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Old 05-16-2013, 06:34 AM   #1816
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Originally Posted by Tommy R View Post

My upper "Y" link that attaches to the shock tower is clearance drilled on one end. The shock tower is also clearanced. And then the screws threads into the other end of the "Y". If I keep it loose enough to get free movement, it introduces too much play. If I snug it up to eliminate the play, it's too tight and doesn't move freely. I think I'll look into what Exita did.

Exita, how did you attach the triangulated link to the camber link?
Caseymcguyver..yes, thanks also..very informative post and thx for the pics.

Tommy, the "Y" need to be loose enough from the tower to freeplay...you don't want any binding, otherwise your suspension won't be good.
I ran it like that for a while and that small amount of slop in the joint has not been a big deal for me...and the whole thing works pretty good..better than stock.

I ended up finding an aluminum piece that I use now for my upper brace for the KPI and it's even less slop now...but still have a little bit of play which is still fine and the KPI works good....part of that is due to the hole and the screw that goes through and holds the upper arm to the tower.
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Old 05-16-2013, 07:14 AM   #1817
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Exita, how did you attach the triangulated link to the camber link?
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Exita...is that brace connected to the yok C-hub/turnbuckle with zip ties?
it's connected with 2 zip ties on each one, it's the strongest way I coul'd think of..

the only thing is that you have to cut them if you want to change the camber, witch does'nt happen so often

the end that mounted on the upper deck is a regular ball cup and the end that goes with the zip ties is the Yeah Racing 4.8mm Delrin Ball End (introduced to me by pickled of course):



got them from Rcmart

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Tommy, the "Y" need to be loose enough from the tower to freeplay...you don't want any binding, otherwise your suspension won't be good.
I thought so also but when I did that mod it didn't effect the freeplay of the suspantion. I could even pull back the upper arm (just a little) to gain more caster and still there's no binding

Last edited by Exita; 05-16-2013 at 07:31 AM.
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Old 05-16-2013, 12:51 PM   #1818
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Caseymacgyver, thanks for all the info.! I'm still a bit unclear, however, regarding the upper arm pivots. It looks like they're on bearings and allowed to rotate, which necessitated the upper shock? Am I understanding that correctly? And you did this to address the jacking effect?
That's exactly it; to address the jacking effect which would lift either the other front wheel or same side rear wheel off the ground, depending on springs and droop settings. It also looked funny when the car would roll heavily in the opposite direction of the slide. I was basically trying to copy the Takeuchi Racing design, but couldn't find single hole pivots. Once I mounted them, it seemed like a novel way to do the roll spring without the clutter of additional pushrods & turnbuckles. The D3 front end is already so cramped.

The 'jacking effect' can be desirable though, as it allows you to alter your sprung weight distribution through the steering range. Lacking the expertise, I found it too difficult to tune to my advantage however. It made my car very difficult to transition since it would spin out whenever I got near full lock. Basically, all the weight would suddenly come off the leading rear wheel, taking lateral traction with it.

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And you and pickled were right about the extra hub bearing! None of the components I bought came with one, but fortunately, it's the same size bearing that's used in Axial rock crawlers (my main RC interest) so I put some in yesterday and the slop is MUCH better now. So thanks!
Awesome. Yeah, the fit is so tight and clean, it's hard to imagine that a bearing would/should fit in there. Once you pop it in though, it makes you wonder why all manufacturers don't do it this way. In my opinion, MST really seems to have it going on right now.
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My upper "Y" link that attaches to the shock tower is clearance drilled on one end. The shock tower is also clearanced. And then the screws threads into the other end of the "Y". If I keep it loose enough to get free movement, it introduces too much play. If I snug it up to eliminate the play, it's too tight and doesn't move freely. I think I'll look into what Exita did.
Ah, got it. When you say "clearanced," are we talking a 3mm hole, carefully drill-pressed for an M3 screw, or are we talking an 1/8" hole hand drilled with a Dewalt/Dremmel? Accuracy counts a lot here to make it run smoothly without slop. Again, the carbon tower is fairly cheap and has perfectly sized, perfectly square and perfectly symmetric holes. The hinge pins from the c-hub delete fit very nicely. With my first incarnation, I had stacked 2 of the plastic shock towers and used a different arm a little wider than the Yok, but still wasn't happy with the flex/slop. The carbon shock tower turned out to be considerably stiffer than the 2 plastic ones stacked and cross bolted.

There's nothing wrong with adding a diagonal link as a brace, but as soon as you do, the Yokomo upper arm will only be working against you since it will move in a fore/aft arc and the arm is largely constrained to move in a vertical arc. You could leave the upper arm loose enough to avoid binding, but a ball connection in place of the Yokomo arm would be better. You'll want the brace's connection point to the chassis to be the same height and distance from the longitudinal centerline of the car as the upper arm connection point, otherwise you'll be introducing kick-up/down, and thus another complex variable.

