boost leaks

[Hotshot8792]

I thought i would bring up this issue to help out some of the twin turbo owners who have boost leaks. I have had problems with these in the past. The easiest way to determine whether you have one or not is where your vacuum gauge idles at after the engine has warmed up. If your vacuum reads around -20 when sitting still, and drops below -20 after letting off the accelerator while in motion, then you are good. If its idling any higher than -18, then odds are you have a leak.

Some of the most common places that i am aware of are on the rear turbo/rear IC pipe connection, the y-pipe to throttle body connection (on a stock y-pipe), and the idle screw (when the o-ring is shot).

I did some pressurizing tonight with my air compressor without any water/soap and noticed i had a leak where one of my intercooler pipes connected to my y-pipe. The other one was fine, but it had a new non OEM clamp on it, while the one leaking had an OEM clamp on it. My conclusion is that these clamps are weak. Although i checked my other OEM clamps and they held nicely, but this one didn't. So word of advice for finding a leak, check your clamps. My clamp was as tight as i could turn it, yet i felt air rushing out of the sides.

I will do more pressure testing, and hopefully with some water/soap. Hopefully i will be able to locate all my leaks, if i have anymore, and if i do, i will post them back up, so hopefully most of the common leaks will be covered.

Also, if you've discovered a leak in any other place other than what i have mentioned, feel free to post it up. Thanks

[Thourun]

Are you talking about the stock gauge? When off boost it is peged at the bottom and when on it is peged at the top right around where 15 would be if it went that high. It sounds like there is air escaping and a little wistle also all coming from the left side somwhere (judging from the drivers seat). Could I just get my dad to rev the car in neutral and use the soap+watter method? I would like to avoid making the leak tester that Raz linked too since it seems like it would be a pain in the ass to pump it up with the bike pump lol. But if it comes to that where do you attach it?

[Hotshot8792]

Originally Posted by Thourun

Are you talking about the stock gauge? When off boost it is peged at the bottom and when on it is peged at the top right around where 15 would be if it went that high. It sounds like there is air escaping and a little wistle also all coming from the left side somwhere (judging from the drivers seat). Could I just get my dad to rev the car in neutral and use the soap+watter method? I would like to avoid making the leak tester that Raz linked too since it seems like it would be a pain in the ass to pump it up with the bike pump lol. But if it comes to that where do you attach it?

lol no, not the stock boost gauge, that thing doesnt even work, it just estimates everything electronically from the MAS. I'm talking about a real boost gauge that actually hooks up to a line thats pressurized along with the engine.

If your hearing a whistle, odds are you do have one as well. I dont think reving with soap and water will work too well, but i may be wrong. The car won't build any pressure sitting still, so it will be in vacuum. When its in pressure, the bubbles will bubble up, but i'm not sure while its in vacuum.

As far as an actual intake pressure tester, i'm not sure which link he sent you. There are 3 possibilities. 1 is from 3sxperformance, 2 is from rob beck, and 3 is make your own with the instructions from stealth316.com. A bike pump isn't going to do you any good. You have to have access to an air compressor, because there's a lot of volume you have to fill up with air at one time to make it work. As far as where you put it, you take your MAS and air filter off your intake T-pipe, and you put the pressure tester in the intake t-pipe and clamp it down and then pressure test.

[Thourun]

But the T pipe opening is large and oval, ohh well I'll go check out stealth316 and try to figure it out. Where could I acess a presurizer? Would going to the gas station work lol? Thats the bigest problem is the pressurization.

[Igovert500]

The opening is oval, but when tightened it turns circular, and then returns to its oval shape afterwards...no problem, same with the ls6 and ls1 MAFs, they are circular, but they fit fine.

The pressurizer thing is my problem too...I had to borrow a friends' dad's air compressor, and it's regulator was retarded, so it was hell. A gas station one would work, but you want to find one that you can preset the pressure and preferably is free...otherwise it could get expensive.

Start with low pressure, and work your way up...if you just try it at 14psi, if something is loss...it could become a projectile!

[Hotshot8792]

Originally Posted by Igovert500

The opening is oval, but when tightened it turns circular, and then returns to its oval shape afterwards...no problem, same with the ls6 and ls1 MAFs, they are circular, but they fit fine.

