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Old 15-07-2004, 04:59 PM
corprin corprin is offline
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Default WI for TD applications

Being in this land of sweltering heat, I am constantly thinking of ways to end my overheating woes in my work truck. M1114A1 (Uparmor Hummer) This thing has an arcaic turbo design, running a single snail off both exhaust manifolds. Placing the turbo between the #7/8 pistons just behind the throttle body. I have already added electric cooling fans to the back side of the radiator, but it's not enough. I am currently running in the neighborhood of 240deg, which is the max my needle will go. Sometimes I have it pegged. Most say to just slow down, that our trucks were never ment to go over 70mph. But those are the same people that have never patched up holes in their buddies from roadside bombs. The faster we go, the safer we are. Now... my question.

What cooling effects will I achieve with a water injection system on my truck. I currently have a 8gal ice-chest in place of the rear right seat. So I have no problem with an ample supply of ice water. (just run a waterline off the dran valve of the cooler) I am nearly unlimited to the mods I can make on my truck. My commander (whom I drive) likes the speed and wants to get more out of our trucks.

Will water injection help with engine/exhaust temps as the only mod?
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  #2  
Old 15-07-2004, 06:52 PM
hotrod hotrod is offline
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Default good question

Need a couple questions answered first.

Do you know what coolant mix you are running?

Many of the racers can get a drop in engine temps by reducing the antifreeze percentage in the coolant mix from 50/50 to something like 20% antifreeze 80% water, and adding a wetting agent like "water wetter". This increases the heat capacity of the coolant and increases the ability of the cooling system to carry heat away from the engine.

I have also had success going to a lower temperature thermostat. If removing the thermostat is a option, you might want to look at that.

http://www.racerpartswholesale.com/redtech3.htm

Another odd ball problem might be that since your driving at greater than design speed, your over speeding the water pump and making it cavitate. If that is the case, its ability to move water may go to hell in a hand basket at high speed, and slightly smaller drive pulley that underdrives it a bit will get it back within its design rpm range and stop the cavitation.

You can also buy accessory 12V water pumps for racing applications to build a secondary cooling system.

In the WRC cars they also put a water spray system in front of the radiator and under high load spray a mist of water directly on the front of the radiator, this can drop the air temp of the cooling air by > 30 deg F, plus the cooling effect of the water that actually reaches the face of the radiator as it flashes to steam on contact with the hot surface. Place the nozzles so they are as far as practical away from the radiator so the spray has time and space to evaporate and spread out across the surface of the radiator.

These changes would attack the temperature of the engine directly.

You may want to consider an aerodynamic approach as well, try to cut some holes in the hood about 1/3 of the way back from the front edge. This is typically a low pressure area at speed and should help the fans pull more air through the radiator. You could also hang a strip of rubber or similar material under the front bumper as an air dam to reduce the air flow under the vehicle, this is commonly in racing applications and lowers the air pressure under the car at speed and frequently improves cooling.

http://www.mirafiori.com/~danb/spoiler/
http://www.datsuns.com/Tech/aerodyna...nd_cooling.htm


You may also be able to make use of your interior heater system. Route the coolant lines for the interior heater, to an additional core mounted so it acts as a reserve radiatior. In a racing environment you can drop the engine temp significantly by turning on the heater with the blower on full, unfortunately it makes the interior quite hot --- a problem you certainly don't need, so an external mount would seem to make sense.

Given the maint capabilities I suspect you have available (ie your not paying for replacement turbos) the simplest set up to rig would be to put a spray nozzle in the air intake as far as possible infront of the turbo compressor. On the Buick Grand National turbo charged cars they frequently run a 7 or 8 GPH nozzle fed by a 100 psi pump. I have the same setup with a 5 GPH nozzle on my 2 Liter WRX.

FYI the supercharged engines in WWII fighters used this exact system to control detonation for "war emergency power". They sprayed both fuel and water/alcohol mix (50/50 water methanol) directly into the eye of the supercharger. It was ultimately used by all combatants during WWII, the Japanese introduced it late in the war on their A6M zeros, the Germans used it on the FW190 ( BMW 801D-2 engine) and the Allies used it extensively, on nearly all combat supercharged aircraft which were powered by the Pratt & Whitney R2800 engines, and the Spitfire and P-51 which used the RollRoyce Merline engine family.

As long as the spray is in the form of a fine mist it will not cause significant errosion of the compressor blades. I have been doing it for quite some time, and I know of others that have done it for years. If you set the turn on pressure properly the water spray will only come on during WOT conditions when your under high engine load.

The Tractor puller folks also use water injection extensively to control EGT temps on their unlimited tractors. Some of these boys are running 200 psi boost pressures. They typically see a drop of 200 deg F in EGT. The info I've seen is that they inject at about 3:1 ratio fuel:water at 160 -180 psi manifold pressure. On gasoline engines the ratio ranges from 10% - 50% of fuel flow.

