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 ;D
M
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
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
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.
The B500 usually has the cooler on the transmission with 2 coolant lines connected to it lol they are expensive 2000 to 3000 bucks
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
Quote from: luvrbus on May 17, 2019, 03:45:09 PM
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.
How many GPMs does the B500 make?
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.
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.
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.
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
Gives a good idea how much heat is added to cooling system.
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.
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
Could we say that you need to cool the trans oil from 250-300F down to 200F, and maybe it equate to removing 60-80 000 BTU.
The point is oil at 250F will emit a certain amount of BTU and at 300F it will emit more BTU, but you dont have the remove all the BTUs (or the oil would be cold). What do you think ?
My understanding is the engineers know the temps in and out, the volume of fluid, the energy inputs and the cooling recommendatiions are designed to result in their preferred temps under specified conditions. So they aren't trying to dump all heat, just excess heat to end up in a good zone for the application. I think for most auto's that's kind of 200 - 225 F-ish. If the recommendation is XXX Btu's, then that's what is required to cool it down to 200, if 200 is the goal temp. Water to oil coolers will probably be specified differently than air to oil coolers. Water to oil is cooling with 200 degree coolant, so pulling big energy out of the trans fluid into the coolant is different that transfering it to 130 degree air. Most bus transmissions are designed to be cooled with coolant, not air, and the heat load is added to the engine coolant. Also helps keep things warm in cold conditions, I imagine.
This is one of those complicated topics, with different goals, depending on the busnut.
Engines and automatic transmissions make lots of heat that needs to be dumped overboard.
Stock systems may have been (polite way of saying WERE) lacking right from the factory, busnuts may be putting more heat in than stock, the cooling system is no longer as efficient as it was new.
Typically, we are limited by vehicle structure and packaging, so have fans and radiators that don't readily upgrade.
Those radiators are all different ages and conditions.
Some busnuts want to raise their horsepower via bigger injectors, turbos or a re-power, all of which makes more heat.
Some busnuts want to add an automatic transmission where the original manufacturer did not consider offering one, and the cooling system is not sized to accommodate.
Some busnuts want to operate in the extremes of mountains and deserts without making the compromises that stock set-ups force one into, slowing down to reduce temps being a big one.
How to free up some existing cooling capacity?
Adding an auxiliary hydraulic cooler gives a busnut a way to remove the transmission heat from the cooling system, for whatever reasons one wants more cooling.
Installing properly placed temperature probes so the busnut can surely see the real temp, in and out, makes for good decision making.
In order to avoid making engineering errors, maintaining the stock style tranny oil to engine coolant cooler is a good move. No fancy controls to regulate the tranny temp are required. If the aux cooler is the wrong size, the engine coolant cooler will add or remove whatever the aux cooler didn't do right.
Running cold in winter conditions can't happen, and if the aux cooler can't take it all out, the engine coolant can valiantly try...
A simple fan switch that the busnut engages under high heat conditions does the job.
Busnuts who have installed a decent sized Hayden in the curb side engine access door of the MCI 8 report they never have to turn the fan on, there is enough airflow to dump enough heat without the dedicated fan in Florida conditions.
Note, they set those fans to blow OUT, as there is positive pressure in the engine room from the big cooling fans running at full tilt. Somewhat counter intuitive, cooler outside, hotter air inside, but an electric fan will have a hard job fighting the big squirrel cages, and the effect could be stalled air in the aux cooler, not desirable.
Even for a middle of the road busnut, an aux cooler gives you more room, as your radiators, fans, seals and shrouds age and deteriorate, even if strenuous conditions aren't in your plans.
That's why we roll our own, everything is right, if you are happy with the results!
Typed riding in the belly of a Megabus double decker, for true flavour...
Happy coaching!
Buswarrior
When I completely rebuilt my entire cooling system two years ago to solve some ever-worsening overheating problems, I also installed a separate transmission fluid cooler, not so much to cool the transmission itself but rather to help lower the coolant temperature. It's a Thermal Dynamics DB-00341DC, the largest that would fit the only space I had for it, with 1" ports and a decent 14" electric fan. And to answer the big question, yes, it does make a difference to the engine's coolant temperature - it's certainly a few degrees cooler when the electric fan is running. The transmission fluid temperature, measured at the top exit hose of the TC housing, now either matches the coolant temperature or is a few degrees cooler, especially when out on the open road when it's locked up in 4th. The DB-00341DC is rated at only 30-something K BTU, but that's enough to help. I have a 195-degree temperature switch to turn on the fan, but most of the time I keep it always on with an override switch.
