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Old 03-24-2008, 08:03 PM   #946
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thanks Tony,
just the reply I was waiting for!

btw, in your opinion, is it worth changing the whole drivetrain of the 5R to the 5T? (front, center and rear diffs)
assuming gear ratios are the same, what's the advantage?
what I've heard is that the whole drivetrain is lighter = better acceleration?
others say it's the low CG..
and I'm suppose to use 16T bell with 44 main spur correct?

appreciate your comments, thanks!
The overall gear ratio of the 5T diffs with 16T clutch bell and 44T spur in the buggy is about the same as just going up to the 48T spur gear with the stock diffs. The gears do have a different cut though so they are smoother. Plus running the larger clutch bell feels better too. But it is a very expensive switch though. The next Mugen will have the truggy gears in the diffs though (just like the RC8 and new Xray 808). The trend is going to a lower geared diff with a smaller spur gear. This allows you to lower the center of gravity on the center diff, use a lighter, smaller spur gear for better acceleration and overall lower weight. Plus with the smaller spur gear the balance is better since the motor can move more in to the centerline of the chassis. The other advantage is both the buggy and truggy will share th esame diffs so you don't have to carry as many spares. The new Xray 808 uses a 41, 42 or 43T spur gear and I'm betting you'll see the same from Mugen on the next car.
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Old 03-24-2008, 08:40 PM   #947
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Hi,

Finally I found it: In the parts list of the MBX5R, the C0107A is listed as (the one and only) part of the C0115 parts package "Upper Arm Link".

So I can second Tony's statement that it is the correct one.

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Yeah TonysScrews is very smart when it comes to all RC cars, but i think mugens are one of his favorites, plus he has the (Screws) to back it up....
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Old 03-24-2008, 09:50 PM   #948
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Just alittle info if you guys want it. I spoke with Kris Moore about running the truggy diffs and he said do not do it. The car was not design to be ran like that. Tillman and Moore were both running stock setups at Silver state.
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Old 03-25-2008, 09:56 AM   #949
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Well with everything i've read here. I'm going to give it a try. I have the extra parts so why not?


Chuck
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Old 03-26-2008, 04:13 AM   #950
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Thanks for the replies on the 5T drivetrain topic.

Well, Tony does make sense with his comments.
I think that if you can reduce the rotational mass on the drivetrain, you can have a better accelerating car.

2T on the main spur gear does not seem much in weight, but considering the hp our .21 engine makes, well, every gram counts!
Plus the fact tt you can bring in the engine closer to the center of the chassis.

I guess little adjustments like these will have a greater effect on such a small car like our 1/8 buggies..

On using the 5T diffs in the 5R, I don't foresee any issues. Both 5T and 5R use the same bulk head and center diff mount so I should think they're compatible.
Major difference other than a smaller spur gear/CB combo are the spiral cut gears on the diffs..

Here's something interesting I read..

Spiral bevel gears operate smoother and quieter than straight cut.
Straight cut gears will 'whine' the faster they go but offer both:

A. More directional application of force allowing for less power loss.
B. Higher acceptable loads until failure. Basically making the transmission stronger and more efficient.

But spiral bevel gears operate much more smoothly than straight cut gears.
So I guess there are pros and cons on using the 5T diffs..

What do you guys think?
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Old 03-26-2008, 04:31 AM   #951
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I'm in the process of lightening my 5R,
so far am using the lightened pillow balls and no longer the aluminium rear uprights.
Also using upper deck ti screw set.
and Lipo rx batteries.

Now looking at other weight saving possibilities..
Anyone using aftermarket chassis for the 5R?
I'm int'd in the BCE chassis, is it really stronger and lighter than the stock one?
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Old 03-26-2008, 05:21 AM   #952
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Guys, as far as I remember, the Mugen uses spurs with the same overall size, whether it be 44, 46 or 48. The engine won't move any closer to the center line. If you haven't noticed, Mugen doesn't space the center diff towers any higher for larger spurs, meaning its the same diameter. I have the 48t spur with a 14T CB. The spur doesn't protrude any further through the bottom of the chassis. I have checked them, and they are the same size, and if not, its very little in diameter, unlike Kyosho's and others.

