2JZ-GTE Water Flow and Pipework

Hey All,

I thought it might be worth while having a seperate technical discussion about the 2JZ-GTE water flow and pipework. We started to take another thread off course talking about it.

http://www.mkivsupra.net/vbb/showthread.php?t=181288

I am just wondering what pipework can be removed/bypassed for a track motor that doesnt have the oil cooler and heater matrix.

Looking at this pic it looks like most could be removed.

To start with I think the heater matrix feed pipe could be blocked at the back of the head and then the return pipe could be trimmed down and welded over.

In the most extreme case if you removed the coolent lines from the throttle, stock oil cooler and IAC you wouldnt need any coolent lines on the inlet side and the large return pipe on the exhaust side could be removed and blanked off.

What do you think?

Hmmm... I like your thinking... I'll have to a look tomorrow you know

I am assuming that all the engine cooling is catered for internally, so in theory you only need the rad in and out.

For single DBB setups where do people plumb the water return, I know the water feed is normally done from the top water elbow.

In the most extreme case if you removed the coolent lines from the throttle, stock oil cooler and IAC you wouldnt need any coolent lines on the inlet side and the large return pipe on the exhaust side could be removed and blanked off.

 

What do you think?

That's exactly what I have done one my engine build, only instead of blanking off the intake side I used a water pipe from an NA which doesn't go round that side of the block. Still have my heater as it's a road car. There's details of what I did on my engine build thread.

For single DBB setups where do people plumb the water return, I know the water feed is normally done from the top water elbow.

Mine goes to the port on the water pump that is used for the stock turbos - I replaced the fitting with a threaded union.

That's exactly what I have done one my engine build, only instead of blanking off the intake side I used a water pipe from an NA which doesn't go round that side of the block. Still have my heater as it's a road car. There's details of what I did on my engine build thread.

Ahh yes I remember now, the NA pipe just takes a feed back from the matrix.

Have you just blocked the feeds to the stock throttle and oil cooler?

What does the IAC use the water lines for and how would it react to not getting them?

Mine goes to the port on the water pump that is used for the stock turbos - I replaced the fitting with a threaded union.

Of course, its the very faint dotted line from the front turbo down to the pump, my setup currently has a pipe connecting the front and rear returns.

It looks like so much can be cleaned up and removed.

Ahh yes I remember now, the NA pipe just takes a feed back from the matrix.

 

Have you just blocked the feeds to the stock throttle and oil cooler?

 

What does the IAC use the water lines for and how would it react to not getting them?

I didn't need to because I have an aftermarket intake. As I understand it the coolant lines are there to stop the throttle freezing in very cold weather. Same for the idle control valve. The stock oil cooler I have removed because I have a Mocal oil cooler, that leaves a threaded feed in the block that I blocked with a NPT plug. There is a feed from the head that goes to the TB that I have just blocked for now.

I also run a seperate oil cooler so the stock cooler is not really required, looks like it could all come out.

Although not an easy job with the engine in apparently.

No, that would be a pain! Not too bad from underneath if you had a lift perhaps.

No, that would be a pain! Not too bad from underneath if you had a lift perhaps.

Do you have the gasket number for the large return pipe?

I am guessing the port on the inlet side from the block to stock oil cooler is 1/8NPT?

Do you have the gasket number for the large return pipe?

 

I am guessing the port on the inlet side from the block to stock oil cooler is 1/8NPT?

Unfortunately not, I reused my old gasket. It's not 1/8NPT, it's bigger than that, I can't actually remember the size now, it's either 1/4 or 3/8 NPT.

Would it be wise to keep the rear cylinder head take off (normally for the heater) to help keep the rear of the head a little cooler on a track car? Maybe run it around and into the rad feed or to a small cooler somewhere?

There's a better layout of the cooling system on here somewhere. A search should turn it up. Its a bit difficult to see what's what from those 3D pics.

Would it be wise to keep the rear cylinder head take off (normally for the heater) to help keep the rear of the head a little cooler on a track car? Maybe run it around and into the rad feed or to a small cooler somewhere?

thats a good point Dan and it may have something to do with balancing flow, Wez as my car never comes out when the weathers inclement (as i'm sure yours does'nt ) i cant see icing of the IAC to be a problem and mine has been off for quite some time now (along with the throttle water connection)

Would it be wise to keep the rear cylinder head take off (normally for the heater) to help keep the rear of the head a little cooler on a track car? Maybe run it around and into the rad feed or to a small cooler somewhere?

Hmmmmm, this needs looking into some more as I need to sort out all the water lines and doing away with them would certainly be the preffered way, less to go wrong.

If the Matrix supply was capped off surely the water would still flow correctly through the head, I am not great when it comes to fluid dynamics so maybe someone with a bit more knowledge could comment

Would it be wise to keep the rear cylinder head take off (normally for the heater) to help keep the rear of the head a little cooler on a track car? Maybe run it around and into the rad feed or to a small cooler somewhere?

I'm not so sure that is a good idea, based on the diagram of the flow, it enters at the back of the head, and then goes towards the front of the head on one path and out the back of the head to the matrix path. My logic for blocking off the matrix pipe has always been that it will force more water through the in-engine route and also concentrate the the flow around the head and out.

How are we going to work out whats best here, what do we need to do next?

I'm not sure...it just looked to me like it exitted the head at the back and went to the heater matrix. Hard to see from that pic and not something I've ever given much thought to.

I'm not sure...it just looked to me like it exitted the head at the back and went to the heater matrix. Hard to see from that pic and not something I've ever given much thought to.

Its not easy to see but it does show flow back through the head to the front of the engine.

Need to find the flow chart that Digsy mentioned.

This pic shows the GE head, sadly cannot find a GTE equiv diagram.

There is an older discussion here

http://www.mkivsupra.net/vbb/showthread.php?t=111270

thinking about it logically the rear heater take off out of the cylinder head can have nothing to do with cooling as it can be shut off via the heater controls, is it placed there as its the first place to recieve heat on engine start up so gives the cabin heater priority of the hot water

thinking about it logically the rear heater take off out of the cylinder head can have nothing to do with cooling as it can be shut off via the heater controls, is it placed there as its the first place to recieve heat on engine start up so gives the cabin heater priority of the hot water

With this in mind do you think its ok to block these off rather than add a pipe to the return, surely adding a pipe without a restriction would increase flow away from the head as it would become the path of less resistance.

If I understand it correctly, when the exit pipe is blocked the coolent can only flow through the head instead of around it.