Just made the run from The Heart of Texas to the Phoenix area and wanted to post my joy at the power of the 8.3 and the Allison 4spd. Previously we had a Coachmen 32 rear diesel with the 5.9L cummins 195 hp and Allison 4 speed. On this same run we would get down to 45 mph on the tough uphills, with semi trucks passing us. With the Barth and our power configuration we held a minimum of 55 mph on the roughest climbs up to the peak of the Great Divide, I think around 5,300 ft MSL. The semi-trucks were at the same speed as us almost exactly and no cars passed us despite a long line of cars just behind us: the non turbo-ed autos were struggling as well.
Most of the time we were set on cruise at 70 MPH and rarely got below 65 MPH, only the once did we fall to about 57 MPH.
Additionally with our possibly highly unusual configured Regency with the radiator in the front with the rear engine, we are so over-cooled I never saw anything over 175 deg F after miles of continuous climbing.
I know the front radiator will be much more maintenance long term, however the cooling can't be beat!
Happy Thanksgiving from Sun City West (mother's house) and Scottsdale AZ (sister's house).

Wow! Sounds like you guys are having a great time! We can't wait to hit the road too. We are heading for Phoenix in about 3 weeks to spend the winter. Our daughter lives there and they are expecting their first baby the first week of March so we have to be there for the big event.
Are you towing anything? We are pulling a 01 Chev Tracker 4 door and found the toughest grades to be Hwy 89 out of Congress Az up to Yarnell Az. We were down to about 35 mph. On the run home 2 years ago,we went out of El Paso up US62/180 to Carlsbad New Mexico. On the long uphill thru Guadalupe National Park we had to lose speed behind a semi because of cars blowing by in the passing lane. That put us down to about 30 mph to get to the top!
The Interstates always seem to have easier hills than the state routes and it really helps to keep up your speed on the approach to the big ones.
We find cooling good too with the front rad, about the only time we get above 175 is in stop and go traffic, pulling the towed. Maybe 200 then.
We have sister coaches, yours is #139 and ours is #140!
Good Luck and have fun!
Don and Patty

quote:

We have sister coaches, yours is #139 and ours is #140!

That makes us kin now doesn't it? Least first cousins...
No toad, but heavily laden, full water and fuel: wife, 5 kids and associated baggagery.... Did I mention shoes?
I was highly impressed with this divetrain combo and now love the cooling of this front radiator.

Out of curiosity, does anyone have thoughts on why they went to a front radiator?

Out of curiosity, does anyone have thoughts on why they went back to a side radiator?

Was a choice offered by Barth, or did it just happen?

Even without cooling considerations, the lack of a radiator back there would improve engine access.

Other than the long run of plumbing, is there a drawback to a front radiator?

I certainly can't answer with authority which is the best or why Barth choose various radiator schemes but here are my thoughts.

I have a rear radiator on the Breakaway and it has been replaced with a high efficiency radiator when the original sprung a leak. Cooling is marginal at best, I have added auxiliary puller fans on the backside and that has help amazingly! I still see 200 occasionally and if the ambient is over 100 and I am at high altitude > 4000' I may even see 215. I drive hard and keep the engine RPMS up particularly up a hill.

Rear radiators:
They get VERY dirty fast, they load up with fine crud from the roadway and unless there would be baffles to keep the windage from the wheels from coming up into the engine compartment,(which would also allow the engine room to get much hotter) I see no way to keep them clean, I wash them off before the start of each trip but they are dirty in the first 1000 miles. I even mounted fans on the rear side openings to draw air into the engine room and discourage air drawn from the lower area. With the rear radiator, there is no way to use a clutched fan, the only air going thru the radiator is what the fan pushes thru, with the stack of 1)turbo intercooler, 2)trans cooler, and finally 3) the radiator, there is a lot of restrictions the air must move thru to cool everything. Further, air that is drawn and pushed thru the radiator is coming from low on the roadway, hot air, and is drawn past the exhaust, turbo and engine, so it is preheated, degrading the cooling. The fan has to operate 100% of the time or cooling will not take place (tried it with only the puller fans, doesn't work!!). As this is a constant drag on the engine, mileage will be effected.

Side mounted radiator:
Here the radiator can draw air into the radiator form, the outside directly and avoid the preheating effects mentioned above. Many of the side radiators have a separate trans cooler and or intercooler so the cooling duties of the radiator has a higher efficiency. Even if the there is a stack similar to mine, drawing the cooler air from outside would be a much more effective cooling system. Downside is a complex belt/gearbox arrangement (Had this on my '54 Scenic Cruiser GM4501) or hydraulic drive system. Probably could use a clutched fan arrangement to disengage the fan at times for better efficiency.

