ECO Hubs Who needs 3:07 gears?

[Xengineguy]

A little more information for those following along. I copied this from the internet somewhere. Torque/horsepower graphics
for cat Fmtv.

 

[Ronmar]

A little more information for those following along. I copied this from the internet somewhere. Torque/horsepower graphics
for cat Fmtv. View attachment 892379View attachment 892380

Yea I wish that info was a little easier to find for the 3116, that and the engagement torque figures(usually specced around 800 RPM for manual transmissions/clutches). Cat made so many different tunes of the 3116 engine for customers it isn’t funny. I ran across an Eaton clutch table that listed peak torque numbers around 1550 RPM for the 3116, but surprisingly had no engagement torque figures listed anywhere. It also didn’t show the 225HP@2600 RPM Tune we have, just a 230@2600 with 605ft/lb@ 1550RPM. From the marine tables I have seen, I am estimating engagement torque just under 200ft/lb@800 RPM. Of course these charts only show the high RPM side of the torque curve…

 

[GeneralDisorder]

This PDF contains the performance curves for the C7 defense engines - including the 370 / 930 map that I can flash to any C7 computer:

https://s7d2.scene7.com/is/content/Caterpillar/CM20170727-49048-12302

 

[Ronmar]

Seems to me the ideal gear ratio might be around 4.30 , makes 7 gear usable and a little lower first. You can put me down for a set for a 1083.

Perhaps that would be about the ideal, but I don’t know that 7th will be unusable with the 3.9. If peak torque is 1450-1550 RPM, 60MPH in 7th is only going to be ~100-200 RPM below peak torque. 6th and 7th are not really very far apart with 7th being about 87% of the 6th gear ratio(smallest ratio change in the trans).

Not sure where the automatic downshift point is at but you will need to hold some throttle to maintain speed, wether this is close to a downshift point @~60 remains to be seen, or if a higher throttle would tend to force it to kickdown(TCU thinking you want to accelerate based on TPS input). And again this might be improved with some programming changes.

 

[GeneralDisorder]

I'm working on getting Allison Doc to hopefully program the vehicle speed outputs and shift points, etc.

In my basic testing - driving around at 25 MPH my truck stays in 6th gear. It upshifts to 7th gear around 32 MPH which means it will stay in 6th around 50-60. and upshift to 7th around 65 MPH. I think we will have no problem maintaining 50-60 without the truck downshifting but of course that depends on your engine configuration (3116, 3126/C7), and transmission (3070 vs 3700) and the adjustments/programming. It looks like from my drive testing that the only thing needing changed will be the speed sensor calibration (number of tire rotations per mile, or whatever the TCU uses).

 

[DeMilitarized]

Great to hear the interest, I’m going to produce them! I’m trying to get the EDM cost down. Not a deal breaker either way.
If you get to this area and want to test drive please contact me. You will be impressed with the drivability for sure!
I will be contacting everyone that expressed interest in purchasing these to complete order details. No money will be required until
that order is ready to ship.
Thanks everyone for your comments.

Could you do a video accelerating from a stop to about 55mph?

 

[patracy]

I have cleaned up this thread since it's turning into a classified ad. Or really more of a vendor related ad. It's ok to discuss the technical aspects of this. But there needs to be a ad posted in the correct area when it comes to the sales/marketing of this.

 

[Xengineguy]

I have cleaned up this thread since it's turning into a classified ad. Or really more of a vendor related ad. It's ok to discuss the technical aspects of this. But there needs to be a ad posted in the correct area when it comes to the sales/marketing of this.

I understand and don’t wish to break the rules. Will limit my info to technical only…. I will Post in the for sale section when they are available…. Sorry for bending the rules.

 

[Xengineguy]

Could you do a video accelerating from a stop to about 55mph?

I assume you mean from inside the cab, sure. Will get to it when the roads clean up a bit.

 

[ramdough]

I wonder what would happen to those with the faster gears already installed? I am guessing that would be too far….


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[Guruman]

I wonder what would happen to those with the faster gears already installed? I am guessing that would be too far….


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I have visions of parts flying off and the tires exploding......

 

[Third From Texas]

I wonder what would happen to those with the faster gears already installed? I am guessing that would be too far….


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I can see it now:

Bonneville 200 club on the Salt Flats here I come!!!!

Will need a little wing spoiler on the back and a cool scarf and helmet....because...reasons !

 

[Wingnut13]

The cool kids wear ascots….. not scarfs. Just sayin’

 

[Xengineguy]

Did another 100 plus miles this weekend to go to a gun show. Nice to talk to people with interest in these trucks. Draws
quite a lot of people wherever it goes. Even McDonald’s had people come up to talk about the truck. Lots of thumbs ups also!
For people following the direct drive Eco Hubs, 4140 bar stock showed up this week and tooling came in. Got good quotes on
EDM work. Looking good! Also had a slight design change, to the backing plate. This improvement will center the adapter
inside the truck hub, and allow for some future torque upgrades if ever needed. Will post some photos when we get a few run.
Again if anyone would like to drive this truck you’re welcome to come check it out. PM me and we will make arrangements.
Thanks again.

 

[Xengineguy]

Started production on hubs yesterday and today. End caps are coming along good also. A few pictures for those of you following along.

 

[Ronmar]

Excellent!

 

[GeneralDisorder]

Amazing!

 

[GTTX]

@Xengineguy great information and ideas. I contemplated a similar solution while looking into which chassis I wanted to use as the base for my overland build. I think your results have sealed the deal on that.

If I were to go this route I would replace the tires with 335/80R20 (41.4") Goodyear military tires. I copied my pro's and con's list below.

Pros:
7th gear would be 75 mph at 1850 rpms.
- Better MPG
- Easier on the drivetrain
Better utilization of lower gears.
- Easier (quicker) acceleration.
73 - 83 pounds lighter (depending on the tire being replaced).
- Lower rolling resistance
- Better MPG
- Easier to change
- Easier to balance
Rated 81 Mph top speed
- Safer at higher speeds as stock tires are only rated to 68 mph

Cons:
Less clearance
- 2.6" less ground clearance
Less weight capacity
- 6395 vs 10200

The only issue I have any concerns about is the weight capacity of the smaller tires. I doubt I would ever utilize the tires in "extreme conditions" and would never go that heavy so I think they would work just fine.

Any thoughts on using the smaller tire?

Also, this is my first post so, Howdy Everyone!

 

[GeneralDisorder]

Any thoughts on using the smaller tire?

I think they would work fine. They would look a little silly on something like my 1079 where it already almost needs larger tires as it's a bit visually out of proportion...

To the weight and balance points - I can tell you from direct experience that these tires don't require balancing and that's per Goodyear as well. Anyone fighting what they believe is balancing is fighting one or more bad tires - mostly flat spots or warping from being on a spare tire carrier their whole life. I installed brand new Goodyear MV/T's on my truck and no consideration to balance was given. Indeed the TM work package for installing them makes no mention balancing or even offsetting/clocking valve stems and bead locks, etc. It's not addressed - which means it doesn't matter. By design there is no balancing required or even possible from what I can tell.

The weight..... 75 lbs isn't going to make much difference. You still aren't picking them up and throwing them around. Handling them and mounting them on wheels will still be the job it always is.

 

[CallMeColt]

Cool project.