30Tooth

iTrader: (1)

Shame about THE Car, I have mine quite good and hoping to make further improvements.

The pill setup I mentioned is if you want to keep the same tire alignment you have now, I believe there's no reason to deviate from the usual 3 toe/2 antisquat so you can go as up as you can and see what the car needs next.
It's a safe setup and works universally, you can run the same camber link position front and rear provided you run the front camber link shorter, out on the tower is a better place to start as it moves RC height slightly. About doing changes both front and rear, once you find a RC height where the car feels good you want to keep the setup as much as you can, at that point either end will roll about the same and it will work almost anywhere with several tire combos.

Interesting mod, it only changes axle plunge. Minor change in the grand scheme, the car has pills to adjust that albeit together with arm angle. What you should do is raise the pins and reset ride height to be arms level. That will reduce roll couple while keeping RC height where it is now, note that the RC could be ill located.
Definitely the common misconception about RC height, it should be as close to ground as possible (there's one occasion where it is good to ahve it under ground) and with CG as close to it. LLTD (lateral load transfer distribution, aka which end rolls more) takes over and then it's roll bar tuning time. Shocks have nothing to do with this, they damp up and down movements nothing more, if you tune roll using the shocks you're in for a bad time.

Stirex

Thanks for the response. I will look at it tonight. I have practice time on Friday and will see how it goes. It's a lot to ask, but given the info I gave..could you fill out a starting setup for the EB48.3 as you would start it? Blank editable sheets are on the Tekno site.

JQ

Which car did you have?

stanleyw808

Hello 30Tooth,

At last I am able to reach page 13 with many confusions and desperations trying to understand some of Your writings. Hahaha.

Thank You very much for responding to my question.

But with Your last explanation, why I am still having the understanding that "Raising Hub Position will raise the RC"? not the way You think as, "..raising the hub lowered RC height.."

Cheers..

30Tooth

iTrader: (1)

Sure.

Try both max and minimum kick up by using the pills in the B plate, other geometry stuff is eyeballed. To be fair, never had good experiences with the inner camber link mounted more inwards than the inner hinge pin so I start with it right above the hinge pin or outward if I have the option. Ackerman and wheelbase start with middle position.

I need to clean up my writing, add a few drawings too

Raising the hub/upright raises the RC (roll center) height, are you thinking I'm referring to the car as RC?

Stirex

1st, yellow, yellow wide, white, ecar, white ecar

Stirex

Thanks.. your setup is where mine ended up.. so we'll see

30Tooth

iTrader: (1)

A word of caution, I don't know effective spring rates nor roll bar stiffness. For that you would need the tune up spreadsheet. Roll bars you can leave them stock but springs are usually unbalanced stock wise, unless you are driving a Kyosho which is spot on...

stanleyw808

Hello 30Tooth,

I am not thinking that Your term for "RC" as the car, I am referring Your "RC" as Roll Center. Is it right??

Btw, Regarding D812/15 Suspension Arm Length, I just measured them and it turns out to be F 101 and R 105.

And the Front Inside Centre Pin to Pin distance is 52mm. MBX7R is also 52mm. Kyosho TKI3 is 51mm. TKI4 is 48mm with 102mm New Front Arm.

Cheers..

30Tooth

iTrader: (1)

Right, see this pic:


That's how you calculate RC height, there's two lines that pas through the suspension pick up points like the lower arm and the camber link mounting points, where they intersect is the instant center (there's also the case where they don't intersect), draw a line from the instant center back to the opposite tire contact patch point and where that line crosses the center of the car is the RC height. Raising the hub/upright causes a change in geometry and results in higher RC height.

Thanks for the measurements. I went with the denominations I saw in books, funny enough the arm length to them is not length but width! Check this.

stanleyw808

30Tooth,

Thanks for the thorough explanation.

Btw, currently there is a FEMCA race in Johor Bahru, Malaysia. Atsushi Hara is the TQ at that race. He is driving MP9 at this race. In the beginning of the practice days, my Friend told me that Hara San is using TKI4 Front and Rear Arms. But after awhile, He was reverting back to TKI3 Front and Rear Arms. This might be due to very slippery condition.

At the last round of qualifying, He was changing the Rear Arm to TKI4, which is the same "Width" as the TKI3 arm but only with more webbing. So, I guess the TKI4 Rear arm is stiffer. Important note is that the traction is getting much better in towards the the later qualifying rounds.

But, the interesting point is that He is still using TKI3 Front Arms, which is the shorter "Width" arm choice between what is available now. I believe He is using the 51mm Inner Arm Hinge Pin Position (Original suggested Factory position). But, I am not sure about this because I am not attending the race. Because if He is using the 48mm Narrow Hinge Pin position with TKI3 Front arms then the Front Track Width will be very very narrow, too narrow I guess.

Cheers..

JQ

Does the TKi4 only come with a narrow high B block or can they get the old low position with the new parts too?
That may be why he prefers the old parts.

30Tooth

iTrader: (1)

Wait, you measured the inner distance between inner hinge pins? Oh now I see! Though it was the arm itself you were measuring. I am not surprised the D815 and the Mugen are the same, that helps me in other ways, thank you!

The more slippery the surface is and the less traction there is the better "slim" (short) arms (like the first THE Car and the HB D8) work. Wide inner width also means that end rolls more, it's lazier responding driver inputs. Therefore I guess Hara's running 51mm inner with TKI3 arms, which means he is after more and smoother grip.

That's what I've been thinking about this last days looking at my XB9. I built it with second most narrowest setting both front and rear it doesn't corner smoothly (too sensitive in bumps and corners, never had a car like this), yesterday changed kick up to see if improves, if not I have to play with inner width again...

Only difference is kickup, the old part provides more kick up (how much IDK). Same width.

inpuressa

iTrader: (10)

The hole width of the B-block has not changed, and can be adjusted as narrow or wide using pills, thus it has the same width as the tki3. The only difference is that the hole is placed at a higher position giving it less kick up and higher roll center. I am sure Hara is using the wide pill position with the tki3 arms to get the original width back. The tki4, having longer arms use the narrow pill position. You need the tki3 b-block to get the original low hinge pin height.

I guess the question that I have is, a narrow hinge pin will make the car roll more, but at the same time it raises the roll center which resists roll. Will it cancel each other out, or one adjustment be prominent than the other?

stanleyw808

JQ Sir!!

TKI4 Kit only comes with High B Block. But You will still able to choose the Pillow to be Narrow (w/ TKI4 arm) and Wide Position (w/TKI3 am).

But, Hara San just posted on His FB that He is trying the TKI4 Front Arm for the Semi Final Warm-Up I guess.

Let see which arm that He will choose for the the main Final.

Cheers..