The pressurizer thing is my problem too...I had to borrow a friends' dad's air compressor, and it's regulator was retarded, so it was hell. A gas station one would work, but you want to find one that you can preset the pressure and preferably is free...otherwise it could get expensive.

Start with low pressure, and work your way up...if you just try it at 14psi, if something is loss...it could become a projectile!

right, when you tighten down the clamp, it becomes circular on it. As far as pressure, this is why you put a gauge on it, i will snap some pictures and post them up of my pressure tester as soon as i can.

[Igovert500]

Haha, no I didn't mean gauging pressure, the compressor I used did have a gauge. I just meant my problem is the lack of anything that produces the pressure. I don't own a compressor, so I have to rely on friend's parents...which isn't great if the friend is question is in the midst of being kicked out of his house...

[Thourun]

Hrmmm, does autozone or home depot lend out tools?

[Hotshot8792]

Originally Posted by Igovert500

Haha, no I didn't mean gauging pressure, the compressor I used did have a gauge. I just meant my problem is the lack of anything that produces the pressure. I don't own a compressor, so I have to rely on friend's parents...which isn't great if the friend is question is in the midst of being kicked out of his house...

when your testing though, you dont go off the gauge from the compressor, that just tells you how much your putting into your air hose (the 2nd gauge of course). You also want to have a pressure gauge on your actual intake pressure tester, as i will show in my pictures in the next post. This is to make sure you dont over pressurize, as you dont want to build up anything more than 25 psi. Of course i didnt have too much of a problem with this as i have a slight leak in my intake pipe (before the turbo) where i tried plugging up the purge line holes
but i'm not worried about that cause that doesnt cause a boost leak since its before the turbo.

thourun- autozone rents out tools but nothing like this. Look at my pictures below, i pretty much used the technique off of stealth316, although my PVC pipe is different, i just used a 1 piece pipe with a screw cap. I found one that fit nicely into the intake pipe.

Now bear in mind that i use a custom dual intake on my car, so i just keep the intake t-pipe for pressure testing purposes, hence my all new intake pressure tester.

Another thing i found the pressure tester useful for is that i took off the PVC piping and i used it to set my hobbs pressure switch for my alcohol injection so that it turns on automatically after the car starts building 5 lbs or so. I may go through alky fast, but thank goodness winshield wiper fluid is only 99 cents per gallon.

[Hotshot8792]

[Igovert500]

Hotshot, I have a friend watch my a-pillar boost gauge when I'm pressure testing.

[Hotshot8792]

Originally Posted by Igovert500

Hotshot, I have a friend watch my a-pillar boost gauge when I'm pressure testing.

well, that can works too, but for those who dont have a friend over, or just dont trust their friends with their cars lol

[Thourun]

Well I had it pressurized by a guy (darthstimpy) who lives 10 minutes away who I met on 3SI. He also gave me a ride in his dr500 97 VR4... wow! Anyways, he said a gasket on my rear turbo was leaky, so was the gasket between the throttle body, so was the Y pipe throttle body connection. He also looked at my coroded little bov and said to replace that lol. So should I take this to the local shop people use for tuning and installs? They charge $55/hr but they come highly reccomended and have worked on lots of VR4s... Hrmmm maybe I could get some toys installed too . Ooo speaking of toys I have a 8x4.5" K&N and 4.5" adapter on the way, weeee first mod! He said it would be a bitch to take the old box out and that I need to take the fender apart lol, ohh well such is the price.

[Igovert500]

What, why would you need to take the fender off to remove the old intake?

http://www.team3s.com/~egross/3S/Mods/All/KN/index.html


My only problem was:



These damn 4 bolts ripped right through the plastic holding them in place, so they spun freely, so I had to cut them out with a damn handsaw...which SUCKED!, but other than that, it is a 5 minute install...definantly one of the easiest mods to do.

[Linebckr49]

Igovert, i had the same problem when installing my K&N filter. those bolts just spun in place, and it was a bitch it get out. and after i did get it out, it was not repairable! oh well, i'll just have to do with a K&N.