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Old 06-17-2013, 07:19 PM   #1966
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Originally Posted by Caseymacgyver View Post
Here's another long one for any fellow gear heads out there

The horizontal shock mounted on the front tower was mostly driven by my...
...Absolutely insane attention to detail. You are an evil genius, and whether it was ur idea or no, I bow to you sir. Taking a simple "entry level" drift chassis, and modding to that extent with success is admirable. While I understand your reasoning for the suspension mods, I know I am no where near where you are with this chassis. I love me some adjust-ability but, where took it is just nuts!

You live up to your name. Mr. MacGyver!
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Old 06-18-2013, 10:33 AM   #1967
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...Absolutely insane attention to detail. You are an evil genius, and whether it was ur idea or no, I bow to you sir. Taking a simple "entry level" drift chassis, and modding to that extent with success is admirable. While I understand your reasoning for the suspension mods, I know I am no where near where you are with this chassis. I love me some adjust-ability but, where took it is just nuts!

You live up to your name. Mr. MacGyver!
Many thanks, I am humbled by the compliment. I guess my crazy is showing a bit .

Historically, I'm more of a reader than a poster, but for whatever reason and by whatever method, this car, or perhaps just CS drifting in general, has turned me into an enthusiast. Having read through this thread over the past months, I had the advantage of more or less starting from where others had already taken it, particularly WRT the KPI mod. After building upon that, I felt a strange obligation to share what I had done and what I learned during the process to add to the existing knowledgebase. You perfectly articulated the most important takeaway I could hope to share. That is, although the D3 is an "Entry level" chassis, it is proving to be a very "Mod friendly" platform (Once the chassis and shock towers are upgraded), providing the driver an array of relatively cheap/simple customizations to suit their preferences. In short, there's a lot of juice in the D3 for those who may want to squeeze it. Thanks for reading.
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Old 06-18-2013, 06:57 PM   #1968
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Caseymacgyver. Thanks for your recent posts dealing with the KPI and posican. Have seen those links in drccentral and driftmission a while back but never looked into it further for its benefits but that video sure highlights it.

Until my recent break of 1 of my dogbones, I didn't realize how much slop has developed in my front suspension. 1 bearing on steering wipers was almost disintegrated..so replaced that and semi rigged the post to mimmic yours until I can get your spacers in the mail. I put one added brace on the upper arm to tie to the top chassis support and that got rid of fore/aft play on the side.
I did some practice and wowed myself...so I guess I have been getting slightly better with driving my D3.

So...when I have more time, I will try out similar set up to your front posican. What weight oil, #of holes in shocks, and front horizontal spring (do we want stiff or soft)?
Looking good man! Let me know if you still haven't got the spacers. I never should have used snail mail.

I know what you mean about the wear; It's such a gradual thing that it tends to sneak up on you. Meanwhile, your skills develop to compensate. Then when you fix it, it's like a new car.

I love the heli blade holders for the upper arms. They really seem perfect and I'm surprised that they still need the brace. Where's the play coming from, the clearance holes, or is it too tough to get a tight fit with washers/spacers between the shock tower and the clevis sidewalls?

RE: Posican, it's been fascinating. The gold Yokomo is an extreme example. Impressive and enviable, but IMO a bit too far, but unquestionably deserving of massive credit. Not because of the extreme caster & KPI, but rather the purity of the suspension geometry. Perhaps the most clever part IMO is the linkage for the rear vertical dampers HERE. I can't find the picture that shows it better, but they terminate on the lower arm on one end, with the other end through the pivot and then terminated to the unused upper arm chassis pivot. At first glance, this seems like it would simply double the damping rate. However, I think the main benefit there is where the line of action of that damping is exerted on the chassis. Meaning, it more directly dampens the separate forces that influence the rear suspension's travel; Vertical travel induced by the wheel, and chassis roll induced by momentum changes (Drifting). A vertical damper fixed at both ends (As mine currently is), will tend to lift the chassis slightly even as it rolls, to offset the opposition of the damping itself. It's a very subtle detail that probably doesn't matter that much, but it makes me appreciate it all the more. I may tackle that linkage at some point, but other neglected projects are already catching up to me.