You can use exhaust color to help you tune the injection. If you have too much water the exhaust goes white, just right, is supposed to be when the exhaust color takes on a gray color, and if the exhaust is still black you need more water.

Injection pre-turbo compressor, will not only cool your exhaust gas temps but will actually increase the effeciency of the turbocharge compressor in high temps --- ie you get more power !!!!!!. The hotter and dryer the intake air the better this mod works. The cooling due to evaporation in the intake pipe dramatically improves the total air flow through the compressor, and reduces the work required to perform the compression.

For every 11 deg F increase in air temp your engine power potential drops by about 1%.

Modern gas turbine power plants use the same system to increase the power output of gas turbine generators in hot weather. It is commonly called "wet compression" "over spray" or " High fogging". It is a very well developed idea in the power generation field. They typically spray about 3% by weight of the air flow.

http://www.caldwellenergy.com/pdfs/EVAPOR.pdf
http://service.spray.com/Literature_...pplication.pdf

Let me look around and see if I can find you any additional info directly applied to diesels.

[edit] I did find some info that diesels really like a water methanol mix. Like Nitrous, you can get carried away with methanol mixes greater than 50/50. At that point the alcohol seems to act as additional fuel, and pushes cylinder pressures up enough to blow head gaskets.

Larry
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  #3  
Old 16-07-2004, 04:07 PM
corprin corprin is offline
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Our repair and replacement facilities are some of the best in the world for quality of work, and turn around. Problem is getting your truck into one of these 4 stations in country is nearly impossasble. We have had a truck there for a blown bottom end since March, and there is no return date in sight.

I am currently running with no thermostat, and your comments to the heater core. Because of the blastics of the armor, and glass installed on my truck, we dont' run with windows down. Turning on the heater even for a short time provides for a cooking effect on both driver and passenger. I use it at times of excessivly high heat for only a few min. Anything more then 5min of low fan has given me 1st deg burns on my legs. Remember that the ambiant temp was 132F in the shade today, and next month it's worse. Along with long pants, and sleeves, I wear an unvented ballistic helmet, and a 45lb armored vest with no vents as well.

Most of the tricks used in racing applications haven't worked here. I spent 3 years as a chassis fabricator for a NATCC, and WC T2 team. The engine on the truck is mounted midship, with 30% of it's girth placed behind the firewall. The radiator is choaked by the cooler assy, and placed in an almost horizontal position. Air is only directed throgh a couple fins that look like an afterthought. I have water wetter on it's way, and I am currently running a 80% water to 20% coolant mixture. The 50/50 was way too thick. Interesting idea about the cavitation of the water pump. This is why I posted here Because these motors are a traditional 6.5TD GM powerplant, are there any companies that offer an underdriven water pump pully?

We have tried the vent holes, to no avail. the trucks are just not built with airflow in mind. Next step is a hood scoop fasioned like the intercooler scoop on the WRX, and like cars with a top mounted air/air intercooeler.

Again, what our your thoughts?
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  #4  
Old 16-07-2004, 04:29 PM
hotrod hotrod is offline
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Default Tough nut to crack

Yes I understand completely on the heater, I was dismissing it out of hand for that very reason, unless you could re-plumb it to an external location. In the past I have had luck with using the aftermarket oil-cooler cores to provide additional radiator capacity.

Not sure of the possibility of a commercial underdrive pulley, I will have to look into that.

I pointed out this thread to a couple other military guys, one's currently at Baghram in Afganistan, I notice he just registered, so perhaps we can get some dialog going. I'll see if I can connect with one of my old friends in the Army Nat. Guard or down at Ft. Carson and see if I can get a view of the underhood configuration of the hummer. They were just coming into service when I got out. I'm not sure how close the commercial version matches up with the mil version, but might take a look at those as well.


Water injection into the intake will both lower your EGT's but should slightly lower your engine temps as well. Due to the higher torque you'll get with the WI you should go the same speed on a slightly lower throttle setting.

The only tip I can give you is, if you can't get a water spray set up on the radiator, then the cooling capacity for a given radiator is directly proportional to the mass air flow, so figuring out some way to increase the air flow would be the best approch. Looks like you have the background and have already tried the common stuff.

Let me dig around a bit and see what I can come up with.
By the way I sent you a PM as well.

Larry
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  #5  
Old 18-07-2004, 04:28 PM
gpatmac gpatmac is offline
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I apologize for taking so long to respond. Unfortunately, I don't believe that I can improve upon what Larry advised. I'd lean more towards the pre-turbo injection or IC sprayer. Also, I am just throwing this out there because I don't have any experience with them, but what sort of potential is there to upgrading or adding an additional oil cooler?

