Doubler ratio choices? (1 Viewer)

[woytovich]

I am considering a Toybox doubler for my 60 and I wanted to ask about gear choices. I'm looking at the real world ratio options I'll have available.

For example, given my h55 5 speed, 4.56 diffs, a split TC and the 4.7 Toybox I can get 50:1 using just the split TC and 103:1 using just the Toybox - in FIRST GEAR. I could get a ratio of about 72:1 (about half way between the 50:1 and the 103:1) with BOTH the Toybox and my split TC in low range and the TRANNY in 3rd gear...

So... is it a BAD IDEA to have the Toybox and TC in low and be running in 3rd gear? At what point will I not have a viable combination - given wanting the RPMs to stay in a good torque range for the 2F (what is that: 1500RPM ?)

Real world experience sought here...

Mark

 

[RHINO]

i dont think anybody understands what your asking, including myself. i have the same 4.7 toybox and have driven around in all possible gear combos. i have noticed some overlapping gear ratios in certain combos, but i dont see any harm if thats what your asking.

 

[woytovich]

Sorry... I was just wondering if there was some problem with some combinations - problems like over reving a gearset for example. Like what can happen if you are in low coasting down a hill with the tranny in neutral and let the speed build up. The transfer case input side can get spinning pretty fast...

So in this case is there any downside to, in the extreme for example, running down a dirt road in 5th gear with both TCs in low range? In this case the tranny would be at it's high/overdive end and the transfers would be reducing that all back down to usable RPMs to the driveshaft?

I'm just trying to understand the physics of the engine at 1500 RPM, the tranny in 4th or 5th gear, and the TCs in low...

 

[inkpot]

Howdy! By my estimated math, your lowest gear is around 180 to 1. If you do the math on all the possible combinations, all the way up to something like 0.8 to 1 in overdrive. If you want to keep your operating range between 1000 - 3000 rpm, there will probably be a lot of overlap on some of them. Not a problem. You will learn with experience to find the right combo of gears to do what you need. You will most likely rarely if ever use the lowest 2 or 3 ratios. John

 

[RHINO]

ok, i get where your going with this now. i dont really know about over reving the gears like that. i do it once in a while and i can hear the gears start whizzing. it doesnt happen often as i am usually in a gear all the time and rarely going down hills in neutral so i think its one of those things that wont generate enough miles to really do any damage.

 

[CruisinFJ60]

For example, given my h55 5 speed, 4.56 diffs, a split TC and the 4.7 Toybox I can get 50:1 using just the split TC and 103:1 using just the Toybox - in FIRST GEAR. I could get a ratio of about 72:1 (about half way between the 50:1 and the 103:1) with BOTH the Toybox and my split TC in low range and the TRANNY in 3rd gear...
Mark

I dont think you added this all correctly...

split case and doubler and trans in first
a first gear of 4.84 x the 4.7 toybox x 2.28 split case x 4.56 gears = 236.506:1

just the split case and then trans in first
4.84 x 1.0 x 2.28 x 4.56 = 50.32

just toybox and first gear
4.84 x 4.7 x 1.0 x 4.56 = 103.73

both cases in high range and transmission in first gear
4.84 x 1.0 x 1.0 x4.56 = 22.07

and you can use any gear while in any combination, the only thing you will over rev would be the engine. I have a sm420 - 2.28 toybox - early 3 speed case - and 4.56 gears and I LOVE all of the options. I have used double low and 3rd gear to climp a loose hill vs using single low and 2nd gear because i needed the double low either right before or right after the throttled attack. There have only been a couple of times where I could have used or wanted a slightly lower crawl ratio for those extremely big climbs or delicate situations but to be honest when i can start my truck (in gear mind you) on a massive nearly vertical hill or ledge and never even touch the clutch and the starter doesnt even bog down i think im doing ok.

here are a couple of cool charts the first being really nice and having several options to choose from if you do not know what your gears in whatever it is you have is.
Gear Ratio Calculator
4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators

 

[woytovich]

Pretty sure I had what you got...

And thanks for the reassurance that this will yield MANY useful ratios....

Here is MY calculator:

 

[CruisinFJ60]

I miss read the first part of your post, I apologize, you are correct.

do it you will love it!

Like i say i have considered pulling my toybox and having the 4.7 gears put in but for now im good with what i have it would only be a hand full of times i could use the really stupid low so for now ill just stick with stupid low. and Im on 40" boggers currently for reference, not sure what you are on or will be on.