It sounds like you are on the right track and asking all the right questions.
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Old 05-16-2013, 01:24 PM   #1819
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Caseymacgyver thanks for your glowing revue lol!
No worries man, although I should send you my therapy bills. Although not in the budget for awhile, an MST (FM) of some sort will likely be my next car too. I love my D3 now, but it seems like it took a lot of time and money to overcome its "Fat kid on a teeter-totter" nature, rather than to leverage it to further benefit. I sure have enjoyed the process though

Having 120+ pages of useful insight and discovery is a phenomenal thing. It's all fascinating to me and very cool to see the different approaches that people come up with. There is no best way to do anything, but there's always a better way and I love to see when someone finds it.
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Old 05-16-2013, 04:20 PM   #1820
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No worries man, although I should send you my therapy bills. Although not in the budget for awhile, an MST (FM) of some sort will likely be my next car too. I love my D3 now, but it seems like it took a lot of time and money to overcome its "Fat kid on a teeter-totter" nature, rather than to leverage it to further benefit. I sure have enjoyed the process though

Having 120+ pages of useful insight and discovery is a phenomenal thing. It's all fascinating to me and very cool to see the different approaches that people come up with. There is no best way to do anything, but there's always a better way and I love to see when someone finds it.
Sorry man I'd probably go bankrupt if you did lol I really like what you've added to this mod I've been thinking of doing this type of mod to mine too and looking at yours I think I will eventually does it reduce the shaking in the front wheels?

I never thought so many people would use this mod lol

notice in this pic of your shocks under the collar you have the o-ring. that o-ring actually fits on the inside of the adjuster collar!

Last edited by pickled; 05-16-2013 at 04:34 PM.
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Old 05-16-2013, 04:21 PM   #1821
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I am a total newb to CS drifting. I was running an old Tamiya TB 02 chassis 50/50 and loved it. Sadly, I toasted the rear diff I "locked" and Tamiya no longer supports that chassis. My Father(53yr old RC nut... love that guy!) recently got a Sakura D3 CS Sport and I saw a lot potential so I grabbed one for myself. Just got done the stock build plus a front one way. There is a lot of info to sort thru out there. I was wondering if one of you guys would be kind enough to point me in the right direction to the proper CS ratio, mods, and upgrades I should seriously consider and those I should avoid. No one at my local shop has found a setup to work well on our carpet track so we mostly run outside on sub par asphalt. Any help would be appreciated.

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Old 05-16-2013, 04:33 PM   #1822
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I am a total newb to CS drifting. I was running an old Tamiya TB 02 chassis 50/50 and loved it. Sadly, I toasted the rear diff I "locked" and Tamiya no longer supports that chassis. My Father(53yr old RC nut... love that guy!) recently got a Sakura D3 CS Sport and I saw a lot potential so I grabbed one for myself. Just got done the stock build plus a front one way. There is a lot of info to sort thru out there. I was wondering if one of you guys would be kind enough to point me in the right direction to the proper CS ratio, mods, and upgrades I should seriously consider and those I should avoid. No one at my local shop has found a setup to work well on our carpet track so we mostly run outside on sub par asphalt. Any help would be appreciated.

Motor: 10.5 Rev-tech
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Hey if you want to reduce the CS replace the rear 13T pulley with an 18T that brings the CS down to 1.55 if that's to low put the 13T back and replace the 22T with the 18T and that gives 1.75 CS the main thing to do is add UWA CVD's I wouldn't go mental modding or upgrading it maybe add an alloy rear pulley mount as the plastic one is prone to twisting and an alloy rear belt tension post rear
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Old 05-16-2013, 04:55 PM   #1823
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Hey if you want to reduce the CS replace the rear 13T pulley with an 18T that brings the CS down to 1.55 if that's to low put the 13T back and replace the 22T with the 18T and that gives 1.75 CS the main thing to do is add UWA CVD's I wouldn't go mental modding or upgrading it maybe add an alloy rear pulley mount as the plastic one is prone to twisting and an alloy rear belt tension post rear
Thanks for the info. I'm not sure how well I will be able to resist the carbon and aluminum hop ups, but I will do my best to start. Why UWA CVD's instead of ECS's? And what of the KPI mod? I think I understand the principle but where can I find a parts list to get it done? Also, is there any benefit to switching to 64 pitch pinion and spur other than them being quieter?
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Old 05-16-2013, 11:57 PM   #1824
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Thanks for the info. I'm not sure how well I will be able to resist the carbon and aluminum hop ups, but I will do my best to start. Why UWA CVD's instead of ECS's? And what of the KPI mod? I think I understand the principle but where can I find a parts list to get it done? Also, is there any benefit to switching to 64 pitch pinion and spur other than them being quieter?
an ESC is Electronic Speed Controller, UWA CVD's are Ultra Wide Angle Constant Velocity Drive shafts they stop the chatter at full lock! I'd get used to the chassis before modding it! the parts list is in this thread you just have to go back and look for it! where do you run you car inside or out? because if you get a little rock or stick flick up into the gears that will be the end of a 64P spur gear if you run indoors well a 64P will be fine
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Old 05-17-2013, 06:47 AM   #1825
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an ESC is Electronic Speed Controller, UWA CVD's are Ultra Wide Angle Constant Velocity Drive shafts they stop the chatter at full lock! I'd get used to the chassis before modding it! the parts list is in this thread you just have to go back and look for it! where do you run you car inside or out? because if you get a little rock or stick flick up into the gears that will be the end of a 64P spur gear if you run indoors well a 64P will be fine
Lol. I was reffering to E.qualized C.ornering S.peed or double cardan drive shafts. Do the UWA CVD's offer more steering angle at full lock than the double cardans?
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Old 05-17-2013, 07:00 AM   #1826
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Lol. I was reffering to E.qualized C.ornering S.peed or double cardan drive shafts. Do the UWA CVD's offer more steering angle at full lock than the double cardans?
The double cardins just help eliminate the chatter at full lock...

