3126, Allison 545, Low Top Speed

knowpistons · 08-04-2015, 06:10 PM

I bought a school bus to convert it to a tailgating bus when I bid on the bus it said it had an International Motor in it (T444E). When I went to go pick up the bus I looked under the hood and it had a big yellow anchor under there (3126), since I drove 400 miles to go pick it up I said just took it for what it was.

The only problem I have is the Webasto Scholastic heater motor is bad and the more pressing issue is it wont go over 62mph. It gets very daunting while driving on the highway just for the 30 miles to the stadium and has completely sidelined any away game trips. My question is, is this thing electronically governed or am I just limited by the gearing/engine power? I don't want to take it to the CAT dealership and have them charge me $200 to tell me there's nothing they can do.

Here is the auction that I won with some info: 2000 Freightliner 3800 BUS, 7.3L V8 DIESEL CONV-MSDE-C-8 # B99376 - GovDeals.com

opus · 08-04-2015, 06:38 PM

Whats your top speed RPM and what gear ratio have you?

knowpistons · 08-04-2015, 06:40 PM

Top speed RPM is about 2600, its pinned. As far as gear ratio, do you mean rear end? I'm not sure the rear end ratio, I'll have to check.

opus · 08-04-2015, 06:43 PM

You're pretty close to the limit there. Not sure on where to find rear end ration on a Thomas. Probably a data plate and thats probably whats holding you back. Not sure you'd have enough umph to go with a taller gear ratio.

knowpistons · 08-04-2015, 07:24 PM

I'll check tomorrow and see if I can find the data plate inside maybe, I just wish I had another gear and some extra HP. I figured it wouldn't be this slow since its not even a full size bus

crazycal · 08-04-2015, 07:39 PM

[quote]once the item has been removed from the sellers location; all sales are final.[/quote]

I think you are SOL as far as the seller is concerned. Sorry to say this but many times the items are post by complete imbeciles that don't know the difference between a school bus and a banana.

Why would a Freightliner have an International engine? A 3800 is an International model number. As soon as I see goofy stuff, I ask questions until I am satisfied. Even if it had a 7.3 in it, what makes you think you would have done better than 62mph? I think you better do some research before spending any more money.

opus · 08-04-2015, 08:17 PM

Webasto motor is about $500-$600.

Kubla · 08-04-2015, 08:35 PM

find out what the rear end ratio is, also 62 is a common speed that buses are electronically governed at out of the factory, being a 2000 model, you are probably hitting a governor if you are not hitting redline, you should be able to go to the freightliner dealer and have the governed speed moved up

claydbal · 08-05-2015, 05:54 AM

max rpm = 2200. i wouldnt turn it up. 62mph is great, just leave earlier and enjoy the trip!

BTW, i merged your 2 threads into one. please dont double post. thanks

turf · 08-05-2015, 07:35 AM

i took my bus in to the mechanic to have him turn up the fuel. the mechanic was the cummins/allison dealer, in my area. they straight out refused to tune the engine beyond stock.
i explained, not a school bus, private vehicle, but the owner still refused. he said something about a fine they'd be libel for if they change the motor out of spec. he also felt any change would be the death of the motor.

its worked this long.... not tuning it was the reason it has worked. enjoy going slow.

Hvbuzz · 08-05-2015, 10:29 AM

Just curious, have you verified the transmission that's really in there? If the seller didn't know what engine was in there pretty sure they didn't know transmission either.

EastCoastCB · 08-05-2015, 11:23 AM

I know a guy with a 3126 and 545 and his only does 55 with a tailwind. Sounds like you got a FAST one, op.

Tango · 08-05-2015, 12:35 PM

Roger "the fast one". And the RPM's you are pulling are at at the top of the limit. Personally, I would not want to run that engine in that range very often..otherwise they go Kablooey. You might...I repeat MIGHT...be able to go a tooth or two taller on the rear end, but that will come down to what axle & gearing you already have. Other than that, taller tires might give you maybe 3mph.

60+ plus in a school bus is pretty close to as good as it gets except for a few "special" rigs that were set up at the factory for higher cruise speeds.

And don't forget...going faster equates to the need for more stopping power.