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Old 10-19-2007, 08:53 AM   #346
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John, that's the stock wing, for the Protoform Stratus AP body. I've been running the Pontiac G6 Carpet body, on ashphalt tracks, since the wing is higher, and in the Mod class, any body goes here.

I normally run Nitro Expert classes, and was wondering on the foam tires. Someone was telling me that the electric cars didn't like the same foam tires that the heavier Nitro cars run. Now that I've been reading these boards on the electric side, I think I'll try a set next event.

Thanks all
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Old 10-19-2007, 05:00 PM   #347
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Thanks for the posts guys. I stole the stock wing from this Stratus for another body. I'll see if I can get another one. I'll keep the silver srpings in mind. At our track we don't use sugar water any more. Traction does build up though, as traffic lays on the blue groove. I think my car will do fine then. The bevel I put on my shocks gives me effectively 30 weight. I have no oversteer at present. The next club race is still a couple of weeks away. We have a big Nitro race scheduled this weekend.
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Old 10-19-2007, 08:29 PM   #348
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Earlier today I was reading this thread when the discussion started talking about LiPo cells and who and what.

It was discussed about certain brands and prices and someone (I can't remember who) was saying just to purchase a DeWalt 36v battery for 10 LiPo cells in it.

If anyone can remember who stated this I would appreciate it.

Also can anyone clarify if the Lithium Ion batteries that are what the DeWalt 36v are listed as are what we are calling LiPo's here? And if so, what kind of discharge rate can they handle.

Just to date myself, the last battery packs I purchased were 1400SCR. The 1700's were called SCE.

So, saying that, I am a little on the rusty side when it comes to battery technology. (Still have my Victor burp charger)


The Don.
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Old 10-19-2007, 09:54 PM   #349
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The Dewalt cells are the same as 123 systems Lithium Nano Phosphate cells. I tested the pack from Horizon hobbies that has two cells in series and two in parallel. The pack is pretty equivalent in voltage to a 5 cell NiMH pack. If your race against 6 cells it will not be suitable. It has a very high ability to deliver current. More than enough for RC, 30C or 138 amps continuous. Individual cells are available from 123 systems and Horizon for about $20. Packs are available from these two suppliers as well. Both packs are 5 cell equivalent. I would not get these from a Dewalt tool just for convenience. The individual cells available from 123 systems or Horizonhobbies.com are about the same price and come with solder tabs. The cells felt very good in the car for 5 cell but not as good as a 6 cell LiPo. Nickel Metal Hydride cells are still the most prevalent cell at the moment.
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Old 10-21-2007, 06:19 PM   #350
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John,

This seems like the kind of thing you might use. For all I know, you may already be testing it. :-)

http://www.teamnovak.com/products/da...try/index.html
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Old 10-21-2007, 09:37 PM   #351
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syndrome-Thanks for the link. The device reminds me very much of the device I use on my full size car but it is miniaturized. A graph of what your car does in a turn is very useful to measure before and after a change. I posted a couple of such graphs earlier in the thread.
The connections are similar to Spektrum Telemetry in that they suck power out of your Battery eliminator circuit. On high drain applications I had trouble with the Spektrum Telemetry. I hope that it is truly a low drain device that does not interfere with the car too much.

Foam tires Continued (Droop Interference)
I had to make some changes to the car to run the much smaller diameter foam tires. It turns out the right rear became unresponsive to the droop screw before I had the desired droop set. The back of the upright was rubbing on the A-arms outermost cross-brace. I dremmeled away some plastic from the upright to get back on the droop screw.

Center Shaft Pulley Rock
My Locktite paste fix, on the centershaft pulley rocking, failed. I applied the superglue fix reported by Kn7671. Clean things up rock the two outer parts apart and then glue things up.

Motor Bearing
I received my Boca bearings already. I expect the motor bearing to last much longer than in my pan car since we use good sized motor pinions. A 12 tooth pinion tends to pound that bearing with vibration. It is good to have a spare for the touring car, though. I did replace the two centershaft bearings already. The left side was toast. I checked the motor bearing. So far so good.
John

Last edited by John Stranahan; 10-24-2007 at 06:40 PM.
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Old 10-22-2007, 07:49 AM   #352
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[QUOTE=John Stranahan;3780636.010 inch bevel on bottom of piston hole to improve uptravel.

