Turbo systems for X1/9's

[Dr.Jeff]

Blowing air from the outside may help in terms of bay heat management, but it won't do anything for turbo longevity.

Agreed, they are two different things but also related. My primary goal with the fan 'after run' is for engine bay thermal management. But reducing heat from the external area around the turbo will help to cool it more rapidly as well. So that will supplement the water cooling of the turbo, which is the primary means of preventing oil coking.

I've tried to mimic the UT's water path for the turbo. But I'm installing it on the X's SOHC which does not have all of the same water ports for the turbo that the UT has. So my arrangement is a bit different. Hopefully it will still work the same. The water source for the turbo feed is the X's original 'heater' water supply off the head. That is much higher than on the UT, where the block has a special port down low close to the oil pan, but it is still the same general (warm) water supply. The water return from the turbo goes to the upper coolant tank fitting (there are now two such fittings on my tank), like on the UT. And the coolant tank is being mounted in the trunk, so higher up than the original location, and higher than the inlet source. Therefore it should still be a cooler and higher location, which I think is the goal. Sound right?

 

[lookforjoe]

Agreed, they are two different things but also related. My primary goal with the fan 'after run' is for engine bay thermal management. But reducing heat from the external area around the turbo will help to cool it more rapidly as well. So that will supplement the water cooling of the turbo, which is the primary means of preventing oil coking.

I've tried to mimic the UT's water path for the turbo. But I'm installing it on the X's SOHC which does not have all of the same water ports for the turbo that the UT has. So my arrangement is a bit different. Hopefully it will still work the same. The water source for the turbo feed is the X's original 'heater' water supply off the head. That is much higher than on the UT, where the block has a special port down low close to the oil pan, but it is still the same general (warm) water supply. The water return from the turbo goes to the upper coolant tank fitting (there are now two such fittings on my tank), like on the UT. And the coolant tank is being mounted in the trunk, so higher up than the original location, and higher than the inlet source. Therefore it should still be a cooler and higher location, which I think is the goal. Sound right?

Makes sense overall - just not clear why you don't add a branch to the stock return pipe under the intake? That would be much lower in the system, and cooler. I personally think feeding off the head is not so great.

 

[Dr.Jeff]

I personally think feeding off the head is not so great.

Curious why you say that? Granted the coolant supply from the return pipe is a little cooler than the coolant supply at the head. But in "turbo" terms they are both MUCH lower than the target temp. We discussed this previously and it seemed the consensus was there should be no real difference between the two sources. But I'm certainly open to better ideas. Please add more of your thoughts on it.

 

[Dr.Jeff]

Regarding the turbo's coolant water supply source. I should have added that the reasons I choose the X' stock heater supply nipple (on the head) as the source were; 1) I won't be using that for the heater and it is a nice handy place to get a good supply of water from, 2) using a nipple off the water return pipe would be a much smaller source compared to the heater nipple (although I'm sure either could be "enough"), 3) the heater nipple makes for much easier plumbing to the turbo. Perhaps none of those on their own are compulsive reasons, but combined it just seemed the more logical choice. However if there is a significant functional advantage to getting the water supply elsewhere then I'm all for that.

The UT taps into the water jackets within the block, down toward the bottom of the block and near the rear (flywheel) end. The '79 block has a similar (but different) spot near there for the EGR valve to mount. There is a tiny hole for coolant water to pass through that mount to help cool the EGR valve. It might be possible to hog out that tiny passage and tap it for use as a turbo water supply source. But I have no idea if it is a good location within the internal jackets, if it will supply a good flow of water, how that might affect other aspects of the engine's cooling, if there is enough 'meat' on the block at that point to safely enlarge and tap it, or how this would affect the turbo's cooling system. So I'd be very reluctant to destroy a excellent block to find out.

Thoughts?

