What size fitting for the oil-line to the turbo?

[pjo046]

I am wondering what size fitting I need to couple the oil-feed line to the turbo to the outtake from the block. (What thread size is it on the piece that goes into the block and that the oil-pressure sender mounts to)

 

Also, I need to know how to hook up the coolant lines to the turbo

[ktm]

1/8" BSPT. However, I recommend doing a search on Oil Restrictor and reading a few threads there. In one of them, a poster references a setup that uses a 1/8" BSPT to 1/8" NPT adapter, then a 3 port 1/8" NPT block. From the block you can run the oil pressure sender, a 1/8" NPT to -4 AN or -3 AN fitting, and an oil restrictor (if you so choose).

 

The oil inlet feed is M12x1.5.

[pjo046]

I know I was told earlier that I should buy 1/8 NPT, so that's what I bought from ATP-turbo. But as one can see on this photo: http://album.hybridz.org/showphoto.php?photo=14198&size=big&cat=recent&limit=recent

That fitting is too small. I tried with a 1/4 NPT plug I had, and that was almost the right size, except the threads were to big. So I don't think 1/8 BSPT can be right? Anyone else knows what size fitting I need here?

 

Also, I need to hook up the coolant lines for the turbo. One I am going to couple onto the thermostat housing, as you can see on this photo:

http://album.hybridz.org/showphoto.php?photo=14199&size=big&limit=recent

 

Should I couple the other line onto the cooling-outlet on the head(The one covered up):

http://album.hybridz.org/showphoto.php?photo=14196&size=big&limit=recent

 

Or onto the small threaded outlet on the water neck?

http://album.hybridz.org/showphoto.php?photo=14197&size=big&limit=recent

 

And what size fittings are needed for the different locations?

 

 

I am not going to have the coolant lines from the engine going into the cockpit, as I won't install the heat exchanger etc in the car.

[ktm]

1/8 BSPT. The following threads provide great information on the oil feed line.

 

http://forums.hybridz.org/showthread.php?t=120784

 

http://forums.hybridz.org/showthread.php?t=104828&highlight=oil+restrictor See post #2 on this link.

 

http://forums.hybridz.org/showthread.php?t=94245&highlight=oil+restrictor

 

As for the cooling, you can run it to where ever you like. Ideally, you would tap into the hose leading from the radiator to the t-stat upper housing, by-passing the thermostat. The feed line would come from a source before the coolant enters the block. That way you are not feeding the turbo heated coolant.

[pjo046]

Hmmm.. From what I can gather from the links, they talk about the threads in the BLOCK being 1/8 BSPT. I am wondering about the size of the top plug in the factory turbo "T". 1/8 inch is the diameter of the plug right? NPT and BSPT is the thread size. But an 1/8 inch fitting has too small of a diameter to fit in the turbo tee, it just sits there losely. It looked like 1/4 inch diameter is correct, from a 1/4 NPT to 6AN adapter I have. But the threading was wrong.

 

Do you know what size the fitting going into the water outlet neck or the head outlet is?

[steveosupremeo]

how long of a braided line do you generally need?

[pjo046]

I'll check the length needed when I get home today.

 

Does anyone have an answer as for which size fittings I need for the various inlets/outlets?

[Tony D]

As for the cooling, you can run it to where ever you like. Ideally, you would tap into the hose leading from the radiator to the t-stat upper housing, by-passing the thermostat. The feed line would come from a source before the coolant enters the block. That way you are not feeding the turbo heated coolant.

 

 

Ohhhhh! I couldn't disagree more! You want to take that coolant from the LOWER thermostat housing so it has motive force provided by the water pump. From there the most common routing is to the turbo and then back to the inlet of the engine using the turbo coolant line as the ersatz bypass hose. Even with a 10mm hose there, the recirculation will not hurt cooling, and will actually help the engine warm up faster than using the standard bypass hose configuration which is 8mm I believe.

 

If you take it from the lower radiator hose, and return it to the upper T-Stat housing there is no motive force, nor any pressure differential to work from and the flow will be stagnant. The ONLY flow through the line would be as coolant in the leg is heated and is moved upwards towards the upper housing (thermal siphon)---that scenario is not a functional coolant circuit.

 

If you have a secondary pump to move it, fine, but it won't work the way it was described.

