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92 2150 king cab
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309 Posts
Discussion Starter #1
My 1250 project continues to take longer than I've ever imagined I've have made some progress on the water to air intercooler. With the help from mmthomas we fashioned up a mount that keesp the intercooler from being heated by the radiator and is easily accessible. Sure looks nice with the intercooler plumbing installed. This Friday hopefully the intercooler water pump and heat exchanger will get mounted and plumbed.

I've only seen one other water to air intercooler on a Mog. Who else has experience with these types of intercoolers?
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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5,856 Posts
Am curious; does it have seperate coolant supply from the engine cooling system?
 

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416L Doka and U1200
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859 Posts
Kinda? I have used that type of intercooler but not in a Unimog application.
One car that it worked great on was a 1/4 mile car. second car was a street driven car and the results were not as good.

Disclaimer**** This is only my opinion and I am no expert, scientist or engineer and I have no data from which I have drawn my conclusion.

I think that the reason it works so good on 1/4 mile cars and not as well on every day drivers is because the drag racing car goes a 1/4 mile and is shut down and given time for the block and water to cool (helps with the ice bags on everything) where as on a daily driver the water is hot all of the time and the intercooler becomes heat soaked and my pea brain thinks it becomes less efficient. My butt and back are the only instruments I used in my conclusion. The daily driver seemed a lot faster accelerating when first started than after driving for a long period then hard accelerating again.

Remember I arnt no expert just a factory worker who makes metal stampings:)

http://www.enginebasics.com/Advanced Engine Tuning/Air to Water Intercooler Design.html
 

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Unimog U1250
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1,671 Posts
I think I may be the other Mog owner :) - unfortunately I don't have my truck on the road.

Water-air inter coolers are more efficient than the air-air intercoolers, but they need a decent radiator to get rid of the heat. There are particularity useful for quick bursts of power, where they can absorb a lot more heat than an air-air unit, especially at low speed. Up a long continuous hill, they will get hot, but if you have a proper radiator, it will still work. I use a Bosch water pump, designed for intercooler use.





I have a quite a few books on turbo charging, and all recommend the charge cooler over the air intercooler, but they are a lot more complex and heavier than an air/air. Heat soak after being parked up is a problem if you don't run an electric fan to keep the water cool.
 

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92 2150 king cab
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309 Posts
Discussion Starter #6
coachgeo, Iain's truck is a good example of the secondary heat exchanger/radiator which is dedicated just to the intercooler though Iain's IMHO looks to be really oversized. Iain, is your heat exchanger sized specifically for your intercooler?

Aaron, I'm using a Bosch pump specifically for water to air intercoolers. I've read on several sites about using a bait pump which is used on boats to circulate water. They are much less expensive but decided to go with the Bosch.
 

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Unimog U1250
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1,671 Posts
coachgeo, Iain's truck is a good example of the secondary heat exchanger/radiator which is dedicated just to the intercooler though Iain's IMHO looks to be really oversized. Iain, is your heat exchanger sized specifically for your intercooler?

Aaron, I'm using a Bosch pump specifically for water to air intercoolers. I've read on several sites about using a bait pump which is used on boats to circulate water. They are much less expensive but decided to go with the Bosch.
My intercooler is supposed to be for 600hp

http://www.frozenboost.com/product_info.php?cPath=218&products_id=219&osCsid=c01e698fb9f7c50e7e2d0b4f1af7fbe7

For the radiator, I got the biggest one I could fit in the space, it is not that big, only 12"x12"x2", they say it is designed for 600-1200hp so might just be big enough :) Everything else on the truck is overkill, so might as well be consistent :)

Air to Water Radiator

Bosch pump is this one:

