Found a bus but top speed is 45mph

[Versatile]

Originally Posted by Oldmopars

Yes, I know this is a Ford 9in rear axle, but the picture is good for showing what the third member is. If you look at the picture, the Orange part is the "Third Member"

Ah yes. Just as i was implying.We mostly seem to go for the interiors and tank designs on these builds. I think to see some going to a new level on some of the mechanical items. That is one fantastic rebuild. Imagine rolling some thing that new being rolled under your bus.(No i am not going to do mine) I am just starting to clean up my engine compartment by armor all on the hoses and anything that is a little oily.
Fore the most part just changing the pumpkin is the way to go. I worked on a farm and those guys built things everyone else said wouldn't work. I helped build a 60 ft field sprayer back when there were not any being manufactured. We sprayed over 250,000 acres with those booms a 500 gallon tank mounted on a D145 Versatile 4x4 articulating tractor. I learned to not be imtimidated by this big stuff.

[Moonshyne]

Oh no you guys are going to make me cry 😭 just bought a 2001 Thomas Freightliner F565 Chassis 7.2L In-Line Cat 3126/CFE that goes 45mph. And I have no clue what to do besides cry after reading this thread.

[EastCoastCB]

Either its limited by the computer or its gear limited.
What's your rpm at 45?

[cadillackid]

Originally Posted by Moonshyne

Oh no you guys are going to make me cry 😭 just bought a 2001 Thomas Freightliner F565 Chassis 7.2L In-Line Cat 3126/CFE that goes 45mph. And I have no clue what to do besides cry after reading this thread.

so the first question to ask is what are your RPMs in top gear at 45? and is it shifting through all of its gears at light throttle?



if the RPM is below 2500 then more than likely you can just have a freightliner dealer turn the speed limiter off. otherwise you;ll have to make mechanical changes..

[Moonshyne]

I have no idea. It's a automatic

[EastCoastCB]

Originally Posted by Moonshyne

I have no idea. It's a automatic

have you driven the bus yet?
Does it have a working tachometer?

The transmission has no affect on why your bus only goes 45.

[PorchDog]

I too would be afraid of a Detroit Diesel Fuel Pincher. The cylinders are not Siammesed together at the top-- so they can possibly move-- and then you have head gasket failure. From an article---
The 8.2 was not expected to achieve the million miles between overhauls of heavy truck engines, but it was expected to last more than 100,000 miles in medium-duty truck service. Unfortunately, due to its inherently weak “Open Deck” free-standing cylinder design and light build, the 8.2 could not reach these goals and proved to be quite troublesome.

[Moonshyne]

Yea I drove it. It says it can go up to 85 on the dash. But there's something with the public school bus system (where I bought it from) that there buses only do 45mph

[cadillackid]

Originally Posted by Moonshyne

Yea I drove it. It says it can go up to 85 on the dash. But there's something with the public school bus system (where I bought it from) that there buses only do 45mph

the dash means nothing. there are a couple ways in which a bus can be speed limited.


1. the computer is programmed to slowthe bus down and reduce engine power when it reaches the set max speed..


2. the gearing can be built so that the bus is mechanically limited. the engine will reach its maximum RPM (red line on the RPM gauge.. usually 2600 on a CAT C7 / 3126).. this prohibits someone from changing the speed in the computer..




this is why we ask about maximum RPM.. if the bus is reaching a high RPM in top gear at 45 MPH then the only way to gain more speed is to change the driveline gearing.. (Rear end gears need to be replaced wit ha ratio that allows for higher speed)..


pretty much all school bus speedometers max out at 80-90.. its a standard gauge installed on them.



without the RPM info we cant beging to help you gain more speed.. thats the starting point.

[Moonshyne]

How do I find out the RPM info? And it's an automatic not a manual. No gears to shift.

[Jolly Roger bus 223]

sounds like an NC bus.
to find RPM you need a tachometer.
i have also read about an app called accousti tac but dont know how accurate it is nor have i tried it yet.
i thought i was the slowest one on the forum at 49mph.
i know what i need to do with mine but other needs and other money obligations keep getting in the way for that project.
good luck

[cadillackid]

I’ve not seen an FS65 that: doesn’t have a tach on the dash. Drive it till it tops out, count the gears it shifts .

It should be in at least 4th gear unless it has a 5 speed auto.

Is this a bus you don’t yet own? If so you can get the VIN and call Thomas or a freight liner deal, ask trans type and rear gear. Pics should show you tire size

[Veloc]

Originally Posted by Moonshyne

How do I find out the RPM info? And it's an automatic not a manual. No gears to shift.

