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Blowing Diff Gear...

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S

Savage.30

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orlando
RC Driving Style
Anyone else have the Collari .30 and blowing diffs like the gears are made of plastic. I have the four gear diffs in and just can't seem to keep em whole. Think I'm gonna have to gear back up?? Right now I have the 13t bell with 49t spur. Too much for it to handle??
 
The Savage diffs are my only complaint with the truck. I am only running the stock S-25 and in the year and a half I have had mine I have had to rebuild the diffs three times. It is getting rediculous, I am going to start looking for an alternative to their diffs.

BTW I see you are in Orlando. Are you going to the HPI Challenge?
 
No, I'm down in Sebring. The HPI Challenge is April 30 and May 1 at Superior Hobbies in Casselberry, just north of Orlando. ImBroken and I will be running in the Savage class, and I am trying to get my RS4 ready, if I can I will also be running in the nitro modified class.

HPI Challenge Race Flyer
 
Are you guys using machine screws where the ring gear screws into the diff case? Ever since I rebuilt them last time with the new screws my diffs have lasted about 2 gallons and still have some life left. And that is with running the WASP .28 and the Collari.
 
Yeah, Using the machine screws that came with the 4 gear set. NCNitro, I will try to make that one. I know my buddy will be there(MaxxFX). I don't think he misses any races at Superior. I on the other hand, have a hard time getting off work on Saturdays since I am in the car biz. You guys going to Race Rock in May??
 
2 things..

First, 13t bell, 49t spur is incredible torque on even an S 25. For comparison, a k4.6 is geared with a 17t bell, 47t spur. Before comparing engines, your gear ratio is putting 36 percent more torque/pain through the drivetrain. Add more power yet with .30 and you may be putting around 50% more torque through that drivetrain compared to a typical k4.6 and typical gearing.. Wow...

Second, diesel is right. Half or more of the blown diffs are nothing more than the stock screws backing out and causing slop. And, of course, when you mix torque and gear slop you get pieces. Definitely look into the machine screws.
 
do aluminum diff cups help cure this problem? I'm wondering as though i may buy some aluminum diff cups next time i rebuild them.
 
Screw it!! I'm gettin' the posi lock spools!!!!!! The screws are all the way in and tight. I think the torque may be the problem here. Hey maxxFX, got some JBWELD I can borrow???
 
JB does the job and I'm actually locking my rear up in my lst as we speak!! :cheers:
 
Looking for this?

DSC_0324.webp


http://www.vertigoperformance.com/products_Lockers.html

be careful with landings and braking!
 
I understand the landings but why watch braking?? Is this what you run in your truck?
Do you think i should put the gears back in and try a much thicker diff fluid?? I was runing 7000wt.
 
Abrupt stops in the driveline will have you breaking dog bones, like mid air stops from full throttle. You will learn to be a much smoother driver with the diff locker, at least while airborne and when you land. btw I only have the rear locked.

Also, the truck will be nearly undriveable on the street, the backend will swing completely around anytime you slow down or turn abruptly, resulting in a sloppy 180. Cool for the first tank but gets unnerving after awhile. I plan on building a seperate rear end assembly to swap out for the street.

7k weight should be fine, I used to run 5k rear, 7k front.
 
Gotcha! but I don't have dogbones. I have MIP CVD's all around. Aren't these strong enough to hold it? If not I wasted my money. I just kept the old dogbone shafts so when my buddy breaks his I have spares so he doesn't have to quit runnin' for the day.
 

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