I am using the BP diffs and running a 47t centre diff spur... and i run 12-14t pinions.

I am considering staying at 13t as it is a good all rounder... but i am able to run 15t and maintain warm decent temps on road....

edit

forgot to mention, i am using a 1520 too and only run 6s

Well I am going to be running 6.84" tires. 47/12 is like estimated 57. I was targeting around the 40-45mph zone. And thats about 50 with a 10 or 11 pinion on 6S with 1520; estimating for speed loss due to weight, restistance, etc, etc. Even running a 54 still means an 11 or 12t pinion.

Switching to 4.3:1 diffs means I can run a 50 with 13-15 pinions. 50/13 gives me a rollout of 1.3 which is just about the rollout of the stock Flux at 1.28 I think it is. Just using that as a ballpark base setup.

Oh and I almost never drive onroad... thats boring to me; if I want onroad action I'll strap myself in and go run laps on iRacing; the best PC level consumer oriented racing simulator on the planet.

haha fair enough bud...

you know what you need to do considering your running some tall chunky tyres/rims...

When i was geared for 53mph on my savage according to the speed calcs.... i was getting an actual top speed of 44mph according to multiple radar guns... That was with badland tyres... maybe that will help you decide your gearing a little.... Oh and my temps were in the 110-120 degreeF range... so running very cool still.... i am have yet to push this motor temps apart from one time when i accidently geared my motor to 75mph but that was a little mistake...

Well yeah thats why I'm estimating about 5mph speed loss over the 'estimated top speed'.

So here's the battle plan for the center diff TVPs. A bit of a different approach. Notice the lack of 'rollbars' built into the TVP. I'm planning on running the Baja rollbars instead so thats some of the reason for the design.

Here are the TVPs. Right now I have it using two 3S batteries inside the rails forward of the center diff. I was debating between the twin batteries, or doing a single battery like I have now that sits just over the top of the drive shaft. But I thought that it might be better to move the weight lower; also using 3S, vs. a 6S, gives me more options to use batteries in other vehicles too.

http://lh4.ggpht.com/_dcy74CG15Qk/TQ...I/s800/tvp.jpg

And here is the new bulkhead/diff plate/motor plate. This will replace the existing Savage rear bulkhead plate. It will hold the center diff using a standard truggy/buggy diff mount. The rear portion of the plate is extended to hold an anchor system for the Baja 5B rollbars.

http://lh4.ggpht.com/_dcy74CG15Qk/TQ...motorplate.jpg

And here is the Vorza 43t ring gear on a Savage diff...

http://lh3.ggpht.com/_dcy74CG15Qk/TQ...00/43tDiff.jpg

And how it sits in the bulkhead...

http://lh5.ggpht.com/_dcy74CG15Qk/TQ...0/IMG_5129.JPG

I cannot wait to see this come to life...

The diffs look good but i am a little worried... I just dont thing that these vorza diffs will work too well if you house them in the plastic savage bulks. The flex of the bulks under 6s load with the torquey 1520 motor will cause you diff problems i think... Hence why the BP diffs were introduced.
BUT
These definitely would work very well if you use alloy bulks which allow no flex of the ring and pinion...

For example....

The old stock HD Ring and Pinion gears (before the BP gears came around) were being sold with the flux... but in the plastic bulks constantly failed... Teeth chipped, pinions broke, bla bla bla... BUT i put them in some ALLOY GH Bulks... and even with the extra torque... and my nose heavy DB-17 chassis that keeps the front down and puts the power down... the diffs always survived as they dont allow any flex and my diff probs are a thing of the past...

Actually i am not definitely considering trying this vorza diff mod in some alloy GH Bulks! I like the idea of running larger pinions!
So is this just a vorza ring gear on a savage alloy bulk and the stock SHD cup outputs?

Thanks bud!

There isnt a comparison with these or the "bulletproof" diff rings and the original Savage rings.

As an FYI, the Vorza has plastic bulks, not to mention almost every truggy has plastic bulks (not to mention most of the truggies and buggies have plastic diff cases); although granted most of the truggies/buggies were designed for nitro power. TBut then again I havent had issues with 5 or 6S on my RC8Te. So not really sure that alloy bulks are necessary but I guess well find out eventually.