John[/QUOTE]


John,
what's up with that? Do you get better traction over uneven sections of the track?
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Old 10-22-2007, 09:51 AM   #353
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.010 inch bevel. Yes exactly. It reduces the effort for uptravel so the bumps don't push the car up off the track. Try it. You will need about a 5 weight higher viscosity oil for the same cornering.
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Old 10-22-2007, 01:38 PM   #354
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Which way is uptravel? Rebound or bump?


I have tried it, many times. (99% of the time on off-road though) But I never got it working consistently. Especially at the front, it made the car roll and center up in a very weird manner. And the concept of chamfered holes didn't blend well with jumps either: the 'pack' is very different.
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Old 10-22-2007, 03:54 PM   #355
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Well here is the history of the mod. I read in full size race car book the benefits of separate uptravel (bump, jounce) and downtravel (rebound, rebound) adjustments on the on-road race cars. Normally the uptravel (of the wheel) is set at a lighter setting on the shock than the downtravel.
I had discussions with a hydraulic engineer on a thread where I discussed this and he said it would be a simple matter to bevel one side of the holes. This lets the fluid flow into the hole easier and lightens the damping when the fluid is going in. When the fluid reverses in the hole it leaves in a compact jet and is little affected by the bevel.
I did find that the initial roll stiffness in a corner is slightly affected by the mod but is easily returned by using 5 weight heavier oil. If you watch any of my touring cars through the bumps with this mod you will find the chassis little affected by the bumps and the tires always in good contact to give forward thrust. I found this helpfull even with stock motors. It is especially helpful if there is a bump midcorner.

Off-road you need a certain amount of pack to keep from bottoming on the jumps. Lightened uptravel would hurt this. I don't necesarily recommend this for off-road as the needs are different. If you did do the mod on average the chassis would ride a little lower to the ground. You would need slightly heavier oil to keep your initial roll stiffness in the corner the same.

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Old 10-22-2007, 04:18 PM   #356
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That makes a lot of sense.
When I ran light bump/thicker rebound damping on the rear of a buggy, the rear stayed lower through bumps and turns. You could clearly see it. I also had more ( a lot more!) rear traction in the corners. But I couldn't get any height off the faces of jumps, and landings were a bit of a mess... Although RPM has cool 2-stage pistons, the beveled hole works much better: it doesn't need that small displacement to open and close the valve.
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Old 10-22-2007, 06:21 PM   #357
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Evo Thanks for the off-road observations. (How's the 5-link coming)

The blue Aluminum Screws from Fastener Express.com came in. I replaced 46 of the stock steel screws with Aluminum Screws. This cut 11 grams off the weight of the car. 25 flat head screws was a few less than needed, but it allowed me to keep 7 steel screws on the bottom in good places like the motor mount plate and the two front screws at the bottom of the front bulkheads. So why is this weight savings maybe less than normal. Associated has done a very good job of using only short light screws in the kit. There is really only about 1 ounce of steel screws in the kit. 45.7 ounces for the car ready to run with transponder now. I made sure to put 3 Aluminum screws on the spur. I had to shorten these.

If you are running ballast this is hardly worth doing. You can do this to the upper screws and offset a lot of the weight of a speed control that is placed high with lead that is placed low. You can see 10 of these new aluminum screws in the pic.
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-blue-aluminum-screws.jpg  

Last edited by John Stranahan; 10-22-2007 at 08:03 PM.
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Old 10-23-2007, 08:38 PM   #358
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I noted just a while ago that I had a Max Amps pack go bad. It just failed to charge properly on my Scorpion balancing chargers. I had time to look at it today to see why. I opened the connector end. I suspected a failure of the center balancing wire since the battery would still run a motor in the car on the bench. The battery is not old and is my best Max Amps pack so I thought it was worth the trouble. I tested the individual cells with a voltmeter, one at 4.18, one at 4.19. Good this means a cell did not die. On the left photo you can see this black balancing wire going into a large blob of solder but the wire is not coated. This usually indicates a solder joint that did not get hot enough to properly solder the wire. Continuity to the solder from the plug measured on a voltmeter was intermittent. The intercell connection was OK. Just the balancing wire to the intercell connector had a problem. I resoldered. I saved the yellow tape and reinstalled it as it is high temperature stuff. I saved the end shrink but retaped the pack. The ends run very hot ever since they changed to the copper connectors. The batteries also run a little too hot in Houston now. I liked the Max Amps packs better before this change.

