Amphibious HEMTT

[aczlan]

Ok, I got some driving numbers. They aren’t making any sense.

I drove about 5 miles at 60 mph to warm it up. Then I turned around and told my son in law to take a pic of the temp box when I waved my hand.

I got back up to 60 for about 2 miles so that it was a constant temp. He took two pics about a minute apart.

The intake air coming from the turbo was 274 in one and 256 in the other. After it went through the intercooler, I had 222 and 229. The cooler is obviously not doing a lot lowering the temp by 52 and 27 respectively. At least it makes sense.

Listen to this, the water on the cold side of the radiator was 174 and 166. Not great, but it is what it is. The water the after intercooler radiator was 229 and 229. Just so you understand, I’m not talking about after the intercooler. How does water get hotter in a cooler? I’ve rechecked the probes. I’m missing something here.

My first guess would be that the inlet /outlet probes are switched.

Aaron Z

 

[Dougal]

The coldest water reading should be after both radiators. It was the coldest after the main radiator and then gained heat in the second. The air that feeds that little rad is ducted from the front of the truck. I don’t see how it could get any hot air. The ambient was around 65-70.

Both radiators? I think we need a diagram of what's going on here.

 

[WaterH]

Both radiators? I think we need a diagram of what's going on here.

There’s the regular radiator for the engine. I have a line coming off the cold side going to the dedicated little radiator with its own cooling fans and then on to the intercooler.

At this point I may have to hook up the 5 gallon bucket again. (I had it only hooked to the little rad) That was a closed system. My thought is maybe the little pump I have is not able to feed water in to the hot side of the engine system. If the water gets stalled then the intercooler does nothing. If that was the case, you would think the bucket would have made a giant improvement. (It didn’t)

 

[bdkw1]

I don't think your intercooler is the cause of your egt situation. Sure you will knock some heat off it with a cooler and denser intake charge, but I'd look into other things.

Gearing (loading) -> fueling (determined by load) -> air to burn it (turbo geometry and sizing)

That's what I've been saying. I've seen less EGT's out of a 12V towing heavy. Something isn't right.

 

[Dougal]

There’s the regular radiator for the engine. I have a line coming off the cold side going to the dedicated little radiator with its own cooling fans and then on to the intercooler.

At this point I may have to hook up the 5 gallon bucket again. (I had it only hooked to the little rad) That was a closed system. My thought is maybe the little pump I have is not able to feed water in to the hot side of the engine system. If the water gets stalled then the intercooler does nothing. If that was the case, you would think the bucket would have made a giant improvement. (It didn’t)

Oh right, that sounds unnecessarily complicated. The water/air intercooler needs it's own divorced loop.

 

[Treefrog]

There’s the regular radiator for the engine. I have a line coming off the cold side going to the dedicated little radiator with its own cooling fans and then on to the intercooler.

At this point I may have to hook up the 5 gallon bucket again. (I had it only hooked to the little rad) That was a closed system. My thought is maybe the little pump I have is not able to feed water in to the hot side of the engine system. If the water gets stalled then the intercooler does nothing. If that was the case, you would think the bucket would have made a giant improvement. (It didn’t)

In your bucket test, was the small radiator still in the bucket loop?

 

[WaterH]

In your bucket test, was the small radiator still in the bucket loop?

Yes. My theory with the eingine rad is it does the heavy cooling and the little rad takes it a bit lower. (Or should)

My first guess would be that the inlet /outlet probes are switched.

Aaron Z

I was thinking that at first, but that would mean the cold side of the engine rad was 229. I rechecked the probes anyways.

At this point, I’m thinking the engine water pump is over powering the intercooler pump and sending hot water backwards through the intercooler and pump. It also would be a short cut for hot water going into the cold side of my engine cooling.

 

[aczlan]

There’s the regular radiator for the engine. I have a line coming off the cold side going to the dedicated little radiator with its own cooling fans and then on to the intercooler.

