B500: How much cooling needed?

[6805eagleguy]

I am wondering what kind and how big of cooler I need for the B500. On the Bluebird the cooler was integrated into the main radiator.

I have a Hayden oil cooler, so I am wondering:
Is it possible to have to big of cooler?

Will this cooler provide enough cooling?

Does it matter that this cooler was used with hydraulic fluid before?

I know a lot of guys on this site have B500's so... What kind of cooler do you have?

Thanks in advance

M

[luvrbus]

Was the cooler integrated in the radiator or just fed from the radiator the only BB I been around the cooler was a Allison cooler on the back of the  transmission and was fed from the radiator   

[buswarrior]

Find the heat rejection numbers for the B500.

And match to an appropriate CAPACITY cooler. It is not physical dimensions alone that dictate a cooler's ability to shed heat.

Size and number of passages, fin construction, hose size, etc etc.

Typically the fluid routing is hot from transmission, thru your added aux cooler, then through the stock cooler in order to moderate any over cooling and back to the cold side of the transmission.

The point is often to remove the transmision's heat load from the engine coolant.

Happy coaching!
Buswarrior

[chessie4905]

Moderate any over cooling??? Routing it back through the existing coolant transmission cooler cancels the benefit of reducing engine heat lode. Unless you are running in the winter, you don't need to worry of trans fluid not being warm enough. Put transmission fluid in the freezer and see what happens. If you are truly concerned about too cool in cold weather, you can partially block the airflow through the cooler. I've driven busses and cars in below freezing weather and transmissions work fine even before warming up.

[luvrbus]

The B500 usually has the cooler on the transmission with 2 coolant lines connected to it lol they are expensive 2000 to 3000 bucks 

[chessie4905]

Here's some for that use:
https://www.amazon.com/Hayden-Automotive-1292-Heavy-Cooler/dp/B000HEADKG/ref=asc_df_B000HEADKG/?tag=hyprod-20&linkCode=df0&hvadid=312136743070&hvpos=1o1&hvnetw=g&hvrand=15824531113099045646&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9006537&hvtargid=pla-569948288121&psc=1

[6805eagleguy]

The B500 usually has the cooler on the transmission with 2 coolant lines connected to it lol they are expensive 2000 to 3000 bucks

Mine has a has two ports on the back of the transmission, towards the engine.  They come right out of the oil pan.  2 , 1 inch or so hoses carried ATF to and from the main radiator. 

[6805eagleguy]

How many GPMs does the B500 make?

[bevans6]

I didn't find a recommendation for a B500, but a HT 740 type trans running behind a 450 hp engine would need between 100K btu and 165K btu (heat rejection varies with air flow, fan driven usually).  A single pass air to oil cooler from Hayden is their part number 1297, 37" by 30" by 1.5" thick, with 1.25" hose fittings.  So kind of ridiculously large, yet that is what is needed.  I put around a 120K Btu air to oil cooler in with my MT 647, on the theory that I could block off air flow if it ran too cold, add fans if it ran hot, and I got it for free.  it is a two row, double pass around 20" by 25" and 3" thick.

[6805eagleguy]

That makes sense.

The cooler I have is actually custom made by Hayden for bluebird, to cool the hydraulic fan.  Hayden did not know how many BTUs it was.  Monday I will try to contact bluebird.
Looks like a Hayden single pass cooler is not terribly expensive, I may just by a new one, which would probably be OK.

[bevans6]

The trick is to find a place to put the damn thing!  Mine is standing up beside the engine where the factory AC compressor used to sit.  It gets some radiator air blown on it from the right hand squirrel cage fan.  Your application is going to be different.

[luvrbus]

I looked it up in my principal of operation manual the 500 with a retarder is 5500 BTU/Min @ 18 gpm flow ,to give you a idea the sump cooler inside the radiator is 3'' x 18'' with 7 plates 530 BTU/Min @ 4.5 gpm flow  this Allison data ,no mention of a air to oil cooler for a B500 Allison forgot to mention it's a 100 psi

[chessie4905]

Gives a good idea how much heat is added to cooling system.

[bevans6]

FWIW. 5500 BTU\min is equivalent to around 330K btu/hr, which is the rating that manufacturers like Hayden use to rate their coolers.  Different ratings, different temp deltas, different flow rates for both cooling air and fluid all make a difference on a air to oil cooler.

[buswarrior]

And the B500 makes that inferno under retarder use, B500 without retarder likely close to 740 heat rejection.

To mess with a smaller cooler, delta T with a smaller cooler, length of time downhill with max retarder before meltdown is expected, more to mix into the math. Watching Trans temps and using the transmission aggressively in lower gears to help slow will be a big heat savings, as well as getting the engine juices and fan running hard.

The worst is dragging full retarder in 6th gear, and forcing all the energy of slowing into the transmission fluid, with the coolant moving slowly and the engine fan loafing.

Allison and MCI screwed it up in the earlier D models, too little cooling for the tranny. At one point, full fluid changes once a month was the only way to maintain warranty until a fix was retrofitted... dialing back retarder power, programming gear downshifts was another, and that was with TranSynd!!!

Shame, it drove a lot of fleets to engine brakes, and made the ride comfort deteriorate for the passengers.

A good tour driver could really run a smooth bus, extend brake life a long way, with full control of the retarder and transmission downshifts.

One simply can't do it that fine with an engine brake.

Happy coaching!
Buswarrior