2G Spyder 4g64 Hybrid Turbo

[alexr254]

The extra connections would be a coolant feed/return line for the center section of the turbo. Sometimes the thermostat has lines for the oil cooler sandwich plate too if that is of any utility to you.
if you want a nice new shiny one look here:
SS Water pipe

Yep the extra lines can surely be used. Or you can Tee off some existing lines.

But my issue was not that. It was the fact that the 4g64 coolant pipe does not align with the 4g63t thermostat housing.
And bending it to the exact angle is not something i have the tools for.
This was a surprise to me since i didnt see anything about this with the limited resources on this head swap online.

And im at a standstill because of it. Until the part comes in maybe by this weekend if im lucky, or next week.

 

[JohntyBee]

Yep the extra lines can surely be used. Or you can Tee off some existing lines.

But my issue was not that. It was the fact that the 4g64 coolant pipe does not align with the 4g63t thermostat housing.
And bending it to the exact angle is not something i have the tools for.
This was a surprise to me since i didnt see anything about this with the limited resources on this head swap online.

And im at a standstill because of it. Until the part comes in maybe by this weekend if im lucky, or next week.

You use the corresponding water pipe with whichever thermostat housing you choose. Even the factory DOHC 4G64 water pipe and thermostat housing is different than the 1G/2G 4G63 combinations

 

[alexr254]

You use the corresponding water pipe with whichever thermostat housing you choose. Even the factory DOHC 4G64 water pipe and thermostat housing is different than the 1G/2G 4G63 combinations

I suppose this is common knowledge to those with experience.
Was not common knowledge to me until now.

 

[JohntyBee]

I suppose this is common knowledge to those with experience.
Was not common knowledge to me until now.

You could also cut a section off and reconnect everything with a piece of radiator hose. I had to do that at one point because my new turbo setup was having clearance issues. I’ve since solved this by converting my cooling system with -16AN fittings but it’s not really necessary if you get the correct pipe or modify what you have

 

[alexr254]

You could also cut a section off and reconnect everything with a piece of radiator hose. I had to do that at one point because my new turbo setup was having clearance issues. I’ve since solved this by converting my cooling system with -16AN fittings but it’s not really necessary if you get the correct pipe or modify what you have

That thought did cross my mind. But I was able to find the correct pipe.
And I figured slow and steady wins the race. So instead of rushing it due to my impatience I decided to wait for the part.

 

[alexr254]

I am attempting to minimize the amount of coolant hoses scattered everywhere. To do this i decided to remove the pancake from the OFH and use a stud adapter in its place for the oil filter.
On the thermostat housing i capped off all the hose fittings except for the main hoses to the radiator.
For the turbo i decided to use the hose fittings coming out of the coolant pipe.
Also on the throttle body i did a FIAV delete, while keeping the TPS.

Does anyone see any issues with me doing it this way?

Here are some pics.

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[99dsmer4g63]

The port beside the radiator cap is for the expansion tank, you seem to have it blocked off.

Make sure they are coolant rated caps and not just vacuum caps.

-Daniel

 

[alexr254]

The port beside the radiator cap is for the expansion tank, you seem to have it blocked off.

Make sure they are coolant rated caps and not just vacuum caps.

-Daniel

Thanks!
I definitely missed that one.
Yes they are coolant rated caps as far as i am aware. I will double check that.

 

[19Eclipse90]

I’m not real sure you’re going to see a tremendous amount of coolant flow through the turbo doing it that way. The port you want to use for the coolant feed to the turbo is originally the return on a 2G. You’d be feeding from the water pipe and trying to return to the water pipe. The pressure differential is going to be minimal from point A to point B and flow requires a pressure differential, else the fluid is stagnant. Maybe it works well enough since you’re returning close to the pump at the original oil cooler return but it’s not something I would do or suggest.

When 2G guys don’t want to run the water cooled oil filter housing, they generally would plug or weld the ports on the water pipe closed, loop them, or switch to a 1G water pipe and thermostat housing.

When 2G guys don’t want to run water to their turbos, they generally would plug or weld the port on the water pipe closed and plug the block feed port, loop the lines, or switch to a 1G water pipe and thermostat housing.

Welding ports closed is great but not everyone is a great welder and it’s not easily reversible.

Capping or looping lines is fine but you still leave potential leak points anywhere you have a hose.

