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I see you've met the resident thermodynamics expert and mechanical system design guru @pboglio .

Then let me throw this into the mix. 2013 SL AWD with 82.6k miles, tuned and beaten as a daily driver albeit 90% city driving and not a single CVT issue. Ever. Not even limp mode caused by the CVT (my posts years ago about high revs or cutouts on the interstate and not moving were caused by overboost and a failed boost control solenoid combined with a failed tune). Sure I have already had 2 drain and fills and plan to do the third before I reach 100k miles. I don't have a CVT cooler. I don't log my temps. I see no reason for me to get one at this point. Sure some say it's "insurance" to delay when the inevitable happens, but I've seen more anecdotal posts about problems either installing or with one installed.
 

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Squirtbrnr,

Lol......Professor Boglio at your service. J/K.

So, your saying all the people who have had their overheating CVT helped by installing a cooler, including the OEM nissan one are wasting their time? Sorry, but the real world testing by hundreds of people and the data myself and dozens of other people have accumulated sort of prove they work. Transmission coolers are used on all kinds of transmissions. The beehive is too small to be able to transfer heat effectively using coolant. In fact, according to diagnostics I did at nissan, the beehive is actually there to help stabilize cvt fluid temps, but will not prevent the temp from rising as milage increases. On the rogue for instance: Older ones came with the Jukes style beehive, and for CVT overheating NISSAN had us install a OEM cooler as a "fix" that was basically the cvt cooler everyone installs on their jukes. As for 330 hp, no cvt Juke will ever see that power level, so no one can confirm anything about that heat. I can confirm that at the CVT limit of 267ish hp the size cooler you need with extra fluid to help maintain a good temp during WOT pulls is very large. Your system you are making osunds interesting, ad more than likely will maintain decent cvt temps, but as the CVT ages, there is nothing you can do to prevent it from eventually failing in one of several ways.
Cruising conditions or brief WOT pulls are not what I was talking about. Some guys like to track their cars, you guys know who you are....lol. A CVT has no chance on a track, but an AWD/CVT Juke done correctly would actually make a really great track setup IF the CVT cooling system were up to the task. And that is what I was talking about.

If those hundreds wanted to hit a road coarse.........oh yeah they are wasting their time. Show me the CVT temperature datalogs of a Juke on a roadcoarse, with whatever CVT cooler you typically sell. Then I will believe what you tell me. To dissipate that much horsepower on a CVT they would need at least 250,000 Btu/hr of heat rejection. There isn't enough room on the vehicle to fit that much oil cooler without parking it in front of the main radiator, let alone the oil flow to support it. Your solutions are nowhere near that, even if the oil pump flow was there. Since what you were referring to was cruise conditions which aren't using much more than 40-50 h.p., they are probably fine. I wasn't taking about that.

You are actually re-iterating what I stated: The stock beehive cooler IS too small, but the design methodology is the correct way to go. That took me a while to figure out because I thought oil/air coolers would work. No they won't, not for racing duty. Using a "high efficiency" oil/water heat exchanger then to a large water/air radiator is the most compact solution and it also is the best way to go with limited oil pump flow availability. The reason for that is because the water cross flow volume rates can be massive thanks to the water pump volume flow, compensating for the CVT low oil pump cross flow volumes. That's why oil/air coolers just won't cut it, you don't have sufficient oil volume flow to make the exchange with the air. The stock GTR use this method, so does the new C8 corvette which is totally suited to sustained track duty. AMS do the same thing on the GTR but just on a bigger scale, they then throw an additional oi/air cooler on top of all that for their racing version of their transmission cooler. The Juke will simply have a miniature version of this setup, and the boys at AMS know a thing or two about track cars.

What you said about the CVT failing is mostly true. The JF011E has too many design flaws......stock. You hit a limit on all the Jukes that you modified because they all had stock transmissions. Mine CVT transmission isn't stock, not by a long shot. I re-engineered the Juke CVT trans for more peak horsepower as well as durability. The 330 h.p. I referred to was crank h.p. and about 258 lb-ft of max torque (crank). Since I can hit 7000 rpms in CVT "normal" mode, that's how I'm going to achieve it. We will see if it holds up, hard to tell.
 