At this point I may have to hook up the 5 gallon bucket again. (I had it only hooked to the little rad) That was a closed system. My thought is maybe the little pump I have is not able to feed water in to the hot side of the engine system. If the water gets stalled then the intercooler does nothing. If that was the case, you would think the bucket would have made a giant improvement. (It didn’t)

So you are trying to pull off of the low temp/pressure (output) side of the radiator and feed back in on the high temp/pressure (inlet) side of the radiator?

Sounds like you need to do one of 4 things with your intercooler loop:

• Make it a fully divorced loop
• Make both connections on the same side (ie: set them up as a closely spaced tee on the cold side)
• Use a bigger pump that can push more pressure and match the pressure of the the water pump
• Leave the supply line alone and tie the return in parallel with the heater return line or someplace else on the inlet side of the engine water pump (high temp, low pressure)

Aaron Z

 

[WaterH]

So I hooked up the bucket system again and drove allot longer. (maybe 25 miles) It appears the temp of the bucket never gets above 150. Also, if I drive slow, the temp goes down. (About 18 degrees in two miles of 30 mph) The motor water temp seems to be good. I guess once the temp difference from ambient to 150 arrives, the little rad can keep up. I suppose the bucket sheds some heat also, but I wouldn’t think much.

Tomorrow, I plan to drive with the bucket for about an hour and a half. If I still feel it’s a good thing, I plan to make a permanent change.

I’m leaning towards a bigger dedicated rad for the intercooler and some kind of tank that would fit under the engine cover. I might make something out of aluminum with fins to get a little more cooling. I probably can’t fit 5 gallons, but maybe 2 1/2 gallons. I’m thinking that the volume is some ”stored cooling”.

The other thing I could do is get a bigger intercooler, but it won’t do much good if I don’t have a better way to shed the heat.

 

[Dougal]

So I hooked up the bucket system again and drove allot longer. (maybe 25 miles) It appears the temp of the bucket never gets above 150. Also, if I drive slow, the temp goes down. (About 18 degrees in two miles of 30 mph) The motor water temp seems to be good. I guess once the temp difference from ambient to 150 arrives, the little rad can keep up. I suppose the bucket sheds some heat also, but I wouldn’t think much.

Tomorrow, I plan to drive with the bucket for about an hour and a half. If I still feel it’s a good thing, I plan to make a permanent change.

I’m leaning towards a bigger dedicated rad for the intercooler and some kind of tank that would fit under the engine cover. I might make something out of aluminum with fins to get a little more cooling. I probably can’t fit 5 gallons, but maybe 2 1/2 gallons. I’m thinking that the volume is some ”stored cooling”.

The other thing I could do is get a bigger intercooler, but it won’t do much good if I don’t have a better way to shed the heat.

The small radiator by itself in a divorced loop will do okay. Your loop temps will likely be lower than current. But a bigger one will do better.
Half a US gallon (2 litres) will be heaps for a header tank.

 

[WaterH]

The small radiator by itself in a divorced loop will do okay. Your loop temps will likely be lower than current. But a bigger one will do better.
Half a US gallon (2 litres) will be heaps for a header tank.

Today I drove about three hours with the bucket setup. When I was driving down the cruise EGT was about 100 degrees lower and I was thinking this is great. My enthusiasm was set back on the way home when it was back to normal. I realize I had a tail wind going south. Lol. Still I think there was some benefit to the separate loop. The bucket averaged about 143 degrees.

Do you think there is any benefit to the “stored” cool in the bucket? Like, every time I slow down, there would be no heat added to the bucket, but the little rad is still cooling it. Then when I step on the gas, the little rad would not start with hot water.

 

[Treefrog]

Do you think there is any benefit to the “stored” cool in the bucket? Like, every time I slow down, there would be no heat added to the bucket, but the little rad is still cooling it. Then when I step on the gas, the little rad would not start with hot water.

All more coolant will do is cause it to warm up slightly slower and cool down slightly slower. It won't affect the temperature under steady operation.

