| Author |
Message |
Michael J (Mjryan) (67.41.239.49)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 22, 2002 - 5:37 pm: | |
4106 "The sports car of busses"
Is this true? What is the different between the 4106 and the 4104? Can the 4104 be upgraded to the above if it is indeed a sport car in bus clothing?
Mj |
Jim Stacy (12.87.109.163)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 22, 2002 - 10:00 pm: | |
The '06 was more than 1000 pounds lighter than the '04 due mostly to thinner siding and other structual changes. It was the first coach with th 8V71 at around 260 hp compared to the 6-71 in the '04 at about 180 hp.
Many '04's have been upgraded to the 6V92TA which can be boosted to 350 hp with a turbo and injector change. This makes a strong runner with the 3 speed V730, would be better with a 5 or 6 speed if they were available. FWIW
Jim Stacy |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 22, 2002 - 10:08 pm: | |
Michael (and others):
Well-known bus industry photographer Bob Redden coined that phrase after he purchased an '06 back in the late '70s to use while journeying around the country on assignment. (You can frequently see his work in National Bus Trader, an industry publication. www.busmag.com)
The basic chassis layout is very similar, with the 4106 being more squared off, and having a rear window (if it hasn't been capped) more in common with the "New Look" transits, which came out approximately the same time.
The suspension is different, as the 4104 uses air beams with convoulted air bellows, whereas the '06 uses rolling lob style, without the leak-prone beams (altho many have been plated nowdays). The '06 also has a pretty hefty anti-roll (or anti-sway) bar on the rear suspension.
HVAC is also different. The '04 had a pony engine located behind the LF wheel driving the A/C compressor, on the '06 the compressor is driven by a PTO off the main engine.
Biggest difference, however, is the powertrain. The 4104 uses the inline 6-71, rated at about 235 hp with the 4-valve heads, the 4106 uses the 8V71, rated at about 275 hp. Both came stock from the factory with manual four-speed transmissions - automatics were not an option.
"Well, I'll just slap an 8V71 in the tail, and away we'll go". Not quite:
The 4104 powertrain layout is engine, transmission, bevel gearset, driveshaft, rear axle. During development work on the 8V driveline, GM discovered that the greater torque output of the eight was destroying the bevel gearset, especially in the lower gears. Their solution was to place the bevel gears between the engine and transmission, where they lived happily ever after, even today in V-drive transits.
Changing the bevel gears also required changing the position of the ring & pinion gears in the differential - on the 4104, the "pumpkin" is off-set to the driver's side of centerline, the 4106's is off-set to the curb side. If you do a powertrain swap without matching the driveline angle properly, the results are severe vibration and shortened U-joint life.
There are numerous other minor differences, but I've covered the major basics. Go back to the BNO main page, and click on the link to "The Bus Stops Here" and scroll down to GMC to see pics of the two models.
(Some folk are now calling the RTS transits the more modern bus sports car, and there's good reason to do so - especially those models with the independent front suspension. No argument from me on that one - the RTS is a great bus to drive!)
HTH,
RJ
PD4106-2784
Fresno CA |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 22, 2002 - 11:01 pm: | |
RJ,
My 4104 had a turbo. Is that standard on all 4104's, and if not, what was the HP difference between turbo'd and non turbo'd? Thanks,
Richard |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 3:10 am: | |
Richard -
According to the DDA spec booklet I have, the stock 6-71 engine, as used in the 4104, is rated as follows:
238 hp @ 2100 rpm with C65 injectors, 600 ft/lbs torque at 1600.
The 6-71T yours had is rated at:
275 hp @ 2100 rpm, N75 injectors, 772 ft/lbs torque.
This is virtually identical to the 8V71:
280 hp @ 2100 rpm, C60 injectors, 770 ft/lbs torque.
As you know, all DDA two-strokes have the rootes-type blower to pressurize the air boxes in order for the engine to run. Some folks call it a supercharger, but it really isn't in this application. All of the 4104s came with the non-turbo 6-71 engine, someone hopped yours up!
HTH,
RJ
PD4106-2784
Fresno CA |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 8:25 am: | |
No, I did not know that. I probably just had the blower and thought it was a turbo. LOL
Richard |
John Rigby (24.174.233.65)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 8:57 am: | |
RJ
When my 671 was rebuilt ( 50.000 miles ago )they put N-70 injectors and did some thing with the timing.it was an out of frame O/H. It never ever black smokes/only grey for the first few seconds on start up.Last week I had DD check and set the rpm 600 at idle and 2200 Max.
Will the HP be any diffrent set up this way??
Thanks
John Rigby |
FAST FRED (209.26.115.59)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 9:16 am: | |
Mere light weight and great construction is not the sole reason for the title ,
"The SPORTS CAR of Coaches."
The tranny shift points are matched very well to the needs in back roads or city traffic.
( kinda like a good Italian Motorcycle)
The brakes are excellent (if maintained) so 4 wheelers and city traffic are easy.
The steering is light and very precise , so cruising at 70-80 is always fingertip.
(Camping sites do require a bit of skill)
One simply rocks the coach a few inches in first by coming on & off the clutch gently.
This produces enough motion in a few inches to lighten the steering effort .
With a moderatly maintained cooling system the coach usually can not be overheated .
Of course if you try to climb hills at 25 in 4 th it may overheat.
