I done a quick boost leak check on the car today and I found a couple of leaks

The one I had a feeling was gonna be there was around where the turbo compressor housing bolts to the core as shown here



I had a 90 bend welded to the comp housing after the engine dyno so this is a new issue, it's warped the housing and when I re fitted it I had to rub it down a bit to get it to seat properly so I knew the chances were it was gonna be an issue,

I may be able to get this re faced in a lathe to sort this but time will tell,



The second spot was from around the TPS where it seats on the theottle body shown here



I can't see there is anything that can be done about this 1 though? This has not been changed so this would of been present during mapping on the engine dyno

Any 1 else had this issue or will the tps 1 be minor and not really an issue?

I pressurised the system to 2 bar and it drops straight away!

Thanks
Marc

 

I doubt they'd be an issue as the volume of air flowing vs the volume lost will be insignificant unless there are majour leaks....imo

 

Odd the housing warped. I've welded quite a few, and I'm a terrible welder and never had one warp

Some housings use a thin gasket, some a thin o-ring, but many use nothing at all. So unless the leak is huge I wouldnt worry too much, maybe use some sealer on it if you're really concerned.

As for the TPS, again it would be very small. You could maybe look into some sealed bearings for the spindle or something. Other than that it will be a difficult leak to totally resolve.

 

Thing is though surely I need to sort the comp housing leak best I can as the system should hold some pressure at least for a small period of time?

 

Exactly how are you testing ?

 

The system will never actually hold pressure Marc, it's not like a cooling system.


As long as the system can sustain pressure without massive loss then that's fine.

 

The engine will always leak of pressure. If you want to test the comp housing pressure into the turbo air inlet and blank of either the turbo outlet or the intercooler to inlet pipe and test the intercooler for leaks while your there.

 

This is how I tested but still doesn't hold on the gauge!



Am I doing something wrong?

 

So you have air leaking past the throttle, idle valve, inlet valves, cylinders, exhaust valves, piston rings......

As well as the small leak you're spraying water near.

edit...just seen the TB end is also capped.

It's still a small leak, and the turbo is producing a constant supply or air, it isnt pumping and then stopping

By all means try and fix any leaks, but dont be overly concerned about small ones

Your compressor via that small hose on the tyre inflator can maintain pressure ok when you have it open.

Your turbo will be flowing hundreds of times more than what the tyre inflator can achieve.

 

Hi mate

That is basically what i wanted somebody to confirm, that the system leaking air like this is normal which you have done so thats good enough for me

Thanks
Marc

 

hi marc
did you preheat housing when welding or bolt to flat surface ,if it has warped i would be concerned about clearance with impeller as well as it leaking marc ,prob best sent to vince to remachine
mark

 

As far as I know it was pre heated etc and there is no problem with impeller clearance, the car has been up and running quite a few times now and there is absolutely no contact with the housing at all so im not worried about that

 

I've welded and never pre-heated and not had issues.

I guess a question you need to ask....did you do the same test for leaks before welding ?

Obviously yes we would strive for no leaks, but small ones like tha just arent worth worrying about.

Some compressor covers just bolt up dry, no seal, no gasket and some arent even a super tight fit. So clearly the manufacturer isnt overly worried about how they seal either..

You could apply some sealer, but it would make taking it apart a ballix.

 

Leaks on the front side of the throttle will just mean the turbo has to work a little harder to fill the plenum with the desired boost level, as long as the leaks are not big it wont really make much difference.
Leaks behind the throttle are the ones that can cause you running issues, as they will change the manifold depression if the leaks get bigger or get fixed, so its important to ensure the inlet is air tight before its mapped, then keep it that way and things shouldn't change.


Sometimes compressor housings leaks will cure themselves once the turbo has had a good few heat cycles through it,

 

And no doubt after a little corrosion builds up...especially after squirting all that water there lol

 

Housing has been on and off since then so water all gone lol but gets soaked through vents when cars washed anyway

There no issues on plenum side as that has not changed since dyno and no issues then

It's a learning curve in a way as I thought the system was air tight and did t realise small leaks were normal so good to know and that's the end of that for me, it can stay how it is

Thanks for all the info

Marc