Water to Air Pump 0392022002
 

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1986 Unimog U1700L (435 series)
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371 Posts
Hi Jason from Sydney. I've boon looking at the OM352A or LA or OM366 A or LA re Unimog application (which I plan to buy). Seems to me (and I'm not an automotive engineer), that the water/air intercooler is only for situations where space is limited. The risk with this solution is pump failure or leak.
If it were me (as an engineer having spent more than 45 years tinkering with vehicles), I would be looking at the simplest (more fail safe) solutions by placing a row of large (the larger the better) radiators in front of the motor from one side of the vehicle to the other. Gear box oil cool radiator, engine oil cool radiator and a 'very' large turbo truck intercooler, all with fitted with electric fans. When you are travelling in the outback for say 500km at 45 to 50 plus C between towns, non stop, you need reliability and simplicity. This however would mean that the front bodywork and grill needs to pushed out to accommodate the radiators (pending consideration of fouling issues when the cab is hinged forward) . This would be the much preferred solution for me rather than trying to squeeze more stuff into a space clearly not designed for it.
One of the biggest problems I have observed, is that people completely forget about correspondingly improving air flow (to get rid of all that hot air). Question for you is: Do you want to direct 100% of the heated air under the vehicle (as per factory design) or some over the top of the vehicle or some out the sides of the engine bay or a bit of everything. Presently I have a split system in my Land Rover Discovery diesel, where I direct most air under my vehicle (as per factory) and some out through the bonnet via grills (after I fitted a large $1k intercooler in the front and tweaked the fuel pressure and turbo). The USA forces guarding the Mexican border for example, found that fitting very large grills in the top of their vehicles bonnets near the bulkhead made a very large improvement in keeping engines cooler. For Unimog, I would be fitting big grills in the top of the bonnet and in the sides to really move that hot air out of the engine compartment so that the air-natural intercooler and any oil radiators can get rid of the waste heat.
 

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U1550L/37 Doka, U1700L/38, Merc 1017A
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1,563 Posts
Hi Jason from Sydney. I've boon looking at the OM352A or LA or OM366 A or LA re Unimog application (which I plan to buy). Seems to me (and I'm not an automotive engineer), that the water/air intercooler is only for situations where space is limited. The risk with this solution is pump failure or leak.
If it were me (as an engineer having spent more than 45 years tinkering with vehicles), I would be looking at the simplest (more fail safe) solutions by placing a row of large (the larger the better) radiators in front of the motor from one side of the vehicle to the other. Gear box oil cool radiator, engine oil cool radiator and a 'very' large turbo truck intercooler, all with fitted with electric fans. When you are travelling in the outback for say 500km at 45 to 50 plus C between towns, non stop, you need reliability and simplicity. This however would mean that the front bodywork and grill needs to pushed out to accommodate the radiators (pending consideration of fouling issues when the cab is hinged forward) . This would be the much preferred solution for me rather than trying to squeeze more stuff into a space clearly not designed for it.
One of the biggest problems I have observed, is that people completely forget about correspondingly improving air flow (to get rid of all that hot air). Question for you is: Do you want to direct 100% of the heated air under the vehicle (as per factory design) or some over the top of the vehicle or some out the sides of the engine bay or a bit of everything. Presently I have a split system in my Land Rover Discovery diesel, where I direct most air under my vehicle (as per factory) and some out through the bonnet via grills (after I fitted a large $1k intercooler in the front and tweaked the fuel pressure and turbo). The USA forces guarding the Mexican border for example, found that fitting very large grills in the top of their vehicles bonnets near the bulkhead made a very large improvement in keeping engines cooler. For Unimog, I would be fitting big grills in the top of the bonnet and in the sides to really move that hot air out of the engine compartment so that the air-natural intercooler and any oil radiators can get rid of the waste heat.

U2400's with he shark nose grills and the UHN's are exactly as you are describing except with mechanical fans.
 

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1986 Unimog U1700L (435 series)
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371 Posts
Thank you kindly Tmax.
I'll look into it. I'm just putting together plans at this stage but sounds like it might save me a lot of work one day, if I can buy the grill already done.
 

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U1550L/37 Doka, U1700L/38, Merc 1017A
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1,563 Posts
there is a thread somewhere here with pictures of this configration.
 

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1986 U1300L; 1976 U900 Cabriolet
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344 Posts
Drembedded and Iain, to fit everything under my bonnet and behind my grill, I'm looking at adding a liquid to air IC to my U1300L. Any views on how well your systems have worked particularly when running along at highway speeds? The extra grunt for riding in sand would also be a benefit. Any views on that usage?
 

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Premium Member
Unimog U1250
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1,671 Posts
I've had my intercooler since I rebuilt it, so hard to tell what it would be like without it. I am happy with the performance of my truck at highway speeds and seems to work fine on the beach. I'll measure the temperature difference pre and post intercooler one day, but might be a while.

If I was doing it again, I might go for a bigger water air intercooler without the 180 Degree bend. There was enough space for the a bigger one but I already had the barrel type in it was rated at over 300hp, so much more than my engine puts out.

2621089

2621091
 
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