With the UWA CVDs, you get the full wider angle steering if you are using the aluminum steering
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Old 05-17-2013, 01:19 PM   #1827
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Sorry man I'd probably go bankrupt if you did lol I really like what you've added to this mod I've been thinking of doing this type of mod to mine too and looking at yours I think I will eventually does it reduce the shaking in the front wheels?
Thanks! I'm a noob and completely suck at drifting, but building upon the work started by others, I think that I've managed to scrap together an impressive machine. Yes, I probably should have spent my money on a better car and more of my time actually driving it, but what fun would that be

Not sure if you mean the upper arm pivots or the offset adapters:
Hell yes WRT the pivots, but they are probably overkill for a 'normal' suspension that doesn't need as much travel. I ended up swapping the pivot bearings for ceramic, and using an oversized post spacer under a locknut to keep them snug. No binding and no slop. Minimal flex from the shock tower, and I never felt it necessary to crossbrace the left and right pivots. At the upper arm ball link, it's about as stiff front to back as the lower ball link. Every ball cup has a ~4mm square piece of plastic sheet cut from a parts baggie dropped in to keep them snug on the ball. I was having to check and tighten the pivot bearings every few batteries as the bearings wore, but the ceramics seemed to have helped greatly. No chatter, wiggle, slop, nada.

Here's a flex pic for reference. Note that the Akerman is not nearly what it looks like here since the chassis rolls the other way when drifting and the bump steer is set for that.
3 Racing Sakura D3 CS Drift-img_0008.jpg

The offset adapter does keep the dog bone from binding in the outdrive cup at lock which did help mine form working their way outboard from the FOW. They wouldn't fall out, but would start to wobble about halfway. The adapters also make the shaft sweep a couple of degrees in the direction of turn, which of course translates to either greater steering angle, or lower CVD angle at the same steering angle. They are Tamiya M-05 rear upright adapters and fit the MST knuckles perfectly, although they are absurdly expensive for what they are. I think I paid $15 a pair.

The adapters were a result of how I prototyped; I had used a D3 rear upright for the steering knuckle. Basically chopped off the bottom half and threaded a ball in, then used the brake caliper attachment point to rig up a steering arm. I assumed the KPI was about the same as the MST knuckles, and worked through the rest of the setup until I was more or less happy and ready to commit to it more permanently. With the rear hubs up front and the D3 UWA's, the drive shafts would swing 8* or so in the opposite direction of the wheel turn, eating up valuable steering angle. When I put on the MST knuckles, they didn't have enough KPI for my setup, particularly in relation to the 25* of caster. It was as though I needed 1 more hole on the top of the knuckle, so I found these adapters

When I brought my caster and KPI down a bit, I just moved the lower ball link in to move the steering axis in. I made up the difference with thinner wheel hexes, so the wheel sweep in the well is about the same. All told, this approach easily yielded 10* in both directions over my rear hub prototypes. Moving the CVD cup into the hub as MST does is hugely beneficial here. I really should get longer swing shafts though, 48mm at least.

I used another pair of the offset adapters mounted horizontally to the front pivots to move the upper arms forward and reduce caster. I can very quickly change/test setup combos between 3 different KPI settings (including 0) and 3 different caster settings, maintaining left/right symmetry, without having to change any parts or re-shim anything.

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notice in this pic of your shocks under the collar you have the o-ring. that o-ring actually fits on the inside of the adjuster collar!
Good eye, but it was intentional, at least temporarily. I just got those RC926 'twin springs' and the groove on the D3 adjustment collar doesn't keep the spring coaxial enough. Normally this wouldn't be a big deal, but the spacer between the upper and lower spring was getting caught on the shock body. The O-ring was a quick and dirty way to help keep the spring centered. I also had the same rate springs on the top and bottom when I took the pic. I was trying to see if the softest setup was soft enough.