 

You can also (if your block has the provision for it) plumb off the lower side of the block, below the #5/6 cylinder area. This gives you much cooler water from the bottom of the coolant passages, and under pressure from the water pump---but you will still want to return it to the pump inlet. This lower hole is not in all blocks, but it makes some of the plumbing easier as you aren't putting hoses on top of the manifold.

 

You can also use the original bypass lines to do the cooling, the circuit that formerly heated the Cold Start Aux Air Valve, throttle body, etc is the fitting on the thermostat you want to use---if you don't have those other components, then you were simply adding the bypass line anyway, just loop the old taps to the turbo and back to the inlet on the bypass hose line that comes in the top of the water inlet in conjunction with the heater hose from the cold side of the heater core.

 

Take a look at the hose routing on the 87-89 VG30ET (those that came with the water-cooled turbo) for a good example of how the OEM routed the turbo coolant lines.

[pjo046]

Sorry for falling totally off here. Obviously too long sentences and too much english too late at night. Hehe.

 

There is only ONE thermostat housing, isn't it? As you are talking about the upper and lower. Or do you just mean the lower part of the T-housing, thus were I have already put one end of the puzzle so far? Is "the top of the water inlet" you are talking about the same as where the lower radiator hose goes?

 

As I have long ago ditched the circuit for the cold start aux air valve etc, I will need new fittings, and I will be using a -6AN line for the turbo cooling. So what size adapter fitting will I need that goes into the threaded part of the lower water inlet neck on the engine? And as I am not using the heater core in the car, must I have a coolant line that goes from here to the inlet on the head as well? If soo a T-piece will be needed, with one outlet for the turbo cooling and one that goes to the head inlet.

 

Any ideas on which size the oil-fitting I am talking about must be? I need a male -3AN to (I don't know what) adapter that connects my -3AN oil supply line to the stock 280ZXT T-piece that goes into the block and which the oil pressure sender mounts to.

 

Ah, this is so confusing. Had only english been my primary language.

[Tony D]

The upper and lower T-Stat housings; the portion that covers the thermostat is the 'upper' and has the connection for the upper Radiator Hose. The lower T-Stat housing holds the thermostat in a small recess, bolts to the head, holds all your sensors and has all the connections for bypass hoses and auxillary heating coming from it.

So yes, we are talking about the lower portion of the T-Stat Housing.

 

The other connection is where your lower radiator hose connects to the front cover---the water inlet fitting if you will. It contains a connector for the lower radiator hose, the return from the heater core (15mm), and the bypass circuit return (8 or 10mm depending I think).

 

-6 is more than enough flow to supply the turbo with water, restrict it to no more than 5 to 8 mm at the WATER INLET END so you have pressure built up in the circuit to prevent flash boiling, same as in the head. So to run the circuit, run your -6 hose from the lower t-stat housing (or the lower fitting on the block under cylinder #5 & 6 if you have it), to the turbo, from the turbo to the water inlet fitting on the front cover of the engine---run it in the bypass hose fitting----sometimes it is an integral diecast piece, other times this fitting is a steel tube welded cojoined with the heater return fitting.

 

I HAVE seen some people without a heater use the heater connections on the back of the head and at the water inlet---but I think it's too hot there---the water at the lower thermostat housing is actually cooler. And ideally if you have a block with the tap on the lower portion of the block, you will get FAR cooler water from there to supply your turbo.

 

Restricting the flow at the inlet will insure you only get the flow you need to cool the turbo, and not a freeflow closed circuit.

 

If you are not running a core in the car, you may simply block those openings---do not connect the head to the inlet---that through a 15mm hose will definately cause overheating issues when it gets hot (does it get hot in Norway?).

 

If you don't have the 15mm line from the heater, connecting your turbo line to the inlet there is probably the esaiest.

[ktm]

Tony, I was looking to plumb the line while providing, as you mentioned, motive force, but without impacting the thermostat. If the T-stat is not open, you will not move water. Attaching the inlet/oulet to the lower t-stat housing makes it dependent on the operation of the t-stat. Secondly, wouldn't the additional heat from the turbo affect your temperature readings, and subsequently electric fan operation.

 

By placing the connection at the hose from the upper T-stat housing, by-passing the t-stat, you can supply coolant to the turbo. You mentioned lower coolant hose. I was not mentioning the lower coolant hose, rather the upper hose. The turbo inlet would be fed after the pump.