The benefit of the 1G thermostats housing and water pipe is that there’s 3 variations that can be used to suit whatever you want to do and they all bolt up in a 2G without making a fuss:
Non-turbo - no provisions to feed or return coolant for either the turbo or oil filter housing
1990 turbo - provisions to feed and return coolant for the turbo but no provisions for the oil filter housing
1991-1994 turbo - provisions for both fees and return of coolant to both the turbo and oil filter housing.

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If the 4G64 pipe was usable with the 2G 4G63 thermostat housing, we would have known a long time ago and 2G guys wouldn’t have as much of a reason to swap to 1G components. Supposedly there is a pipe used in European non-turbo 2Gs that would work to eliminate both, but I’ve never seen one to verify.

My suggestion would be using a 1G thermostat housing and water pipe that suits you and work to eliminate as many of the lines and potential leak points as possible.

 

[alexr254]

I’m not real sure you’re going to see a tremendous amount of coolant flow through the turbo doing it that way. The port you want to use for the coolant feed to the turbo is originally the return on a 2G. You’d be feeding from the water pipe and trying to return to the water pipe. The pressure differential is going to be minimal from point A to point B and flow requires a pressure differential, else the fluid is stagnant. Maybe it works well enough since you’re returning close to the pump at the original oil cooler return but it’s not something I would do or suggest.

What would be the symptoms of not enough coolant flow?
Besides overheating ofc.

I can try it like i suggested, then if i see any lack of cooland flow symptons i can change it to how you suggest and at the same time post the results here.

When 2G guys don’t want to run the water cooled oil filter housing, they generally would plug or weld the ports on the water pipe closed, loop them, or switch to a 1G water pipe and thermostat housing.

When 2G guys don’t want to run water to their turbos, they generally would plug or weld the port on the water pipe closed and plug the block feed port, loop the lines, or switch to a 1G water pipe and thermostat housing.

Welding ports closed is great but not everyone is a great welder and it’s easily reversible.

Capping or looping lines is fine but you still leave potential leak points anywhere you have a hose.

I know what you mean by what 2G guys normally do.
I am water cooling the turbo, didnt even consider not to.
However when it comes to the OFH, i really dont think its needed for my use case. And I have also read the pancake is prone to failing, it can start making a milkshake of oil and coolant.

But to be honest, nothing i am doing is normal. I am trying to use some logic and common sense to try some things that may or may not work. But one thing i dont do is just do what others normally do without first understanding why exactly and knowing alternatives dont work or can cause damage.

If the 4G64 pipe was usable with the 2G 4G63 thermostat housing, we would have known a long time ago and 2G guys wouldn’t have as much of a reason to swap to 1G components. Supposedly there is a pipe used in European non-turbo 2Gs that would work to eliminate both, but I’ve never seen one to verify.

My suggestion would be using a 1G thermostat housing and water pipe that sits you and truly eliminating as many of the lines and potential leak points as possible.

I totally understand those with experience would have known. However its not something easily known to those without experience and for those without both engines/parts in front of them. And its not in any online resources i could find.
If i had both in front of me to compare of course i would see the difference. Unfortunately i am working with only one car and one engine, and its a 4g64.

I already went with the 2G 4g63 thermostat housing, not gonna change it unless i run into some serious issues.

 

[alexr254]

I’m not real sure you’re going to see a tremendous amount of coolant flow through the turbo doing it that way. The port you want to use for the coolant feed to the turbo is originally the return on a 2G. You’d be feeding from the water pipe and trying to return to the water pipe. The pressure differential is going to be minimal from point A to point B and flow requires a pressure differential, else the fluid is stagnant. Maybe it works well enough since you’re returning close to the pump at the original oil cooler return but it’s not something I would do or suggest.

From what i saw and researched the turbo coolant feed is typically from a feed right under the pipe, straight from the block (its capped on my block). And the turbo coolant return is the same i am using.
I figured the feed i decided to use was originally for the OFH coolant and should be sufficient for the turbo coolant feed. Its very close to the water pump and should have a good amount of pressure.

Source:

1G Water Pipe/Thermostat Housing on a 2G

This is one of my favorite mods to do when I first get a 2G with an original…

eatsleepdsmmag.com

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[19Eclipse90]

My main concern is, assuming worst case scenario of no flow through the turbo, the coolant that sits there will get super heated and will stay extremely hot after shut off which will provide a great environment for the oil in the turbo to super heat and coke in the turbo itself. It may not happen, but that’s my worry.

