How To: Boost Pressure Tester

LinuxRacr

Contributor
:
2001 Mazda MP3
This is a small how-to that is designed to show you how to make a basic boost pressure tester.

1. Depending on what the size of your compressor inlet on your turbo is, you will need to get about a 2-3 inch section of silicon or rubber coupler hose. I was able to source a 3 inch diameter coupler at AutoZone picutred below. Notice that there is a black reducer ring in there so that one is enabled to connect to a 2.5 inch pipe as well. It comes with worm clamps as well.

$4.00

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Next, I went to Home Depot and souced a 3 inch knock-out cap from the plumbing/PVC section.

30 Cents. Ea.

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The next thing to do is to drill a 5/16 inch whole in the 3 inch knock-out cap so that the valve stem below can go thru the whole. A multi-step drill bit is perfect for this, but not that cheap.

$3.00

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Since the knock-out cap isn't that thick, you may want to wrap a "few" turns of teflon tape around the base of the valve stem to get a better seal. (I couldn't source a deeper cap that fit)

The next thing I did was put the cap with the stem installed on one end of the coupler, and clamp it down tight enough so that it won't pop off:

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For ease of use, I decided to install the tester on the 2.5 inch intake pipe, instead of directly on the 3 inch inlet of the GT-28RS. The black reducer ring that came with the coupler was key:

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BE AWARE THAT IF YOU DO THIS, IT IS AT YOUR OWN RISK!!! I WILL NOT BE HELD LIABLE FOR ANY DAMAGES! DO NOT TURN ON YOUR CAR'S ENGINE WHILE DOING THIS!!!
 
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Using an air comressor, and the tire inflator attachment, pressurize with about 10-15 PSI into your intake trac. Listen all around for leaks. They will be very audible, and a hisssing sound. Listen around your intercooler, your intake pipes and couplers, and your intake manifold, and throttle body gaskets.
 
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Spray bottle with soapy water helps pinpoint.

I did two sizes one for my throttle body which helped my find a large leak at my injectors and intake manifold at the top to bottom seam. Then I checked my intake system separately and found one at my HKS SSQV at the adjustment screw.
 
I AHVE A QUETSION...
it might be stupid..but...the throttle body is the only one closing the other side right??
and the throttle body is shut tightly enough to prevent leaks form that side?
it looks like a good idea to check for leaks when yo suspect a kit of having badly welded pipes or just tro make shure everything is in top working condition...BOV leaks come to mind as stated by the how-to writer..
 
The throttle plate does not close completely and beyond that the intake and exhaust valves are never closed all the way all at once. But this is enough to be able to find leaks. I cap my intake piping at the throttlebody end to separate and make it a little easier to pinpoint. I also swapped the valve stem for a barb and hose attached to a regulator.
 
yashart@work said:
Or, if you are extremely lazy and dont want to make your own, you can just buy this:

$30 from www.siliconeintakes.com

LOL, thats great, I may have to order this when I order new t-bolts, they keep loosening.(peep)

Great write up Linux. Perrin told me that they test theirs to 40psi. (I think intercooler only). So I wont be worried about 15psi.
 
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it's ok to pressurize before the turbo? I was thinking of starting at the turbo side of the hot pipe.
 
or you guys can go to a shop with a smoke machine.


BTW,most leaks tend to be at the EGR on most cars I test.
 
good write up, i've been wanting to buy a tester but if i can make my own why not

Thanks
 
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