Also, if you guys really have to know, I would prefer not to be center line the engine. If you think Losi was that great for doing it, then why are 8ights so awkward coming off jumps and ruts? It because when you centerline your center of gravity, the car will tend to rotate on its axis more easily, meaning, if the car is upset or not squared off a jump, it will rotate or bobble in the air, needing correction. The lighter the car, and the more centerline the weight is on the chassis, the harder the is to drive IMO.
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Old 03-26-2008, 05:28 AM   #953
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I have to agree on the lightness part.Although i don't know about the centering of the CG.
Weight though does affect performance the wrong way most of the times especially on rough tracks.
I have noticed this comparing my car and my brothers...we have more than 400gr (14.3oz) and his heavier car works better on the rough part and jumps and doesn't get thrown away as easily===consistent driving!!!
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Old 03-26-2008, 06:55 AM   #954
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You are correct about the 48T spur gear diameter. It is the same 48mm diameter as the stock 46T spur gear. Just about all Mod1 pitch pinions are 2mm larger in diameter than the number of teeth. So a 44T spur is 46mm, 46T spur is 48mm, but Mugen modified the pitch and height of the teeth on the 48T spur gear so as to not have to include 1mm shims to raise it. Personally I think this was a mistake as the 48T spur gears don't last anywhere near as long as the 44T or 46T spur gears. I'm sure though that if they do make smaller 40, 41, 42 or 43T gears, they will be sized correctly (or at least they should be).

As for the weight with the center line and center of gravity, I don't think the motor should be centered in the car either but moving it inwards shifts weight away from the outside of the car and makes it better balanced. This is one of the reasons why Chad Bradley ran a huge 2500mah AA 5-cell hump pack in his MBX5 when he ran for Mugen. The car is out of balance in the left rear. I have a MBX5R brushless/LiPo conversion that I have been playing with. I ran the car for the first time at the CRCRC electric Midwest champs and used a huge 602 gram 6000mah MaxAMps 4S2P LiPo and the car was about 150g heavy in the left rear. It SWOWED on the track. When I went to Las Vegas a few weeks ago for the SilverState race I ran a dual 2S1P 4000mah LiPo setup for the same 14.8v but the two packs with y-harness only weighed 420grams. The car felt awesome on the track. Bobby Tillman ran it for about 4 laps and said the car was absolutely amazing how good it handled and drove.

With all the new cars coming out weighing in very close to the ROAR minimum weight (7 lbs, 0.9 oz's) they have a huge advantage in the acceleration department as well as run time. Less weight makes things easier on all parts as well. Many people have said the same thing about a heavier car feeling better in the rough but that is due to the suspension setup. If you take 1/2 lb or more out of a car you have to compensate for it with re-tuning the suspension. That could mean different fluids, pistons, springs or even all new shocks as well as arm and tower position of the shocks. I can guarantee you that Mugen's top priority with the next car is shedding weight. The only unfortunate thing about that is the incredible durability of the Mugen driveline we are all familiar with may have to be sacrificed some.

BTW, another way to lose weight is to use center diff outdrives on the front & rear but you need to modify them slightly. Also all the steel pivot balls (camber links, steering rods, servo rod, sway bar ends and the chassis braces if you run the old standard MBX5 turnbuckle braces) add up in weight. If you replace them with lighter titanium/aluminum options you can save a good amount of weight. The shock stand-offs are also steel so I'm sure there is an aluminum option out there that will work. If you have access to a machinist/machine shop, you can lighten the spur gear and the F/R ring (conical) gears.