Front mounted radiator:

Obviously the best but there would be the issue of the LONG cooling runs to and from the engine. Would be the coolest outside air of the three systems and also the ram effect can not be discounted. The only downside I could think of is that the turbo intercooler would still have to be at the rear and have its own fan system as well as the trans cooler, Where these are located those that have the front rad know, but I am sure that the rear coolers would still be subjected to higher temperatures and dirt.

Speculation:
The 5.9L from the 160 to the 230 HP engines had the radiators in the rear and I believe there are cooling issues that if are not watched can/will lead to over temp and possibly engine shut down. When Barth used the 8.3L there is a bigger heat load to consider and perhaps that is why they went to the front and then later to the side.

I have played with mounting a small front radiator normally used for vehicle interior heating to be placed in the front heat lines. There is water flowing thru these lines all the time and part of the water circulation is used to preheat the hot water heater. I have made up a housing that would hold a small thermostat that would open at 190 to give extra cooling, the circulation to and from the engine would not change nor would I have to run any extra tubes/hoses. Placing this radiator after the main front heater, would not effect the output of the heater when called for interior heating. I have turned on my heater a couple of times when the temps were going up and it really helped for a bit until the heater core warmed up, no air thru it as I didn't need to scorch my feet. Haven't had time to try it yet but if see more runs at high altitude, high ambient temperatures getting the engine temp over 200, I will try it.

Spartan literature we have says you have a choice of front, rear or side rads. Also you can have Cummins, Cat or DD engines. Guess the customer can order what they like and Barth would build it.
Biggest drawback is the front mounted diesel generator does not have a roll-out cradle. OTOH the engine is on a roll out bed.
You are right about front rad making engine accessiblty easy. Two side doors and the rear double doors open things right up in there.
I knoticed a slight coolant dribble off the bell housing a while ago. I could tell it was coming from up above and crawled over top of the engine with a flashlight to have a look. Found a hose up there with a loose clamp. It just meant I didn't have to lift the bed from inside to get at it.
We are very happy with the Spartan/Cummins combo.
Don

quote:

Originally posted by bill h:
Out of curiosity, does anyone have thoughts on why they went to a front radiator?

Out of curiosity, does anyone have thoughts on why they went back to a side radiator?

Was a choice offered by Barth, or did it just happen?

Even without cooling considerations, the lack of a radiator back there would improve engine access.

Other than the long run of plumbing, is there a drawback to a front radiator?

One other consideration for side or front mounted radiator is that the 8.3L engine is a bit longer then the 5.9L, would have been a larger overhang and probably harder to tame the tail-wag!

quote:

Originally posted by MWrench:

When Barth used the 8.3L there is a bigger heat load to consider and perhaps that is why they went to the front and then later to the side.

I wonder if the radiator decision was Barth's decision or the chassis manufacturer's.

What years used front radiators?

Did all 8.3s use them, or just some of them during those years?

Cat?

Which chassis makers did the front radiator thing?

Went out to the bus and looked some things up. According to the documentation we got with our coach the rear over hand is 109" and the wheel base is 223".
We have taken the Barth out west to California and Arizona and down to Florida. Driven in all weather including torrential downpours. There is no noticable tailwag. There is no problem with passing big trucks either. Maybe the air suspension makes the difference because the thing runs like it is on the proverbial rails.
I especially love driving it solo without the towed.
Don

quote:

Originally posted by MWrench:
One other consideration for side or front mounted radiator is that the 8.3L engine is a bit longer then the 5.9L, would have been a larger overhang and probably harder to tame the tail-wag!

quote:

Front mounted radiator:

Obviously the best but there would be the issue of the LONG cooling runs to and from the engine. Would be the coolest outside air of the three systems and also the ram effect can not be discounted. The only downside I could think of is that the turbo intercooler would still have to be at the rear and have its own fan system as well as the trans cooler, Where these are located those that have the front rad know, but I am sure that the rear coolers would still be subjected to higher temperatures and dirt.

The intercooler on my buildout is actually an -aftercooler-. This is it is water cooled from radiator coolant which obviously works well due to the front radiator and low coolant temps. It employs a water to water tube and shell heat exchanger in the engine compartment. It all works very well, but as mentioned the long coolant runs can only add up to additional maintenance over a rear or side configuration. As well I can tell the water to water heat exchanger on the coolant loop will have to be replaced in the future due to corrosion. I can't see the condition of the actual aftercooler on the water to air coolant loop, it as well may need to be replaced at some point in the future.
So, considerably more maintenance: but seemingly unmatchable cooling.