Boost leak test/check

[dodgedieselnewbie]

Good evening,  

Can someone tell me when doing a boost leak test... should the system stay pressurized if you have no leaks? Should your boost gauge rise to the pressure you apply? Thanks!

Edited November 16, 2015 by dodgedieselnewbie

[dodgedieselnewbie]

Umm.. my boost tester came with a valve stem. I changed it over to quick connect because based on my searching the pressure needs to be constant. I'll try again tomorrow. Is 20 PSI too much to test with. My compressor is difficult to regulate much below that....

Edited November 17, 2015 by dodgedieselnewbie

[TFaoro]

I'd do around 30. You won't hurt anything.

[dodgedieselnewbie]

Okay.. cool. I don't know if I have any problems. It seems to build boost easily but something weird happens up around 30. I don't know what kind of boost number I should be able to hit with my set up.  

Edited November 17, 2015 by dodgedieselnewbie

[Mopar1973Man]

HX35W turbo should hit a max of 35 PSI safely. Then a HY35W turbo should hit max of 32 PSI safely.

Quote

It seems to build boost easily but something weird happens up around 30.

Explain what its doing...

Edge Comp will get about 30-32 PSI tops.

[dodgedieselnewbie]

I'm not sure how to explain it correctly.. it seems to sound like a flapping sound with air and it falls off...

btw.. I hit like 34 once but never pushed it again

Edited November 17, 2015 by dodgedieselnewbie

[Mopar1973Man]

If your jumping off the throttle and getting a whooshing noise that's called a "Turbo Bark". That when you got the turbo spun up tight and loaded with high boost then jump off the fuel and driven pressure fails. Now the compressed air is attempting to spin the compressor wheel backwards venting the pressure it just built. This can do damage to the turbo. So just ease out of the throttle just a bit before dropping it out right.

[dodgedieselnewbie]

and.. what it something similar happens if you don't let off the throttle?

Or what happens when you reach max boost? 

Edited November 17, 2015 by dodgedieselnewbie

[Mopar1973Man]

My thoughts... If its under load and making noise.

• Boost leaks, torn/cut boot(s), manifold gasket leaking
• Drive pressure leaks, crcked exhaust manifold, blown exhaust gasket(s).
• Turbo bearing issues, compressor wheel making contact with housing

[dodgedieselnewbie]

Okay.. thank you. I will check for boost leaks tomorrow. I didn't see any problems with the turbo compressor wheel... I spun it and there isn't noticeable play. I don't know if it's a characteristic of my turbo but it seems to whistle constantly. It was a little annoying on my 800 mile round trip last weekend.

[Mopar1973Man]

Quote

I don't know if it's a characteristic of my turbo but it seems to whistle constantly

Silencer ring is missing. That is normal. I reinstalled my silencer ring to tone that down gets rather old after awhile towing heavy through the mountains.

Quote

I don't know if it's a characteristic of my turbo but it seems to whistle constantly

Silencer ring is missing. That is normal. I reinstalled my silencer ring to tone that down gets rather old after awhile towing heavy through the mountains.

[Dieselfuture]

I just tested mine last week with a rubber cap from menards that I punched a hole in it to put my quick connect, cost me about $10. Put 20 psi to it and it was all it would hold before trying to blow off the turbo, because cap is slightly bigger. Then I used soap water and found few very small leaks, one on intake horn boot, one on intake bolt, and one by intercooler driver side boot itself had tiny bubbles pushing through rubber. Might be getting all new boots some day.  

[dodgedieselnewbie]

Okay.. I have just a few boost leaks :-) So will all these tiny leaks effect what happens to boost under load at say 30 psi? Does effect anything lower? How about MPGs?

The intake bolts seem to be tight.. Do I need a new gasket? What is the plug and how do I fix that? 

 

I tightened the clamps under the turbo which seems to have taken care of that one. Both intercooler hoses leak. Will attempt to tighten those later as they are in a tight spot...

 

Edited November 17, 2015 by dodgedieselnewbie

[Me78569]

Even the smallest boost leaks add up.  Doesn't take as much as you would think.

[dripley]

Some of the bolt holes go all the way thru into the plenum and could be leaking around the threads. Not sure how many are like that. The one with the wires is most likely for your boost gauge. Mine is in that location using a hollow bolt. Mine is mechanical and has  tube instead of a wire. You might try tightening the clamps on the boots and see if that helps. I have heard of using hairspray on the the connections to help seal them. Never tried it my self. Once I get my clutch replaced I am going to tackle some leaks of my own.

[dodgedieselnewbie]

Thanks for the info! I stopped using hairspray back in 77 I believe ;-) Is there an automotive product that'll do the trick? 

Still would like to know how all those little leaks effect performance? EGTs? MPGs? Or nothing really accept boost dropping off under load? 

Just trying grasp and understand. Thanks!

[Me78569]

Boost leaks will cause EGT issues, MPGS and performance, the truck is working x amount to spin the turbo and x amount to move, but the boost is going to waste, so more fuel = more EGT's = less MPGS  for the same amount of power to the ground.  

[dripley]

I dont know of an automotive product to use for sealing the boots. i have never tried to look for anything. I have some leaks to deal with but probably wont touch them until I can park the truck and pull some things off of it first. I hope the clamps just need some tightening. 

[dodgedieselnewbie]

Well.. I only had time this morning to tighten the upper clamps this morning. The 2 bolts, boost plug and 2 lower intercooler still had those minor leaks. I decided to see if it changed anything.. Edge was set to 5/3

It reached around 41 psi. This is a first.  I read that this turbo was capable of 40. 

 

Then I tried it set to I think 4/4 and it did that "turbo bark?" noise I was telling you about. I didn't let off the pedal when it happened. Not sure why. It seemed like it happened when it was shifting.

 

 

I also have a question about the Edge and fueling. How do you know what to set the edge for fuel? How do you know when you have too much or too little?

[Me78569]

sure sounds like bark,

 

I am gonna guess some sort of fueling issue?  did the truck buck at all?