Gear Splitter

[tm america]

you cant compare the top speeds of a multi to a gas to compare ratios since the gasser is a 4000rpm motor and multi is a 2600rpm motor.and if those are the correct ratios that rebel raider posted then running a 3052 would be a huge improvement for us guys with bigger tires since the 2nd ratio would be just about perfect and everygear after that to.since 2nd would be just a little less gear than first is now and every gear after seems to be the right spread to put you where you would need to be.with the 15.5 tires and a 1 to 1 ratio it would give you a slightly higher top speed than running 9.00s with the .79 od .the ratios would be such that you wouldnt need to start off in first unless really loaded

 

[mudguppy]

not all MF trans are equal - most of the examples given in this thread are not showing all 3053 options. the argued 3-4 rpm drop in the 3053 is not near what it is in the 3053a trans.

i have the 3053 trans in my truck, though i realize that it seems that the -A model is most common and -B is least common.

 

[stumps]

you cant compare the top speeds of a multi to a gas to compare ratios since the gasser is a 4000rpm motor and multi is a 2600rpm motor.and if those are the correct ratios that rebel raider posted then running a 3052 would be a huge improvement for us guys with bigger tires since the 2nd ratio would be just about perfect and everygear after that to.since 2nd would be just a little less gear than first is now and every gear after seems to be the right spread to put you where you would need to be.with the 15.5 tires and a 1 to 1 ratio it would give you a slightly higher top speed than running 9.00s with the .79 od .the ratios would be such that you wouldnt need to start off in first unless really loaded

Did you by any chance notice that I got the nominally same numbers when I used the gear ratios published by rebel raider?

If you ignore the affects of wind resistance, etc. The engine doesn't care at all what speed the vehicle is moving. What is important is that when you run the engine rpm up in a gear, and shift to the next gear, the new gear ratio doesn't throw the engine out of its torque region. This is what the tables I generated show. They were generated to illustrate that there is no missing gear in the MF transmission.

I'll give you an example:

Suppose our MF engine likes to produce torque between 1400 RPM and 2400 RPM. That range requires a transmission that has its gears selected to give separations of:

2400/1400 = 1.71

Every gear ratio must be selected so that it, and its adjacent gear ratios differ by that separation ratio. If they do, then when the engine reaches 2400 RPM in one gear, it will be at 1400 RPM in the next gear.

If the transmission gear separations are too small, you will need too many gears to go from your starting speed to your maximum speed. If the gear separations are too large, you will lug the motor when you up shift.

Understand?

-Chuck

 

[booger]

so the 3052 would give you a lower gear set for bigger tires, however, your kind of loosing two gears. Now your not using 1st because it's too low ( or not necessary ) and you don't have an overdrive. I understand 5th will be a little taller in direct with 53's than overdrive is with 9.00's. But, I hate to give up overdrive even with 53's. 60mph @ 1900 is really nice. A direct 5th would be about 527rpm higher at the same speed which doesn't seem like much but the noise level, fuel consumption, and wear & tear difference between 1900rpm and 2400rpm is a huge..

 

[mudguppy]

.... 60mph @ 1900 is really nice. .....

how'd you calculate that? i calculated 60mph at 2200rpm (w/ a 0.85 OD). ironically, i calculate 60mph at 1900rpm for when i put the nv4500 in (w/ 0.73 OD).

 

[booger]

a GPS and a tachometer

 

[mudguppy]

a GPS and a tachometer

tach is off??

59.6mph = (rpm x tire dia) / (axle gear x gear ratio x 336) = (2200 x 52) / (6.72 x .85 x 336)

 

[mudguppy]

a GPS and a tachometer

... unless you have a 3053B model trans...

 

[booger]

I think my 5th gear is a .79 My tire roll out is 166 inches. Anyway, what ever it is, there is about a 32% difference in RPM vs MPH for me. And, who know how much these tires 'grow' at 60mph.

Maybe what we are missing is the 'net' result. Or, what the motor see's. The rear end ratio (6.72 to 1), the tire roll out (about 128 inches I thinkfor a 9.00x20) and the size of the 'steps' between gears are all matched to work with the MF. With a 53 inch tire ( a roll out of about 165 inches ) you now have a 'net' rear end gear of about 5.24 to 1. That's loosing a lot of leverage and now the 'steps' between gears are too big and the MF falls out of it's power band. That's why I was leaning towards an Axillary box to "split' the gears when necessary to keep it in it's power band and not rev the crap out of it before shifting into the next gear.