Best regards,
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Old 03-26-2008, 09:22 AM   #955
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Tony

Is this the battery you are reffering to that Chad Bradley used to run?

http://www.amainhobbies.com/product_...ducts_id/18754

I was looking a getting one of these packs for long mains. I also noticed that the chassis seems unbalanced even when I am setting my ride height.

Would this pack solve that balance issue? Would the truggy also be off balance, and benifit from running one of these packs?

Thanks in advace
Sean
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Old 03-26-2008, 02:47 PM   #956
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AA packs are a little heavier then a 5 cell hump....so i dont know if ur trying to go lighter or heavier on the pack but thats how it is....Lipo would obviously be the light solution
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Old 03-26-2008, 04:28 PM   #957
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I have done a bunch of milling to the drivetrain, and also milled out any other stuff I thought I could get away with.

I was thinking about lipo's but thought it would make the left/right balance of the buggy, even worse. So I would be willing to add weight(bigger battery) if it helps the consistency/balance, and handling of the car.

thoughts anyone???
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Old 03-26-2008, 04:43 PM   #958
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Tony

Is this the battery you are reffering to that Chad Bradley used to run?

http://www.amainhobbies.com/product_...ducts_id/18754

I was looking a getting one of these packs for long mains. I also noticed that the chassis seems unbalanced even when I am setting my ride height.

Would this pack solve that balance issue? Would the truggy also be off balance, and benifit from running one of these packs?

Thanks in advace
Sean
Hi Sean,

Yes, that is like the battery that Chad used to run in the MBX5. I forget if he ran the Ballistic Batteries 5-cell AA pack or perhaps the Team Helotes pack, but basically it used 5 AA cells and weighed around the same as that pack you linked to at 159 grams. Normal 2/3A 5-cell hump packs weigh about 105 grams. The 1500mah HT Batteries LiPo I run in my car in nitro form is around the same 105 grams. I run LiPos as I like the consistent higher voltage with my 7.0v regulator. The servos are crazy fast and super strong on 7.0v and the brakes feel the same from the start to finish of any race. The run time on a 1500mah LiPo is better than a 1500mah NiMh pack too. The pack plus the regulator adds a bit more weight to that side of the car. The unbalance is also another reason why I run the ligher (and thinner) Novarossi or MSR1005 pipe and headers. I'll never use the JP pipes just due to the weight alone...LOL I also won't use an aftermarket cooling head as they are usually heavier.

Best regards,
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Old 04-02-2008, 09:57 AM   #959
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I have found after owning several MBX5 versions that the center diff top plate brake bushings SUCK. After several long mains with heavy braking the bushings are blown and the lever arms become sloppy...i suggest the optional hopup top plates with bearings...King Headz comes to mind.

Also, the brake cams tend to wear rather quickly (IMO) causing the brake engagement point to change....also causing you to either flip it if you havent already and buy a new one if youve already smoothed out both corners of the cam lobe. This makes setting the brakes a pain.

In the end, i would also swap out the standard steel rotors for some G10 units and scrap the "pads" on the shoes. This guy makes some killer G10's for the Mugen.

Look up "xrayeddy" on the forum and shoot him a pm for some.
Hi,

I run the Xtreme Racing carbon fiber center diff mount plate with ball bearings. So far has worked great.

Best regards,
Frank
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Old 04-03-2008, 08:29 AM   #960
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Raced my 5r last weekend for the first time and was running between second and third place for about a third of the 20 minute A-main until my servo arm came loose.The car was awsome it handled like it was on rails. Whats amazing is that it is box stock and that I had just broken the motor in and painted the body the day prior so the car had never seen any dirt until the heat races, this was my first 1/8th scale buggy race though I've been racing
1/10 scale 2wd nitro stadium trucks for years. The rear-end was slightly loose in fast corners so I will increase the wing angle to get more bit.I'm running an novarossi p5sx motor with the 9886 pipe and the 41021 smooth flow short manifold. One question novarossi glow plugs are hard to find so I'm
wondering could I use an mc8 instead of the nova g6s?
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