Centre Diffs have landed!
 

The wait is over. Mines built and fitted. Can't wait to give it a run. Roll on Sunday. :thumbsup:

http://i45.photobucket.com/albums/f5...psrplnu8js.jpg

http://i45.photobucket.com/albums/f5...psqbmjhslv.jpg

Where from and what's the part number? :-)

Ah. Header card went into bin last night. I'll have a look for it. Mine came from the Distributor RC Disco so they'll be in shops any day depending on shipping I'd guess.

• Gear Center Differential - Set #364901

For those wanting metal gears in either the center or front & rear diffs:

• Differential Bevel & Satellite Gears (2+4) #335030
  
• Alu. differential Pin - Hard Coated (2) #335081

Bent

For those who've had the early chance to run the centre diffs, how are they performing? Do you feel like you have more traction? What surface & oils did you run? There's a lot of debate over the diff oils suggested being really high (vs. the B44.3 & D413)? ie. 1,000,000 for carpet, 500,000 for clay?

I run 100,000 in my centre diff on my b44.3 and it handles fine, why people are going higher is beyond me, 10k front, 100k centre and 7k rear and it goes fine !!!

500.000cst for low grip (dirt/clay/loamy) and 1.000.000cst for high grip (carpet/astro) is our preferred diff oils.
This is what we have been running and always coming back to for the last 6months of use outdoors and indoors ;)

The diff gears on the Xray are small and with very little resistance so it needs a bit higher viscosity.

And with a thicker fluid you also get more traction on power.
A thinner oil will be easier to drive but won't be as fast and create as much traction as a thicker oil.
But there is no right or wrong here.
Some will always prefer a looser diff than others.
Right now on high grip carpet we are using the slipper instead of the diff with 1.000.000cst as the slipper is faster.
The center diff is easier to drive but not as fast.
So from 6 months of testing the center diff is not THE definitive answer but instead another tuning aid for different track conditions :)

Bent

I can only echo what Bent says. I ran at Worksop yesterday(low-med grip)with the slipper fitted for the qualifiers. Car was close to perfect. Very good indeed. For my final I fitted my centre diff with 500k in. The car was just as fast and easy to drive. Honestly I think it was better and worse. I definately need more testing but I was surprised how good it was. 500k isn't as stiff as you'd imagine. I ran 300k in my D413 and that diff was stiffer than the Xray with 500k. As said, a great addition to our car for tuning and a very easy thing to swap in and out. Some will love it and some won't.

Sounds like I need to pick up some 500,000wt!

Thanks guys!

Anyone run the centre diff on astro yet? Have you seen improvement and was the track wet or dry?

Same as on every other surface…….the lower the grip the bigger the advantage for the slipper.

On dry high grip astro the slipper is usually quicker (but can be more difficult to push as hard).

Great thing about the XB4 is that it is so quick and easy to swap between slipper and center diff (much unlike the HB).

And with the thicker chassis and no top decks it's even more quick and easy :thumbsup:

Treat the center diff as another tuning option and test it like you would test different shock and diff oils.
There's no right or wrong on the preference of running a slipper or center diff.
We always test both when on a new track and choose what feels the best and produces the quickest and most consistent runs ;)

Bent

Well, it's cool that Xray is always improving, I'm a little disheartened now, I just bought the new 2015 chassis and top decks, only to see now that the not currently available, optional 3mm chassis and no top decks, looks to be the way to go (very Yokomo looking now). I run 90% of the time on clay, so does the std chassis and top decks go in the bin?:cry:

New 3mm chassis with front X-brace is primarily for high grip tracks like carpet and astro.

So far we haven't tested this on indoor clay but will be doing so probably starting next week after putting together a 2nd XB4 with the new chassis.
Results and impressions will be posted on Malin's page ;)

Bent

Sime
I was wondering if you could explain what was "better" and what was "worse" about the center diff, I'm just trying to understand which handling characteristics are effected by running each option. Have you had chance to test the car any more with each and do you have a definitive preference yet.

Lol. Tricky to explain. I've not used the centre diffs much tbh as I prefer the feel of the slipper so far. Er, the car with a diff fitted seems to settle quicker through rhythm sections and jumps/landings. I also like how it appears to help rotation when coming into a tight turn from high speed. However, the diff makes the car spin up the inside front wheel when getting on the gas hard going onto a straight and can make it feel unpredictable sometimes too. It's a feel thing. With the slipper the car feels the same every lap. The diff just takes a little confidence away from me when pushing. As I said, I've not done much with the diff if I'm honest cos I feel faster with the slipper. I've got 500k in one and 1m in the other. I need a test day to get into it more and play with oils and set up changes to take full advantage.

Just to add, raced at Worksop today which is med grip rubberised cork floor with the slipper and the car was phenomenal.

Thanks for the info, it's much appreciated. I race on a very slippy gym floor and currently have a 2013 XB4, I am considering buying the 2015 primeraly for the center diff option, the main handling characteristic I would like to improve is rotation in tight turns (additional grip is also always welcome too) as mine just seems to carry on pushing past the apex. It sounds like the center diff could definitely help with this but maybe the trade offs aren't worth it.