arse_sidewards
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Nah. He basically admitted he was being misleading or engineer dickwaving when he said that:This should be a good one.....
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Amphibious HEMTT
- Thread starter WaterH
- Start date
WaterH
Well-known member
Been working on it all day and Not much to show. Here’s the two hard lines to the tranny cooler.
Another with the rad in place.
Its done, and I’m beat. I got word my brother is in the hospital and I might be driving down to Orlando tomorrow. My whole family has high blood pressure and he has it the worse. (And he’s my younger brother) He feels fine, but they are saying he’s having a heart attack right now. I don’t really understand. The Bronco’s AC is not working and the Delorean and the Vette have no room. So I really need this to work at least as good as before. I’m taking a break right now and a test drive in an hour or so. Fingers crossed.
Another with the rad in place.
Its done, and I’m beat. I got word my brother is in the hospital and I might be driving down to Orlando tomorrow. My whole family has high blood pressure and he has it the worse. (And he’s my younger brother) He feels fine, but they are saying he’s having a heart attack right now. I don’t really understand. The Bronco’s AC is not working and the Delorean and the Vette have no room. So I really need this to work at least as good as before. I’m taking a break right now and a test drive in an hour or so. Fingers crossed.
Lowrollin70gmc
Flatland Wheeler
I've never been in a Hemtt, but it's articulated cousin,the USMC LVS, has a gigantic radiator (4' x 5', maybe?) mounted near horizontal above the 8v92TA.
Heat can rise all it wants into open air, as we had minimal overhearing issues dragging dozers through soft sand at full throttle on 120 degree days. No AC, so it sucked in the cab, but plenty of cooling.
OP, your fans have to overcome a whole lot of turbulence to get air into the rad and pressure differences getting it out. I'd increase fan size and /or rad size to give you a better margin of error, even if it hasn't overheated yet.
Your EGTs being 1000-1200 at cruise seem high as well, my 6BT burb is 800ish at 80mph. That EGT adds a ton of heat to the whole engine system. Drop that via better intercooling or fuel settings and you could be happy with the current rad setup.
WaterH
Well-known member
So I went for my test drive and the results were good. Maybe not spectacular, but good. At a constant 60 the needle stayed under the 210 line. For fun, I got up on the highway and push it to 70 mph for a solid 15 miles. The gauge read 230. It never overheated. Another interesting thing, when I got on the off ramp, I pulled over and attempted to feel if both fans were running. I thought they were and got back in the truck to find the gauge read 190. I was out of the truck for less than one minute and it went from 230 to 190. It always did cool down fast when I slow down, but not that fast.
When I got back to my shop I pulled in and shut it down. I left the battery switch on so the fans were running. I took this pic with a piece of paper sucked to the grill.
Wile the fans were running, I happened to walk on the other side and hot air was flowing out the AC condenser from the engine fans. Can’t really complain about the air flow being blocked by the bed.
I was waiting for one fan to shut down. It never did. Eventually, I whet under the engine cover to see if the relays were stuck. I found that the one fan was already off. The second fan shut off while I was under there. One of the fans comes on at a lower temp and I guess it got down to that just driving the mile of dirt road to my house.
All and all, I’m pretty happy. I have been up to 75 mph on a long down hill in North Carolina, but I have never drivin 70 for 15 minutes on the throttle. The EGT was 1200 during that time.
There is still some testing to be done.
1. Make sure both fans are running. (I know the fans and relays work, but I don’t know about the second thermoswitch.
2. It was 89 degrees this time, so I need to go mid day when it’s 95.
3. Not sure if the coolant level is quite full.
When I got back to my shop I pulled in and shut it down. I left the battery switch on so the fans were running. I took this pic with a piece of paper sucked to the grill.
Wile the fans were running, I happened to walk on the other side and hot air was flowing out the AC condenser from the engine fans. Can’t really complain about the air flow being blocked by the bed.
I was waiting for one fan to shut down. It never did. Eventually, I whet under the engine cover to see if the relays were stuck. I found that the one fan was already off. The second fan shut off while I was under there. One of the fans comes on at a lower temp and I guess it got down to that just driving the mile of dirt road to my house.
All and all, I’m pretty happy. I have been up to 75 mph on a long down hill in North Carolina, but I have never drivin 70 for 15 minutes on the throttle. The EGT was 1200 during that time.
There is still some testing to be done.
1. Make sure both fans are running. (I know the fans and relays work, but I don’t know about the second thermoswitch.
2. It was 89 degrees this time, so I need to go mid day when it’s 95.
3. Not sure if the coolant level is quite full.
Bebop
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ThePanzerFuhrer
The Rock Breaker God
I always used the once it started going past thermostat temp you are starting to over heat.
My 900hp gensets will never go about 180 unless the radiator gets dirty. As soon as I see them climb above 180 I pressure wash the radiators out.
elbekko
Captain Slow
Even modern stuff tuned for emissions shouldn't go over ~210 in normal running (had to do some conversions to and from °C here, 110°C is just asking for trouble IMO).
