coolant Flow direction

[nsantos23]

Hey Guys

on the turbo expansion tank what is the coolant flow direction. all on the back, is the bottom nipple out and the middle nipple into the tank?

The reason i ask is that i want to eliminate the tank and connect everything with a N/a radiator.

Thanks

Neo

[vrg3]

It doesn't matter. Just connect the two big hoses together with a 1/2" barbed coupler. I think a 90-degree elbow ought to fit well.

The small hose coming off the cap fitting won't be needed, since the overflow bottle can connect straight to the NA radiator cap fitting.

And the small hose coming off the back won't be needed either, since the NA radiator doesn't have a fitting up in the burp area.

[nsantos23]

But would I have any cooling problems with the N/A radiator? even running with a IC?

[vrg3]

Swapping to an NA radiator would certainly decrease your cooling capacity. You'd certainly want to be careful about what you do (avoid sustaining boost for too long, avoid using the A/C while taxing the cooling system, etc) and keep an eye on coolant temperature.

But our cooling systems, if maintained, seem to be pretty robust. Even the NA radiator is pretty big. It kind of depends on what your goals are with the engine, but there's a good chance you'll be fine.

You might consider keeping your turbo radiator fans, since they're stronger than the NA ones.

Also, instead of just putting a coupler in between those two hoses, maybe you should put in a tee with a temperature sender for a water temperature gauge. That way you can actually monitor coolant temperature meaningfully. That's what I did when I removed my filler tank.

[nsantos23]

And what temperature range it should be on a normal summer operating condition?

[vrg3]

It shouldn't ever go more than a few degrees above 200 degrees Fahrenheit, or drop much below 180 degrees.

[nsantos23]

any precautions as far as the way i have my IC setup right now (saab), or the way i drive 110mph+?

[vrg3]

What turbo are you using and how much boost are you running?

How much boost do you usually see when cruising at 110+ miles per hour? Do you sustain these speeds for long times?

[Legacy777]

You might consider keeping your turbo radiator fans, since they're stronger than the NA ones.

How are the turbo fans stronger?

I'll be dealing with the whole na/ vs. turbo radiator thing when I do mine.....not sure what I'm going to do yet......

[nsantos23]

they spin faster

[vrg3]

They're just stronger electric motors. It's not a huge difference -- something like 140 watts as opposed to 120 watts -- but it's a difference.

[NuwanD]

just fyi, the tank is there to provide fresh coolant to the turbo via convection currents long after the engine has been shut off, removing may hurt the turbo in the long run.

also i'm not sure about the height of the turbo in regards to the rest of the system but could there be a possiblity of air trapped in the system?

[vrg3]

Without the tank you need to pay special attention to idling the car after using the turbo, but if you do that it shouldn't affect the turbo's longevity.

Not having the tank where it is does make it harder to burp all the air out of the system, but not much harder. The radiator cap and burp screw will both still be higher than the turbo.

[nsantos23]

well that we all know, i'll just have to let it idle for 2 or 3 minutes after hard driving (parkways, interstate @ 100mph )

[nsantos23]

hey vgr3 sorry i didnt answer your question, i'm running stock turbo and 110mph only lasts about 30 mnts. what ya think?

[vrg3]

I think it kind of depends... If you have to go on boost in order to maintain those speeds, I would recommend against downgrading your radiator. That's really hard on the cooling system!

Do you just want to switch radiators in order to eliminate the coolant filler tank? Cuz there are other ways to do it... You could relocate the tank, or you could put a filler neck in the upper radiator hose, which is what I've done.

[nsantos23]

do you have pics, and where do I get the filler neck for the hose?

[vrg3]

I don't have any pictures handy -- maybe I should try to get some -- but it's pretty straightforward.

You need to get a 1.5" filler neck like Moroso part number 63730 (see http://moroso.com/catalog/categorydispl ... code=29014).
and splice it into the upper hose. You can get them from places like Summit Racing.

It's a good idea to get a new hose to cut up. Use hose clamps to secure the filler neck.

Get a 13 psi standard-size radiator cap. Make sure it's the kind for coolant recovery systems (that opens under vacuum as well as pressure, and has two rubber gaskets).

Route hose from the nipple on the filler neck into the bottom of the overflow tank. This replaces the small line going to the neck of the stock tank. The Moroso neck has a 3/8" nipple while the stock hose is close to 5/16", so I used an adapter in the middle. I also chose to use some rigid aluminum tubing to go most of the distance.

Join the two large hoses that used to go to the filler tank with a coupler. I used a tee and installed a temperature sender for a gauge.

Then you have to somehow deal with the remaining fitting and the fact that the radiator cap is not the highest point in the system. One option might be to cap off the small nipple at the burp area of the radiator and use a vacuum fill device to fill the system. What I did was more complicated, messy, and weird.

I connected a short piece of 5/16" fuel line to that nipple on the radiator and put a ball valve at the end of it. To fill the system, I connect a container full of coolant (I actually used a generic coolant recovery tank) to the ball valve and open the valve. The coolant flows into the radiator and then into the rest of the engine, and air bubbles out. It helps to keep the radiator cap off at first until coolant starts to spill out. After a certain point, you need to run the engine to get the rest of the air out. It's kind of funny -- it looks like you're giving the car an IV drip. I guess that's kind of accurate though. After burping/filling, you just close the valve and tuck it away somewhere.