Flyer D900 Series (1979-1981)

[Benjamin]

I have some thoughts about the Flyer D900 series of buses.

Mainly, about their engines: I would think the mega-rare Cummins VTB903 diesel engine was the only hi-power option for the USA-spec buses until the 6V92TA was made available and when the D900 was being phased out in favor of the D901, since unlike the GMC RTS II Series 03 and the Grumman Flxible 870, the Detroit Diesel 8V71 engine was not cataloged (the lo-power 6V71 was, though).

I would think the VTB903 was not available in Canada given that country's preference toward the 6V71N Detroit Diesel.

~Ben

[BCT-3122-D800-10240]

I have some thoughts about the Flyer D900 series of buses.

Mainly, about their engines: I would think the mega-rare Cummins VTB903 diesel engine was the only hi-power option for the USA-spec buses until the 6V92TA was made available and when the D900 was being phased out in favor of the D901, since unlike the GMC RTS II Series 03 and the Grumman Flxible 870, the Detroit Diesel 8V71 engine was not cataloged (the lo-power 6V71 was, though).

I would think the VTB903 was not available in Canada given that country's preference toward the 6V71N Detroit Diesel.

First of all, the D900 model was only built in 1979 and 1980. Remember, AC Transit received some D901A's in 1980, so by 1981, production was the D901A only. Secondly, to my knowledge, none of the D900's were ever built for Canada with the VTB-903 engines. They were all 6V71N. The only VTB903 engine equipped D900's that I know of that ever ran in Canada were the second hand units leased by BC Transit in Vancouver from Seattle Metro back in the mid 1990's.

Also, regarding your comment about Canada's preference towards the 6V71N engine... I would believe that is more due to the fact that the 6V71N engine was probably cheaper to spec a bus with than a Cummins VTB903 or a 6V92TA at that time. I await corrections now...

[BBC 9197]

Most Canadian properties did not order air conditioning in their D900's so there was no real justification for ordering the more powerful engine option.

[Orion V]

I have some thoughts about the Flyer D900 series of buses.

Mainly, about their engines: I would think the mega-rare Cummins VTB903 diesel engine was the only hi-power option for the USA-spec buses until the 6V92TA was made available and when the D900 was being phased out in favor of the D901, since unlike the GMC RTS II Series 03 and the Grumman Flxible 870, the Detroit Diesel 8V71 engine was not cataloged (the lo-power 6V71 was, though).

I would think the VTB903 was not available in Canada given that country's preference toward the 6V71N Detroit Diesel.

~Ben

There was also the 8V71N as a higher powered engine.

[Benjamin]

There was also the 8V71N as a higher powered engine.

I wish I knew which TA here had actually ordered their D900s with such an engine as that. Since the D900 series was only made in 1979 and 1980, the number of TA's becomes much narrowed down.

~Ben

Edited January 27, 2013 by Benjamin

[Orion V]

I wish I knew which TA here had actually ordered their D900s with such an engine as that. Since the D900 series was only made in 1979 and 1980, the number of TA's becomes much narrowed down.

~Ben

Probably no D900s ever had the 8V71N but I stated that engine under the impression that you were wondering how many hi powered bus engines were available in that time period.

[northwesterner]

Most Canadian properties did not order air conditioning in their D900's so there was no real justification for ordering the more powerful engine option.

Some of the American properties that order D900s with the Cummins 903 did not order air conditioning. The more powerful engine wasn't just there for a/c load considerations. American properties starting in the 70s ordered their vehicles with big engines to allow them to perform on all types of service (in city, hill climbing, freeway) for maximum flexibility. Canadian properties continued (through the late 80s in some cases) to spec small engine with specified gear ratios for the service the vehicle was expected to perform.

[Benjamin]

Some of the American properties that order D900s with the Cummins 903 did not order air conditioning. The more powerful engine wasn't just there for a/c load considerations. American properties starting in the 70s ordered their vehicles with big engines to allow them to perform on all types of service (in city, hill climbing, freeway) for maximum flexibility. Canadian properties continued (through the late 80s in some cases) to spec small engine with specified gear ratios for the service the vehicle was expected to perform.

I think the Allison V730 (and its electronic counterpart, the V731) always had the same three transmission gear ratios in its whole lifetime, so it's really also all about the rear end ratio, too. V730-equipped buses would use a 5.38 rear for 55 MPH tops, while the 4.56 is desirable for up to 65 MPH. Direct-drive transmissions such as the Voith D863.2 would use a 4.56 rear for 55 MPH tops and a 4.1 rear for 65 MPH.

~Ben

Edited January 29, 2013 by Benjamin

[BCT-3122-D800-10240]

I wish I knew which TA here had actually ordered their D900s with such an engine as that. Since the D900 series was only made in 1979 and 1980, the number of TA's becomes much narrowed down.

To my knowledge, not a single Flyer Industries model were ever built with the 8V71N engine. The closest to that were the AM General's built for U.S. systems only.

[Detroit Diesel 6V92TA]

To my knowledge, not a single Flyer Industries model were ever built with the 8V71N engine. The closest to that were the AM General's built for U.S. systems only.

So pretty much either VTB-903 or 6V71N. It seems like most of them out here had VTB-903's and some were re-powered to 6V92TAs.