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Old 01-22-2007, 06:19 PM   #1231
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Default Diff building

For the 6 gear diff make sure that you are including the 5x10mm washers
behind the diff gears (8402 - 6 gear), (37771 - 4 gear).
1. Assemble the diff (without packing lube) to determine if the gears mesh ok.
What I mean is that the parts turn easily by hand.
What I have done is substitute the rubber o-ring with one from the shock kit.
The combination of these blue/red rubber rings is what I use to set the internal gear mesh.
Though it is a pain to assemble and disassemble the diff, it has worked for me.
2. When installing the tapping screws make sure the holes are free of
diff grease (easier said than done) and try a plastic friendly thread locker.
If the gear mesh is too lose/tight you may need to add or delete one of the washers.

The 4 gear diffs don't seem to be as sensitive to end play of the gear assemblies attached to the cap joints.
I disassembled a factory built unit this weekend, and I found that the two diff gear assembly
meshed better when installed in the slots located between the four screws. When I installed the assembly in the other slot, the operation was notchy.
I don't recall this characteristic when I built two 4 gear diffs from parts last summer.
The key is to set them up so that there is positive contact (by feeling the operation when it is assembled) but no binding while turning the parts when assembled.

My current chassis setup is pretty good if I have time I will try a 6 gear diff again, but I will only run it at a high traction track.

The diff case (38252) takes a beating and the slots get broken inside, more so on the 6 gear diff than the 4 gear. I usually keep a couple of spares on hand for a diff rebuild.

good luck Delta9 !!
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Old 01-23-2007, 12:34 AM   #1232
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Thanks Curvetracer! Awesome info!
I will rebuild them as soon as the the shims get here.
I might have mine in the wrong notches as you mentioned!
Thanks again
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Old 01-23-2007, 12:23 PM   #1233
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You're welcome Delta9,
Just remember the diff gears for the 4 gear are 13T(teeth) and the 6 gear diff gears are 12T. These are the only unique parts between the two.

hey nitrothug,
have you inspected your 6 gear diff yet?? Luke and I chllenged you on for some hard acceleration on the staright at Leisure Hours last season. I am wondering how it held up to serious punishment.
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Old 01-25-2007, 02:44 PM   #1234
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delete

Last edited by hammadown; 03-05-2007 at 10:24 PM.
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Old 01-25-2007, 03:15 PM   #1235
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If anyone needs a few practice shells I've got a few listed in the for sale/trade section:
http://www.rctech.net/forum/showthread.php?t=146347
PM me for pics. Thanks y'all.

Kevin
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Old 01-25-2007, 09:35 PM   #1236
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Quote:
Originally Posted by CurveTracer
...
hey nitrothug,
have you inspected your 6 gear diff yet?? ....

oh yeah,
i already checked it out and it looks good. remember, i didnt put too many miles on it though because it was the end of the season when i got it. i have sinced rebuilt it and it seems pretty smooth. but i know it still has to be "broken in".

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Old 01-26-2007, 12:14 AM   #1237
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Default One way

Hi I will be getting my CD3 very soon, the kit comes with a front one way, how did you find it working with the one way? I be running the car on a short curcuit with bands and you have to use the brake in many parts of the track. Do I opt for a front diff?

Regards
Joe F
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Old 01-26-2007, 12:21 AM   #1238
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Joe, you will want a front diff if you are on a technical course, the one way will spin out under heavy braking. They are more for flowing high speed tracks.
Hope this helps!
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Old 01-26-2007, 12:45 AM   #1239
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I preferred the front One-way on technical tracks. I tried diff & spool.

