Quote:
Originally Posted by Tango
ECCB...great numbers! --- I wanted to hit this point because so many folks seem to jump in and buy a bus with no idea what it is like on the interstate. And they are later stunned to learn it may only have a top speed of 50 mph or that they have to run at or beyond redline to
maintain anything like reasonable highway speeds.
NOTE to Newbies:
Running the numbers before making a buy will help inform you of what to expect if you plan on spending much time traveling.
Find out...
The rear axle ratio
The transmission final drive ratio
The tire diameter
The engines RPM "Sweet Spot" and Redline
From there, you can use any online gearing/speed calculator to see where you stand. If you go in well informed (like Mr. ECCB), you can find a rig that will give you excellent performance and durability for your intended purpose right from the get-go.
Otherwise...figure on spending a fair amount of money to make it right.
At least I went in fully informed and understood what it was going to cost to make a 45 mph Skoolie roadworthy. For some, the fix can cost far more than the original purchase price and be a back breaker.
It is best to know in advance.
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another piece too is.. "is the bus you desire even manufactured?" in my case there were very few pre 2005 busses built with overdrive transmissions.. the T-444E was thought to be a budget engine so many schools ordfered AT545's with them.. the DT-466E is a sought after engine and thus commands very high prices right off the gate for one with overdrive..
in my case I had it in the back of my mind if my AT545 ever blew up id be upgrading... granted im sure with what my 545 was doing it couldve been fixed fairly easily.. it was a valve sticking. or a clogged internal filter.. neverthless I chose to Build what I want rather than try and find it..
Tango didnt have much a choice.. but in the end is going to have a near perferct combo.. the folks at CAC have been running 4BT's with allison 1000s for years in their own personal trucks and their customers..
the 1000 and the 2000 are generally the same.. though the 2000 can be bouight with a wider gear ratio set.. a lower first.. the same 6th and a slightly lower 5th.. wider ratio helps a bit for faster starts in heavy vehicles..
GM used the 1000 in their pickups and their medium duty trucks up through the C-8500, International used the 1000 in their lighter 3000 series (aka the IC BE school bus platform)..
I think friehgtliner used it behind the MBE906 in the FL60's / 70's as well..
allison transmissions are work transmisisons.. they dont necessarily have the super smooth shift manners of a consumer trans like a 6L60E or the 4RL stuff.. they also dont take kindly to extreme high horsepower and torque thrown at them in overdrive.. (unless you build them with updates)... the Duramaxx guys know all about spinning the CLutches in 5th gear with the smoke turned way up...
the allison I have is updated and a mild performance build.. good to 500 HP.. more than ill ever throw at it in a school bus... medium duty long chassis arent designed to be ripped hard with extreme consumer-kid Horsepower.. esp with a school bus body.. (ever study the body mounts on a bus? they are simply clips that keep the body from, falling off.. they appear to provide NO rigidity to the frame...). so dropping huge amounts of power into a bus requires a lot of thought and fabriacting / stiffening of the frame to accomodate.. not to mention, motor mounts, rear, driveshaft, axles, you name it...
cruising at 65-70 is perfect for me..
-Christopher