I walked all around Bagram AF today looking for an MP who would let me check out their truck. The last time I had any UAH's was in Kosovo and at that time, I didn't know a turbo from a water pump (1999). I finally found a very nice SFC who let me climb all over one of his. WE COULDN'T FIND THE TURBO nor IC!!! I know I'm not the smartest dude, but it made me say hmmmm. These variants, the soldiers reinforced, were Turbo'd and IC'd, just like the FMTV's. I didn't have a lot of time to look, but all I saw was a large intake pipe coming from the big air filter. The pipe ended on top of the intake manifold. The radiator is still dual core, like they used to be and unless the IC is within that extended grille with the mesh over it, I just don't know.

I did a quick search for the Technical manual online (9-2320-280-10/20-1) and found a few, but am still searching. Gotta get back to work but I'll reply more later.

Last thing, although you're commander wants to go faster, more reliably. You may want to talk to him about the ramifications of modifying the HMMVWs. Even in times of combat where innovation is the word of the day, the Army don't forget what you owe them.
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  #6  
Old 18-07-2004, 09:56 PM
hotrod hotrod is offline
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Default TM's

Looks from that, that the 998 series are 6.2 L NA diesels.

The TM's for the M1114 looks like they are;
TM 9-2320-387-10
TM 9-2320-387-24-1
TM 9-2320-387-24-2


Still looking. May have to pay for a download PDF if I can't find a free site.

Larry
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  #7  
Old 19-07-2004, 12:04 AM
gpatmac gpatmac is offline
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https://www.logsa.army.mil/etms/data/A/075913.pdf
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  #8  
Old 19-07-2004, 02:28 AM
hotrod hotrod is offline
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Default Thanks -- got it

Thanks Pat that link worked for me here at work, but couldn't down load at home.

By the way looks like the turbo is buried all the way at the back of the engine (1-17)

Relevent pages seem to be:

TM 9-2320-387-10
1-16
1-17
2-11
2-56
2-111
3-4
3-26

Rich I'd be inclined, if I was in your positon, to try the heater clutch overide (3-26), and the general PM checks on 2-56, 3-4 and advisories on 2-111.

If that didn't get the job done two ideas come to mind.

1. Looks like a water spray on top of radiator /oil cooler (1-17) would be a no brainer --- one possible problem would be mud build up due to wet radiator surface and heavy dust.

2. I'd try to find some small copper or steel tubing and wrap about 10 wraps around the lower coolant pipe (2-11 / 1-17) and run water through the tubing. It should flash to steam when the engine was hot. You could either duct the hot water to a catch tank where it could cool or simply blow if off. The best part about this approach is it does not penetrate the actual cooling system and if you take a ballistic hit of the coiled line or its feed or catch can discharge, it will have no effect on the engine cooling system.

At least that is what comes to mind for this old GI.

Larry
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  #9  
Old 19-07-2004, 08:54 PM
corprin corprin is offline
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the fan clutch override that I think you are talking about is done by unplugging the time delay device that activates the cooling fan. This kills the acceleration, and top speed. We have tried this method on a number of occations, but to no avail. It actually works worse then when the fan is plugged in. The constant load on the motor doesn't help very much.

As for the modifactions to the truck. All have been given the green light by the brigade commander, as we are doing the work with the AMG techs that are working in our Bn motorpool. All of our data that is gathered from the different methods are sent to AMG to make the trucks better. They were never designed to do more then 55mph, but that is far too slow here. The water injection looks as if it will be a bit more envolved, and require too much maintance for the standard foot soldier to take care of.

The trucks that are turbocharged are easy to spot. When you open the hood there is a large black tube running from the airbox to the center rear of the motor, under the windshield. 99% of the N/A trucks are fed by a yellowish plastic intake tube that plums right into a verticle mounted throttle body, with the words "no step" written on it. The turbocharger is located just over the bell housing and the rear of the intake mani. It's a direct feed into the TB with no room for an intercooler. It would make some sence to help that out, but oh well. The exhaust is routed through a cat, and 3" plumbing. Although it has some tight bends, they are all done on a mandrel press, and quite smooth. As we have no facilities to do exhaust work, or most other custom plumbing here, that's right out. The water wetter, royal purple, and fan orignally pulled from a Ford Taurus 3.8L will be put in.

I will keep you informed on this.
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Old 20-07-2004, 10:33 PM
gpatmac gpatmac is offline
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Ok then. You are in an enviable position...R&D for the Army (or for the Army's contractors) I wonder if you come across a good idea that AM General decides to use, will they compensate?

Two thoughts. One you've already mentioned, but I think would actually be a really good idea. WRX-style hoodscoop and potentially an undercarriage cowl. I'd say that if you could direct the incoming air in such a way that they are pointed towards the turbo itself, that you'd see quite a lot of benefit. I'd imagine that the heat radiating from the turbo, as well as the tract that the charge air is travelling are probably heating up everything in the engine bay.

Second thought would be a little less practical for your situation. Any potential in installing a slightly larger, more efficient turbo? I'd imagine that, if you do it correctly, you could query some patriotic turbocharger vendors in the states and have them ship you one or two. Then, if your manifold requires modification, it sounds as though the AMG facility might be able to fashion you one.
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