I plan to quarantine the pack overnight. Charge it fully outdoors tomorrow at the track. It started a charge fine tonight which it previously would not do.

There were a lot of crystals in this center connection under the tape. Probably flux and a couple of solder attempts caused this. This would tend to corrode an almost good connection and make it poor.
Pic left note lack of solder bleeding up the wire. Picture right: corrected.

If one of the high current connections has desoldered from an incident such as reverse hookup. Do not resolder. Chunk the pack. It has other internal damage that is hidden from sight. This can cause a fire as much as hours later. Yes I have a picture.
John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-max-amps-failure-charge-problem-003-resized.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-max-amps-failure-charge-problem-004.jpg  

Last edited by John Stranahan; 10-24-2007 at 06:34 PM.
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Old 10-23-2007, 09:07 PM   #359
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Regarding the easier uptravel shock and harder downtravel...

A long time ago there was a piston modification people did offroad instead of beveling the holes in the piston.

Cut a precise piece of saran wrap to cover half of each hole on the piston.

Same effect. I even think there was one company that was selling cut pieces although I can't remember the name now. It has been 17 years since I was racing offroad.
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Old 10-24-2007, 06:18 PM   #360
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Dondor-When you start talking about machining Saran Wrap, I shudder. I take it you make a flapper valve with the stuff. What prevents rotation. This is similar to what fullsize cars do in the way of valving of orifices in the piston with thin steel plates.

Jaco Prims Foams
I received the Jaco Prism Foams today. Diameter is at 61.45 mm. You might think I got some extra foam, but no, the wheel is bigger than my GRP foams leaving the same thin sliver of foam. Width is .030 inch wider than the GRP's. These are current production just not on Jacos website yet.

Short Turnbukle
I was missing a camber link turnbuckle from very early on. I received a ASC 1418 set of turnbukle from tower they are .825 inch long which is shorter than the stock set. These are ideal if you run your inner camber link pivot on the outer hole like I do.

Track Test
Track very dusty, cool, LRP Sphere Comp TC edition with X11 3.5 motor.

I made three good runs tuning up the setup for some weekend action against the Nitros.
I ran three different gears.
Started out at 90/19, 9.47 overall,18.3mm rollout This was OK
Went to 90/20, 9.0 overall, 19.3 mm rollout. Motor was a little hot, car was very smooth, I lost a lot of rip out of the corners.
Split the gear with a 87/19, 9.15 overall, 19.0 mm rollout. This gave me the best balance of traction, good rip out of the corners, and good top speed.

I raised the rear wing to compensate for lowering the rear of the body some. I used pedestals from an HPI wing set. See the pic. I could use a bigger wing and lower mount and probably the carpet body for the foam tires.

Tire wear is a about 3 mm off the diameter for 4 runs. I am using Jack the Gripper from Corally which really helps traction in dusty conditions. I was close to race speed on a green track maybe within .75 seconds. The most worn tire was the outside rear on the sweeper. The inside front had a reverse cone. I rotated by swapping side to side as the inside rear was least worn.

I reordered my TIR spool as my first order did not "take".

Now that I have limited my traction with foams on a green track, my front pin pillows last much longer.

Foam Tire Wear Pattern
I got my nice wear pattern on the front foams which looks like tiny ripples lined up with the circumference. Pic is of the same pattern which is enhanced with lighting from my pan car. This usually shows the tire is the right hardness and is hooking up well. The pattern is hard to see normally. It is better seen by wetting the tire.

The body posts are still long as I am evaluting the foams still. They are not keepers yet. Body is resting on both the front and rear shock towers.
It is an outlaw TC.

The repaired Max Amps pack worked great.

John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-jaco-prism-foams-002-resized.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-foam%2520tire%2520wear%2520pattern.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-jaco-prism-foams-003-resized.jpg  

Last edited by John Stranahan; 10-25-2007 at 12:30 PM.
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