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Old 10-18-2006, 10:34 AM   #6511
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Quote:
Originally Posted by blanks596
I didn't realize that lightening the car was this complicated. I know that most of the weight of the car is below the radio tray, so wouldn't using ti pivot balls raise the CG? for that matter, wouldn't all of the after market parts raise the cg since they are mostly below the radio tray-ie-pivot ball, 2 speed shaft, 2spd housing

I guess it's all in compromising and adjusting. What are the lightening products that are just not worth purchasing besides the lipo batt?
You lowered the CG only IF you able to reposition most of heavy hardwares even lower than the current location, which is impossible. A good designed car should also consider the weight distribution or mass concentration. The mass of the car is spread evenly instead concentrated into 1 place.

When you change to Ti screws, nothing change, only the weight of the car.
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Old 10-18-2006, 11:33 AM   #6512
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Quote:
Originally Posted by Corse-R
Nope.. the problem is to know how much you can go without changing radically the way some car handles... lowering too much the CG makes the car nervous and less docile on their reactions.

Changing the pivot balls (steel) for some made on Ti isn't bad at all. But the ones to change them if you plan to lower really the CG are the upper ones, leave the steel on the lower side (the weight is where it doesn't hurts, at the lowest possible on the car).

Also... the Ti pivotballs has a dark side that many people doesn't know or will know someday. Are more prone to break rather than the steel ones (Ti is more brittle than steel). Many people can argue that changing all two you leveage the unsuspended masses, but at which price? At the price of a DNF if you manage to whack the boards and the pilloballs break.

Exchanging parts for aftermarket ones sometimes is due you're searching another side, maybe strengtening, maybe lightening, maybe more adjustability, maybe... the last judge are yourself, think if you really need that part and what advantages and what disadvantages you get changing that part (if not, ask the people).

I repeat what I told in the past, the unique part that's really needed for a MTX-4 straight out of the box are the front CVD's no more no less. Adding the Ti screwset you remove a nice quantity of grams on the best place you can do (on the highest part of the car).
I agree with you corse-r. I am very happy with the set up of my car at this time and don't want to mess with it too much. I have skyline front cvd's and 1-piece motor mount and despite knowing that track time will improve my seconds, I would be happy to get it faster with some proven option parts. I'm only looking for a 3/4 second difference in lap time to compete with the top dogs of my tracks, but I don't want to risk durability for lighteness. Ti screws it is!! Your explanation makes more sense to me and sounds the safest way to go.
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Old 10-18-2006, 11:42 AM   #6513
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I put Team Tamale Xray spring holder into MTX4 damper, perfect fit on both front and rear. Nice little option...
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Old 10-18-2006, 11:49 AM   #6514
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rc-champ says Kawahara doesn't have an Alum. front sway bar mount..
Whose should I buy? I dislike 3racing....

Sato Seiki
or
JP racing
or
Kfactory
or someone else??

also,
on the kfactory website they show a rubber cvd boot, can I buy these for Mugen anywhere?

Thank you,
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Old 10-18-2006, 12:09 PM   #6515
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Quote:
Originally Posted by JayL
rc-champ says Kawahara doesn't have an Alum. front sway bar mount..
Whose should I buy? I dislike 3racing....

Sato Seiki
or
JP racing
or
Kfactory
or someone else??

also,
on the kfactory website they show a rubber cvd boot, can I buy these for Mugen anywhere?

Thank you,
Jay
Sato Seiki, Kfactory, 3Racing are manufactured either in China or Taiwan.

If you really want the best I think is Kawahara. Second choice is Kfactory. Third is 3Racing ( don't buy the CVD !!! ).
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Old 10-18-2006, 12:11 PM   #6516
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I know some of you feel that Lipos aren't worth the weight loss. And that's cool, I too am very happy with my car in stock form. But what was mentioned earlier was club/no-tech racing. CG/RC can be off-set with the weight of a 4mm chassis, heavier batt. tray, lower fuel tank, or lead weights. And having the car lighter allows you to strategiclly place weight. A little on the muffler side, a little under the one-way/frnt diff... etc at the lowest point. If you put the stock car on 4 scales at the wheels, I guarantee that everyone would have different numbers due to equipment... motor weight, motor head height, wiring jobs, PT location, servo type, bling parts, option parts, whatever your pleasure.

The car feels balanced, but technically it isn't perfect. If you race EP carpet, you'd know that a + few grams here and - few there makes a big difference in balance & cornering speed which = faster lap times. It holds true in any racing.

Regarding Ti pb, I ran them in my K cars for years, but they've cost me some good finishes. For the cost, it wasn't worth the weight loss or not finishing because of front end breakage. The stock Mugen pb's are the strongest I've ever experienced so I only used the Ti's for the rear. I've never had a rear Ti pb bend or break, but I think it's because of their positioning strength being side-by-side and at the rear.
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Old 10-18-2006, 01:02 PM   #6517
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Quote:
Originally Posted by asw7576
Sato Seiki, Kfactory, 3Racing are manufactured either in China or Taiwan.

If you really want the best I think is Kawahara. Second choice is Kfactory. Third is 3Racing ( don't buy the CVD !!! ).
I really like the overall quality of Sato Seiki parts (I have some Sato parts for my old MTX3 and some sets of engine mounts), attached is one of the engine mounts, really good quality and better price. Unbeatable IMHO.

Regarding 3Racing Cra... errr... CVD's... better to not touch them. Are just iffy and prone to breakage, better to get the Mugen ones, much stronger and durable.
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Old 10-18-2006, 01:33 PM   #6518
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I'm planning to go for LiPo and lower tank as low as possible. But I wanna be sure I didn't get it wrong.