I wouldn't say my setup is completely dialed just yet, and the "Right" oil weights will depend even more heavily on the surface and tires (Traction = roll force) than a more typical setup. On the bench with the wheels straight, I can roll the chassis to the side and it will pretty much stay there, with only a small bit of rebound from the front verticals. However, they are enough to return it to neutral when drifting, and it took me awhile to accept how soft they needed to be. Oil Wt in the front verticals doesn't seem to be that important, but should definitely be thinner than the horizontal, since they have to fight each other.

The rear horizontal has to be fairly stiff due to the very low roll center. I have the rear camber links set to keep the wheels flat when the chassis rolls edge-to-edge at ride height. The consequence is that there's a lot of camber gain on dive/squat, which isn't all bad, but has to be managed. The dual rate springs worked perfectly here, allowing useful droop, a small bit of soft travel, yet limited by the hard spring. So, the rear wheels are flat when neutral and on throttle, and sharply roll up on the outside edges when I let off the throttle, giving it good lateral bite if I ease up too much in mid-drift. The rear vertical dampers are the dominant controlling factor in the chassis roll rate and target transition speed. It's worth noting that with this type of rear setup, the chassis roll rate doesn't massively affect the transition itself, as the rear wheels remain flat at any roll angle. It does however affect the rate of weight transfer, which certainly affects traction, although to a lesser extent than roll induced camber changes in a "normal" rear setup. I tried to imagine how the mass of a real car would roll through back-to-back S turns. I basically put the car on a bench with the body mounted. Then cupped the top of the car with one hand and rolled it back and forth to where the body sides hit the bench as fast as I could without the wheels sliding sideways. Pretty slow actually. This gave me a good idea of the fastest the chassis could theoretically roll (Static friction) through a transition for a given oil weight, going thicker as traction and vehicle speed increase.

My current setup is:

Front Horizontal Shock
Spring: D3 White
Oil Wt: 50
Piston: 3 Hole Machined Delrin
Front Vertical Shocks
Spring: Ultra-Soft & Super-Soft (RC926 1.2mm Twin Springs)
Oil Wt: 35
Piston: 4 Hole Machined Delrin
Rear Horizontal Shock
Spring: Ultra-Soft & Hard (RC926 1.2mm Twin Springs)
Oil Wt: 35
Piston: 3 Hole Machined Delrin
Rear Vertical Shocks
Spring: None
Oil Wt: 35 (Plan to reduce to 20)
Piston: 4 Hole Machined Delrin
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Old 06-19-2013, 04:31 AM   #1969
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Guys i just got the batteries. They are these
And they barely fit. I need to push them to get it position which destroyed the sticker on them
Should i disasseble the uper deck every time i put the batteries ?
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Old 06-19-2013, 06:50 AM   #1970
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Guys i just got the batteries. They are these
And they barely fit. I need to push them to get it position which destroyed the sticker on them
Should i disasseble the uper deck every time i put the batteries ?
No, you don't need to disassemble. Some have put a .5 or 1mm spacer under the rear screws of the top plate to raise it slightly to gain clearance for the battery. I scraped my batteries as well...but after some use, it gained enough slack to be able to slide the battery in and out smoother.

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Originally Posted by Caseymacgyver View Post
Looking good man! Let me know if you still haven't got the spacers. I never should have used snail mail.

I know what you mean about the wear; It's such a gradual thing that it tends to sneak up on you. Meanwhile, your skills develop to compensate. Then when you fix it, it's like a new car.

I love the heli blade holders for the upper arms. They really seem perfect and I'm surprised that they still need the brace. Where's the play coming from, the clearance holes, or is it too tough to get a tight fit with washers/spacers ...

My current setup is:

Front Horizontal Shock
Spring: D3 White
Oil Wt: 50
Piston: 3 Hole Machined Delrin
Front Vertical Shocks
Spring: Ultra-Soft & Super-Soft (RC926 1.2mm Twin Springs)
Oil Wt: 35
Piston: 4 Hole Machined Delrin
Rear Horizontal Shock
Spring: Ultra-Soft & Hard (RC926 1.2mm Twin Springs)
Oil Wt: 35
Piston: 3 Hole Machined Delrin
Rear Vertical Shocks
Spring: None
Oil Wt: 35 (Plan to reduce to 20)
Piston: 4 Hole Machined Delrin
Caseymacgyver, thank you very much for all that good information and also for those spacers!!!!! (For them)
Praticed yesterday and was having some binding issues with steering was almost afraid those braces I added on were too stiff? I was having a hard time with steering...and to your point with the compensating for the slop and irregularities...I finally figured out what was binding...the lower portion of the heli arm binding with the steering turnbuckles due to the ride height...for some reason I had the shock collars screwed down. I readjusted...got rid of binding. Practiced more and whoala! It drove great! Better than I have ever felt it before!

