Jeepin Jason
NAXJA Member #1100
- Location
- Lewisville, TX
Is the B&M 70268 tranny cooler suffient if bypassing the radiator? (PS cooling too)
I know there's a similar thread about this here on the first page, but all I seem to keep finding on this subject is bits of info, and nothing really "definitive". The B&M 70268 seems to be the popular model to use, and it appears to be the biggest 3/4" wide stacked plate cooler than B&M makes. It also supposedly has some thermostatic bypass built in:
"B&M’s SuperCooler low pressure drop coolers reduce the risk of lube system failure. A controlled amount of automatic transmission fluid (ATF) is allowed to bypass the stacked plate core, passing through a self-regulating orifice, which monitors resistance to flow. Controlled by viscosity, the thicker ATF is returned directly to lube through two open bypass passages positioned in the stacked plate core. As operating temperatures increase, more of the ATF flow is directed through the core. The result is highly efficient cooling technology that combines improved protection against lube system failure with the required levels of optimal heat transfer."
Now, I've searched and read back through about a year's worth of threads on tranny coolers and B&M coolers in particular. I've already got the Mopar aux tranny cooler from the tow package, but it's not really sufficient for hot-n-heavy wheelin' (tranny likes to top 220* often). So my plan is to get a new, bigger aux tranny cooler and mount it on the passenger side, bypass the in-radiator "cooler", and possibly reuse the OEM cooler as a PS cooler (ala Richard) and move it more to the driver's side.
I want to bypass the radiator to simplify the system and reduce the thermal load on the radiator (and hence the engine cooling itself), especially when wheelin' for long periods of time. It seems that others have done this with good results, but most of the info on this is along the lines of "don't be stupid when you do it" and "make sure you use a cooler that's big enough". Well, what's big enough?? Do you absolutely need a thermostatic bypass valve to get the tranny up to temp and keep it from running too cool?
I like the stacked plate design as I think it's more efficient at cooling vs the tube/fin design, and if the B&M has a thermostic bypass feature built-in (not exactly sure how they do it, but they say they do), that eliminates the need for an external thermostatic vavle when bypassing the radiator. The B&M 70268 measures 11"x7.5"x3/4" and is rated at 19,000GVW. Will this be sufficient as the sole fluid cooler for the tranny? Is anyone doing this exact thing?
If you are bypassing the radiator, what specific setup are you running? Brand/model/size cooler? thermo bypass valve? external filter?
Or should I go with something like the 12"x11" Imperial model from Advance Auto Parts as shown in this write-up?
http://www.electronicimpulse.net/~vissagoth/jeep/tech/trancool.htm
And for those of you running a power steering cooler, is there anything "special" in plumbing one of those in? For you guys using a Mopar tranny cooler as a PS cooler, have you had any issues with that? The tubes on the Mopar tranny cooler look relatively thin (vs the round 1/2" tubes on something like a PermaCool model), so I wasn't sure if it would be able to flow enough? Of course, I have no idea what kind of flow rates the PS system has, so it may be a non-issue.
I know there's a similar thread about this here on the first page, but all I seem to keep finding on this subject is bits of info, and nothing really "definitive". The B&M 70268 seems to be the popular model to use, and it appears to be the biggest 3/4" wide stacked plate cooler than B&M makes. It also supposedly has some thermostatic bypass built in:
"B&M’s SuperCooler low pressure drop coolers reduce the risk of lube system failure. A controlled amount of automatic transmission fluid (ATF) is allowed to bypass the stacked plate core, passing through a self-regulating orifice, which monitors resistance to flow. Controlled by viscosity, the thicker ATF is returned directly to lube through two open bypass passages positioned in the stacked plate core. As operating temperatures increase, more of the ATF flow is directed through the core. The result is highly efficient cooling technology that combines improved protection against lube system failure with the required levels of optimal heat transfer."
Now, I've searched and read back through about a year's worth of threads on tranny coolers and B&M coolers in particular. I've already got the Mopar aux tranny cooler from the tow package, but it's not really sufficient for hot-n-heavy wheelin' (tranny likes to top 220* often). So my plan is to get a new, bigger aux tranny cooler and mount it on the passenger side, bypass the in-radiator "cooler", and possibly reuse the OEM cooler as a PS cooler (ala Richard) and move it more to the driver's side.
I want to bypass the radiator to simplify the system and reduce the thermal load on the radiator (and hence the engine cooling itself), especially when wheelin' for long periods of time. It seems that others have done this with good results, but most of the info on this is along the lines of "don't be stupid when you do it" and "make sure you use a cooler that's big enough". Well, what's big enough?? Do you absolutely need a thermostatic bypass valve to get the tranny up to temp and keep it from running too cool?
I like the stacked plate design as I think it's more efficient at cooling vs the tube/fin design, and if the B&M has a thermostic bypass feature built-in (not exactly sure how they do it, but they say they do), that eliminates the need for an external thermostatic vavle when bypassing the radiator. The B&M 70268 measures 11"x7.5"x3/4" and is rated at 19,000GVW. Will this be sufficient as the sole fluid cooler for the tranny? Is anyone doing this exact thing?
If you are bypassing the radiator, what specific setup are you running? Brand/model/size cooler? thermo bypass valve? external filter?
Or should I go with something like the 12"x11" Imperial model from Advance Auto Parts as shown in this write-up?
http://www.electronicimpulse.net/~vissagoth/jeep/tech/trancool.htm
And for those of you running a power steering cooler, is there anything "special" in plumbing one of those in? For you guys using a Mopar tranny cooler as a PS cooler, have you had any issues with that? The tubes on the Mopar tranny cooler look relatively thin (vs the round 1/2" tubes on something like a PermaCool model), so I wasn't sure if it would be able to flow enough? Of course, I have no idea what kind of flow rates the PS system has, so it may be a non-issue.
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Odd thing is, engine temps appear to be slightly higher than previously, though still 210* or under so they're perfectly fine. 