Where is your intake and how are your IATs? Is your intake sucking in hot radiator air and causing a vicious cycle?
Where is your intake and how are your IATs? Is your intake sucking in hot radiator air and causing a vicious cycle?
Bebop
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We're running at higher temps than 210; but we're talking about an old Cummins here.
arse_sidewards
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Shouldn't matter. A turbo car will suck air hotter than what comes off the back of the rad all day.
elbekko
Captain Slow
Oh, really? Must be running really close to glycol boiling temps then?
Maybe with a big intercooler. Post-cooler IAT would matter most, agreed.
arse_sidewards
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I'm saying that your average car with the boost turned up a couple pounds over OEM is probably sucking 200deg air some of the time and they stay cool so occasionally sucking 200deg air off the back of the radiator shouldn't matter for a NA engine that's got ~half as much fuel burning inside it per cubic inch per combustion event.
Heck, first generation turbo cars that didn't have intercoolers had insane IATs and they mostly stayed cool.
WaterH
Well-known member
I guess I should have said boiling over. My temp sensor is mounted at the hottest point in the engine. Normally, that is where the fan switch is mounted and the temp sensor is mounted in a cooler part. So it is possible that a stock setup could be running as hot as mine and not read as hot. And we don’t know how accurate the gauge is. (That could go both ways)
The Air cleaner is not getting hot air, but it has a long run of tube that can get heated by the radiator heat. This, of course, was exasperated by changing the flow direction. Before the rad was sucking the hot air out from under the truck. Now it’s putting more under there. I have a large piece of 1/2” insulation I got from McMaster I plan to wrap that intake tube with.
It has its own system. My brother is waiting for a stint, but his BP is too high to operate. Thanks.
You do realize this truck is 7’ tall and 8’ wide. I’m guessing your burb has at least a 100 more hp. The superior aerodynamics of the HEMTT don’t really show themselves at this speed. Mine is pushing 15 psi boost at 60 mph and over 20 psi at 70. That makes heat.
Overall, the temp at 60-62 mph has gone down from 220 to 205. I feel that 205 is reasonable for cruising indefinitely. That is the speed I normally run in this truck.
Bebop
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It's all fair assumptions.
That said the liquid boiling over has nothing to do with an engine overheating or not. It has to deal with pressure in the system.
At 15psi, boiling point of straight water is around 250. Above that to me is overheating. Run a 20psi or higher cap and shut it down at 250. Running NPG will generate some scary numbers without harm to the motor.
gt1guy
Apparently a racist
Sounds like reversing the airflow worked.
Could you possibly put a third row of slots in the vertical section under the first two rows? Let in all the air you can.
Also, I'd duct the radiator right out to the slots. Any scrap of air entering the slots should only be able to go through the radiator. It seems you have the air flowing in the right direction, now you need to use it all.
Could you possibly put a third row of slots in the vertical section under the first two rows? Let in all the air you can.
Also, I'd duct the radiator right out to the slots. Any scrap of air entering the slots should only be able to go through the radiator. It seems you have the air flowing in the right direction, now you need to use it all.
WaterH
Well-known member
Is NPG that waterless coolant?
Sounds like reversing the airflow worked.
Could you possibly put a third row of slots in the vertical section under the first two rows? Let in all the air you can.
Also, I'd duct the radiator right out to the slots. Any scrap of air entering the slots should only be able to go through the radiator. It seems you have the air flowing in the right direction, now you need to use it all.
I have a ramp that goes from the slots to the rad. If I pulled that out, I guess I could make a new set of slots in the section below. I am a bit surprised that one fan could make so much suction on that grill. I have about 3/4” around 3 sides of the rad that is not sealed, so some hot air could leak from the back side into the cool side. I think my next mod will be to seal that better.
Yes, it works but it's a giant pain in the dick.
Firstram
Well-known member
That much restriction just reinforces what everyone is saying, you need more airflow though the body! Cut a rectangle out of the body the same size (or larger) as the radiator, go for a 70mph drive and report back. You have the skills to build a cool looking grill that can be bolted on and still look like a feature! You’ll be able to experiment with the percentage of open space to dial it in.
Or just leave that cover panel off and go for a drive.
I think the fact that you had hot air coming out the other side through the condenser is telling. Before the airflow may have been through the condesor then through the radiator. With the fans going the other way now it will be interesting to see if the AC works as well as before.
One thing that might help is a skirt/airdam in front of the radiator area full width. Make a low pressure zone. May or may not be very effective do to ground clearance.
I think the fact that you had hot air coming out the other side through the condenser is telling. Before the airflow may have been through the condesor then through the radiator. With the fans going the other way now it will be interesting to see if the AC works as well as before.
One thing that might help is a skirt/airdam in front of the radiator area full width. Make a low pressure zone. May or may not be very effective do to ground clearance.
GLTHFJ60
Stupid is as stupid does
Fwiw, the only time my 4bt has seen 230* was when I was crawling up a hard ass obstacle for an hour and had my electric rad fans off because I'm retarded. It didn't boil over, but it's been down on power since. Yes, I measure coolant temp from the very back of the head also.
