How do I make / buy / use / troubleshoot a boost leak tester? [merged]

[Turbo Monk3y]

All boost leak tester threads are combined here.

i read somewhere maybe the Vfaq about making or buying a boost leak tester of some sort but never found it.... the reason being my acceleration seems slower than normal and all ive done to my stock car so far is take out the air box put on a K&N filter and cut the dump tube i have my boost guage sitting in a box not hooked up yet. and since those 2 mods it when i go wot on the car i can hear the turbo spool up and it sounds nice but i can also hear a sound as my rpm increases the SHHHHHHHHHHHHHHHHHHHHHH sound does too. the sound comes from the same area as the BOV i think maybe i got a #@%#@%#@%#@% stock bov and it cant handle over 11-13 psi??? Then i shift and it makes the nice BOV sound WHOOOOSHHHH... but my car seems to be a little slower.. any ideas before i go check every tube clamp and tube????

 

[1gTurboTuner]

Well I did a boost leak test today, didn't hear any leaks other then by the throttle body (think that's what it's called, the thing that houses the throttle plate) which I assume is normal? But the problem is I did a couple pulls earlier today while watching my boost gauge, and it'd only get up to about 6-7psi then drop back to zero, even though I was still accelerating. I have my gauge in the hose that goes from the BOV to the intake manifold.

Also check your nylon hose from your boost gauge to the source, i seem to remember a friend of mines boost gauge doing the same thing and the nylon hose had a hole in it from rubbing where it went through the firewall.

 

[99gst_racer]

Note - it was hard to find a 2.5" hose to make the tester... I ended up using the rubber piece connecting the intake pipe to the turbo inlet and that worked too.

Really? You don't have a local hardware store? The plumbing isle should have an abundance of those.

 

[95redturboawd]

Also check your nylon hose from your boost gauge to the source, i seem to remember a friend of mines boost gauge doing the same thing and the nylon hose had a hole in it from rubbing where it went through the firewall.

Actually I did another pull today and it was better. Went up to 11psi then dropped slightly in the high RPMs. I think I just wasn't going WOT the first time. Newbie mistake. I looked at Home Depot and Murrays and neither had the 2.5" hose. But either way, might as well use the hose connecting the intake pipe to the turbo so you don't have to buy another hose.

Should I be capping off the throttle body? Or is it supposed to let zero air out? I'm guessing zero air, just asking to appease my dad.

 

[1gTurboTuner]

Should I be capping off the throttle body? Or is it supposed to let zero air out? I'm guessing zero air, just asking to appease my dad.

When I test from my turbo inlet I do not cap the throttle body.

 

[rich3389]

The throttle body should have no leaks.

 

[steve]

Should I be capping off the throttle body? Or is it supposed to let zero air out? I'm guessing zero air, just asking to appease my dad.

The idea behind pressure testing to to make sure there are no leaks between the turbo and the combustion chamber. Since we can't open all the intake valves and close all the exhausts we just try to make sure we don't stop the engine at a place where both are open.

So, no you don't cap off the throttle body, because there are lots of things that can leak behind it like manifold gaskets, PCV lines, EGR valves, Injector seals, etc.

 

[95redturboawd]

Thanks alot guys... looks like I'll be getting new rings and taking off the throttle body with the link romeen posted. Sorta looks like a lengthy process, but the steps don't seem too difficult.

 

[black_eclipse96]

which one to by from Boostpro.net : Products - Boost Leak Testers

 

[LiquidX]

Well you need to use a gauge first off. So now the questions.

What kind of air compressor fitting are you going to use? Bike pump style or an actual air fitting?

Will the compressor you are using have an accurate gauge that you can moniter the PSI going into the intake? If not, then get a gauged one.

Word of advice, I have one of these and it's a pain for anything over 20psi because the plate will pop out of the coupler. It's not a flared/beaded end. Makes one hell of a pop too.

 

[black_eclipse96]

im just pumping it up to 12 psi. This one will do for now i don't plan on upping the boost till later. i have both fittings. i just feel that my car has lost alot of power. so this is one good way of finding why and where.

 

[1stGenTSi]

Just saw this thread and was wondering what people are using for a 4'' inlet turbo? I've rigged all kinds of stuff up but nothing seemed to work very well.

 

[LiquidX]

Just saw this thread and was wondering what people are using for a 4'' inlet turbo? I've rigged all kinds of stuff up but nothing seemed to work very well.