What is pictured is a Vorza/D8/Ve8/LightningStadiumSport ring gear (HBC9010), attached to a standard Savage X diff with the XL/Flux SHD drive cups. It does require a 8x16 bearing on the ring gear instead of the 11x16 that the bulletproof ring gear uses.

That is true regarding the plastic bulks... But none of the mentioned RCs are anywhere near as heavy as a savage nor do they use wheels and tyres as heavy as you intend to use.

I dont know why i had so many probs with my plastic bulks and 1520 motor... But since running GH Alloy bulks... all my probs are a thing of the past...

Anyway.. lets see how this badass truck turns out

Valid point... with one exception; I've been running my truggy with ProLine Badlands on Maximizer beadlocks or ProLine Trenchers. Both are fairly close in weight so well see. Also remember I'm only planning on running under 6S power.

Like I said, we'll see. If it ends up needing alloy bulks, so be it; good news is the 43t ring gear is going to be readily available since its used in the Vorza plus a bunch of HB vehicles.

Oh I forgot to mention that what is pictured is the HTBC9009 10t spiral pinion and the HBC8068 cup from the LightningStadiumSport. I hadnt thought of the Vorza until a bit later, but you can probably use the 67499 10t spiral pinion and the 103663 cup from the Vorza. The latter should work with the standard Savage drive dogbones but haven't tried them.

As reference...

ProLine Badlands on Maximizer beadlock wheels: 12oz
ProLine Trenchers on Tech 5 wheels: 13 7/8 oz
ProLine Baja BowTies on ProLine SplitSix beadlock wheels: 18 1/8oz

Dont have my BigJoes on Axial beadlocks but pretty sure they are somewhere between Trenchers and Baja Bowties.

Re the FLM drag link hitting on the steering arm. I have the black metal sleeves that go in the drag link around the other way. The top of the sleeve then creates a little clearance between the drag link and the arm allowing it to move enough for normal steering.

I am interested in seeing the results of those spiral gears. Hope you have more luck than this guy. I'm happy with center diff using 52/11 atm but i guess you would need a lower ratio for the heavier vehicle.

The flat rear bulkhead plate is good simple idea. Keeps the rear diff in normal orientation but allows the bottom of TVPs to be completely flat. Would make it easy to add a bottom skidplate the entire length of the TVPs.

Yeah I tried the sleeves both ways. Once I assembled it all though I've got something else binding because the drag link isn't going full lock to lock. Probably going end up going to truggy arms eventually anyways.

Yeah, we'll see. Read through the thread you referenced, but hadn't thought about the bevel pinion sliding in like that. Havent had that issue with the truggy, so I guess well see.

Well thats the backup plan.. go back to bulletproof diffs and run either a 52 or 54 spur with a 9-11 pinion.

Yeah, thats what I was thinking. Use something cheap to make a long skidplate for it.

Top view of the mockup of the custom TVPs showing the front 5T dogbone from TCS Crawlers, an RC8T center diff, and a New Era extended Savage dogbone (120mm).

http://lh5.ggpht.com/_dcy74CG15Qk/TS...0/IMG_5132.JPG

The New Era extended Savage dogbone was the longest 8mm ball dogbone I could find and I was trying to avoid going the custom dogbone route. Unfortunately between the two dogbones and the center diff, the chassis is about 8mm too long. So that basically takes the 22.4" wheelbase down to a 22" wheelbase. Not that huge of deal.

Because someone asked for the measurements for the sleeve that allows the 24mm hex hub from the Baja 5B to work with the Savage XL axle.

https://lh5.googleusercontent.com/_d...hubmod.png.jpg

Given your experience with std savvy hex adapter failures, and your mod to allow baja adapter I wonder what you think about having 8mm axles in a savage?

Looks like the small stock hpi pin casue the failures on the hex adapters. Just not enough material and the slot wanted to cam off the pin the whole time it was under load.

I see the setup you have now as much better, as long as the xl axles will survive.

I plan to use an 8mm truggy style setup, and hope it will last better under power.

Any thoughts on this?