 

[lookforjoe]

Every factory turbo set up (Volvo in my experience) feeds the turbo from the coolant return hose (or pipe), not from a block or head source. That way, the thermosiphon is always aided by the flow direction, drawing from lower in the system. Since the coolant is being drawn through essentially from the radiator output, how is that a smaller source? Once the T/stat is open, the flow from the rad through to the return pipe is pretty much wide open. I don't see how feeding it off the (the hot side of) head will function the same way, since the coolant source is now higher than anything in the block - but maybe in practice it won't matter. That would seem to be more practical (and easier to accomplish) than modifying the block, no?

EDIT - forgot that on the X, the rad return through the T/Stat housing is at the same level as the heater port off the end of the head, so the only difference will be the coolant temp. Functionally, I can't see the siphon effect being any different between the two sources. Is that the conclusion we arrived at earlier? I don't recall.

 

[Bjorn Nilson]

Regarding the turbo's coolant water supply source. I should have added that the reasons I choose the X' stock heater supply nipple (on the head) as the source were; 1) I won't be using that for the heater and it is a nice handy place to get a good supply of water from, 2) using a nipple off the water return pipe would be a much smaller source compared to the heater nipple (although I'm sure either could be "enough"), 3) the heater nipple makes for much easier plumbing to the turbo. Perhaps none of those on their own are compulsive reasons, but combined it just seemed the more logical choice. However if there is a significant functional advantage to getting the water supply elsewhere then I'm all for that.

The UT taps into the water jackets within the block, down toward the bottom of the block and near the rear (flywheel) end. The '79 block has a similar (but different) spot near there for the EGR valve to mount. There is a tiny hole for coolant water to pass through that mount to help cool the EGR valve. It might be possible to hog out that tiny passage and tap it for use as a turbo water supply source. But I have no idea if it is a good location within the internal jackets, if it will supply a good flow of water, how that might affect other aspects of the engine's cooling, if there is enough 'meat' on the block at that point to safely enlarge and tap it, or how this would affect the turbo's cooling system. So I'd be very reluctant to destroy a excellent block to find out.

Thoughts?

I don't think the cooling source is very important. Go for what is as close to the UT engine as possible. But as discussed, the placement of return hose is important to keep some kind of flow also when engine is hot but not running.
We all do our best to keep our engines as cool as possible which is a hard to obtain with the limited air flow in X1/9. On the other hand, modern high perf engines handles high temperatures quite well due to efficient oil cooling etc. But I think modern oils also have a role here. UT oil specs says semi synthetic 15W40 but I am thinking of going for a fully synthetic 10W40 oil or even 10W60 race oil. I assume a fully synthetic oil made for high performance turbo engines would handle high temps and loads the best. However, I am not sure if that would have an impact on other components.

 

[Janis]

Not sure if I understood all cortectly, but if You are going too feed turbo's water inlet from head, isn't it already "hot".
Or is it originally same? (in picture is 1.4UT)

 

[Dr.Jeff]

how is that a smaller source?

I was referring to the size of the nipple; the ones on the return pipe are very small diameter, the one on the head for the heater is large diameter. So a greater flow potential. However I don't know that will make a huge difference, just on of the thoughts in the equation.
As I recall that was the prior consensus, as you and @Bjorn Nilson just said; the head vs the return pipe shouldn't make a huge difference in terms of siphon. Although the return tube is a fraction lower than the heater nipple. The bottom of the block is definitely much lower, but adapting it doesn't seem worth the risk.

 

[lookforjoe]

The UT taps into the water jackets within the block, down toward the bottom of the block and near the rear (flywheel) end. The '79 block has a similar (but different) spot near there for the EGR valve to mount. There is a tiny hole for coolant water to pass through that mount to help cool the EGR valve. It might be possible to hog out that tiny passage and tap it for use as a turbo water supply source. But I have no idea if it is a good location within the internal jackets, if it will supply a good flow of water, how that might affect other aspects of the engine's cooling, if there is enough 'meat' on the block at that point to safely enlarge and tap it, or how this would affect the turbo's cooling system. So I'd be very reluctant to destroy a excellent block to find out.

Thoughts?

This does look way better (mkmini's post - if you can tap the block & follow that setup, that is definitely the way I would go.