 

I saw in another thread where you mentioned the return is the lower radiator hose....why? You are completely by-passing the radiator at that point, are you not?

[Tony D]

Nope, you have it backwards!

 

When the thermostat is closed, the motive force comes from the water pump.

 

When the thermostat is open, the motive force comes from a function of the water pump's pressure, and the differential from the lower radiator hose. This is the ONLY practical way to do it, and si how the circuit is designed in the OEM application. The car needs a bypass line anyway, why not use it for cooling the turbo as well.

 

If you take the source from the upper thermostat housing, you get NO FLOW. The only way to do it without a supplemental pump is to take it from a place where the water pressure is raised by action of the water pump. The only practical places on the engine to do this is the lower thermostat housing (llike OEM), the lower plug on the block between #5&6 cylinder bores (if you have it---and probably the best place considering the temperature there), or the heater connection on the head below #6 (probably the worst place to take it because it's the hottest place on the engine).

 

Yes, you are bypassing the radiator, there is no way to do it elsewise without serious modifications and reengineering of the coolant flow system. The engine is designed for a bypass hose from the lower thermostat housing circulating uncooled hot fluid back to the inlet in the basic design of the engine, the easiest and most trouble proof way to accomplish the objective is to use THAT circuit to do the cooling.

 

Like I said, check out the later models Z31's, and how they route the coolant lines for the turbo on the bypass loop. They are not taking it off the pump before the engine, they take it off the engine, towards the end of the cooling loop, and simply recirculate it. Easiest way to do it, and provides the POST COOLING requirement nicely through a thermal siphon action from the lower radiator hose through the turbo and to the HIGH POINT on the engine when the engine is not running---and THAT is when you want coolant flowing.

 

During engine operation flow is flow, but after shutdown having a circuit that functions from a cool place to a high point where steam bubbles formed in the turbo after shutdown can rise and be dissipated---and my discribed circuit functions in that way. As does the OEM setup.

 

It does nothing for electric fan operation nor temperature readings...not any more than the OEM stock Bypass Line does anynway. That is a moot point.

 

This does not impact the thermostat in any way. The bypass line is there from the factory, all you are doing is letting it perform another function. JeffP reports that his engine seems to warm up quicker after installing the line as it allows more internal recirculation before the thermostat opens...quicker warm-ups, that's a good thing, no?

[pjo046]

Actually, the inlet neck on my engine only has the outlet for the heater and for the lower radiator hose. Not that third small one you talk about. So, is that a 15NPT fitting that is needed there then? As for my block, it is an F54 block, so I do have the lower plug on the block. If I use this as inlet for the circuit, then I'll need a restrictor there? Or maybe the transition to -6AN is restriction enough? Any idea of what fitting I'll need for the block plug opening?

 

Any ideas on the oil-fitting for the original T I am talking about?

[pjo046]

Nevermind about that block plug I was talking about. It's not the one between cylinder number 5 and 6. I don't have a plug there. I only have the one far to the right, which is for flushing through the coolant passages I think.

[ktm]

Thanks Tony.

[Tony D]

http://www.cardomain.com/ride/735451/4

 

Hopefully this is the correct link to show the BYPASS LEG I am talking about, it's off my Cardomain Page, and I forgot it was there all this time---DUH! This came up before, so I went out and shot it, then posted it there---these at the supply line and return line I am talking about---this should make it all clear for everyone.

 

Tony D

[pjo046]

Forgive my incompetence, but:

When you measure the diameter for a bolt, is that the hole-diameter, or the bolt diameter(which is wider because of the threads)?

[Tony D]

"Root Diameter" not the "Pitch Diameter"

 

Translated:

 

"Pitch Diameter" is the outermost portion of the threads.

 

"Root Diameter" is technically the valley of the threads, and should be close to the 'size' of the bolt. The "Shank" of the bolt---that is the portion of the bolt from the threads to the head---may or may not be the 'size' due to different design parameters. Sometimes it's larger, sometimes the same, sometimes (like in Aircraft Fasteners and Studs) it is quite a bit less.

 

One day, I will get 'the bill' to you Paul. Still working on Taxes! >:^( Getting closer though! :^)