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99.99% of people do not track their jukes. So all the R and D being discussed is for a road car to prolong life. I would never ever waste my time making a CVT cooler for a race track. Lars Wolfe tried for years and finally just did a six speed swap, it was cheaper and easier than re-engineering a CVT.

The OP definitely is not tracking his car, so all conversation in this thread is about a road car, and problem/solutions associated with that.

I am excited to see what you can accomplish with a more sophisticated system, don't get me wrong, but the applications are apples and oranges for what you are trying to accomplish. There is a proven system available in a dozen places online to help the OP.

I would love to see your designs for your cooler, it sounds like it would be a blast to make, and i hope thats how it turns out for you.
 

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so you havent actually done that yet, when will u have it done and tested?

as to aeration, u think that may be why my cooler is not getting any CVT fluid? I'll warm it a little and drain it tomorrow to within the hash marks. Fortunately I have a 2011 with a CVT dip stick. I wonder how to check level on the ones without a dip stick?
The external oil coolers are tricky to purge the air, not sure if that's your problem or not but it sounds like you've attempted to correct it. I still think you should check the cartridge filter, if that were to clog the oil flow would be seriously restricted. I replaced mine and the oil temps went down. But the "aeration" I'm talking about is like "oil foaming". Most of the time, the fluid level is not correct. If you get it right, the CVT is very quiet, get it wrong and it will whine. It'll cause transmission overheat, oil pump pressure issues, reduced performance, etc.

The oil lube circuit is a separate low pressure circuit, so I suppose a slug of air in the oil cooler wouldn't make it's way into the valve-body directly. Anything lube related get's either dumped into the cartridge filter, beehive cooler, bearings, & pushbelt oil injection coolant jet, finally into the sump thru gravity. The lube circuit relief valve inside the valvebody dumping anything back to the sump if the coolant circuit become obstructed. I'll have to review the lube circuit again. It sounds like the oil flow in the cooling circuit isn't there, the cartridge filter I'd check first. These cheap coolers also have some decent pressure drop, combined with small oil hose diameter, might cause a problem.

As far as my setup, I haven't run my setup yet, I'm hoping by end of fall but it won't be in time for the summer temps. It's been about almost 2 years on build/development.

The engine is in the final stages of machining process to rebuild it, re-polished crankshaft, upgraded forged rods, upgraded forged pistons, RS oil pump, RS rod bearings, cometic head gasket, the cylinder head is fully ported w/3 angle valve job, custom upgraded springs/retainers, upgraded Crower regrind cams. The CVT is fully rebuilt and upgraded with: Rebuilt/reman CVC torque converter, custom higher capacity 4-clutch forward clutch packs, improved clutch pack release gap clearances, upgraded high torque pulley sheave axial bearings (i.e. cobalt slider pin vs. 6mm ball bearings), upgraded Sonnax oil pump flow regulator valve w/brand new OEM oil pump, brand new valvebody (OEM), latest TCM reflash, custom reinforced forward clutch drum (pending the machine shop), latest factory updated CVT pushbelt 90183, running the high torque AMSOIL synthetic CVT fluid. That's what's done already sitting on the bench, minus the reinforcement insert for the clutch drum I designed, that'll take another couple months to retrofit. The custom Laminova CVT cooler will also have a full flow oil filter like an engine oil filter for improved filtration capacity, plus the oil pan has an additional pan magnet installed already for improved debri pickup. That custom oil filter mount I rapid prototyped and it's sitting on the transmission sitting on the bench, need to get off my butt and send it to the machine shop but it's lower priority for now. Most guys don't know but the stock CVT filter can restrict the oil cooler.........then the oil temps get out of control. When I swapped mine my oil temps dropped, so something to watch out for on maintenance. My solution will make oil filter changes a snap, plus have much higher capacity for filtration.

