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Old 02-25-2008, 11:02 AM   #436
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Something I forgot to post about Jeff Brown's setup at Snowbirds is the motor position in the rear pod. We had a pinion/spur combination (something like 31/94) that moved the motor toward the front of the car. There was clearance behind the carbon fiber crossbrace, but not much. Jeff Cuffs (thanks, Jeff) pointed out that the motor looked like it was hitting the crossbrace when the rear pod flexed toward the front. Not a good thing.

We went to a smaller pinion/spur combination to avoid the problem. Just wanted all 12x owners to be aware. We have now cut down the crossbrace in the motor area by 1 to 1.5mm to allow for more motor movement without interference.
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Old 02-25-2008, 11:11 AM   #437
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Fairly sure that carbon cross brace has changed at some point. Early ones were 4mm wide in the motor area, but newer ones seem to be 6mm. I think this is because there were a few breakages.
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Old 02-25-2008, 12:13 PM   #438
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Fairly sure that carbon cross brace has changed at some point. Early ones were 4mm wide in the motor area, but newer ones seem to be 6mm. I think this is because there were a few breakages.
Sure enough, Jeff's is 6mm (before dremeling). We'll be sure to have a spare. Thanks, Matt.
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Old 02-25-2008, 04:42 PM   #439
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btw does anyone know what corally red is equivalent to in diff fluid?
Oops. My earlier answer was in error. It is somewhat heavier than Kyosho 20,000 wt. diff fluid. Don't have 30,000 to compare.
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Old 02-28-2008, 08:22 PM   #440
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Has anyone tried Jeff's setup from Snowbirds, and if so how was it? Traction varies so much from track to track that it's difficult to compare results, but if anyone has tried that setup on high bite it would be interesting. Especially if you found something better!
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Old 02-29-2008, 10:52 AM   #441
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Quote:
Originally Posted by Larry Brown View Post
Snowbirds update- There were 5 12x cars in the 27T main, 2 in 19T and 3 in modified. all with different drivers. So 10 out of 30 spots in the 1/12 scale mains were Corally SP12x cars, driven by 10 different racers.

Jeff Brown's setup (TQ 27T):

Tires: Jaco lilac front, 1.60 " and yellow rear, 1.71", full front and 1/2 rear tire sidewalls glued with CA
Front suspension: Corally WC (same as Assoc. dynamic strut) with 10 degree reactive caster blocks, 2 spacers rear and 1 front, 1 1/4 degree camber, raised steering arm ballstuds, threaded axles from Parma
Front springs: .020
Servo mounting: flat, rear mount (ballstuds for steering arms facing forward)
Front width: 165 mm at top of tires
Toe in/out: 0 degrees
T-bar: Corally 2mm, with center screw on rear pod removed and spacer cut to only have spacers under 2 pod mounting holes, no spacer under front pivot ball
Center shock: IRS VCS shock, front mount raised 1.5 mm and rear mount moved back 6 mm, 25 wt Assoc. shock oil, olive center spring
Ride height: 3.5 mm, chassis level when race ready
Rear pod droop: this is checked by lifting center shock rear mount and measuring height at rear of main chassis. Difference between static ride height and lifted height was 1 mm
Rear width: 171 mm
Chassis: stock kit chassis
Speed control: Novak GTX
Batteries: Team Kwik Ener-G 4600 NiMH (Note: the SAME pack of batteries was used twice in practice, in all 4 qualifiers, practice the morning of the main, and in the main)
Motor: handout CO 27T tuned by Team Kwik

The carpet was high bite, and very smooth. Bumps were not an issue.

Let me know if I forgot to mention anything!
Larry,

Thanks for the setup. I'm going to be building Juan Aveytia's car for the carpet nats with this as the starting setup. Approx. what is the corally red lube equivalant to in 1/8th scale diff oil? Do you have any pics of the car you can post so it's easier to see the mods you did to the t-bar spacer, shock mounting, and where you dremeled the dampener brace? Is there anything else that needs to be modified from how the car comes?