 

[aczlan]

All more coolant will do is cause it to warm up slightly slower and cool down slightly slower. It won't affect the temperature under steady operation.

Exactly, if you are drag racing stoplight to stoplight, it will help, pulling up the Continental Divide or a long hill it will heat up a little slower, but will then stay hot longer as well.

Aaron Z

 

[Bebop]

Do you think there is any benefit to the “stored” cool in the bucket? Like, every time I slow down, there would be no heat added to the bucket, but the little rad is still cooling it. Then when I step on the gas, the little rad would not start with hot water.

No.
Get a bigger radiator.

 

[aczlan]

WaterH you have a heater core on that, right? Take out the bucket, leave your inlet to the intercooler loop where is (radiator cold side outlet) and put the return from the intercooler loop into the heater core return (suction side of the water pump).
That will let you see if the 2 radiators would be enough cooling capacity if you could get flow right.


Aaron Z

 

[WaterH]

WaterH you have a heater core on that, right? Take out the bucket, leave your inlet to the intercooler loop where is (radiator cold side outlet) and put the return from the intercooler loop into the heater core return (suction side of the water pump).
That will let you see if the 2 radiators would be enough cooling capacity if you could get flow right.


Aaron Z

Interesting thought, but I see some issues. The heater core is up in the cab. I don’t want heat all the time. I know I don’t have to turn on the fan, but you would be surprised how much heat a heater core makes inside your dash. My 90’ Bronco had no cut off to the hot water. It would make the dash hot in the summertime. I ended up putting a valve in that bypassed it. Also, that has the possibility making my heater work poorly in winter. (not much of an issue for me living in FL, but I do occasionally make trips to the north.

On the Cummins swap site someone did mention that there is a way to plumb a intercooler using the coolant without a stand alone pump. I don’t believe he was using the heater lines. I do like the idea of not having the electric pump. There are several unused ports with plugs in them. I would need to find out which is which. This could be a temporary solution to the backwards flow, but not really a fix to the total temp issue.

The other issue I see is the bucket system as it is never gets over 150. It would appear that my cold side of the radiator is hotter than that, so that means the IC rad has to work harder. I will agree that even if the water is 180, it still could cool 250+ air in the intercooler.

Get a bigger radiator.

Assuming you mean IC radiator, I tend to agree with this, but difficult to package. I’m looking into locations now.

 

[Bebop]

Assuming you mean IC radiator, I tend to agree with this, but difficult to package. I’m looking into locations now.

Put it in front of the engine rad.
And fix the engine rad air ducting / shrouding / extraction.

 

[aczlan]

Interesting thought, but I see some issues. The heater core is up in the cab. I don’t want heat all the time. I know I don’t have to turn on the fan, but you would be surprised how much heat a heater core makes inside your dash. My 90’ Bronco had no cut off to the hot water. It would make the dash hot in the summertime. I ended up putting a valve in that bypassed it. Also, that has the possibility making my heater work poorly in winter. (not much of an issue for me living in FL, but I do occasionally make trips to the north.

Sorry if I was unclear, I was just meaning to do this to test it.

If that worked, you have that as an option, or the plugs you mentioned.

If not, I agree with Bebop and stack a larger thinner radiator in front of your current one.

As for storage volume, do you have a "burp tank" on the existing system? If so, tee into the line coming out of the bottom of that and tee a pair of small vent lines from the top of the intercooler and intercooler radiator into the vent line on the tank.


Then you have shared storage for makeup water, but you won't have much moving back and forth between them.

On the Cummins swap site someone did mention that there is a way to plumb a intercooler using the coolant without a stand alone pump. I don’t believe he was using the heater lines. I do like the idea of not having the electric pump. There are several unused ports with plugs in them. I would need to find out which is which. This could be a temporary solution to the backwards flow, but not really a fix to the total temp issue.