The empty coach is about 19,000 lbs , with a light weight interior 24,000 cruise away is easy,
The factory N-60 injectors need no hot rodding and you climb hills faster than the "450" Hp behemoths that weigh 50,000+ lbs .
This keeps the fuel milage in the 9.5 to 10.5 range so any "speed" advantage from having a 4 mpg coach is soon lost by having to stop for a refuling every 350 miles , instead of every 1,100.
It also makes trips to fuel Expensive Canada doable , as you can return to the US before you need a drop.
Being inder 10 ft high there is no need to be stuck on the Truck Route in every small town , as the 13.5 ft campers do.
I could go on , but too many folks wanting to scrap a MCI or Eagle house bus only send the GM prices climbing even higher!!!
OPINION
(Biased for sure , I am priveleged own one ).
FAST FRED |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 12:30 pm: | |
Good points, Fred.
Never did get into how much fun they are to drive in my little discourse. . . but you hit the nail right on the head.
One minor detail, tho. Using the stock 60 injectors, the '06 WILL drop down and require second gear if you're pulling a 6% grade at 5,000+ ft with 35 passengers and full baggage bins. BTDT
RJ |
Scott Whitney (66.82.9.17)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 11:16 pm: | |
How big are the baggage bays? How much could one reasonably tow?
Scott |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 11:33 pm: | |
Scott - Are you asking about the 4106's baggage bins?
97 cu/ft in the front luggage bin
90 cu/ft in the rear luggage bin
11.75 cu/ft in the bin behind the LF wheel
10.5 in the bin behind the RF wheel.
Additional space is available in the old HVAC blower compartment and the A/C condensor compartment, if you remove the OEM HVAC.
There is another little cubby that can be built behind the LR wheel after you pull the OEM A/C compressor. Many '06 owners move the start batteries here, and gain an additional 7 cu/ft of space in the rear bin.
4104s are similar, w/o the buildable LR cubby.
(Don't forget, both of these coaches are 35'x 96", and automatic only if repowered.)
HTH,
RJ
PD4106-2784
Fresno CA |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 23, 2002 - 11:36 pm: | |
Scott - I forgot the second part of your question:
The 4106 will tow as much as your Flx will - basically the same engine cradle assembly, but care needs to be taken not to burn the clutch away from a stop with a heavy load.
The 4104 will also tow as much as your Flx, but will slow down more pulling grades, and the same caution regarding the clutch.
HTH,
RJ
PD4106-2784
Fresno CA |
Larry (208.18.102.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 24, 2002 - 10:25 am: | |
RJ,
I interested in moving the batteries in ours.
Do they make the supports on the cradle or to bus structure?
The batteries I use are 104 lbs each I use four by putting the other two in the right bay, which services house and will boost start in cold weather, it would be nice to put the other two in the rear behind them to free the other side of rear bay.
Will that put to much weight on one side that way.
I keep them topped via using a converter charger.
I do also have a block heater. Everthing functions just fine.
Larry |
Larry (208.18.102.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 24, 2002 - 10:28 am: | |
Oh by the way my bus is well balanced the way I have it now.
Larry |
Buswarrior (Buswarrior) (64.229.213.196)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 01, 2002 - 2:09 pm: | |
Here's some seat of the pants experience gleaned from the local old timers who drove both the 4104 and the 4106 in those days.
The 4106 was the rocket ship of its day, not unlike the improvement today's drivers will tell you about the four stroke vs two stroke in the modern stuff. For the regular bus driver, faster usually means better.
However, up here in the snow, many of the old drivers say they really preferred the 4104 over the 4106 if the road conditions were to deteriorate. They all say the 4104 just "held the road better" and didn't give them as much cause to feel the coach was about to scare them.
No one knows why, and most don't seem to care. The "Traveller" was the choice over the "Flat Back" for running in the snow.
Of course, in conversion duty, who's worrying much about snow?
FWIW, old timers stories passed along for your consideration.
happy coaching!
buswarrior |
FAST FRED (209.26.115.55)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 02, 2002 - 4:47 am: | |
Perhaps more of the 04 were fitted with the front brake de boost than 06.
There was an optional switch on the dash that could cut the power of the front brakes in half , that would be used in ice & snow.
The steering would be able to function with less breaking loads.
OK so its not ABS , but not bad for 6 decades ago.
FAST FRED |
Luke Bonagura (Lukeatuscoach) (12.90.0.211)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 02, 2002 - 6:13 pm: | |
Hi Buswarrier:
I would like to add to your (seat of the pants) story with regard to operating a bus in snow.
In 1962, the first bus company I worked for Full Time was in Philadelphia and we used to get a bunch of snow back then.
We had a fleet of ACF Brills, Aerocoaches and a few GM 4103's & 4104's along with 1 NEW SDM5302, 40 foot GM Suburban.
In the winter, on a snow day, the old timers wanted the 4103's or Aerocoaches as they felt safest with them.
Now both models road on Springs, as opposed to air-ride. I wonder now whether that is what made the difference????
Back then I was still 2 years away from my bus-license so never had the opportunity to find out for myself!!!!
The way the weather is going this year, I have a hunch that there will be a lot of converted coach owners driving in snow on their way to warmer winter climate, whether they planned it that way or not!!!!
Happy Bussin to ALL!!!!
LUKE at US COACH |
|