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#1
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Stock vs. External Tranny Cooler
I understand that the efficiency of the stock cooler is higher because of the liquid-to-liquid interface. However, the temperature of the coolant in the radiator must be far higher than ambient air.
Given the higher coolant temperature (I'm guessing 150 - 180 degrees F) in the radiator, and the lower ambient air temp (Santa Fe seldom gets up to 100 deg F), is the actual cooling effect (as opposed to cooling efficiency) of an external cooler higher than the stock cooler?
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Dick ************** 1999 Legacy GT 30th Anniversary Edition 2001 Outback Sport |
#2
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what a good question. I have no idea and have to think for a while and would have to investigate heat echangers.
one thing to keep in mind is I "believe" (those who read the alignment thread know what my thoughts are worth - not much) that the ideal operating temp is somewhere around 150F. Just high enough to get the TC to lock up, but not so much as to markedly degrade the life expectancy of the ATF. |
#3
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I think the radiator and a 1/4 size (of orginal radiator) add should be in series, add on after the radiator.
A very large AFT (3/4 size) cooler is needed if the radiator is by passed. I still do not know the answer to how hot the radiator fluid gets. If the fluid never goes over 180F the setting for the T-stat then the radiator should be included in teh cooling path with the add on. The question is: How hot does the radiator coolant get after a repeated romping around on the gas pedal? |
#4
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Re: Stock vs. External Tranny Cooler
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[This is what people generally say when they don't know the answer ] The stock liquid/liquid cooler is more efficient as you say, which means it is better at taking away heat than a liquid/air model. If the coolant liquid was as cool as ambient air, it would be a no contest, stock would win over the additional cooler. The stock cooler has one big advantage over the add-on model, it can heat up the tranny oil in the morning to the optimum viscosity, and maintain it within the desired range, usually. I have the extra cooler on mine, and the high viscosity of the cold ATF causes clunky shifts in the mornings. What the extra cooler does in warmer situations, heavy traffic and hillclimbs, it will keep the temp from going too high, i.e. prevents heat spikes beyond the normal range. This stops the ATF from breaking down and saves our trannies. In colder climes, the extra cooler may be overkill. Remember, the ATF has to be above a certain temperature range [150ish I think??] before the lockup clutch will operate in 4. Oil being too viscous is also sure to affect fuel consumption. Joe
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
#5
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Re: Re: Stock vs. External Tranny Cooler
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#6
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Re: Re: Re: Stock vs. External Tranny Cooler
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A good fix is fit a valve that will deny oil to the extra cooler in cold winter weather, and work as it is supposed to using the stock one. A cheaper solution, and just as effective, is to fit a piece of card or light aluminium across the front surface of the extra cooler, again, only in cold weather. Be aware if it is big and fitted in the usual place out front or in the sandwich position, you will also be denying cooling air to the rad and/or the aircon condenser. This would not be good or clever. If you hear the fans coming on a lot, working overtime, compromise and only block half the surface of the extra cooler. The divert valve is the better solution. In either case, when the weather warms up, don't forget to open the valve or remove the card as the case may be. Joe PS Enjoy Reading!
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
#7
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My dashboard temp gauge never goes beyond half way, in any hot weather, in heavy traffic, or when thrashing it speed-wise. Good cooling system IMO. Harvey mentioned in a thread elsewhere that the tray beneath the rads acts in a way to duct extra air through for better cooling at high speeds. Don't know how this works, but I believe it. My temp needle never stirs for any kind of provocation. Joe
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
#8
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hehe, guess what...I don't have a separate cooler.
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#9
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FYI: The engine temp sensor does not give any indication of the tranny temp. There is simply too much heat mass and too little transfer area in the engine cooling system for the tranny fluid to significantly alter the thremal content. If you install a tranny temp sensor, you'll be able to see that the tranny temp can be significantly higher, in the area of 220+, and yet the engine temp needle will remain steady. The fans will just cycle more often and stay on longer to keep the cooling system at optimal temperature.
KuoH Quote:
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#10
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I didn't suggest the engine temp gauge relayed any indication of tranny temp. I was answering his query on whether the coolant temp went up when thrashing the car. Must admit, if I was going to put in extra equipment, a tranny oil temp gauge is at the top of that list. Joe
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
#11
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Oops, sorry. I see where you were going with that now.
KuoH |
#12
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Touche. Joe
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
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