Turbo Question I am stumped.

[subie22]

Ok well i am stumped. Ok well i put the new jpipe on my car, but know its seems like i may have a leak, but then i noticed on my compressor housing, there seems to be a threaded hole on the compressor housing. Not rele sure what its for but it seems like it would be used as a pressure source. And its at the top where the compressor meets the jpipe. I was wondering if anyone knows what this is, or is it actually a boost source, looks like it would tread in a nipple.

 

[synthetek]

Some turbos have a hole in the compressor housing as a boost source for the WG actuator. What kind of turbo is it?

 

[subie22]

its a big 16g MHI. I am trying to post up a pic but putfile is making me wait 15mins....

 

[tristanmb81]

You could put a barb fitting into that whole and use it as a WG source. I'm not sure what the thread size it is, but I'm sure if you search in here you'll find it.

 

[subie22]

I really dont want it as a pressure source, i would also like to know whats the thread pitch so i can put a bolt in there, so it wont cause a boost leak.

 

[romeen]

As far as I know none of the MHI 16G turbos came from the factory with a pressure source off of the compressor housing.

Did you buy the turbo used? It may have been custom modified.

I would reconsider using that as your boost/pressure source as it will give the most reliable and consistent results as well as minimizing any chance of boost spike. Also, short of welding the hole shut this will also minimize the risk of developing a leak there after it has been fixed.

Since I don't think that it came from the factory that way I cannot take a guess as to the size. But you may want to try a 1/8 NPT barbed fitting. As long as it seems somewhat snug, you can then apply some JB Weld or JB Kwik around the base of the fitting to further help stabilize it and also to seal it against leaks. If you do this consider cutting or grinding down the threaded portion so that not too much of it sticks out into the inside of the compressor housing.

 

[subie22]

I dont want to use it to control boost. I just want to block it off. I guess it would cause a boost leak, Can i just put some rtv in the hole so, i dont have to hunt down a bolt to put in there.

 

[Eagle18g]

thats a good call as long as your turbo is working well and you already have the vac lines hooked up to the proper place. RTV might blow out of the hole under high boost.

 

[romeen]

I dont want to use it to control boost. I just want to block it off. I guess it would cause a boost leak, Can i just put some rtv in the hole so, i dont have to hunt down a bolt to put in there.

I don't think that RTV silicone will work very well at all for filling a hole that will be exposed to air pressure.

The bolt is your best bet. Once you get the bolt in I would still recommend putting either some JB Kwik around the bolt or using a washer with a dab of RTV under it to help things seal. You may even want to put a very small amount of RTV on the bolt threads. Remember to use the shortest bolt that will get the job done so that not too much of it protrudes to the inside of the compressor housing.

 

[subie22]

so does anyone knoiw the bolt thread pitch and such, i used rtv to seal the jpipe to the compressor housing. Since i didnt have a gasket for it. Or what bout just cover the hole with jb weld, i dont plan on using it. Also if i knew that was there for the pressure source i wouldnt off even drilled and tapped my jpipe for the pressure source. I never even relized and i dont know if most people relize it. I never even came across any info on it.

 

[turbosax2]

Since the turbo probably didn't come with the hole in it from the factory, whoever tapped the hole could have used any size tap they wanted. You're going to have to guess and check until you find a proper plug for the hole. Like romeen already said, first try a 1/8 NPT plug and see if it works.

The other option is to use the hole on the turbo for your pressure source and block off the hole on your j-pipe instead. Either way works, it's up to you.

 

[erald01]

If this is what you talking about there should be no leak out of it

<a href="http://tinypic.com" target="_blank"><img src="http://i13.tinypic.com/89kzzmq.jpg" border="0" alt="Image and video hosting by TinyPic"></a>

 

[subie22]

well theres deff some air comming out of it. Not much but some.

 

[romeen]

I don't think that was intended to be a location to tap for a pressure source. Are you sure it's not leaking at the j-pipe flange right above that location making you think it might be from the hole?



I got curious so I went out and checked my EVO III compressor housing. That hole is tapped for an M6 x 1.00 bolt. Hope this helps you out.

 

[zero97tsi]

Yah, that hole is not for teh air. It's a mounting hole.

 

[ktmrider]

I'm pretty sure it's a pressure source for a WG hookup. The Garrett and Subaru IHI models I used previously had this as the primary WG signal port.
Advantages to this port are like stated, less chance for boost spike. Downside is when using it without some type of BCS as the pressure at the inlet is always lower than the manifold due to loss from the IC, flex hoses, etc.
I remember it being 1/4 NPT but had the barb with me at the store when I bought a brass plug. I then coated it with pipe sealer ( not tape in case some got into the intake ) and never had issues.

 

[erald01]

If you want to be sure just call one of the vendors and ask them about it im sure they have the answer.

 

[synthetek]

If its the same hole as in the picture air should not be coming out of it unless someone drilled it. I have a 16g and it has the same hole and no air comes out, I would double check the j pipe flange for leaks.

 

[snohacking]

thats to mount up the oil feed line!!!

 

[Calan]

Yep... that hole in the pic is for a "P" clamp for the oil/water lines.

If it is leaking air (and the turbo is used), my bet is that someone used too long of a bolt and punched through and into the comp housing.

So the obvious next point would be... don't block it off. Use it as intended to clamp your lines, but use a little high temp copper RTV on the bolt threads (close to the bolt head to keep it out of the turbo).

Or really do it right and have it tig'ed and re-drilled/tapped.

 

[subie22]

The people who are saying its for the oil and water lines you may have something. But since my turbo was put in by a shope who it seems like they know somewhat on what they are doing. I dont think its for oil/water lines, that makes absolutely no sense. Since my car has those lines hooked up already. So the person who said that we are retards, cmon do dude, you just started on this forum, i would calm yourself down a lil bit. I am still stumped theres very very little air that comes out of that hole. So I dont know. I just hear a lil bit of air comming out of it. But people have to chill with there disrespecful comments.

 

[synthetek]

He didn't mean a water or oil line actually goes in that hole its for a P clamp to bolt in to hold the line from moving around.

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