Get a 4" reducer coupler and here is a link to a site that has them. Just searched "silicone couplers" on ask.com

Intake Pipe Reducer

 

[alwesterholm]

I have a 4" inlet for my turbo aswell and was reading through this and came up with a great idea in making something that works for a variety of sizes. I was walking around ACE Hardware and came across these flexible PVC pipe caps!

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They come in 2 different styles and a variety of sizes. With all the components used in the other setups, I think it leaves multiple areas for leaks with the tester itself.
Just need to drill a hole for the schrader valve and air pressure gauge.

 

[99gst_racer]

^^^ So, the wall thickness isn't too thin to simply thread in a schrader valve?

 

[LandoAWD]

I have one built like that with a schrader and a ton of RTV. It distorts, but I have more problems keeping it on the snail than keeping it together.

 

[alwesterholm]

I havnt tried it yet. I went out and bought the my supplies for this right after I posted it yesterday. Hope to put it together tomorrow. It looked sturdy enough to me to be used in this application. I didnt consider that it would be much of a problem keeping it on the turbo as Kris describes with its integrated clamp and all. That is kind of a disappointment to hear. I will let you know how it goes when I am done with it.
If nothing else it gave me a chance to get out of the house and over to the hardware store. I am sure I am like most guys, I see tools and can't leave the store without getting more then I came for. I knew I was going to need to drill a hole for this and I couldnt find my drill bit set before I left the house so now I will have 2 when I find my old set.
Kris, any suggestions when putting this together for best results since you have already built yours?

 

[nek]

Since we can't open all the intake valves and close all the exhausts we just try to make sure we don't stop the engine at a place where both are open.

This is the only thing I dont understand, how do you know where its at? Guess and check?

 

[steve]

This is the only thing I dont understand, how do you know where its at? Guess and check?

There is a timing mark on the harmonic dampener (crank pulley) and a set of marks on the front plastic cover. You can see how far it is for 15* so you turn the crank until it lines up with TDC and then move it twice that distance past TDC. I picked 30* ATDC not because that's where the valve closes but because it easy to judge and far enough that if your off a bit it won't matter.

 

[dented_coffee]

I know this is an old post but I thought I might share what I made for under $10. All of the parts are brand new. The only thing extra that I did was sprayed the 1.25 inch PVC cap with spray on adhesive to help prevent it from poping off and possibly hurting someone. The gauge on it allows me to view how fast im loosing pressure to determin how severe my leak is, and to moniter how much air im compressing in my system. Some people might like to use a portable air tank. I do because someone walked off with my tire chuk for my air hose .

I have pressure tested this unit by its self with another PVC cap to make shure it would hold pressure and not leak (a pressure testing unit that leaks is as usless and a bike with no wheels). My boost leak tester held in at arround 35psi for a few hours untill I released the pressure myself. Im shure it will hold more as there was no leaking and no signes of stress. But I will never run past 20psi of boost ever again so it will be perfect for what Im using it for.

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[motozachl]

I need some help finding a boost leak. Holds pressure for a few seconds but only up to 6psi. Have done extensive searching and fixing all known leaks using soapy water and repairing them.

Info:
-testing from the throttle body & engine at tdc with plugs in
-fiav bypass plate is good and sealed
-brake booster is good
-pcv good
-new injector seals good
-new im gasket good and sealed
-biss screw good
-egr block off plate good
-fpr good
-valve cover is off (does this make any difference? i don't think so)
-outlets on tb are capped

Now what

 

[1990AWD]

Okay, I've done a couple boost leaks an it's not holding steady. Still runs alright but the lack of holding boost when testing worries me.

I can't get an accurate reading. I get a lot of air going into the crankcase, even if I plug the pcv line, and my bov keeps venting when testing at 15-20 psi. What can I do to fix these two problems? Everything is tight and solid, can't find anything leaking other than these; its frustrating!!

Oh and btw, I'm testing at the turbo inlet.

 

[frontdriver]

Test it at TDC and you're BOV probably needs replacement or crushing.

 

[yeti-gvr4]

How do you test at tdc

 

[steve]

How do you test at tdc

You don't. If you try and pressure test at Top Dead Center, the air will flow into and out of cylinder 4 where the valves are in overlap and both the intake and exhaust are open.