In the stock cooling system you have 3 zones:

• High Pressure, High Heat (water pump to thermostat to radiator)
• Medium pressure, Low Heat (radiator to block)
• Low pressure, high heat (block to water pump)

You have a medium pressure, low temp water source already (radiator output, you just need a low pressure place to dump it to and your electric pump won't have to do anything.
Your heater core should be pulling from between the water pump and the thermostat, so it will have a higher pressure (until it drops pressure going through the heater core), so you returning the intercooler to near the heater core return shouldn't hurt heater core flow.

The other issue I see is the bucket system as it is never gets over 150. It would appear that my cold side of the radiator is hotter than that, so that means the IC rad has to work harder. I will agree that even if the water is 180, it still could cool 250+ air in the intercooler.

My question would be what does your small radiator do to the temp from the cool side of the radiator?
If the big radiator can cool to 180F (with essentially unlimited capability) and the small one can cool the intercooler flow another 30F, that would be the best of both worlds IMO.

Aaron Z

 

[WaterH]

Sorry of I was unclear, I was just meaning to do this to test it.
If that worked, you have that as an option.
If not, I agree with Bebop and stack a larger thinner radiator in front of your current one.

As for storage volume, do you have a "burp tank" on the existing system? If so, tee into the line coming out of the bottom of that and tee a pair of small vent lines from the top of the intercooler and intercooler radiator into the vent line on the tank.

Then you have shared storage for makeup water, but you won't have much moving back and forth between them.


Aaron Z

Ahh, that would be an interesting test. It would give me an idea of how much bigger a IC rad I need.

Note, I don’t have the IC cooler in of the engine rad. It’s on its own and has its own cold air ducted to it. If I mount a bigger IC rad, it will be set up the same way.

I like the shared tank idea. Since the IC water doesn’t ever get over boiling, I don’t need a pressure cap.

 

[mobil1syn]

They hold the lines nice.

The bed is perfectly square and centered on the frame.

The only issue is the side of the bed is going to be right next to the radiator line. I should have it off center, but my OCD wouldn't allow it. Now I might have to jog the side.

Then I replicated them in aluminum.

Started body tear down for final riveting and paint.

Before screwing down the bed, I changed the intake tube. Not sure if I have a pic earlier in the thread, but originally I had one long flex tube. It is aircraft high temp tube of good quality, but I didn't like so long a run of flex tube. So I put aluminum tube on the long straight runs.

ok so i just went back through your thread and there are a few issues i see

• you are blocking the a lot of the inside of the radiator
• i bet your fans are stalling out when you are at highway speeds
• the AC works because it has somewhere to send the air
• if it were me, id mount the fans to the body and seal the area the fan is in and forcing it into the center of the chassis. even with the fans reversed in their current position i dont think you will get the results you want
• ooh and id explore some ducting or louvering

 

[Bebop]

I'm assuming the radiator is on the passenger side ?

 

[Dougal]

Yeah I agree with Bebop You don't need extra volume past what you need for thermal expansion/contraction and leak detection. A bigger intercooler radiator and better air-flow is the go.
Is that your air-intake behind the left side radiator? If so you can drop EGT by getting that a cold air feed.

 

[WaterH]

Yeah I agree with Bebop
Is that your air-intake behind the left side radiator? If so you can drop EGT by getting that a cold air feed.

Weird, I didn’t get any alert that someone posted here.

To answer your question, the intake runs over to the left side, but it’s not finished in that picture. Now it goes through a giant air cleaner that is behind the AC condenser. When I say behind, I mean to the rear of it. The air cleaner intake is not getting any hot air from the condenser. It could be getting heated on the way to the turbo during its long run, but it’s feed is cold air from outside the truck.


Anyways, I’ve got some work done, but before I get to that. I had plumbed the 5 gallon bucket back in for the time being. It doesn’t help with EGTs, but I have noticed that my engine water temp is never hot now. I believe the engine water pump was not only over powering the intercooler pump, pumping hot water to the IC, but it was also a short cut for hot water to get to the cold side of the rad without going through the rad.

So it would appear that all my testing for reverse flow fans and such was for nothing. Lol.