The oil cooler feeds from the thermostat housing and returns to the water pipe. I agree it’s not likely needed for you so that’s not really my worry. If you’re trying to reduce as many lines as possible and have solid plugs rather than caps, a 1G setup is still what I would recommend if for nothing other than it makes everything so much easier and cleaner.

 

[alexr254]

My main concern is, assuming worst case scenario of no flow through the turbo, the coolant that sits there will get super heated and will stay extremely hot after shut off which will provide a great environment for the oil in the turbo to super heat and coke in the turbo itself. It may not happen, but that’s my worry.

The oil cooler feeds from the thermostat housing and returns to the water pipe. I agree it’s not likely needed for you so that’s not really my worry. If you’re trying to reduce as many lines as possible and have solid plugs rather than caps, a 1G setup is still what I would recommend if for nothing other than it makes everything so much easier and cleaner.

Is this information on this website completely off and misleading?

1G Water Pipe/Thermostat Housing on a 2G

This is one of my favorite mods to do when I first get a 2G with an original…

eatsleepdsmmag.com

Thats the gotcha with this entire thing. There is so much misinformation out there its incredibly hard to discern whats correct without actually having the original engine in front of you.
I have a couple service manual books and they have not helped me very much.

What are normal running temps for a MHI EVO III 16G turbo?
I can monitor it with a temp gun after i fire it up.

 

[19Eclipse90]

A quick skim through, I’m not seeing anything incorrect on that page. But I also am not getting all the pictures to load. Care to grab a snippet of exactly what you’re referring to?

This post shows everything correctly: 2G Turbo Coolant Return Banjo Bolt

Can’t speak to operating temps of the turbo. I am not running coolant at all to my Evo III 16G. And have been for ?4-5? years. It’s the coolant retaining heat preventing the oil from being able to cool that worries me.

 

[alexr254]

A quick skim through, I’m not seeing anything incorrect on that page. But I also am not getting all the pictures to load. Care to grab a snippet of exactly what you’re referring to?

This post shows everything correctly: 2G Turbo Coolant Return Banjo Bolt

Can’t speak to operating temps of the turbo. I am not running coolant at all to my Evo III 16G. And have been for ?4-5? years. It’s the coolant retaining heat preventing the oil from being able to cool that worries me.

I see what you mean. Like a closed loop.
Ill definitely keep an eye out for overheating. And if anyting seems odd, ill redo the cooling tubing.

I was mainly refering to this pic where it shows the turbo cooling feed coming from the block right below the coolant pipe, and the turbo coolant return in the same place im using it for the coolant return.
Based on this pic the only difference for me is the feed, which is coming from closer to the water pump, so would suggest it will get even better water pressure.
Unless i am totally misunderstanding the flow direction.

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[19Eclipse90]

Yeah, coolant flows the other direction. Water pump pulls coolant from the water pipe and pushes coolant into the block. Block into the head. Head to the thermostat housing. Thermostat housing to the water pipe or looping via the radiator back to the thermostat housing and then water pipe.

 

[alexr254]

Yeah, coolant flows the other direction. Water pump pulls coolant from the water pipe and pushes coolant into the block. Block into the head. Head to the thermostat housing. Thermostat housing to the water pipe or looping via the radiator back to the thermostat housing and then water pipe.

Thanks! This is the crucial part i was wrong about.
Based on this, yes the return is before the feed -- not good.
I'll need to see what i can do, without needing to take the entire exhaust manifold off.

I can swap them easily.

Or if it comes to it, i can take the plug out the block and use the factory feed.

Thank you for bringing this to my attention!

 

[19Eclipse90]

No worries. Although it may not always seem like it, I am trying to help make it a little easier for you.

 

[alexr254]

Yep. And although it may not always seem like it, i do always really appreciate any advice given.
I know i can come off like someone who is very stubborn.
I promise its not that. I just really try my hardest to understand and i dont always get it right away.

I will be redoing the turbo coolant feeds tomorrow.
But i will continue to not water cool the OFH... For now.

 

[alexr254]

The benefit of the 1G thermostats housing and water pipe is that there’s 3 variations that can be used to suit whatever you want to do and they all bolt up in a 2G without making a fuss:
Non-turbo - no provisions to feed or return coolant for either the turbo or oil filter housing
1990 turbo - provisions to feed and return coolant for the turbo but no provisions for the oil filter housing
1991-1994 turbo - provisions for both fees and return of coolant to both the turbo and oil filter housing.

