with mine, that is used to block that off.

No hissing, well as far as I could tell! Will take it up to 15psi, and see how long it takes to drop.

[Nige_RS4]

Yes, you're supposed to bung the PCV connection (after removing it from the Y-pipe)

[jimbo1234567]

and dont forget to take the oil filler cap off so you dont pressureise the crankcase via the rings and blow a gasket.

[nol]

You should take it up to about 15 psi. I had leaks that showed themselves first at around 12-13 psi. Mine also drops to about 5 psi in 15-20 seconds. I also have a fair amount of air coming out from the PCV breather (red circle in the picture). A common problem is leaks in the spider hose (yellow circle) and the two none-return-valves (green circles). I will change mine and see if this makes any difference.

/Niclas

[Virdee Autos]

Thanks for all the input

AFAIK the RS4 doesn't have the spider hose....already has all new one way valves, including those green ones.

Yep removed the oil breather pipe from the y-pipe, and then used the bung to block it off

Will maybe check again tomorrow, if I get time, by uping it to 15psi, and see roughly how long it takes.

[nol]

The picture above is from the RS4 so yes, the RS4 has a spider hose. The article number is 078 103 235 G.

[Blue_Thunder]

And how much pressure is lost through the PCV breather? I'm sure when i've tested mine in the past not much at all came out, but when doing it last weekend I had to hold my thumb over the PCV breather pipe in order to allow the system to hold pressure.

Dragging this one up again following a pressure test today to diagnose a leak. I don't normally quote myself, but it seems I have been misunderstood (even though on re-reading, it makes sense).

I'm well aware you need to block off the bit on the side of the Y-pipe, I was referring to the PCV breather, the black plastic thingy which usually attaches to the Y-pipe (circled in red above).

I permanently lose pressure out of this when pressurising the system. The only way can get the system to build any pressure is to cover this up. Surely this isn't right??

[ogg14]

On reading this... I did a pressure test this afternoon...

I put in 15psi... It deflated at around 5 psi for the first 20 seconds... This might have been caused by the leak i found in my TTB... It was a very , very small pin hole on the right hand flange... but it was coming out at a good rate... so like i said this might have caused it to come at faster... I will be replacing this asap... then do another pressure test...

Cheers

Andy

[Virdee Autos]

Ahhh this makes better sense now...!

Yeh I would also like to hear the answer to Blue Thunders question.

I haven't had a chance since to do another test, but will be soon, so any help on this matter would be appreciated

[Rs4-Digitec]

Im suspecting a leak on my rs4 and was wondering how to do this. Does anyone have any pictures of a pressure test?

[Rs4-Digitec]

,5.09,2760,12.0,95.3,1160.0,,,,,,,,,,
,5.39,2960,12.0,95.3,1350.0,,,,,,,,,,
,5.69,3240,12.0,81.6,1650.0,,,,,,,,,,
,5.99,3600,12.0,68.6,2050.0,,,,,,,,,,
,6.30,4000,12.0,71.0,2190.0,,,,,,,,,,
,6.61,4440,12.0,72.2,2150.0,,,,,,,,,,
,6.94,4800,12.0,73.3,2110.0,,,,,,,,,,
,7.28,5280,12.0,73.7,2130.0,,,,,,,,,,
,7.63,5720,12.0,74.5,2080.0,,,,,,,,,,
,8.00,6160,14.0,75.3,2030.0,,,,,,,,,,
,8.37,6200,15.0,0.0,2170.0,,,,,,,,,,
,8.71,5000,15.0,64.7,1220.0,,,,,,,,,,
,9.04,4480,15.0,92.2,1620.0,,,,,,,,,,
,9.35,4680,17.0,70.2,2340.0,,,,,,,,,,
,9.68,4880,18.0,69.4,2230.0,,,,,,,,,,
,10.02,5080,18.0,71.0,2080.0,,,,,,,,,,
,10.35,4920,18.0,0.0,1780.0,,,,,,,,,,
,10.66,4400,17.0,0.0,1240.0,,,,,,,,,,
,10.98,3800,17.0,0.0,1120.0,,,,,,,,,,

Tested the boost with vag com and i am not sure if it is ok.
Can also hear a hissing noise from the right side from 4000rpm to about 6000rpm`s.