Back to Basic... Correct way to do boost leak test?

[TommyDSM]

Just wondering how you guys are doing boost leak tests on your car?

Ive been turning my regulator on my air compressor down to 20psi and making sure only 20 psi is going into my system to test for leaks....

But I remember reading back, one way was to look at your boost gauge... well with the aircompressor set to 20 psi, my boost gauge never gets more then 7psi I believe....


Do you guys turn up the pressure on the regulator to full and just watch the Boost gauge to test for boost leaks?

Do you ever hold down the throttle?

Whats the correct way of doing this? Because you read alot of people saying oh I test my system to 20PSI and no leaks... Does that mean Regulator at 20Psi or Boost Gauge reading 20psi?

[FORMONTOYA]

I test mine to 25PSI. The regulator on the compressor is set at 25PSI. The boost gauge in the car will read 25PSI. Once the compressor is unhooked it will hold the 25PSI for several seconds before slowly (and I mean very slow) drop down to zero. As a matter of fact, once it gets to around 15ishPSI it takes forever to drop to zero.

You DO NOT want to turn up the regulator on the compressor any higher than the max PSI you want the intake track to see. You would be surprised how fast it will fill up the system and how fast you will blow just about every seal and coupler in the track with too much pressure being feed into the intake track.

If you're set at 20PSI and only see 7PSI on the gauge, you have quite a way to go before your test is complete. On mine, boost leaks are common at the PCV valve, under the BOV and TB shaft seals. Of course you will want to check every sealing area on the intake track...couplers, seals, plugs, nipples, etc. Also, the first thing I do is find TDC and then rotate the engine to ~30* past TDC. DO NOT TURN THE MOTOR COUNTER-CLOCKWISE! This first task of finding ~30* past TDC will ensure that at least a set of valves are closed in each cylinder so the air doesn't pass straight through the cylinder and out the exhaust.

A spray bottle of soapy water will be your best friend.

[TommyDSM]

Originally Posted by FORMONTOYA

I test mine to 25PSI. The regulator on the compressor is set at 25PSI. The boost gauge in the car will read 25PSI. Once the compressor is unhooked it will hold the 25PSI for several seconds before slowly (and I mean very slow) drop down to zero. As a matter of fact, once it gets to around 15ishPSI it takes forever to drop to zero.

You DO NOT want to turn up the regulator on the compressor any higher than the max PSI you want the intake track to see. You would be surprised how fast it will fill up the system and how fast you will blow just about every seal and coupler in the track with too much pressure being feed into the intake track.

If you're set at 20PSI and only see 7PSI on the gauge, you have quite a way to go before your test is complete. On mine, boost leaks are common at the PCV valve, under the BOV and TB shaft seals. Of course you will want to check every sealing area on the intake track...couplers, seals, plugs, nipples, etc. Also, the first thing I do is find TDC and then rotate the engine to ~30* past TDC. DO NOT TURN THE MOTOR COUNTER-CLOCKWISE! This first task of finding ~30* past TDC will ensure that at least a set of valves are closed in each cylinder so the air doesn't pass straight through the cylinder and out the exhaust.

A spray bottle of soapy water will be your best friend.

I figured I was doing it the right way. But the TDC is a suggestion I will try today.
Thanks!