Vac Leak Tip, Tricks & Hints

[LANDSCRIBBLE]

Took me a while but I found several leaks when holding 25psi in mine.

[R.3.2.G.T.R]

doesnt the smoke tester run very low psi through the system?

[Hanaldo]

Took me a while but I found several leaks when holding 25psi in mine.

What method did you use to do this man? I should really have a better look at mine.

[LANDSCRIBBLE]

What method did you use to do this man? I should really have a better look at mine.

I put my plug with valve stem in the throttlebody join and plugged the join coming out the turbo, aswell as any other vac lines to the carbon cannister/plenum. So effectively pressurizing from just after turbo to just before the throttlebody.

[Manuel Kasko]

See the plugging is where I struggled

The one I found was the same size as my joiners and so wouldn't fit into my silicone to make a tight fit.

No plumbing place had the correct size

Also when I finally tried to get pressure it would just go via the hose to the cam cover and leak

So I guess the trick is blocking directly from the turbo with a suitable plug (couldn't find one)

Then as you said directly at the throttle body

[scotty nm35]

I could spin something up on the lathe for you, not difficult. Do you have a compressor?

[Manuel Kasko]

I have a little electric bike pump haha.

Would purchase them off you if you could make 2 the correct size for a good price.

Also a small hole to put a bike nipple thing

So one to fit in that silicone going to the throttle body. (This is between the crossover and the throttle body itself?)

Then one to fix straight to the front of the turbo.

If the intake is 3inch then what size silicone hose do you purchase to make a snug fit?

[scotty nm35]

You have one of my intakes, they are 80mm, like the afm.

Why do you want to block the pipe at the throttle? You want to test the vac lines and manifold too.

I usually just put a brass hose barb in the end, just let me know what size you need (they are imperial like all air fittings.) A bike pump won't cut it, you need a compressor to supply enough flow or the leaks will drop the pressure.

Has anyone pressurised the intake to over 40psi? I noticed the new silicone joiners compress and leak no matter how tight you do up the clamp, making funny squeak noises. (like blowing through a gum leaf.)

[Manuel Kasko]

I found that it leaked to much air via the hose coming out of the cam cover.

So when I was doing it from the intake pipe it would just leak.

Doing it direct from the turbo cuts out that.

Also I found my engine just wouldnt build or hold the compression when I had it going into the manifold etc.

This is why I just gave up and took it for a smoke test, which in the end didn't tell me anything really

[scotty nm35]

Because there is a problem. Like I have already said, as long as there are no valves in overlap, there should be no leaks. If your catch can/breather is leaking or not plumbed into the intake then you will have issues, either fix them temporarily or permanently.

[Manuel Kasko]

So if that is fixed, then you do it and it does not hold and you can not hear a leak.

Turn the car on and off to try make sure the valves are not overlaping?

[scotty nm35]

Or just turn the crank with a socket and bar? You will definitely hear leaks, at 30psi there will be plenty...

[Manuel Kasko]

I might go measure my little thing I made up

And see if I can get a silicone joiner to go over your 3inch intake & over it.

Sounds funny but when I first installed your intake I purchased the wrong silicone joiner

And had to use heaps of time making it fit over it.

Thanks for all the info scotty

[Hanaldo]

How do you purchase the wrong silicon joiner? Their measurements are for internal diameter, so unless your intake pipe has like 5mm walls then a 3" joiner should go onto a 3" pipe just fine.

[Manuel Kasko]

Let me go check my ebay and see what exactly I purchased

[Manuel Kasko]

The one I used between the AFM and the intake pipe. - Silicone Straight Hose Coupler 3 inch/ 76mm Black (Was hard as fark to fit)

The one I used between the intake and the turbo - Silicone Straight Hose Coupler 3.125" 80mm (This was easy)

[scotty nm35]

Yep, it's an 80mm (3.125 inch) intake, with 2 mm wall = 3 inch internal. Tube is measured as outside diameter though.

3 inch silicone will stretch over luckily as 80mm silicone reducers are impossible to find. You may need to heat the silicone to soften it enough.