If I had space for a second one of these coolers (they're about 18" x 24", about 8" deep over the motor), I would also have one for the engine oil which now always runs about ten degrees hotter than the coolant, but I haven't any more space. Too bad. The new transmission cooler and the original Hayden 10421 hydraulic fluid cooler now sit behind the driver-side rear wheels, at a slight angle to catch the airflow under the bus while driving, but protected by the wheel well and mudflap from being hit by stones or road debris.
John
So you DON'T have a coolant transmission cooler anymore?
Buswarrior, Where does a '96 lie on that timeline? Should I be thinking about an aux trans cooler? (I may have one if I grab it today.)
Jim
Yes, '96 had problems.
Now, that being said, you aren't a hired steering wheel holder, and you aren't dragging 55 passengers around.
You know to use the transmission along with the retarder on long downhills, to keep engine fan and coolant moving, not just yank back on the joystick.
You want to know what your coach is programmed to do. How much retarder percentage, activated by the joystick, activated by the brake pedal, activated by throttle lift.
4 position joystick?
It all depends what the last fleet's brake life goals were, and what they thought of their drivers' abilities to use the equipment on their own to achieve that, or just programmed it to act all the time.
I wouldn't think twice, the small cost of a good cooler vs the game ending cost of a reman makes a great justification.
Heat is what kills all auto trannies, big and small.
Take the heat out, they live long lives.
Happy coaching!
Buswarrior
The first generation B500 had short lives anyways not much you can do to save one most series 60 in their life had at 3 behind them before the series 60 gave up
Well now that's an interesting perspective. The seller said he thought it likely the transmission had been replaced, but when I looked at it, it seemed pretty crusty compared to the engine so I just assumed it hadn't been. Maybe it had. Do you think the history in the DDEC3 controller would tell me anything about that? After I get it registered one of my first trips will be over to the neighborhood Freightliner shop to check that out.
I pulled that oil cooler yesterday. Don't know how much help it would be, it's probably pretty small in relationship to bus parts. But it does have rather large lines, pretty close to 1" and the core is probably something like 16" square by an inch and a half thick so it could reject some heat. But maybe not much more than a drop in the bucket for this beast. Anyway I snagged it.
I think the retarder control is the 4 position you mentioned. I didn't exactly count but my impression was 5 so you are probably right. No idea how it might have been programmed, guess I should add that to the list. Also of course being in the east there are only a few long downhills steep enough to challenge it I expect. That one headed down the east side from Va into NC would be the one I'd see the most of.
Jim
I have driven many S60/B500 buses. I don't think heat is a problem. Yea you can see the transmission temperature go up when using the retarder, but it quickly goes back down when you're done. Isn't transmission oil good to like 300F ?
Transmission oil temperature in a 2 stroke affects the coolant temperature much more, because the engine puts out twice as much heat as a 4 stroke.
JC
Got some good comments over the weekend!
I do not have a retarder! ;D
Which is just fine with me! I would rather use the jakes any day, even though they are not quite as smooth.
So, judging from the comments here, cooling is minimum without a retarder.
Cliff said it was 5500btu's a minute with the retarder.
What is the max heat with out a retarder? (I do not have an Allison book, need to order one)
Quote from: lostagain on May 21, 2019, 07:08:30 AM
I have driven many S60/B500 buses. I don't think heat is a problem. Yea you can see the transmission temperature go up when using the retarder, but it quickly goes back down when you're done. Isn't transmission oil good to like 300F ?
Transmission oil temperature in a 2 stroke affects the coolant temperature much more, because the engine puts out twice as much heat as a 4 stroke.
JC
The synthetic's will stand a little more heat than 300F it is the only reason some people use in the B500, I cannot see where the B500 last any longer using the high dollar stuff over 15/40
Quote from: 6805eagleguy on May 21, 2019, 07:18:30 AM
Got some good comments over the weekend!
I do not have a retarder! ;D
Which is just fine with me! I would rather use the jakes any day, even though they are not quite as smooth.
So, judging from the comments here, cooling is minimum without a retarder.
Cliff said it was 5500btu's a minute with the retarder.
What is the max heat with out a retarder? (I do not have an Allison book, need to order one),download a Mechinic Tips for the B500 is all you need a lot of info is only found in the Application Manuals and they are to come by
I posted it for you 530 BTU per minute for sump cooling and gave the size of the cooler inside the radiator from the Allison manual
Even though the synthetic fluid will stand more heat, the lip seals are still the same. They are robust, but can gradually degrade with extreme heat.
I like Jakes way better than a retarder.
JC
never had a retarder but due like the jakes .
on the mci I used them most of the time on high but there was times that I would run them on low
on the cat most times I use them on low then med. and hardly ever use them on high
dave