 

[mudguppy]

... That's loosing a lot of leverage and now the 'steps' between gears are too big and the MF falls out of it's power band. That's why I was leaning towards an Axillary box to "split' the gears when necessary to keep it in it's power band and not rev the crap out of it before shifting into the next gear.

sort of. the gear steps and power band are fixed - adding larger tires does not decrease or narrow the power band. if it was 1400-2400 rpm w/ 9.00's, than it's the same with 16.00's.

what you are describing is adding gears to narrow the split in order to take advantage of a narrower (and presumeably higher) section of the original power band because this original power band is now effectively too low. while this is possible, the net gain will not be that great because the MF's power band is not a very tall 'bell pattern' - it does not have a steep peak to narrow in on. rather, the power band has only a moderate rise to its power peaks. you can only access the 'area under the curve' as it exists, regardless of where it exists.

therefore, the most fruitful effort is for the entire power band to be raised - as in, turn up the fuel and add 'area under the curve'. trying to accelerate or go up hill with larger tires is the same as adding weight to the truck because it is a leverage/gearing effort (as you said).

it's like driving around w/ 6k# in the bed - adding gears won't make it any more quicker, you'll just be shifting a lot more. however, adding power will compensate for the added weight (leverage) and therefore will put you back to stock or better performance. i have done this and am pleased with the results rather than shifting twice as often.

naturally (before someone else chimes in to point out the obvious), we then get into the adding power versus reliability in an already non-reliable engine. well, if that's a concern, than either live with driving an 'always loaded' deuce or don't put larger tires on.

having said all that, i'd like an extra gear or two in my deuce for comfort cruising and have [unsuccessfully] been looking for an FSO-6406A. i wouldn't see it as a necessity, but, rather, a luxury.


but, for now, i'm going for the tri-fecta: power, rpm, and reliability - at least this way i'll know that i've greatly extended capability. if i find gears too, then i'll claim 'full-monty'...

 

[mudguppy]

I think my 5th gear is a .79 ....

still doesn't add up: if you use 52" as actual diameter, then 60mph @
0.85=2214 rpm, 0.79=2058, 0.75=1954, and 0.73=1902.

if you use 53", then
0.85=2173 rpm, 0.79=2019, 0.75=1917, and 0.73=1866

so, either you have the rare -B model trans with the 0.73 OD (which is possible) or your tach is off.

... And, who know how much these tires 'grow' at 60mph. ...

well, i'm thinking that a tire rated for more than 14.5k# each is not going to 'balloon' much, and much being at all.

now, don't get me wrong, i'm sure there are two ways to get one to 'balloon': 1) run it up to a coulpe hundred mph or 2) peel the tread off.

i've seen a 16.00 balloon because of #2...

 

[booger]

Travis,
Thanks for all of the helpful information. My RPM's and MPH's are what they are, what can I say...stranger things have happened. It sounds like you've been around these things for a while and I appreciate all of your feedback. I am just getting into the M35. I hope you will share your experience and opinion on power steering ( or assist ) for the deuce as well. I need to get on that before I lose a thumb.

So, turn up the fuel. Doesn't that make the turbo spool up quicker ( at a lower RPM ) ? Wouldn't making more power at a lower RPM be lowering the power band ? I'd sure be willing to try it.

I thought "under the curve" is camshaft terminology. In reference to how well they breath. A cam that has a steeper ramp ( like a roller ) breathes more in the same amount of duration than a flat tappet. That extra breathing area is called " area under the curve"

 

[stumps]

One thing, booger, your first priority should be verifying your tachometer. Having a tach that reads low is worse than not having a tach at all.

-Chuck

 

[booger]

Stumps,

I do have another Deuce, I'll pull the tach out of it tomorrow and try it. I'll also try putting my tach in the other one and make sure it reads the same.

 

[tm america]

ok i got it all figured out first off first is not syncroed in a deuce and is a pita to use .the gear splitter they are asking about gives you 1 to1 and an overdrive . to get the best easiest to drive setup you would need to switch to a 3052 trans and run the gear splitter between the trans and transfer case .this would give you six gears easy to run 1,2,3,4,5 in the trans then shift the gear splitter to get overdrive ,this would give you better gear ratios at lower speeds without having to use first which isnt synroed. accelleration would be greatly improved and no lose of mpg or top speed. one of the biggest factors in drivabilty is torque multiplication since torque is what moves you .and hp is what keeps you going.another benifit of running the 3052 trans would be that the pto also is reduced by the different ratio of the input gear this would give you more torque to the ptothe rate of accelleration is determined by ratio of torque applied to the forces against it such as weight wind and friction .deuces greatly suffer from the lose of gear ratio with bigger tires since this puts the forces on the engine above the amount of usable torque you have by increasing the gear ratio in the trans it would be back to stock accelloration but adding a gear splitter with od would give you the benifit of higher top speed with no ill side effects

 

[booger]

So what box would you use? What series is big enough but not too big? I imagine which ever auxillary trans you used the transfer case would still need to be moved back a little bit. Or maybe even a lot.