My plan at this time is to fab a radiator overflow / IC duel purpose tank, get a bigger IC rad and possibly a bigger IC. I’m build ing the tank now. I don’t expect the duel tank to help EGTs, but I have to get rid of this 5 gallon bucket in the bed. It’s a PITA.

I started with a aluminum tube.

This tube is 1/4” thick, so it will allow me to tap fittings into it. I cut end caps out of 1/4” plate.

I tried to weld them, but I couldn’t make them water tight. I ended up taking it to a professional welder.

Next step was to build a mount. I hate making angle iron out of box tube. But sometimes you got to do what you got to do.

I welded a strap on and drilled a hole.

If you look close you can see a slot for the hose clamp. (The tank is upside down) Of course, that hose clamp is a 1/2” too small.

I hope to finish this tomorrow. Than I can start looking for room for bigger IC rad.

 

[WaterH]

ok so i just went back through your thread and there are a few issues i see

• you are blocking the a lot of the inside of the radiator
• i bet your fans are stalling out when you are at highway speeds
• the AC works because it has somewhere to send the air
• if it were me, id mount the fans to the body and seal the area the fan is in and forcing it into the center of the chassis. even with the fans reversed in their current position i dont think you will get the results you want
• ooh and id explore some ducting or louvering

Those pics don’t show very good. The inside of the rad is not blocked except for the top 6” and even that is on just the rear half. You can’t even really call that blocked because it has about 4” clearance to the bed side. This pic shows it better.

It maybe that my water temp problems are over. (See in my last post) The IC system obviously still needs work.

I'm assuming the radiator is on the passenger side ?

Yes.

 

[AK_F250]

Have you tried any waterwetter type additives? I know it’s just a bandaid and I’ve never used it but back when I was racing cars there were a couple guys with marginal cooling systems that swore by it.

Can you move the intake somewhere temporarily that gets rid of most of that tube? Even some of the flexible rubber exhaust hose to hang the filter in a few different spots would give you an idea on if a redesign was worth it.

 

[WaterH]

Have you tried any waterwetter type additives? I know it’s just a bandaid and I’ve never used it but back when I was racing cars there were a couple guys with marginal cooling systems that swore by it.

Can you move the intake somewhere temporarily that gets rid of most of that tube? Even some of the flexible rubber exhaust hose to hang the filter in a few different spots would give you an idea on if a redesign was worth it.

I don’t know about moving it because the air cleaner is so big It won’t really fir anywhere else. (Unless I want it outside like a big rig) I have thought about insulating it. I did get a turbo blanket for the turbo and a high quality heat barrier for the exhaust that goes through there.

 

[AK_F250]

I would give it a shot with the little filter from that picture just to see if it gives you a noticeable drop in egt. Then you could decide if it was worth trying to move it or building your own into or on the body somewhere else.

 

[WaterH]

I would give it a shot with the little filter from that picture just to see if it gives you a noticeable drop in egt. Then you could decide if it was worth trying to move it or building your own into or on the body somewhere else.

I guess I could put one of my temp probes on the tube up near the intake for the turbo. If that air was much warmer than ambient, it would be a clue that I need to do something there.

 

[WaterH]

I finished the IC resivour mount.

Resivour mounted and plumbed. Not sure if the sight glass is a good idea, but I can plug the openings if it gives me trouble. The heat shield is probably not needed, but the hoses are kind of close to the turbo/exhaust and I had it on hand.

I turned on the IC pump and I can see the flow through the cap.

Again this is not going to help with temps, but it gets rid of the 5 gallon bucket in the bed. I’m scoping out bigger IC rad locations. It appears I can only fit a 12” width, so I will probubly be looking at 12” by 12”. That would be twice the size of the current one. I feel like that’s not going to be enough. I guess anything that Is an improvement is better. I could probubly fit a 12” by 14-15” , but not sure if that’s really any benefit because the fan can only be 12” diameter.

 

[Bebop]

You should put your IC in front of the engine radiator.

And get a bigger one. 12x12 is nowhere near close to be big enough