It's best is if you can adjust the EPA on the brakes on the fly, otherwise it is going to be very hard getting it right (mine I adjusted with my thumb while racing). I also used two long pen springs on the brake rod to kinda set my own tension (spring on both sides of the brake arm)
I had mine set so I could hit full brakes without spinning out but would also help the ass come around in corners if I hooked it with the brakes on full, then back on the gas for the one-way to pull you around and out

If it is a low traction track then you may want to shoot for a diff.
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Old 01-26-2007, 07:07 AM   #1240
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Well guys, I didn't sell the CD3, so I have decided that I am going to do some more work to it and prove to all those belt guys (kyosho, mugen, etc.) at my track that my little CD3 can very easily compete with them. The funny part is that my car is one of the heaviest on the track even to the 1/8 guys. Still have a lot of get up and go power with a heavy car. If I can figure out how to drop some weight, it would be great. The only CNC parts that I have are what is on my sig. I just ordered some more stuff from Nitrohouse (power clutch, replacement CVA one piece shafts, floating body mounts, etc.). So I have some work ahead of me. I am also in need of a setup station, which I think is most of my problem, so I am constantly on the look out for it, so if you know of anyone getting rid of a good setup station, please let me know. I also got an airbrush kit for Christmas, so I will be doing my own painting soon, as soon as I get some practice in.

Talk to ya'll later.
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Old 01-26-2007, 07:34 AM   #1241
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Quote:
Originally Posted by Joe Tanto
Hi I will be getting my CD3 very soon, the kit comes with a front one way, how did you find it working with the one way? I be running the car on a short curcuit with bands and you have to use the brake in many parts of the track. Do I opt for a front diff?

Regards
Joe F

you wont like a one-way if you drive with a heavy brake finger. but as they said, there's tricks you can do to help yourself. the pen springs to seperate the brake pads you should do anyway and the radio aid that was mentioned.
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Old 01-26-2007, 12:51 PM   #1242
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Default CD3

thanks for the info, another thing what diff oils I can use, front and rear? the reason I am asking this, is I am used to off road and I think it's a different story when it comes to onroad.

From where I get set up sheets?

Thanks guys

Joe F
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Old 01-26-2007, 01:30 PM   #1243
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Joe,
You can go to www.ofna.com and check out the setup sheets there. That is where I started, and it helped a bunch.

g/l
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Old 01-26-2007, 07:56 PM   #1244
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Default Chassis setup and Diff setup

Set up sheets:
The Jeffery Lin setup from the Ofna site is a good starting point. I tried a blalnced setup meaning equal
front and rear springs etc, and the more technical ( S curves, switch backs etc) the less performance that
setup could deliver. I have slight variations of the Lin setup on both my CD3's. The roadholding capability
of both my cars has improved as well as my driving performance.

As far as diff fluid is concerned:
Remember you are making a limited slip diff when you add viscous fluid (10k,60k,100k and up). If we all coasted
through corners we wouldn't need the different fluid viscosities. But under power, the inside wheel will
unload at some mismatch between the track tractions and the diff fluid thickness. You are trying to locate
this balance "for your driving style".
For example, I tried a much heavier fluid in the front diff (100k) and a light fluid in the rear (20k). When
the track got wet, all the car did was fishtail and spin,... severe oversteer, flip the fluid weights around,
and you will get lots of understeer, both of these behaviors are under power. So balance is what you are
looking for.

My car #1 with the Picco engine has low torque and the diff fluid is F/R 10k/30k.
Car #2 with the STS D3R high torque enginge has diff fluid F/R 10k/30k, and has more understeer and could
benefit from a thicker fluid in front, like 30k. I notice this mainly on high speed sweepers, and corner exit
and switchbacks. That's where I will be testing my changes on the same type of turns.
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Old 01-27-2007, 09:42 AM   #1245
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My car #1 with the Picco engine has low torque and the diff fluid is F/R 10k/30k.
Car #2 with the STS D3R high torque enginge has diff fluid F/R 10k/30k, and has more understeer and could
benefit from a thicker fluid in front, like 30k. I notice this mainly on high speed sweepers, and corner exit
and switchbacks. That's where I will be testing my changes on the same type of turns.


So should I start 30000 front and 10000 rear? I will be using a STS D3R. Then I will see what the results are. I will let you know.

Thanks guys

Joe F
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