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-   -   DD 8.2 MT643 cruising question (https://www.skoolie.net/forums/f35/dd-8-2-mt643-cruising-question-27715.html)

meyermobile 07-03-2019 02:47 PM

DD 8.2 MT643 cruising question
 
I know DD 8.2... no Boos, please.
MT 643... Yeah!

My speedometer is off so I check my speed by the tach. I figured my actual speed thanks to a speedometer app on my phone. Now I just use the tach... Just to clarify.

I think I'm taking it easy as I just drove from east KS to west AZ... At 2700 RPM I'm going 55 MPH, pretty much lived here unless it was a cool morning in the 70's temp, them I would go to 2900 RPM, which is 60 mph.

It did seem to have a sweet spot at 2900 rpms. But then again this is the first diesel I've ever owned.

Does this seem about right?

Thanks in advance!

- Lewis

Jolly Roger bus 223 07-03-2019 04:18 PM

my 8.2 with the 545 only does 49 on flat lands and might driving to texas from NC without any changes soon.
caint answer for your tranny but my 8.2 non turbo is governed at 175 if yours is turboed i doubt it is more than 250?
good luck

Jolly Roger bus 223 07-03-2019 04:28 PM

yes it does seem about right.
with that transmission your rear end gearing are probably limiting you?
i have 6.50 in mine and can pull tree stumps if i want but but as i go into the 5,4,3 gear range i would gain road speed but lose towing power respectively in each gear range change? for what is in my needs now i need to keep what i have and take the backroads.
which grew up with and would much use to stay away from the interstates

meyermobile 07-03-2019 04:28 PM

Quote:

Originally Posted by Jolly Roger bus 223 (Post 335972)
my 8.2 with the 545 only does 49 on flat lands and might driving to texas from NC without any changes soon.

caint answer for your tranny but my 8.2 non turbo is governed at 175 if yours is turboed i doubt it is more than 250?

good luck



It's a turbo model 225 HP. I try to keep the pedal out of the turbo mode. I'm pretty thankful is a MT643 trans.

Tough to keep it off turbo when starting out...

Engine says 3050 max RPM.

What are your cruising rpm's at 49mph?

Jolly Roger bus 223 07-03-2019 05:00 PM

dont know yet? no tach at all.
use a stick with a string tied to my arm as cruise control between the seat and the pedal for now?
will read my data tag again as soon as i get a break in the rain but your turbo model hopefully has the head bolts added beccause the turbo models at first had a head warping problem when they first added turboes to the original design.
mine runs like an old singer sowing machine so i kinda wanna run it till i kill it so i am gonna do a tranny change and go from 9\20 tubed tires to 22.5 and still debating reargears?

o1marc 07-03-2019 05:23 PM

Quote:

Originally Posted by meyermobile (Post 335951)
I know DD 8.2... no Boos, please.
MT 643... Yeah!

My speedometer is off so I check my speed by the tach. I figured my actual speed thanks to a speedometer app on my phone. Now I just use the tach... Just to clarify.

I think I'm taking it easy as I just drove from east KS to west AZ... At 2700 RPM I'm going 55 MPH, pretty much lived here unless it was a cool morning in the 70's temp, them I would go to 2900 RPM, which is 60 mph.

It did seem to have a sweet spot at 2900 rpms. But then again this is the first diesel I've ever owned.

Does this seem about right?

Thanks in advance!

- Lewis

Do you have a GPS? Most, or all the ones I have, show current speed, posted speed limit. Changes speed from orange to red when ever you are exceeding the posted limit. Though construction and stuff may show higher limit than actual at the time.

meyermobile 07-03-2019 05:26 PM

DD 8.2 MT643 cruising question
 
Quote:

Originally Posted by o1marc (Post 336011)
Do you have a GPS? Most, or all the ones I have, show current speed, posted speed limit. Changes speed from orange to red when ever you are exceeding the posted limit. Though construction and stuff may show higher limit than actual at the time.



I don't have a gps, but after driving from KS to AZ and back again... My tach looks like a speedometer to me 🧐


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