The CVT filter housing is custom machined, uses a Setrab oil thermostat & Setrab oil filter mount, plus an automotive style filter w/14 micron rating. The Laminova cooler (not ordered yet) mounts at the base of the radiator, replacing the stock radiator hose plastic joint fitting & mounting point and slips neatly in it's place with minor trimming of the radiator hoses. The Laminova cooler is like a super-beehive cooler, much more efficient. I relocated it so I had room for a bigger oil filter, and cause it looks baller......lol. Anyway, all the radiator water flow passes thru the oil cooler, while the CVT oil is pushed thru in counter-flow using the stock CVT oil pump. The CVT oil then stays at between 85*C and a max of about 98*C or thereabouts. Kinda important to keep the oil warm in that range in terms of oil flow and where it needs to get to actually lubricate and flow correctly thru the many orifices. The setrab fanpack cooler is there actually the engine oil cooling instead, which will take the heat load off the engine and give some back to radiator cooling capacity back to the CVT, or I'll run it in parallel with the stock engine oil cooler.


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99.99% of people do not track their jukes. So all the R and D being discussed is for a road car to prolong life. I would never ever waste my time making a CVT cooler for a race track. Lars Wolfe tried for years and finally just did a six speed swap, it was cheaper and easier than re-engineering a CVT.

The OP definitely is not tracking his car, so all conversation in this thread is about a road car, and problem/solutions associated with that.

I am excited to see what you can accomplish with a more sophisticated system, don't get me wrong, but the applications are apples and oranges for what you are trying to accomplish. There is a proven system available in a dozen places online to help the OP.

I would love to see your designs for your cooler, it sounds like it would be a blast to make, and i hope thats how it turns out for you.
I know he's not tracking it, but the point is that even a track setup can be used on the street. I'd almost recommend going back to stock and checking the filter and beehive cooler or just replacing them, also checking the CVT coolant thermostat which wasn't mentioned.

Yeah, I seen Lar's car. I know nothing about Rally cars or how to build them. In some areas, impressive build, in other's....not what I would do. Because he tried and failed, that's him. He's not an engineer......I am. I disassembled the JF011E and targeted each of it's weak points, including the cooling system. I designed it to be bullet proof on the street, time will tell if it works. If it can see a track day here and there or an auto-x without burning up the transmission, that's a bonus. A stock CVT car has no chance on the track based on the couple of articles I read of those that tested them. They can barely hold together on the street with mods. I built my car for durability, couple tracks days, auto-x, commuter car.
 

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YEP, Matt is 100% right on this one. The Jukes CVT are a ticking time bomb waiting to deteriorate. My daily is running terrible right now due to overeating and causing the cvt fluid viscosity to sponge + foam internally. Im fixing to re-service the CVT actuator modules and completely drain out the old fluid out of the cvt unit on my daily. My cvt didn't even make it to 50,000 thats some sad S**T.

Stick shift juke transmissions are way better and last longer.
 

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I would put the cvt cooler off to the left side and not posteriorly behind the intercooler. Sorta like Porsche and Bentley equips their vehicle. Better air flow, plus you can probably get a fabricated air vent for direct air flow to the cooler as well. Thats a nice diagram thought man, Thumbs up(A+)
 

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Also if that pump fails that you sandwich between the cooler and the lower main radiator hose, then you can kiss your cylinder head goodbye. I would stick with the OEM Nissan non restrictive CVT fluid route.Ive changed a lot of CVT thermostats or just simply delete them and put a straight hose.
 

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It's not a pump, it's a water/air heat exchanger. My head is totally safe, trust me. There is no restriction to coolant flow in normal full flow configuration, though it can be throttled with restrictor caps to gain oil cooling performance, it's difficult to explain the process. The Laminova coolers are intensely efficient due to their .010 or less thick cooling fins which are cut from a billet rod using some fancy shmancy electrode wire cutter, they pack 2x the cooling capacity for an equivalent front surface area, fins transfer heat better because there is no brazing joint, plus they are like a rolled up radiator core so they are super compact. Anyway, very pricey for the special dual core I have shown but I needed the most compact solution for the highest cooling potential. The Setrab oil cooler you see has nothing in front of it except a pressure feed duct, the 2J FMIC is in front of the radiator.