I'm using Mugen 4mm chassis and stock 2F mount. Is the red area right area to dremel? is there other place I need to dremel to lower tank?
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Old 10-18-2006, 01:36 PM   #6519
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With regards to lightening and changing the CG. I do not know where the actual CG on the car lies. I can say this. By lightening certain parts... even ones slightly below the CG you can still improve your car. If that part is part of the drivetrain you will have the effect of increased power. My car still uses nimh batteries and is already under race legal weight. If I remove weight no matter where it is and then replace it in a lower spot I have lowered the CG. At this point if I put in a lipo pack (my car is already under legal weight) I would have to add lead back onto the car in the same amount of weight I just removed. Removing weight from the car is a good thing I just think that a lipo battery pack is the least beneficial place to do it.

With regards to ti pillow balls and strength. I can only give my experience. I had an MTX3 prospec and got an MTX4 as soon as they go to the USA. I kept the ti pillow balls off the MTX3. I have only bent two of them in two years. I have never broken one.
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Old 10-18-2006, 07:08 PM   #6520
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Quote:
Originally Posted by ttso
I'm planning to go for LiPo and lower tank as low as possible. But I wanna be sure I didn't get it wrong.

I'm using Mugen 4mm chassis and stock 2F mount. Is the red area right area to dremel? is there other place I need to dremel to lower tank?
That looks good, ttso. A buddy of mine actually left a .5mm ledge to protect the bottom of his tank. Cut the plastic sections down a little at a time. If you want to get it a little bit lower, carefully shave a flat spot on top of the front shaft mount.
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Old 10-18-2006, 07:21 PM   #6521
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Quote:
Originally Posted by Corse-R
I really like the overall quality of Sato Seiki parts (I have some Sato parts for my old MTX3 and some sets of engine mounts), attached is one of the engine mounts, really good quality and better price. Unbeatable IMHO.
I like the Sato hollow shaft and light weight front shaft. They don't make a mono mount do they? Where did you find those mounts?
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Old 10-18-2006, 07:28 PM   #6522
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Default MTX-4 parts

could you direct me to where to get parts online besides ace hoobies and nitrohouse, my LHS takes forever to get parts. Looking for parts to make a front diff.

I found this at nitrohouse

Fr. Universal Joint Set

Is this all I need to make a front diff. not a front one way which come with the kit

Thanks
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Old 10-18-2006, 08:30 PM   #6523
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I think some people are taking the whole CoG thing to the extreme. I wonder if anybody on here has actually caculated and measured where the CoG of the car really is?.....I don't think anyone here has. Just because YOU can feel the difference doesn't mean there is. You need a larger test pool and even then it's not definitive although it can be taken with at least more relevance over just one person saying it's better.

On the subject of titanium pillow balls: These do more to lower the unsprung weight of the suspension than they with regards to CoG. The car's responsiveness has more to do with the suspension reacting faster to surface irregularities although I'm not saying it has nothing to do with the CoG. Example: You can move your arms up and down a lot faster than if they had 10lb. weights strapped to them.

Also, do you notice any handling differences when the fuel level changes? I wish I was that good. I certainly can't, and that's a big chunk of weight that is changing constantly, shifting back and forward, left and right. If I can't notice that, I HIGHLY doub't I'll notice a 10 gram difference.
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Old 10-18-2006, 08:50 PM   #6524
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Quote:
Originally Posted by Racing4Evo
I think some people are taking the whole CoG thing to the extreme. I wonder if anybody on here has actually caculated and measured where the CoG of the car really is?.....I don't think anyone here has. Just because YOU can feel the difference doesn't mean there is. You need a larger test pool and even then it's not definitive although it can be taken with at least more relevance over just one person saying it's better.

On the subject of titanium pillow balls: These do more to lower the unsprung weight of the suspension than they with regards to CoG. The car's responsiveness has more to do with the suspension reacting faster to surface irregularities although I'm not saying it has nothing to do with the CoG. Example: You can move your arms up and down a lot faster than if they had 10lb. weights strapped to them.

Also, do you notice any handling differences when the fuel level changes? I wish I was that good. I certainly can't, and that's a big chunk of weight that is changing constantly, shifting back and forward, left and right. If I can't notice that, I HIGHLY doub't I'll notice a 10 gram difference.
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Old 10-18-2006, 08:58 PM   #6525
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Quote:
Originally Posted by Racing4Evo
I think some people are taking the whole CoG thing to the extreme. I wonder if anybody on here has actually caculated and measured where the CoG of the car really is?.....I don't think anyone here has. Just because YOU can feel the difference doesn't mean there is. You need a larger test pool and even then it's not definitive although it can be taken with at least more relevance over just one person saying it's better.

On the subject of titanium pillow balls: These do more to lower the unsprung weight of the suspension than they with regards to CoG. The car's responsiveness has more to do with the suspension reacting faster to surface irregularities although I'm not saying it has nothing to do with the CoG. Example: You can move your arms up and down a lot faster than if they had 10lb. weights strapped to them.

Also, do you notice any handling differences when the fuel level changes? I wish I was that good. I certainly can't, and that's a big chunk of weight that is changing constantly, shifting back and forward, left and right. If I can't notice that, I HIGHLY doub't I'll notice a 10 gram difference.
You are probably right, but you also missed the overall point. If you want to bling your car fully to the hilt (presumably with Skyline products in your case) I certainly will never tell you not to. But if you race at a track where they weigh your car, you can't lighten the car that much and you are better off taking the weight off the rotating mass and suspension before installing a lipo pack etc. See Keisuki's winning car for an example. If you want bling then knock yourself out!
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