 

[tm america]

ya it would have to be moved with any of them we sell gear venders overdrives where i work they are good to over 1200hp i have installed several of those that mitchel unit in this post looks pretty beefy i like the looks of it for one of these trucks.i would switch the trans to a 3052 and run one of those and pretty much just use it for overdrive instead of using it to split all the gears .as with anything how duralbe something is depends greatly on how you use it .i think it would be really busy using it to split all the gears.the 3052 gives you just about perfect gearing for the tires we are running first on a 3053 is 5.09 and second is 4.10 on the 3052 which would be right where i need to be so you would only need first when offroad or haulling really heavy loadseven without od you would probably still have a top speed over 70 with the 53s.my top speed with the 46s without od would be around 62-63 and i would be happy since it would get there alot faster than it does nowit would be quicker and faster than it was with the 9.00s and with the fuel turned up

 

[tm america]

right now we're trading top speed for accelleration if you ran a 3052 you would be still gaining top speed but not loosing accelleration .it would make it take off faster and stop better to since you could use the engine braking better at higher speeds where now engine braking does help much till you go back down to third

 

[mudguppy]

Travis,
Thanks for all of the helpful information. My RPM's and MPH's are what they are, what can I say...stranger things have happened. ...

let us know what you find after you swap tachs around. did you see what model trans you have? the tag is on the side of the case.

... I hope you will share your experience and opinion on power steering ( or assist ) for the deuce as well. I need to get on that before I lose a thumb. ...

you have 16.00's and no power steering? oh my.... your arms must be larger than Magnus von Magnusson's.

that'd be something pretty high on my list of things to do. i did the PSC full-hydro kit and love it, but my rig was built for offroad. it drives the highway great, i just wanted the simplicity of hydro. do the search and there are fantastic threads about adding hydro-powered steering gear boxes that are basically bolt-on. i was afraid of bump-steer or binding when combined w/ the lift springs, but don't know if this is an actual concern or not.

... So, turn up the fuel. Doesn't that make the turbo spool up quicker ( at a lower RPM ) ? Wouldn't making more power at a lower RPM be lowering the power band ? I'd sure be willing to try it. ...

not neccissarily - low rpm fueling is controled by the fuel stop in the injector pump. this adjustment will have more of an effect on turbo spool than the max fuel rate will, unless we get into swapping on a very large turbo (which is another, lengthier, discussion). once under load, however, more fuel will produce more drive pressure which will produce higher boost levels. i went from a maximum of ~8psi to 12+ psi after i turned up the fuel, but i didn't notice a faster turbo spool rate at lower rpms, just that it would spool to higher levels.

... I thought "under the curve" is camshaft terminology. In reference to how well they breath. A cam that has a steeper ramp ( like a roller ) breathes more in the same amount of duration than a flat tappet. That extra breathing area is called " area under the curve"

i was referencing a power band graph or curve, and the associated "area under that curve." what i was mentioning was that having more gears is a good practice to access better power out of engines that have a very steep or 'peaky' power curve.

take a look at this wiki article - while not the best write-up ever, it does a decent job at explaining differences in power band characteristics. it also mentions how wider/flatter power bands allow the use of fewer transmission gears whereas peakier bands will require tighter gear ratios in order to keep the engine performing well.

in my opinion, the power band is actually fairly flat on the MF engine - this is because of the injector pump fueling rates and govenor set up and because the overall power output is very very low. and my point is that a relatively flat power curve does not benefit greatly with the addition of more gears.

so, because the curve is so low and relatively flat, i would suggest that the MF would benefit from increasing the power before it would benefit from more gears. both would be best, but the better bang-for-buck would fall on the fuel increase.

compare the attached late model light duty diesel power curves to the 6.4 medium duty application power curves - same motor, but different tuning for different applications. in the light duty trucks, you'll see broader torque and hp curves with extended rpm ranges for good, well-rounded driving. in a medium or heavy duty curve, they'll be sharp angles and steep peaks with limited rpm ranges which is why they use transmissions with more gears. example: on the chart you'll see the Ford make over 600ft-lbs for over a 1400 rpm span, and from the International link you'll see over 600ft-lbs from as little as a 400 rpm span. you could drive the Ford comfortably from 1500-3500rpm whereas you could only drive the Int'l from 1300-2700 rpm.

 

[mudguppy]

... first on a 3053 is 5.09 ...

source? and which model?

edit: ah, you got that from this post, yes? i was going off of this info, but understand that the TM is likely more correct for the -A than the link.

however, does the TM cover the 3053 or the -B model? because i have the 3053 and i don't believe it'd move w/ a ~5:1 first, rather i believe it is quite a bit higher and closer to the 5.9:1 as noted in the link.

other sources to confirm this?