It runs 180* or below on the highway in my 6000# truck in all weather, all year, in the south.
Maybe if he built a big flywheel on the front of the engine with big fins, almost like extra fan blades, it would move air, and cool his coolant better, lol.
It runs 180* or below on the highway in my 6000# truck in all weather, all year, in the south.
Maybe if he built a big flywheel on the front of the engine with big fins, almost like extra fan blades, it would move air, and cool his coolant better, lol.
Clemson13
Evernoob is a douchcanoe
It sounds like your fans are working really well and you got the natural air pressure differential figured out on the highway.
I also agree that the next step would be to try ducting so that all the air coming in those grill slits has to go through the radiator.
With the radiator location in relation to the engine, I'm going to say no.
WaterH
Well-known member
The radiator is over sized for this engine, so yes, it has to be an airflow issue. The question is, is the airflow issue serious enough to make major modifications? I have driven this 30 K miles and it really hasn’t been a problem except in my mind.
When I use to balance helicopters for a living, I had a saying “I can’t garentee I can make it better, but I definitely can make it worse”. I like to make small changes and see the results.
I probably will try the cover off test. The AC seems to still work fine.
Not sure I understand where you are suggesting an air dam, but anywhere it would work probably I won’t like the looks.
Why not have your fans come on with a thermoswitch? You can always have a manual off for fording deep water if that’s what you’re worried about. What are you concluding happened to lose power?
With a front mounted rad, you certainly should not have an issue. These are known to be cold blooded engines.
Not sure why you keep bringing up my dynamic balancer? Yes, I made my own and it works better than the stock ones. That bothers you?
They are working better. I’ll keep at it. I like that I get to enjoy it while doing minor changes to improve it. I’m not really trying to cruise at 70. I think it drives pretty good, but its still a short wheel base, giant tire, full hydro truck. The faster I go, the more it feels like I’m herding cats. I would like it to stay cool if I’m running from the cops.
Think of it as front mud flaps that go all the way across the underside of the truck. Since your radiators vent under the vehicle, this would help create a low pressure zone behind it sucking air through the radiators. Distance off the ground would effect its usefulness.
WaterH
Well-known member
I see. Don’t think I would like it, but it makes sense.
Dougal
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I don't see a problem with air-flow as long a the radiator is sealed to the intake side. If those fans can recirculate air in that cavity they will and you'll have no cooling. This may have been happening above a certain speed.
Also guys, don't confuse intake air temperature with manifold air temp. Feeding a turbo warm air just brings the suck as it delays spool, reduces charge density and heat-soaks intercoolers and engines. 30C increase in intake temperature reduces mass airflow by 10%.
Also guys, don't confuse intake air temperature with manifold air temp. Feeding a turbo warm air just brings the suck as it delays spool, reduces charge density and heat-soaks intercoolers and engines. 30C increase in intake temperature reduces mass airflow by 10%.
GLTHFJ60
Stupid is as stupid does
I didn't share my story looking for advice. I shared it to say yours is running far too hot for normal highway driving imo. The only time i am able to get mine as hot as yours runs normally is if my cooling fans are broken.
Also, learn to take a fuckin joke.
WaterH
Well-known member
So yesterday I decided to insulate my intake tube. My air cleaner is on the left rear of my truck and the intake turbo is on the right side of the engine. It’s about a 7 foot run through 3” aluminum tube. I don’t know how much heat the incoming air picks up, but it can’t be good. I've had a big aluminumized blanket I ordered from McMaster for awhile.
Here is the before pick after removing the engine cover and sliding the bed back.
The intake tube comes from the left, makes a 90 on the right and carries forward. The tube off center to the right is the exhaust going back. It is about 4” below the intake tube. You can see I already had some heat protection on it. It didn’t work out so well. I put some insulation around it also. This blanket material is not as high quality as the stuff I put on the exhaust, so it might disintegrate quickly. I did put a torch on a small piece of it and it won’t support a flame. (It did melt the thin aluminum)
After pic. My battery on the trouble light was dying.
My only indication of any success here will be the EGT gauge. I think it will be hard to tell if it’s any better.
Here is the before pick after removing the engine cover and sliding the bed back.
The intake tube comes from the left, makes a 90 on the right and carries forward. The tube off center to the right is the exhaust going back. It is about 4” below the intake tube. You can see I already had some heat protection on it. It didn’t work out so well. I put some insulation around it also. This blanket material is not as high quality as the stuff I put on the exhaust, so it might disintegrate quickly. I did put a torch on a small piece of it and it won’t support a flame. (It did melt the thin aluminum)
After pic. My battery on the trouble light was dying.
My only indication of any success here will be the EGT gauge. I think it will be hard to tell if it’s any better.
ThePanzerFuhrer
The Rock Breaker God
Your charge air cooler that run on its own circuit with its own radiator? You have a temp gauge on those coolant lines?