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WI-FI FTW, GTFO fuse box!
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so how would i do this test with a single turbo??
Even easier...a 4''(normally) piece of plastic pipe from a plumbing store, cap, "pipe dope" or "sealant" and a valve stem secured in the cap. 20 psi is a good number to use. Make sure you have a reg. on the hose.
 

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39 Posts
I had a boost leak test done at a local turbo shop, max pressure bossted through was around 18 psi...

pretty much this test found 5 leaky tubes and hoses and discovered a worn clamp on my aftermarket intake pipe.

After installing high quality hoses and new clamps the test was ran again,

the difference is noticable....

37WHP gain on the dyno.
can certainly fell it on the road.
 

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Is it turbo? Is it stick?
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4,560 Posts
You should be able to bring pressure up to at least what your turbo boosts to, however there is one part I dont agree with from what has been said so far...

I would highly recommend disconnecting anything plumbed to the intake that doesnt normally see positive pressure. You could potentially blow out a main seal if you dont, and the 2JZs are prone to that anyway so I wouldnt want to do anything to risk it.
Anything after the turbo sees boost so thats not a concern. Just disconnect whatever lines you have running to the intake such as crankcase breather, charcoal canister, etc etc (if you have any of them) and boost away... I actually prefer to bring the boost up to the level that the car sees to do a full test, and have found leaks that dont reveal themselves until higher pressure in the past.
 

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i always say toyota !
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2,761 Posts
i think i should correct myself. it sounded like it leak through the turbo, but i think it was leaked through the motor. i blocked the hose in front of the throttle body.
 

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i always say toyota !
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2,761 Posts
i think i should correct myself. it sounded like it leak through the turbo, but i think it was leaked through the motor. i blocked the hose in front of the throttle body.
ok, i just read the whole thread today. i think what happened to me is just like what happened to people above. i think its leaking through the intake valves to the exhaust valves.

to completely check your boost leak. you need to remove unbolt your intake manifold, block the intake runners.
 

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409 Posts
The key is to have a compressor that has a storage tank for the compressed air you can set it at 10psi and it will constantly flow that amount into the intake.

Then you can listen for leaks.
 

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478 Posts
I did a leak down and boost leak test.Results were confused.I have good leak down results that at 100psi there are no leaks.
But at the boost leak test my intake valves are leaking over 18psi and i changed the valve springs with the new ones(ferrea dual).With the new springs intake valves are still leaking over 28psi.Does this mean that over 28psi of boost,the valves will take air while theyre close.Does this hurt turbo s efficiency?
I dont understand while at 100psi leak down test it doesnt leak but at the other side of valve 28psi leaks??If someone helps.

Sertan
 

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Well, this boost leak test seems like there's a lot of bs involved to me. First I was told you can do it with a regular compressor, then after I do it and it doesn't work, I'm told you need a compressor with a TANK. Then people are saying that you have to disconnect things that don't normally see positive pressure and block things off, and now people are saying the pressure leaks through the intake valve into the exhaust valve. Seems like there's a lot of bs with this test.

Also, another issue with this test is that the compressor inlet does not see positive pressure either. However, this test seals the intake pipe and then pressurizes the system from the intake pipe. This puts positive pressure on the compressor inlet, an area that normally doesn't see positive pressure. Positive pressure isn't produced by the compressor until the compressor OUTLET. Therefore, the compressor outlet is the area that should be sealed off and the system pressurized from that location. Instead, this test pressurizes the system from the compressor INLET at the intake pipe. Since the compressor doesn't normally see positive pressure at this location, my concern is that it could potentially cause damage to the compressor somehow or bearing somehow. Another thing that seems suspicious about the whole test is the fact that Toyota doesn't have a procedure for such a test. That calls into question the credibility and reliability of such a test also.
 

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Banned
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2,624 Posts
Just get a smoke machine...
 

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Premium Member
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4,432 Posts
This thread cracks me up. Its so easy to do and people are making it wayyyy more involved and a PIA then need be. Home meade boost leak tester, air compressor and some soapy water and your ears...and that is it.
 

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XECUTOR
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209 Posts
well...it was very easy for me...although my leak was right under the turbo...took me longer to assemble than find the leak. Thanks much for the thread!
 

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ex BPU'er
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5,096 Posts
Need some clarification. I have a stock intake manifold, stock charcoal canister, and egr. What should I be blocking, if I need to block anything? I'm just using a 12V pump into the intake area (removed filter) and plugged it away. However, all I can make is 8 psi. What am I missing?

Thanks,
Jeremy
 

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ex BPU'er
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5,096 Posts
You should be able to bring pressure up to at least what your turbo boosts to, however there is one part I dont agree with from what has been said so far...

I would highly recommend disconnecting anything plumbed to the intake that doesnt normally see positive pressure. You could potentially blow out a main seal if you dont, and the 2JZs are prone to that anyway so I wouldnt want to do anything to risk it.
Anything after the turbo sees boost so thats not a concern. Just disconnect whatever lines you have running to the intake such as crankcase breather, charcoal canister, etc etc (if you have any of them) and boost away... I actually prefer to bring the boost up to the level that the car sees to do a full test, and have found leaks that dont reveal themselves until higher pressure in the past.
Can anyone elaborate on what Bryan is saying regarding the blowing out the rear/front main seals (so DON'T put a cap on these)? How are we supposed to see any pressure then (if it's vented to the atmosphere)?

Thanks
 

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1,281 Posts
I have a ?. I know I have leaks out of my Accufab TB. What is the normal loss range for psi of these motors. I can't seem to even hold 5 psi for 30 seconds. With cams in the car there is going to be some loss because the motor has valves open. So I know its a simple test but what is the threshold?


Staats
 

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Spray all rubber pipes, pipe joins, manifold joins against each-other, the head etc with soapy water. This will clearly ID any leaks in you system with a mass of bubbles.

I managed to find a couple of small leaks where the two inlets manifold halves bolt together the other day with only 1psi pressure from my vacuum in 'reverse' mode. I couldn't hear them over the vacuum motor, but the soapy water doesn't lie.
 

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1002hp denim blue beast
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1,327 Posts
i've done the test on my car and i founded leaks like a ship going down! having all the right tools to do the test will make your life a lot easier also. all i have to say is thanks rsa for the write up!
 

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Raising the BAR
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3,325 Posts
Wait. How can you say its normal if you don't know if its normal and would also like to know if its normal or not?
At any given time an engine will have valves that are open and will let air escape the engine through the exhaust.
 
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