 

[Dr.Jeff]

if You are going too feed turbo's water inlet from head, isn't it already "hot"

Correct. And this is one concern. However the temp of the turbo is MUCH higher than the head, so it is still "cold" water relatively speaking. Somewhere I read that the temp difference between the water in the head and the water in the block wasn't as great as I always imagined (I don't recall the figures they gave, and it wasn't for the SOHC). But ideally I'm guessing the lower the water temp the better....or is it? I suppose you don't want to subject a really hot component to really cold water. However we aren't talking about those extreme of temps. Either way coming off the head my not be best...

 

[Dr.Jeff]

This does look way better (mkmini's post - if you can tap the block & follow that setup

Ya, that's what I was referring to earlier. But see my comments about tapping into the block. I'm not sure it is worth the risk, and no idea if it would be at all the same as how the UT has it in reality. They are not the same blocks.

 

[lookforjoe]

Ya, that's what I was referring to earlier. But see my comments about tapping into the block. I'm not sure it is worth the risk, and no idea if it would be at all the same as how the UT has it in reality. They are not the same blocks.

I have an 81 block from the parts car in the back yard. I'll have to look at it to see if anything can be ascertained from external viewing. A good diagram of the water passages in the two blocks for comparison would be helpful here.

 

[lookforjoe]

Considering the options, I think I would still go with adding a pipe off the return to feed it - something like this:

 

[Dr.Jeff]

A good diagram of the water passages in the two blocks for comparison would be helpful here

Very true. I don't recall seeing anything like that for these engines though?

As mentioned, the '79 block has a little flat mounting pad for the EGR valve, about mid way up the block just off to the rear. And there is a tiny water passage through it that cools the valve. So it must connect to the internal water passages. But what extent of a water flow that would supply I have no idea. It might be in a small corner of a water jacket to prevent too much water from flowing into the valve. I suppose if I was really ambitious I could get a bad block and cut it up....but that's not going to happen, I'd use one of the other sources before going to that extent. That flat mounting pad is where I bolted the turbo support bracket to, which also serves to block that tiny hole.

 

[Bjorn Nilson]

I have an 81 block from the parts car in the back yard. I'll have to look at it to see if anything can be ascertained from external viewing. A good diagram of the water passages in the two blocks for comparison would be helpful here.

Not really a diagram but maybe this picture can help.

Wikiwand - Fiat 128 SOHC engine

Designed by Aurelio Lampredi, the Fiat SOHC engine first appeared in the front-wheel drive (FWD) Fiat 128 of 1969. The in-line four-cylinder engine comprised an iron block with an aluminium cylinder-head containing a single overhead camshaft operating directly on both the inlet and exhaust...

www.wikiwand.com

 

[Dr.Jeff]

I think I would still go with adding a pipe off the return to feed it - something like this

Still a consideration. The location isn't really convenient relative to the turbo's water inlet. The turbo directly covers the return pipe. So the feed hose would need to snake around things, to go around, up, and over the turbo. By comparison the heater nipple is a straight shot to the turbo water inlet with a slight downward flow.

 

[Dr.Jeff]

Not really a diagram but maybe this picture can help.

Thanks, I'll have to read through that article. The picture doesn't help me too much - maybe someone else can see more than I do?

Looks like the water jackets don't go very low on the block. Compare the two yellow arrows with the yellow line:

But a cross section view from the other plane may show it differently. I'll have to look at the '79 block again to see if I can estimate where the EGR mounting location is relative to this pic (opposite side of the block).

 

[Bjorn Nilson]

Not really a diagram but maybe this picture can help.

A little bit late here... I realized the picture shows the wrong side of the engine.

 

[lookforjoe]

Typical whiteblock Volvo setup - couldn't find a decent pic, it's not something I focused on in terms of documenting

I've not seen the UT manifold & turbo in the flesh - it wouldn't be feasible to add a pipe downwards like this (left side is feed)

another older setup I braised AN fittings and used the same lines sold for oil feed

another older setup

This one I had to redo -I had fed the (water cooled) WG return into the oil cooler feed line, didn't work in terms of any siphoning

 

[Janis]

A little bit late here... I realized the picture shows the wrong side of the engine.

By the way, Have a nice midsummer celebration!