I think I can assist you here.

To find the engine RPM, there is typically an RPM gauge called a tachometer next to, and about the same size as, the speedometer. It will be numbered in increments of 1000, and can go anywhere from 4000 to 8000RPM depending on how fast the engine can be expected to go. You will also see a colored band under the numbers, with either green, yellow then red or just yellow then red. Green is good, yellow means you are approaching the maximum RPM the engine is rated to turn, and red means you're in the danger zone. While not guaranteed to do so, running an engine past the redline means you are close to blowing it up. Now then, all that being said, there is no guarantee that your bus will have a tachometer. Not all vehicles come with them. If you don't have one, not a real problem, just drive the bus at its top speed and listen to the engine. If the tone is low and quiet, you are running at a low RPM but if it is loud and higher pitched, then you are running at a high RPM.

Automatics do have gears and they do shift, but the transmission does it automatically, hence the name automatic. Know how an automatic vehicle goes waaaa, waaaa, waaaa, waaaa as it picks up speed? Each waaa is the engine RPM increasing with the tone getting higher, each short pause is the automatic transmission shifting itself to the next gear, followed by the engine tone dropping down then increasing again as the RPMs build back up. You won't typically hear this on decel because the trans won't shift down until the speed falls enough, and when it hits its downshift speed the shift is usually unnoticed.

What they keep asking about is, when the bus is at its maximum speed of 45MPH, what does the tachometer show? If you see something like 2000RPM then it should be a simple matter to increase top speed, but if it is closer to 4000-5000RPM (whatever the engine's redline is) then the engine is mechanically limited and you aren't going any faster without major work for major money.

[magnakansas]

Wanna call and talk about this.?

William Seven eight five too zero seven seventy six hundred

[Moonshyne]

Wow! Ok Thank you!

[Moonshyne]

Yes a NC bus

[cadillackid]

Originally Posted by Veloc

I think I can assist you here.

To find the engine RPM, there is typically an RPM gauge called a tachometer next to, and about the same size as, the speedometer. It will be numbered in increments of 1000, and can go anywhere from 4000 to 8000RPM depending on how fast the engine can be expected to go. You will also see a colored band under the numbers, with either green, yellow then red or just yellow then red. Green is good, yellow means you are approaching the maximum RPM the engine is rated to turn, and red means you're in the danger zone. While not guaranteed to do so, running an engine past the redline means you are close to blowing it up. Now then, all that being said, there is no guarantee that your bus will have a tachometer. Not all vehicles come with them. If you don't have one, not a real problem, just drive the bus at its top speed and listen to the engine. If the tone is low and quiet, you are running at a low RPM but if it is loud and higher pitched, then you are running at a high RPM.

Automatics do have gears and they do shift, but the transmission does it automatically, hence the name automatic. Know how an automatic vehicle goes waaaa, waaaa, waaaa, waaaa as it picks up speed? Each waaa is the engine RPM increasing with the tone getting higher, each short pause is the automatic transmission shifting itself to the next gear, followed by the engine tone dropping down then increasing again as the RPMs build back up. You won't typically hear this on decel because the trans won't shift down until the speed falls enough, and when it hits its downshift speed the shift is usually unnoticed.

What they keep asking about is, when the bus is at its maximum speed of 45MPH, what does the tachometer show? If you see something like 2000RPM then it should be a simple matter to increase top speed, but if it is closer to 4000-5000RPM (whatever the engine's redline is) then the engine is mechanically limited and you aren't going any faster without major work for major money.

A cat C7/3126 max RPM is 2400-2600 depending on software level. It will never go 3000 let alone 4 or 5 thousand RPM. If it’s at 2500 rpm at 45 mph then the bus needs mechanical mods to go faster.

[Jolly Roger bus 223]

NC loves the 6.50 rear gear range and if you bought down around the beaches it is governed to 45-50

[cadillackid]

Originally Posted by Jolly Roger bus 223

NC loves the 6.50 rear gear range and if you bought down around the beaches it is governed to 45-50

ha! 6.50. my SUperior had that gear.. with a Gasoline 392 from oregon.. drove it 2700 miles across the country with the 392 screamin and the straight no-clutch fan roaring!

[EastCoastCB]

Originally Posted by Moonshyne

Yea I drove it. It says it can go up to 85 on the dash. But there's something with the public school bus system (where I bought it from) that there buses only do 45mph

If its from North Carolina 45 is their standard top speed for buses. Most are geared for low speeds.
Again- you need to look at your tachometer if you have one and tell us what rpm's you're at when going 45. If you're at 2500-2600 you're limited by gearing.