And then got cut short....found front wheel in ectreme negative camber...top heli arm broke front shock tower probably from all the forces from aluminum citting into the carbon from the slop before.
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Old 06-19-2013, 09:29 AM   #1971
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Here is what I broke...


Will go back to stock plastic for now until I can order a new one
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Old 06-19-2013, 04:00 PM   #1972
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D3 hopups and new items arrived today.

http://www.tqrcracing.com/shop/produ...id=56&s_sort=4

FYI, Thanks.
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Old 06-21-2013, 12:30 PM   #1973
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Here is what I broke...


Will go back to stock plastic for now until I can order a new one
Ah, I see. Bummer way to end a good day . Thanks for snapping a pic. As the D3 logs more owners and more hours, it's interesting to see how the various mods, and the D3 itself, hold up over time under regular use.

When I first saw this pic, I got worried about mine, because CF shouldn't be subject to fatigue failure under these loading conditions for years, if ever. I'm relying heavily on the tower's ability to absorb a lot of the wheel vibration without deterioration. Looking closer, I see what you mean about the heli arm slicing an arc on the face of the tower, likely leading to the failure. It looks like the clevis is pinched down a bit so the sidewalls weren't parallel. The scallops in there probably didn't help the interface either. Still a clever approach and I like it.

If the heli arm wasn't snug enough fore/aft from the start to not need a brace, you could probably eliminate it altogether and just run with the original ball & cup in its place. Keeping the brace of course, it's be nice 3-point upper arm setup. You'd have truly adjustable caster, with no chance of binding through the whole range of vertical travel. Are you running 2 stacked balls on the knuckle side?

Something like this would be ideal
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Old 06-23-2013, 06:52 AM   #1974
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Ah, I see. Bummer way to end a good day . Thanks for snapping a pic. As the D3 logs more owners and more hours, it's interesting to see how the various mods, and the D3 itself, hold up over time.

If the heli arm wasn't snug enough fore/aft from the start to not need a brace, you could probably eliminate it altogether and just run with the original ball & cup in its place. Keeping the brace of course, it's be nice 3-point upper arm setup. You'd have truly adjustable caster, with no chance of binding through the whole range of vertical travel. Are you running 2 stacked balls on the knuckle side?
no, it wasn't the fault of the CF...it was due to the heli arm alum cutting into the tower CF. I have no reservations that it would have lasted quite a long time without any problems. I should have ground down to smooth out the edges (they were sharp). Right now, I put back the stock plastic tower and am using the Tamiya rocker arm and post with your spacers and works great without any fore/aft movement.

My new CF tower just arrived and will be transplanting it over( also new battery holders, left side snapped from hitting too much). Which brings me to my other dilemma...so, I think I might just continue into trying out the posican. I am just waiting on the other bits to arrive so I can move further away from the towers to be able to fit the horizontal shock. I will try with regular springs since I don't have twin springs...and maybe only for the front suspension.

What do you think? Or will I need to do that for the rear also?
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Old 06-24-2013, 05:39 AM   #1975
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Can someone tell me what size bearings I need for the MST knuckles so I can make a start on the KPI mod?
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Old 06-24-2013, 07:19 AM   #1976
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Guys now that i have placed my motor is seems that my front supension won't rebound fully like it did without it .. is this normal ?
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Old 06-24-2013, 12:27 PM   #1977
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Guys now that i have placed my motor is seems that my front supension won't rebound fully like it did without it .. is this normal ?
Yes. The stock front springs are VERY soft
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Old 06-24-2013, 02:18 PM   #1978
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no, it wasn't the fault of the CF...it was due to the heli arm alum cutting into the tower CF. I have no reservations that it would have lasted quite a long time without any problems. I should have ground down to smooth out the edges (they were sharp). Right now, I put back the stock plastic tower and am using the Tamiya rocker arm and post with your spacers and works great without any fore/aft movement.

