Some good reading here

I'd like to do my own boost leak tests, however I don't have an air compressor. I'm sure one of my neighbors would have one, but is there an other way to get air in the system other than a compressor that I may not have thought about?

 

i guess my car will be getting a boost leak test saturday

 

STM checks for boost leaks on my car at the start of every season.

 

I just thought that you should be prepared before you go in for a tune. You know do a boost leak test, check the oil, change the plugs (unless they're new), etc. If you can't do something yourself and need any of these services done, you talk to the shop performing your tune ahead of time.

 

+1 for boost leak testing. You can recover as much as 20ft lbs of torque or more when you go from leaking to no leaks.

 

Its important to test for boost leaks often with an evo. Its especially important to do when you mess around with the IC piping.

 

That's a vacuum line. Little different. Vacuum line runs to a specific source.
That's like dropping your tire pressure 4 pounds in each tire, compared to dropping one tire 16psi.

You're not going to lose 1psi of air pressure from a leak that you can barely hear and not even feel on a throttle shaft seal. I tested the heat theory. The tiny leak that my car does have, goes away when tested w/ the engine is warm, due to the thermal expansion. You're right there.

To say a leak is a leak is wrong. That's like saying an ounce of water is a gallon of water.We're not talking a $1,000,000 race car here, they're passenger cars.
The MAF sensor is not even capable of metering the amount of airflow (with the same time span) equal to that lost from a "leak that you can barely hear and not even feel at 30psi" on a throttle shaft seal. The system wasn't designed to be that accurate.
And yes, I understand that a bunch of small leaks can add up.
Yes I run periodic boost leak tests on mine to make sure it's not getting any worse, I data log periodically to make sure my trims a:f ratio is in check.
Now, if my trims were showing that the ecu is compensating for a lean condition at idle, cruise, and/or the a:f was getting a little on the rich side at WOT, then I'd say my leak is negatively affecting it.
I guess I'm looking at it from the realistic/technical side, tolerance.


I guess I do see you point... If you going to go through the trouble of the leak test, you might as well go all the way and fix the seals. Damn it! Now it's buggin' me I guess I'm working on the car today.

 

bump for some good info...

 

A small leak in one of the intercooler couplers that you would barely be able to hear can drop 1 psi per 3 seconds easily when your trying to test and check for leaks. It may not seem like alot but thats just that much more your gonna be overworking your turbo. I do see your point though, if you are tuned at 24 psi and have a tiny leak at 23-24 psi, then its probably not too big a deal (but should still be addressed). But, if you had a small leak at 16 psi and your tuned at 24 psi, that small leak will much greater at 24 psi.

 

i agree but also you have to agree that if its leaking its just going to get worse the longer you let it leak. so its best to just knock it out early before it gives you trouble down the road. but ya ive experienced the cold vs hot thing with the shaft seals so i was speaking from experience.

injector seals can do the same also.

but the thing is, if they are leaking at all, its time to change them.. they are not supposed to leak in any conditions.

Mil.spec = shaft seals ftw. wont ever leak again after you drop those in.

I boost leak check maybe 2 times a year if that or if i feel the car is laggier then normal or it feels down on power.

I do maintenance my clamps tho on my ic piping. I tighten them every now and then because they will loosen up by themselves or require alittle more snug fitting.

i double ziptie + super glue my lines so they never really leak, but ive seen better solutions at CBRD. some of the cars in that shop have insane setups for vacuum lines and etc.

 

most shops will do it if u ask but will charge u. some will just tune and not care. best bet to do it yourself

 

When I first moved back up north I didn't have a boost leak tester or air compressor at my new place...I had a tuning session scheduled at CBRD and asked them to do a boost leak test also...Glad they did, haha, they found at least 3 leaks...2 were from flanges that weren't perfectly flat...Since then I now have my own boost leak tester and air compressor...

 

**UPDATE** - Found boost leak, caused by POS Hondata phenolic spacer on intake manifold melted at number 4 cylinder.

Same issue as yours. According to the Cobb article referred to in the first post, you could use a bicycle valve instead of a compressor valve. I have a tire compressor that I figure I could use, just need to figure out where to get a proper valve and install it in the pipe cap.

I need to do this because my new CBRD BBK Full turbo set up went south (bad idle/stumble/stalling) about a week after they installed it, and being I'm about 6 hrs away from them, I need to do the troubleshooting myself. CBRD did find a leak in my TB and fixed it during the install - no one had found that one previously. I had MIL.SPEC rebuild that TB and when it came back with new shaft seals I had to turn down my boost since I no longer needed to compensate for the leaks there. Word to the wise - if your TB is 4 yrs old or older and is using the OEM shaft seals, I guarantee they're leaking.

 

someone should create a youtube video on boost leak testing

also how do u guys check the IC endtanks on a evo 9 w/o removing the bumper?

 

Here is my travel set-up when not working on cars at my garage or shop.

Air tank, hose, in-line air regulator, spray bottle with soapy water, adapter made from home depot racing
https://www.evolutionm.net/forums/ev...er-5-02-a.html

Remember when testing, use the soapy water because you can't hear boost leaks unless they are big.