I'll also be trying in the future a rear differential cooler which actually will need a small pump, a modified fuel pump for oil actually, that'll get fitted in the rear passenger fender well. Mishimoto did that on their Ford RS with outstanding track results. Seems the RS was going into thermal protect due to the rear end overheating the clutch packs. The Juke would probably enter limp mode if the AWD-V were active the entire time on a road coarse, the exact problem the Ford RS had.

And so, because I have an expensive built motor along with a completely customized expensive CVT transmission to protect, I'm going a little bit overkill.
 

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Yeah I would put that little guy up in the front where its exposed to direct air flow. Laminova cooler are good but expensive. I have one actually welded internally on a manifold on my H22 for my Supercharged Prelude. The Laminova coolers is cooled by direct water flow from the windshield washer fluid recirculating with a motor pump. Good idea man (A+)
 

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Yep, thanks. Front was an option but the coolant hose routing makes it more convenient to mount it behind the radiator.
 

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Not a problem, that’s a great idea. Also if limitation is due to a rubber hose you can use nylon stainless steel braided hoses and you can route the hose to the front. That’s what I’m using and they hold up really sturdy. A legit spool for AN 6 is expensive but it’s worth it. Stainless steel nylon hoses are more heat resistant and durable against grime and oil corrosion.
 

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It's such a complex issue because you want to keep it cooler, but not too cool because the CVT relies on heat to kind of activate the fluid and provide the appropriate grip efficiency with the belt and lubrication capability with the pulleys and other components. It seems like the CVT would be happiest perpetually at 85c but that's probably nearly impossible to achieve using any means.

I have been considering an external cooler but it seems the results are mixed, even using the OEM one that is stock in other markets. Even seen some people say that they saw an increase in temperatures after adding auxiliary cooling radiators with fans. A few years ago I had an idea of attaching some sort of heat sinks, but really at that point you might as well just have a custom CVT pan fabricated that has lots of fins and surface area - but who knows if even that would help.

One thing that has also kept me from adding one using that beehive with the four ports is that I would be concerned that by the time you are adding a large enough additional radiator to really drop the temperature that you might be adding so much additional stress to the pump that you are negating the wear and tear benefits you are after.

It's too bad that all these years later there still isn't a consistent and reliable way to manage CVT thermals. I like the CVT - the torque vectoring alone make its worth it and even in pure driving characteristics it actually has some really positive attributes that you grow fond of like having that nice smooth power available coming out of corners; but the once in a blue moon mine kicks into protect mode I feel like I am killing it and really yearn for a way to prevent that.
 

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The factory are mainly worried about the power loss in pumping the colder oil and also pumping thicker oil, though the thicker oil will cavitate in the pump which is bad too. This is why they are running lower viscosity oils now and doing all they can to turn the oil pump pressures down, even as far as going electric auxiliary oil pumps for on-demand requirements. I'd say 85*-90*C would be ideal but not totally sure.

The Beehive cooler is doing most of the cooling, but it's still not efficient enough. The auxilliary cooler is splitting the oil flow. This can be good or bad depending on how good the oil cooler is and how restrictive it is. Some guys have completely bypassed the Beehive and did see higher temps. Let's say an oil cooler has it's oil flow cut to 50%, it's thermal heat transfer get's reduced to 70%, something like that. Thus if I now have equal (2) coolers in parallel I split the oil flow 50/50 % but pickup 70% + 70% of the total Btu/hr capability. So I'm still up +40% over what I had or 140% of the original heat transfer capacity. That's IF the oil flow is split evenly, and IF the heat transfer capability are also equal. Too many unknowns for that to be correct unless the coolers are identical, and a Beehive and auxilliary oil cooler are no where near identical. Now that I think of it, having a restrictive auxilliary oil cooler is probably MORE beneficial on this type of setup. Running an unrestrictive auxiliary oil cooler could potentially pull a lot more oil flow away from the Beehive without a lot of Btu/hr to go with it, which is exactly what you don't want to do.

More than anything else, this is probably why you see such inconsistent results, since it's a balancing act of oil flow restriction/throttling and thermal capacity of the auxiliary oil coolers.
 

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If it was me. I would try to source the cooling plate instead of the 4 pipe beehive. We heard they mite leak but the flow has to be better as the channels are bigger as well as the lines / fittings.
 
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