My new CF tower just arrived and will be transplanting it over( also new battery holders, left side snapped from hitting too much). Which brings me to my other dilemma...so, I think I might just continue into trying out the posican. I am just waiting on the other bits to arrive so I can move further away from the towers to be able to fit the horizontal shock. I will try with regular springs since I don't have twin springs...and maybe only for the front suspension.

What do you think? Or will I need to do that for the rear also?
Sweet, happy to hear they're getting put to good use.

I wouldn't worry much about the twin springs unless or until you start getting it close to where you want it. I don't think they buy me much in the front, as compared to a traditional spring (D3 white or a bit softer). The one in the rear horizontal did work out really well, but definitely one of those fine-tuning things. On carpet, my guess is that you may not need the tiny bit of soft travel I'm getting and could probably get the rear horizontal suitably stiff with a D3 spring to limit compression. Keep in mind that you can't use the rear droop screws in the same manner though. They can be used to limit roll, but this is too far out to have any effect on dive.

In general, the springs do add a lot of flexibility that will likely help a variety of applications (Different cars, geometry, etc...) and I would certainly recommend them. They seem to provide better rebound than a comparable D3 spring, particularly in the softer rates. For example, for a given ride height and oil weight, the D3 white spring might return 1/2 -2/3 back to the ride height after compression, whereas the twin setup would return nearly all the way. There's other variables of course, but it was consistently observable. If you do buy a set, note that the spacers that go in between are sold separately. With the number of springs included, I recommend buying more than 4 spacers in case you end up using them in other locations.

I'll snap a pic in a bit of what I did to get the shock to clear the tower. I filed the half-moons on the adapters to get a flat surface that could key against the pivot. I filed it just enough so a screw would fit through and thread into the pivot. All surfaces nice and square and flat = No Locktite needed.

Had I to do it over again, I probably would have done the horizontal shock in the rear first, because it had a much bigger affect on the driveability. With the route I took, I spent a lot of effort on trying to get the front end to articulate so smoothly and symmetrically so as to keep the front bumper flat and not twisting the rear wheels undesirably. Although I was able to achieve that, I realized that there were downsides to having such low resistance to roll, and no restoring force to return to neutral. It was when I added back the vertical shocks in the front that the rolling-rear setup became inevitable. I think that had I done the rear first, I probably would have reached my current setup more quickly and cheaply.
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Old 06-24-2013, 08:59 PM   #1979
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Sweet, happy to hear they're getting put to ...

Had I to do it over again, I probably would have done the horizontal shock in the rear first, because it had a much bigger affect on the driveability. With the route I took, I spent a lot of effort on trying to get the front end to articulate so smoothly and symmetrically so as to keep the front bumper flat and not twisting the rear wheels undesirably. Although I was able to achieve that, I realized that there were downsides to having such low resistance to roll, and no restoring force to return to neutral. It was when I added back the vertical shocks in the front that the rolling-rear setup became inevitable. I think that had I done the rear first, I probably would have reached my current setup more quickly and cheaply.
Thank you for the insightful info...I will start to tweak it when I get my parts order which I hope will be within the next week. And I will start on the rear first as you suggested and leave the front with just the KPI and see how that goes.

I have not been able to find twin springs trying to search rc926 and other key words from rcmart, amain, tqrcracing, broadtech and even banzaihobby. But will try my other springs (not twin or dual ) for now and see how it goes.

Last edited by eunique; 06-25-2013 at 11:07 AM.
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Old 06-25-2013, 05:24 AM   #1980
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Guys i feel that the stock springs are way too soft .. Do you know any good place to buy springs for fast shipping in europe ? Which should i get ?
Aslo i noticed that on the rcmart and r2hobbies in the D3 product they say

Wide Angle Driveshafts: The universal driveshafts of the Sakura D3 has been given a redesign to minimize chattering vibrations of the front inside wheel when using a front solid axleand steering is near maximum lock, which is crucial to maintain the front inside wheel will stay on the ground and provide a more consistent drift action.

Does this mean that i got the wide angle driveshafts ? how can i check it ?
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