Boost Leak lawn chair and a massive bump

XR4Ti / Sierra / Sierra Cosworth Discussions - Questions, problem resolution, general talk, technical tips and modifications.
Post Reply
Merkur Club web site
C-Rock
Level 2
Level 2
Posts: 199
Joined: Wed Apr 14, 2010 6:57 pm
Location: Findlay Ohio

Boost Leak lawn chair and a massive bump

Post by C-Rock »

We have a boost leak and it's a little tough to find while driving and putting the car under load. I took a lawn chair and some duck tape and I strapped my son in law to the front of the car and took it for spin. Duck tape did not hold well and he fell off. So after some road rash and a massive bump on his head I thought I would make up something to test it and not take a chance of breaking that lawn chair.

So made up some fittings and have a 30 lbs pressure gauge and plan on hooking this up to the air intake on the turbo and then pump it up to 20 lbs. If I don't have any leaks than I should be able to hold 20 lbs of pressure with this set up going from the air intake on the turbo through the intercooler and into the throttle body and into the engine? Am I thinking right?

Thanks Cliff
User avatar
Esteban
Level 7
Level 7
Posts: 1980
Joined: Wed Mar 24, 2010 2:07 am
Location: San Diego

Re: Boost Leak lawn chair and a massive bump

Post by Esteban »

Duct tape? You should have used zip ties!
The system wont hold boost forever as it can seep out past the piston rings.
Pressurize the system, take a spray bottle of soapy water and start spraying the couplers, seals, gaskets, etc. You will bubbles where the air leak is.
One very common place are the throttle body shaft seals.
timandsam
Level 4
Level 4
Posts: 390
Joined: Thu Mar 08, 2012 10:31 pm
Location: Auburn, PA

Re: Boost Leak lawn chair and a massive bump

Post by timandsam »

I agree with esteban, the system isnt airtight. Air will leak past the rings and out the exhaust. As well as the spray bottle the esteban suggested, i used a 3' length of tubing. Hold one end to your ear and move the other end along anywhere that could possibly leak. You WILL hear it.
Mono Silver 85 XR4Ti: Ported Head| Ported Intakes|Schneider Roller Cam|Big NPR IC|3” Exhaust|Ported E6|Walbro 255|PiMP|80lb injectors|HE341|Alkycontrol|T5Z
C-Rock
Level 2
Level 2
Posts: 199
Joined: Wed Apr 14, 2010 6:57 pm
Location: Findlay Ohio

Re: Boost Leak lawn chair and a massive bump

Post by C-Rock »

I agree it will bleed past the rings but it will give me some time to find the leaks and should hold the 20 lbs for a while,right?
User avatar
Mike McCreight
Level 7
Level 7
Posts: 3987
Joined: Fri Oct 31, 2003 8:44 pm
Location: Ottawa! Well, Manotick, actually...

Re: Boost Leak lawn chair and a massive bump

Post by Mike McCreight »

Here's an easier way.
Get the propane tank from your BBQ, or better, borrow one from a neighbor. Attach it using your duct tape to the turbo outlet. Crack the valve, and let sit for 1/2 hour or so, then send your son in with a spark lighter to check for leaks.
It's not a hobby, it's an obsession!
timandsam
Level 4
Level 4
Posts: 390
Joined: Thu Mar 08, 2012 10:31 pm
Location: Auburn, PA

Re: Boost Leak lawn chair and a massive bump

Post by timandsam »

C-Rock wrote:I agree it will bleed past the rings but it will give me some time to find the leaks and should hold the 20 lbs for a while,right?
I really don't think so. I would hook it up to the air compressor (regulated to 20psi) and just keep it hooked up to whatever boost leak checker thing you made. It will leak alot of that air out in a hurry past the rings and such.
Mono Silver 85 XR4Ti: Ported Head| Ported Intakes|Schneider Roller Cam|Big NPR IC|3” Exhaust|Ported E6|Walbro 255|PiMP|80lb injectors|HE341|Alkycontrol|T5Z
turboplz
Level 6
Level 6
Posts: 901
Joined: Sun Feb 26, 2006 1:42 pm
Location: Holly Srings, Ga

Re: Boost Leak lawn chair and a massive bump

Post by turboplz »

To properly test the entire intake tract for leaks, you're going to need to remove the followers from the intake valves. Assuming you have good valves and seats, this will keep the entire system pressurized until you can find the leak.

A couple common places I have found leaks are at the pcv fitting, under the lower dash there are a couple vacuum lines that have rubber couplers that like to rot over time and the most common is the throttle body shaft. If you have no obvious leaks in the system, I would thoroughly inspect those areas.
Jason

89 Xr4ti..."Bronze Turd"...long term project/current garage queen

2014 Focus ST
lucky87
Level 3
Level 3
Posts: 280
Joined: Fri Nov 18, 2011 1:57 pm
Location: Borden Ont.

Re: Boost Leak lawn chair and a massive bump

Post by lucky87 »

You could try using smoke to find the leak, use all those fittings and attach it to a smoke machine. smoke comes out of the leak. I did a ghetto version with cigarrette smoke, worked well enough to find a leak near the vaccum ball thingy, (broken tube) which was easy enough to fix.
C-Rock
Level 2
Level 2
Posts: 199
Joined: Wed Apr 14, 2010 6:57 pm
Location: Findlay Ohio

Re: Boost Leak lawn chair and a massive bump

Post by C-Rock »

I had made up a set up with a pressure gauge and it worked well and we have some leaks and will be getting them ironed out. I will also do this on my 89 red car. This is something I would suggest everyone do I was surprised at the leaks.
Post Reply