Thanks,

James
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Old 02-29-2008, 12:19 PM   #442
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Hi James,

-don't know the equivalent diff oil, I just know the Corally red is a little thicker than 20,000 wt. Kyosho
-on the T-bar spacer, you will see that there is a 1 piece fiberglass spacer with 3 holes to accommodate the mounting screws to the rear pod plate. Just cut off the ends (about 8mm) with a dremel and use the cut-off ends as spacers under the 2 outside T-bar mounting holes.
-on the front shock mount, we put 2 nylon spacers under the mount to raise it about 1.5mm. Then use a 2mm longer screw to attach the mount.
-on the rear mount, drill a hole to accomodate a new ball stud location 6mm behind the original and cut off the excess (where the old mounting hole is)with a dremel. You can use an AE ballstud and nut, or do it metric. Ballstud height was not changed.
-on the dampner brace, install a motor and mark where each end of the motor would hit the brace. Then use a drum sanding bit to remove material, up to 1 or 1.5mm, slightly wider than the motor location. Note that Jeff has not run this yet and there may be an issue with strength of the brace. Apparently the original design was 4mm instead of 6mm wide and had some breakage issues.

The only other thing I can think of is a cutout in the chassis for the servo saver on the flat servo. From the rear edge of the existing front cutout, we cut an additional 8mm toward the rear, but only 15mm wide, not the full width of the existing cutout. If you put a servo with servo saver in the approximate mounting location you'll see what I mean.

Hope this is adequate. No photos, unfortunately.
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Old 02-29-2008, 12:39 PM   #443
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Thanks for the info larry, i'll build the car up with 20,000wt. kyosho and go from there.

what servo saver are you guys using and what holes do you put the ballstuds in? Then i'm guessing you use taller ballstuds on the steering blocks and shim them until there's no bump steer.

Any diff tricks? It's been a while since i've built a small ring diff.

Thanks,

James
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Old 02-29-2008, 01:05 PM   #444
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James-

We use the small Kimbrough servo saver, middle holes. And yes, we use tall ballstuds with shims on the steering arms.

The diff can be a little tricky. To keep the nut tight, we filled in a little of the bottom of the threads on the axle with CA, then had to sand the outside of the threads a little with 600 grit because some of the CA ended up there. Then used locktite (after the CA was totally dry, of course) in final assembly.
Be sure the diff o-ring is totally degreased prior to assembly. We also put some thin strips of 600 grit in the o-ring groove with CA before the o-ring was installed.

We used a #75926 thrust spacer instead of the thrust bearing, because we weren't sure if the thrust bearing was clearing the inner race of the hub bearing.

Have fun!
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Old 02-29-2008, 02:11 PM   #445
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LArry, how do you guys find the car is with the flat servo? not something i think we've ever tried over here.

I haven't ever had any issues with the diff - as mentioned, make sure that the O ring is very clean, if i have time i like to clean and leave for a day or so to properly dry out - and warming the O ring helps it bite a little as well. I know there are a couple of people who have gone with the CA in the threads. For me the std diff thrust race set up is spot on, diff lasts for ages, no issues at all.
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Old 02-29-2008, 06:33 PM   #446
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I prefer the flat servo most of the time. It makes the car more aggressive generally. The only time I find the angled servo mounts to be better is when the track is really bumpy. It just has some better bump steer characteristics than the flat servo (with the corrected steering geo that Larry had mentioned with the taller ballstuds) and makes the car a little more stable over bumps.
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Old 02-29-2008, 07:45 PM   #447
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Quote:
Originally Posted by MattW View Post
LArry, how do you guys find the car is with the flat servo? not something i think we've ever tried over here.
Korey beat me to it. On medium to high traction we have run a flat servo for a long time. On lower traction the angled servo is probably better, but Jeff rarely races 1/12 on low traction or bumpy surfaces.
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Old 03-01-2008, 01:19 PM   #448
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Hey Guy's what the best way to mount a servo flat, oh and where can one purchase long ball studs.
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Old 03-04-2008, 07:50 PM   #449
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Hey Guy's what the best way to mount a servo flat, oh and where can one purchase long ball studs.
You can get long ballstuds from CEFX, at www.cefxraceway.net. The silver ones are #12702 (tall) and #12701 (med). They also have them in green.
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Old 03-04-2008, 09:30 PM   #450
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Originally Posted by MattW View Post
The "normal" tyre of all of us UK corally guys is Parma Magenta front with Grey rear. I think the bite in our carpet tracks is generally a fair bit lower than in the US, and we alwasy run on odourless adative.
Matt, do you know what the Jaco equivalent tires are to the Parmas you use? At Snowbirds the stock racers liked Jaco lilac fronts/yellow rears, using Jack the Gripper. The 19t and mod racers were using yellow rears with magenta (Jaco 32 shore hi rubber content), or even pink fronts cut very small. And do you use the Assoc. style front end? If so, what springs and caster and reactive caster settings?
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