[clifton23]

bump of an old thread.. but I have a question before I try this.

How did you prevent air from exiting through the engine intake/exhaust valves?

[itsbrokeagain]

good writeup. I actually have a pair of caps that i use for 911 turbos similar to yours for finding boost leaks...which they are plenty common.

[ironic]

here's a great youtube video that walks you through a similar test:

[jdbretz]

If you don't want to mess with building one, you can always buy one here:

http://www.siliconeintakes.com/index.php?cPath=8

[joro2077]

thanks for the info

[Joshboody]

I was thinking about this the other day. Sorry i did not read through this thread and assuming most are checking from the hot side which is good. BUT you eliminate testing hot side to IC. Pressurizing before turbos would be best, but n54 intake pre-turbo is not the most solid piping. You don't want to pressurize the rear turbo due to the difficult access if it pops off. I wonder how much pressure the front intake pipe can handle?

[JamesM3M5]

It pops onto/off of the turbo the same way. The inlet piping is only thin molded plastic, designed for flow, not pressure. You'll either blow the pipe up at a seam or pop it off the inlet of the compressor housing.

[Sniz]

Originally Posted by Joshboody

I was thinking about this the other day. Sorry i did not read through this thread and assuming most are checking from the hot side which is good. BUT you eliminate testing hot side to IC. Pressurizing before turbos would be best, but n54 intake pre-turbo is not the most solid piping. You don't want to pressurize the rear turbo due to the difficult access if it pops off. I wonder how much pressure the front intake pipe can handle?

yes pressurizing into the turbo is ideal but not doable on the n54. I pressurize right into the intake on my gt35r on the M3.

[diegopiedra]

Sorry to bring up an old thread but would u be able to remove the intercooler completely and pressurize the 'cold' side piping that leads to the chargepipe/throttle body and seal off the hot side piping? Nice write up btw!

[Chefcg1]

Exactly how I have tested boost leaks since the 80's except I used a valve stem and add a cheap pressure gauge.

[diegopiedra]

Originally Posted by Chefcg1

Exactly how I have tested boost leaks since the 80's except I used a valve stem and add a cheap pressure gauge.

Does the air circulate through the throttle body when it u pressurize through the chargepipe?

[JamesM3M5]

Yes, it goes all the way into the head and any open intake valves. Since it is nearly impossible to stop the engine exactly at one cylinder with both intake and exhaust valves open at the same time (overlap), you pressurize the entire system. Even if the throttle is shut, air still makes its way past in any engine.

[diegopiedra]

Originally Posted by JamesM3M5

Yes, it goes all the way into the head and any open intake valves. Since it is nearly impossible to stop the engine exactly at one cylinder with both intake and exhaust valves open at the same time (overlap), you pressurize the entire system. Even if the throttle is shut, air still makes its way past in any engine.

Oh man thanks thats so much thats easier than having to go down to the intercooler lol

[mythek]

my car just started to have a bad boost leak two days ago, where I can feel dramatic drop in power. Before investing more time to build the pressure tester, I'm going to start looking for the problems at some of the common places like charge pipe, intercooler, and intake. Anywhere else I should be looking?

[Scrippy]

Good moves man! Simple and clear.

[wolfusor]

2007 n54. No fault codes, just slow boost build up and some overboost when off the gas pedal. I've set up the system for boost/intake leak test, capped the PCV pipe. As soon as start pumping in pressure, I can hear hissing sound coming from inside the engine valves cover, more audible when I open the oil cap. Any ideas would be appreciated.

[djtalal]

based on the last comments on this thread and the last 4 youtube videos i watched of people removing the dci's and capping one / pressurizing the other is bad because your adding too much pressure to the plastic inlets right? if the leak is from the outlet to the hot side intercooler it's easier just to replace and tighten down with a good silicone adapter and t-bolts clamps right?

[djtalal]

Originally Posted by Sniz

Finally got around to posting this. With the help of Adam (clem) we put together a quick and cheap boost leak test for my car.

in Adam's awesome garage.......

notice the cans of Sunoco race fuel.......love this stuff, smells so good. Me in the background. Sorry for the crappy pics, Adams camera was having focusing issues apparently.



Here is how it was done:

I have a Helix FMIC which uses 2.5" ID silicone couplers, i'm going to assume that all other aftermarket FMIC kits use the same size.

- Drive to Home Depot or Lowe's

-Park

-Purchase a PVC end cap w/ a 2.5" OD

-Purchase a quick release compressor "nipple"

-drill a hole in the end of the cap that will allow the nipple to be very very tightly screwed into the end cap, size of drill bit will depend on the nipple you purchase



-drop both sides of the intercooler allowing better access

-we used the sophisticated hanging green wire shown below to hold the passenger side of the FMIC a good 12" or so below the bumper, this will require the removal of the "hot" side coupler and the loosening of the "cold" side coupler to allow the FMIC to rotated



-using a few worm clamps or any type of clamp, fasten the end cap w/ nipple into the "hot" side coupler very tightly. We had this end cap shoot out once, loud as h*ll when it blew and we both puckered our you know whats .

-tighten everything up, set your compressor to around 20psi and pressurize the system, you willl hear all types of weird sounds from the engine/piping when the pressure hits.



-shut off the compressor and ANYTHING else making noise, you want your work environment to be 100% quiet other so you can better hear small pops, hisses, etc.

-LISTEN.......anything you hear may be a boost leak, I had a small boost leak in the stock plastic/rubber coupler on the charge pipe....it sounded like a bubbling as the oil inside the pipe was trying to escape. This was the cause of a high RPM limp I was getting. After tightening the clamp just a half turn, the leak was ended and my car was happy.

-once you have determined where any leaks are and fixed them, put everything back together.

If this was unclear, just ask, i'm in a hurry and already late for a work appointment.

I'm still trying to understand this, but why dont you cap the outlet to the turbo?