Speed Limiter / Governor Safe Tweaks

rabryant1 · 02-19-2019, 01:18 PM

Greetings -

Here's another one of those questions. I've tried using the search feature, but honestly got a little lost in translation. My bus specs are below, and the bus is currently limited to 52MPH. I believe its speed limited because the second you hit 52, you can hear the engine rev down substantially.

We are going to be using this bus mostly on highways where the speed limit is set to 70-75 and would like to go a bit faster then 52. Given the vast knowledge of the members on this form, what would be safe speed to limit the governor to given the information below?

Model:2000 Bluebird TC FE 3700
Build Date: 08/16/1999
Engine: Cummins ISB-190-BUS ENCORE / ISB CM550
HP: 190 @ 2600RPM
Idle: 800 RPM
Trans: Alyson AT545
Rear: 4.44
Tires: 40.5"

I appreciate all the help in advance.

turf · 02-19-2019, 01:56 PM

whats your rpm at 52?

it could be your fuel pump, your transmission, or somewhere else.

i see its a '99. i don't know anything about ecm

Booyah45828 · 02-19-2019, 02:08 PM

https://www.youtube.com/watch?v=vbuIrpfpwXU

rabryant1 · 02-19-2019, 02:21 PM

Quote:

Originally Posted by turf

whats your rpm at 52?

it could be your fuel pump, your transmission, or somewhere else.

i see its a '99. i don't know anything about ecm

Its a 2000, built in late 99. Not 100% sure of the RPM's at 52, I'll have to get my driver out to go check. Havent gotten my CDL yet.

geminusprime · 02-19-2019, 02:29 PM

Quote:

Originally Posted by rabryant1

Its a 2000, built in late 99. Not 100% sure of the RPM's at 52, I'll have to get my driver out to go check. Havent gotten my CDL yet.

Once you take enough seats out so it cannot sit more than 16 people, you don't need a CDL. And being honest, most of us drove our buses home (some thousands of miles) without removing the seats and without a CDL.

rabryant1 · 02-19-2019, 02:36 PM

Quote:

Originally Posted by geminusprime

Once you take enough seats out so it cannot sit more than 16 people, you don't need a CDL. And being honest, most of us drove our buses home (some thousands of miles) without removing the seats and without a CDL.

So still government-owned bus being operated by government employee. County policy requires us to have one even if it's not used to transport passengers anymore. I get looks whenever I just go start it to check something.

Check my thread in new members if your currious about our plans.

o1marc · 02-19-2019, 03:47 PM

I'd start looking for a transmission upgrade if you plan on going faster with that AT545.

Booyah45828 · 02-19-2019, 03:59 PM

With your specs you can theoretically hit 70 mph at 2600 rpm. Real world you'll probably get to 65 running wide open.

The video I linked shows how to remove the limiter. Any other questions ask away.

rabryant1 · 05-13-2019, 01:16 PM

Quote:

Originally Posted by Booyah45828

With your specs you can theoretically hit 70 mph at 2600 rpm. Real world you'll probably get to 65 running wide open.

The video I linked shows how to remove the limiter. Any other questions ask away.

So - Here is an interesting question. Our bus wont exceed ~1500 RPM's. Pedal down, all the way to 52 where it wont go any faster. Never exceeds 1500 RPM's.

Any ideas on that one?

cadillackid · 05-13-2019, 01:50 PM

what kind of engine? what year? sounds like it could be a speed limiter? or maybe there's a fuel issue where the engine wont rev higher?
need to more about what it is..

rabryant1 · 05-13-2019, 02:07 PM

Quote:

Originally Posted by cadillackid

what kind of engine? what year? sounds like it could be a speed limiter? or maybe there's a fuel issue where the engine wont rev higher?
need to more about what it is..

Is the information in the first post not enough? If so -what specifically do you need?

o1marc · 05-13-2019, 02:41 PM

Quote:

Originally Posted by rabryant1

Is the information in the first post not enough? If so -what specifically do you need?

He was probably replying to a subsequent post and didn't see the bus info in the OP. If you go to the UserCP and join the community by filling in your profile with your location and bus info. That way we see it on every post and can answer your questions easier.

Sleddgracer · 05-13-2019, 02:47 PM

Quote:

Originally Posted by Booyah45828

https://www.youtube.com/watch?v=vbuIrpfpwXU

looks simple enough

cadillackid · 05-13-2019, 03:46 PM

oops yeah I see it now.. and it defimnitely sounds like an electronic speed limiter.. changed by the program in the vid above..

-Christopher

brokedown · 05-13-2019, 04:03 PM

ON the up side, a 1500 rpm limiter means your AT545 transmission will last FOREVER

cadillackid · 05-13-2019, 04:05 PM

if its been rated at that its whole life that engine likely has a lot of life left in it too

Booyah45828 · 05-13-2019, 04:50 PM

I'm not sure why anybody would have rpm limited it to 1500.

At 1500 that at545 is most definitely not going to last forever. They're not really designed to be lugged that low, and live much happier lives at rpm's higher then what most diesel engines will run. Has to do with line pressure and fluid flow.

How do you know it's only going to 1500 rpm?

A tachometer can very easily be inaccurate.

drew78634 · 08-07-2019, 09:16 AM

Any update on this problem? Did you find a solution?

Drew

EastCoastCB · 08-07-2019, 02:01 PM

Quote:

Originally Posted by Booyah45828

I'm not sure why anybody would have rpm limited it to 1500.

At 1500 that at545 is most definitely not going to last forever. They're not really designed to be lugged that low, and live much happier lives at rpm's higher then what most diesel engines will run. Has to do with line pressure and fluid flow.

How do you know it's only going to 1500 rpm?

A tachometer can very easily be inaccurate.

My 545 seems perfectly content at 1700 rpm @ 65mph. Seems to slip a lot less than my last high revving one.

Booyah45828 · 08-07-2019, 04:47 PM

Quote:

Originally Posted by EastCoastCB

My 545 seems perfectly content at 1700 rpm @ 65mph. Seems to slip a lot less than my last high revving one.

Yeah, Charlie, I haven't figured out what's going on with your bus yet.

It must have some sort of aftermarket low stall converter in it because all the converters that I've seen that allison spec'd from the factory are all way too loose for you to be doing what your doing.

Allison had a minimum full-load engine governed speed of 2400. That means they want engine rated hp at that # or above. So the torque converters they used reflect that, which is why most engines with the at545 seem to be ran higher in the engine rpm range.

You can put a lower stall converter in it, and it's not a bad idea to do so, so long as you're easy on it. We did that with a pulling truck and an at545 and slipped/burned up the clutches because we applied too much power at too low of an rpm.

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