 

[Cruiserdrew]

There are some combos to stay away from.

For instance with your tranny in 4th and the toybox in low, it does spin the toybox fast enough to make extra noise, which can't be good for it. So with the Toybox in low and the t-case in low, I keep the speed down. If I need more speed, I'll shift the toybox into high range. You do need to play with it to get the shifting feel.

It is the best thing you can do to a wagon. 1st low low is really really slooow.

 

[woytovich]

I'm running Q78s... they are about 35" tall... and BTW 4.7 is the only way the H55/split TC Toybox comes...

mark

 

[RHINO]

drew your not kidding, first low low is real low,, i hardly ever use it.

cruiser 60, the 4.7 is nice to have the option. its about the same as your dbl low and i find myself using it alot, but rarely super stupid low. if i was in your shoes i dont know if the 4.7 swap out would really be worth it.

mark go for it man,,, many of us have been running it in many gear combos w/o any problems that i know of.

 

[tornadoalleycruiser]

Just play with them. I normally left my tcase in 1:1 and toybox in 4.7. shifted into second a lot or third.
if I needed to keep up with the "crew" shift toybox to 1:1 and tcase to low to play with normal trucks.
DON"T roll back in neutral . you can explode your clutch disk.

 

[jp78fj40]

OK, I have toybox envy!!!!
"78 fj40 all stock(for now)
Went to Marlin(they are down the street from where I work ) to learn they don't have a box for me :-(. Sounds like they used to but no more?? I have too change trannys & T.C. to run a Marlin box...This sucks, any ideas????
Sorry for the hi-jack!!

 

[Cruiserdrew]

OK, I have toybox envy!!!!
"78 fj40 all stock(for now)
Went to Marlin(they are down the street from where I work ) to learn they don't have a box for me :-(. Sounds like they used to but no more?? I have too change trannys & T.C. to run a Marlin box...This sucks, any ideas????
Sorry for the hi-jack!!

Change tranny and t-case. You'll end up with a stronger unit, and not that much $$ in the scheme of things.

Or...a 40 does not need to be geared a low as a wagon. So you would have the option of using your tranny and an Orion or an SM465 + orion which would be nearly ideal.

 

[John Smith]

I do most of my wheeling with just the 4.7 Toybox engaged using first through third gear at idle. Blip the gas pedal if the engine bogs down. I only engage both cases when doing a trail like Rock Creek where I just steer and watch the spotter and rarely touch the pedals.

The biggest thing to remember with a doubler is to never coast with the clutch pedal depressed while the doubler is engaged. You can get the RPMs crazy high in a situation like that and people have blown up clutches doing it.

 

[tornadoalleycruiser]

"to learn they don't have a box for me "
you need to RE-ask.. if they have the output shaft 10 spline option anymore or do more research. It's pretty easy to do a toybox, they're like lego's. either that or get a 19spline trans, there are tons of options for the toybox stuff. To say I just can't do one is probably not an accurate answer.

 

[FJ40Jim]

I suggest using the toybox secondarily. That is, if 4low is needed, use the TC low. If silly low is needed, add the toybox to the TC low.

The reason is driveline components like transmissions and t-cases are rated for their maximum input torque, eg the SM465 is rated for a max input of 465ft/lbs. We do not know what the max input is for the Cruiser split case, but rest assured a healthy 2F, twisting through a 4.7 toybox is applying 4.7 times more torque than a stock t-case normally sees.

 

[woytovich]

I suggest using the toybox secondarily. That is, if 4low is needed, use the TC low. If silly low is needed, add the toybox to the TC low.

The reason is driveline components like transmissions and t-cases are rated for their maximum input torque, eg the SM465 is rated for a max input of 465ft/lbs. We do not know what the max input is for the Cruiser split case, but rest assured a healthy 2F, twisting through a 4.7 toybox is applying 4.7 times more torque than a stock t-case normally sees.

you're such a buzz kill....

 

[Cruiserdrew]

you're such a buzz kill....

He's right though, and in stupid low, I use almost no throttle for just that reason. Idle is plenty to move the truck over the hardest of spots.

Also why a 4.7 toybox with a 1 piece case is problematic.

 

[woytovich]

In general I wheel with a light right foot. I never bounce it or hop it to get over stuff... I drive my truck to go wheeling so I need it to get me home... It's my daily driver too.

That said, thanks for the advise and insight from all that have chimed in... I ordered the Toybox today!