I also just wanted to comment on this part.
You list the benifits, which are all great. And all make complete sense and i agree with fully.
The huge problem though is availability. And this is true for almost anything 1g or 2g now. Its getting worse and worse.

I have the 1g thermostat housing, but finding a 1g pipe with the configuration i want - Nearly impossible
It takes alot of patience, good timing, and a fair amount of luck. Either that or a endless supply of money.
All of which i admittedly dont have.

 

[August578]

I used the timing belt idler pulley from a WRX EJ engine for my 2.4 swap. It is half sized and allows you to use a 4g63 belt instead of searching for a 4g64 belt. My engine has a performance 4g63 belt and a 2.4 swap ( blue belt as seen in my pictures). It fits like a glove and NO need for putting the timing off 1/2 tooth. I will have to reply later with the exact part #.


Consider the 68hta. I've previously installed the 20g on my 2.4 swap, (stock cams) and I started boost around 3100rpm. Very Fun for the street. I've just had the 68hta installed. Not tuned yet, don't have numbers.

I'm also doing the 4g64 head swap sometime some and was wondering if this is true ^ and if anyone else has anymore information on it.

So in theory if I run the EJ idler its a basically a plug and play head besides the ports that need to be blocked off?

Just want to double check and fact check this, because this sounds almost too good to be true!

 

[alexr254]

I'm also doing the 4g64 head swap sometime some and was wondering if this is true ^ and if anyone else has anymore information on it.

So in theory if I run the EJ idler its a basically a plug and play head besides the ports that need to be blocked off?

Just want to double check and fact check this, because this sounds almost too good to be true!

Far from plug and play.
If you read through the last few pages of this thread you will see some complications I ran into.
For the head swap you require parts that fit that head. Like the intake manifold, coil pack, etc.

 

[alexr254]

My main concern is, assuming worst case scenario of no flow through the turbo, the coolant that sits there will get super heated and will stay extremely hot after shut off which will provide a great environment for the oil in the turbo to super heat and coke in the turbo itself. It may not happen, but that’s my worry.

The oil cooler feeds from the thermostat housing and returns to the water pipe. I agree it’s not likely needed for you so that’s not really my worry. If you’re trying to reduce as many lines as possible and have solid plugs rather than caps, a 1G setup is still what I would recommend if for nothing other than it makes everything so much easier and cleaner.

I was thinking about this a bit more, on a fresh head.
From what i understand on the 16G it does not matter which port is coolant in or coolant out, as long as coolant flows through it.
That being the case, i dont see how it would be an issue with the setup ive proposed. It would not be causing any mini closed loop.

It would be near the thermostat housing and out would be near the water pump.

 

[alexr254]

Can anyone help me with a diagram of where are the vacuum lines go?

Im specifically confused about the cold air intake. It seems to have 3 vacum line connections, plus the hose connection for the BOV.
Where do those 3 vacuum lines go?
Also there is a small vacuum line on the wastegate, where does this go?

 

[19Eclipse90]

I was thinking about this a bit more, on a fresh head.
From what i understand on the 16G it does not matter which port is coolant in or coolant out, as long as coolant flows through it.
That being the case, i dont see how it would be an issue with the setup ive proposed. It would not be causing any mini closed loop.It would be near the thermostat housing and out would be near the water pump.

It’s possible, and I do understand your outlook here.

As I don’t have a 2G water pipe handy at the moment, what does that nipple nearer the thermostat housing look like inside the water pipe? Like, at what angle is it joining with the normal curvature / flow of the water pipe? If the port is angled facing downstream (in the direction of flow towards the water pump), I wouldn’t expect flow to happen.

Can anyone help me with a diagram of where are the vacuum lines go?Im specifically confused about the cold air intake. It seems to have 3 vacum line connections, plus the hose connection for the BOV.
Where do those 3 vacuum lines go?
Also there is a small vacuum line on the wastegate, where does this go?

Aside from the recirculation connection for the BOV, there is one from the valve cover breather, one for the emissions system (purge control valve, cap if emissions have been deleted), and one for a port on the waste gate / boost control solenoid.

The small vacuum line on the wastegate goes to a boost controller or, in case of no boost controller, a port on the J-pipe or somewhere close right after the compressor.

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