not yaris related, but looking for a cooling system guru

[turboyaris]

Hey guys, I am looking for a little help from maybe a heat transfer expert or thermodynamics guy, or any articles that would pertain to this. I'm working on a 2005 Mercedes CL600 with a V12 twin turbo, anyways it has some work done to it, and we are starting to experience higher then normal engine temps. I haven't had a chance to monitor oil temps yet, but I will be working on that. The cooling system on the car is just silly it has 1 radiator with oil cooler, 1 ac condenser, 1 radiator for the asjustable suspension, 1 for the intercoolers (water to air) and another smaller radiator that I am trying to figure out, (guessing since the turbos have a seperate coolant tank, that thats probably what that is. My thoughts were to seriously upgrade the main radiator and remove the oil cooler from it, and go with a water to oil cooler from like setrab or laminova. They will be able to help me, but I need to know what kinda of heat I need dissipated. Any help that you guys know of or have on cooling systems would be greatly appreciated. Thanks, Nick

[turboyaris]

p.s. I'm awaiting the super huge 10gb service manual maybe that will be able to help.

[yaris-me]

Shouldn't you look at water pump and thermostat first?

[turboyaris]

Yea they have already been looked at, and as you could assume, no one makes a higher flow version, higher flow water pumps are not always the best solution, because too fast of a flow doesn't cool as well as it should. Larger heat exchangers (radiators) are more effective for increased cooling.
http://www.opcon.se/index.asp?sPage=1&langID=2&cID=15
This is a good example of how increased flow doesn't effect cooling as greatly as a larger cooler.

We will probably start with a colder thermostat, but these engines generate insane amounts of heat, I know we will need more then that. It's difficult to wrap your head around dissipating heat while this car goes 190 haha or at least for me it is.

[turboyaris]

woops link didn't quite work, click on the sidebar rally & racing, then ecd54, then performance

[jkuchta]

You might want to look into coatings on the radiators if you can't go much larger.

Swaintech has a "black body emitter" coating that I've used on 2-strokes with pretty amazing results.

Also, if I understood you right, the oil cooler is fed water from the radiator right? If thats the case, the excessive heat from the oil could be driving up the water temps.

When did this thing start running hot?

[AlexNet0]

^probably when the two turbos start spooling... lol

on a more serious note, can you get bigger radiators for it?

[turboyaris]

yea I can, and I am getting bigger radiators for it, the main radiator will be upgraded, he already has an upgraded heat exchanger for the water to air intercoolers.

jkuchta, the stock radiator setup is air cooled, but the oil cooler is actually inside the radiator its a setup similar to the 300zx setup sold by spl http://www.splparts.com/main4/index.htm
then go to z32>engine>cooling and its the McCulloch setup there.... My question though, was that if we went with a straight water to oil cooler, we could go with a much larger just water radiator for all the coolant, I just don't want to tell them to spend the money, before I can assure him that it will lower his temperatures.
His system seems to need a bleed as well because of semi erratic water temps. But basically when the boost and power was turned up the temps crept up with it.


and no one makes a replacement for it, I will have to make him one.

[YarisSedan]

Have you tested your radiator cap yet. They go bad every couple of years. Seal could be deteriated. I have seen cars that have overheating issues and performed full diagnostic to find out it was jsut a faulty radiator cap. The radiator cap is a crucial part of the cooling system. I would test or replace that before even looking at things such as water pump or thermostat.

[Nexus1155]

Wait, so did you start experience higher engine temps with new mods, and what mods were added?... I deal with a shitty european car all the time i can probably help you.

Let me know some specifics and ill try and help what went wrong where.. Is this a friends car or do you own a shop?

[turboyaris]

When the ecu was reflashed and the boost was turned up, thats probably the time the temps crept up, part of the problem too is that that was also in the winter time, so ambient temperatures are also increasing. More then anything, I'm looking for info on how auto makers determine sizing for their radiators, I would guess its a formula based on engine power (heat generated from the engine). The radiator cap is something that I will have to test out, its easy enough to do.

[Nexus1155]

Ok, well I flash ECUs for a living so I can probably tell you a couple of things you can do. Find a temp sensor compatible with the car so the system kicks on faster. I'm assuming with the tune that they didn't tune it so that the system can keep up with the cooling needs. If the case is that the turbos are making the engine heat up way too much you might want to think of installing either a shield to dissipate the heat or a turbo blanket and some heat wrap.

I don't know the specifics of that car and haven't looked them up yet, but that i know is a big engine, and possible with big turbos that glow red hot with the added boost...

How much of an overheating problem are we having here? I can't tell if its internal or externally being caused because it could be both

[turboyaris]

yea it has big glowing red turbos, its a 5.5L V12 with twin turbo pushing something like 30 some pounds of boost (I think, had to convert from inches of mercury, damn germans) and power wise you are looking at 800ft lbs of torque to the ground. The stock radiator is only about 30"x 24"x 1.5 maybe 1.75" and just driving around its only like 210 water temps (haven't installed a sensor for oil temp yet) but when he does 180 or so on the highway (which he does often cause he is a little loose in the head haha) I'm sure the temps get pretty high. I know that one issue is that there doesn't seem to be alot of places the hot engine air can escape from.

It's not really like a "problem", as it just gets to the point now where he wants his cooling system bumped up because he is installing a 150 shot of nitrous and upgrading the turbos sometime in the near future, so upgraded cooling is a must first. I'm just trying to figure out how big of a radiator to go with if I were to go with the water to oil cooler, I think this would be a wiser choise, because of all the heat exchangers already located up front, that would allow one less.


here gives you an idea of the engine, the first picture shows how hot the turbos get on the engine dyno
http://www.mbworld.org/forums/cl55-a...hing-else.html

[06silveryaris]

http://oscarvelez.com/ these guys can help or a least guide you. These are old friends of mine. they do great work in your case I am sure they can at least recomend a set up or cooling upgrades that will work. They are from my town which is far from you.

[hatchbackkid82]

[Nexus1155]

That is a very nice engine, alot of places that power is being restricted from the exhaust/etc but you have a serious issue here you need to adress.

There are multiple ways you can fix this situation. I think you can throw the tuning part out the window as the turbos will be way to hot regardless being where they are. Well unless you are running the EGT's through the roof.

You need to either get a new cooling system there/work on protecting the engine from the excessive heat/Create a vent if he doesn't mind it losing the sleeper look. You can see what MTM did here for the RS6 in terms on cooling/Air intake. You have many options available to you!

http://www.mtm-online.de/en/showbild...alerie2&bild=6

[turboyaris]

yea we had discussed getting a carbon fiber hood made, no one makes one, get some vents similar to the ones there.

The only thing I'm trying to figure out though, is how much increase in water cooling will i need going with the water to oil cooler.

[jkuchta]

Without current oil temps, I'd say go with the biggest rad you can fit in the thing if you want to do oil-water cooling.

Figure you'll need to dissipate not only the heat from the water, but also the heat from the oil (which can be a bit higher).

C&R makes not only sweet radiators, but also oil-water cooler manifolds and some really neat oil valves, which can be used to regulate the flow of oil to the cooler.

If the rad that's on there now is at the limit, when this guy leans on it any further then the cooling system will really be stretched too thin (especially if bigger/better turbo's go in the thing).