I love the idea of the twin springs, but they are quite difficult to tune with, at least with 2 rigid attachment points. The idea is to have 1 spring rate (That of the upper and lower in series) up to the point that the softer spring fully compresses, then the harder spring rate for the remaining travel. The difficulty is getting that transition point at the desired total deflection. Since both springs deflect during rate 1, the transition point moves whenever either spring is changed, which also changes the proportionality to the resulting ride height. Tightening the pre-load collar still changes the ride height, but doesn't actually move the transition point. I want more control over how it rolls and returns to center. I need more experience with them, but I see more pushrods in my future.
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Old 05-17-2013, 02:44 PM   #1828
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I am a total newb to CS drifting. I was running an old Tamiya TB 02 chassis 50/50 and loved it. Sadly, I toasted the rear diff I "locked" and Tamiya no longer supports that chassis. My Father(53yr old RC nut... love that guy!) recently got a Sakura D3 CS Sport and I saw a lot potential so I grabbed one for myself. Just got done the stock build plus a front one way. There is a lot of info to sort thru out there. I was wondering if one of you guys would be kind enough to point me in the right direction to the proper CS ratio, mods, and upgrades I should seriously consider and those I should avoid. No one at my local shop has found a setup to work well on our carpet track so we mostly run outside on sub par asphalt. Any help would be appreciated.

Motor: 10.5 Rev-tech
ESC: Novak Edge
As others have suggested, drop the CS ratio. That is easily the best bang-for-buck mod (demod) for improving the D3's driveability for anyone new to CS drifting.

In my opinion, 3Racing's choice to put a 2.14 CS ratio in an "Entry-level" drift car was done specifically to increase the sale of upgrades, not to increase your enjoyment of the car. That is their business, so I can't fault them for that. The box-stock car is horribly inadequate for a ratio this high IMO. It's certainly not undriveable at 2.14 and does the most beautiful donuts with ease. But, good luck to a newb getting it to transition on demand, let alone both directions on a track at speed. Don't get me wrong, it really is a good car, especially at this price point. But, it's an entry level car with an expert level CS ratio. Again, just my opinion after falling hook, line and sinker.

The upgrade path to get the chassis to support the 2.14 CS is long and incremental. Most of the available upgrades are "worth it," but each will expose something else that will need to be upgraded. UWA's will need the aluminum steering rack and knuckles to achieve the max angle. But... it will still chatter with that much angle on the CVD's and you'll find there's too much slop in the c-hub setup, and so on and so on. "Good enough" is different for everyone, so when starting out it's very difficult to know when the driver's skill reaches a level high enough to compensate for the car's shortcomings.

Conversely, the downgrade path is quite short with immediate dividends. At 1.55 CS, the D3 is way more manageable. You'll still very much be CSing, but you won't get stuck in drift-lock, and the tail won't swing around as fast during transitions, allowing you to better catch it as it crosses over. Throttle control is paramount here. Work your setup to have as much throttle accuracy as possibly through your transition speed (EXPO, pinion size, etc...) You want to be able to gently ease off the throttle just before the crossover so that the rear wheel speed roughly matches the car's forward speed, then back on the throttle just after the crossover. To a large extent, rear wheel speed through the transition controls how fast the car rotates. The driver's responses and available steering angle determine whether the rotation is caught in a CS drift, or simply spins the car out. Try to drive such that the front wheels are moving at roughly the same speed as the car is traveling. Countersteer as the car is transitioning at the same rate as the car is rotating. You can intercept a fast transition by countersteering a tad early.

1.77 is a good step up from there and still very manageable. You'll start to see what needs upgrading here though and will have a much better idea of how far you want to take it.

Last edited by Caseymacgyver; 05-17-2013 at 03:14 PM.
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Old 05-17-2013, 09:31 PM   #1829
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Thanks again to all that have replied. I really appreciate the input thus far. I'm sure I will have more questions to come.
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Old 05-18-2013, 01:45 AM   #1830
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About steering angle.

IMHO there is a big difference between the steering angle when the car is standing and you take pictures (on my mst, if I take down steering angle limiters I can take very sexy pictures at almost 60 degrees) and the actual steering angle you can use (I can use only like 45 degrees), limited by

- chatter (any single joint cvd will chatter even if it's not at full angle, no matter how uwa it is)

- the point where then angle between steering link and upright arm (or knuckle, not sure which one is the correct term) aproaches 180 degrees, at which the link cannot hold the upright steady (smallest steering slop gets amplified big time), inner wheel dances like crazy and may even lock.

Just remember, pictures are pictures, what you can get while driving is the real usable angle.
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