stanleyw808

Hello inpuressa,

I noticed Your sig that made me assume You are running TKI4, right??

Did You run TKI3 before TKI4?

Some of my Friends who drives TKI4 still have the "Feeling" that the steering is somewhat Not as "Precise" as TKI3 but TKI4 are able to do "smoother" arc around sweeping corner.

In my understanding, this TKI4 front end seems to have "too" narrow Inside Hinge Pin Width, which makes the Front-end Rolls "too" easy?? Maybe?? Then Kanai San try to make it less "Twitchy" with moving the B Block Bushing Insert position Higher to increase RC. Then again, Kanai San even more reduce the Twitchiness with coming out with 19" Caster Block.

I am not an expert with Suspension Geometry, just trying to share my assessment for the TKI4 front-end changes.

One more thing, Have You guys seen the latest Kanai San car Picture on FB while He was in Las Vegas Race a week ago. The picture showed that He is using unanodized Front Shock tower and Front Upper Suspension mount. I am guessing that He is trying to move the Upper Arm position to Higher position.

I met with Naoto Matsukura and Wataru Takashiro, Kyosho Japan Driver, I remember that they we were discussing about the D815 upper arm position and trying to figure out that why David's and Ty's Car was too good at that race.

I just hope that nobody from Kyosho read this. Hahahaha..

Cheers..

JQ

Unless they moved the upper arm in, along with the narrower pivot, that is probably what he is doing now.

30Tooth

iTrader: (1)

I have a small amount of certainty that you can run the wide tread in the TKI4 and still be within legal width. I would do that instead of going back to TKI3 arms and holder.
Got that wrong, narrow has a tendency to stop rolling once it started and wide the opposite. RC doesn't stay at the same height in roll motion nor at the same degree, for example the MP7.5 front RC height at 4 degrees of roll is 5mm (for example) and THE Car at the same 4 degrees of roll could be 2mm even if they started at the same height.

Some manufacturers (mainly Kyosho) design their cars towards the expected conditions at the World Championship track to increase their chance at winning. In that regard the TKI4 will corner more smoothly (very rough track expected). Kanai San knows what he is doing and I'm with JQ here, he is trying longer upper arms.

The reason the D815 was good at the worlds warm up is blatantly evident, very low RC height (close to or at ground). It's obvious in the pictures they struck the sweet spot between low RC height and enough camber gain. Damping doesn't need to be different from what they always use when you got the jacking forces figured out. Jacking forces are the forces the RC suffers from the track surface. High RC (above ground) have a tendency to throw the car up, low RC (bellow ground) have a tendency to "suck" the car down towards the track. Long camber links and their configuration, low ride height and arms angled give away whatever the HB team is doing. Kudos to them, they work with what's available to them.

30Tooth

iTrader: (1)

I wonder why HB doesn't run the HRC rear end setup. They have all the parts...

stanleyw808

JQ Sir,

The MP9 Front Upper Arm position is not possible to be move in again. There is no more room left unless they change the Upper Plate and Bulk Head.

Cheers..

My ST-RR EVO

iTrader: (5)

What do you mean?

High r/c throws the car up and low r/c sucks it down? Can you explain this too?

30Tooth

iTrader: (1)

The possibility that Kanai took a dremel to those places is high but "these aren't the droids we are looking for"

Sure my good man. Don' forget that the middle point is the ground so to the car to be sucked down the RC has to be underground.

Place the car on the table and pick up one wheel, that wheel moves up because it has force applied directly and the rest of the car is settled, only has influence from the loaded spring force and the sway bar. If the car has low RC height you can raise the wheel and the car itself will twist towards the opposite side you picked the wheel, with higher RC height it is like you are lifting the entire car, the car will twist less just like you see on the track.

Care is to be taken, front setup will work with the rear and vice versa and by work it can be works terribly. For example higher rear RC than front (one higher than ground and the other lower than ground which was typical in the Losi style suspension), you pick up one rear wheel, the front opposite tire will sunk down and the entire rear will lift. Now same example using a front tire, you pick up a front tire and the rear will twist upwards a bit and the opposite front tire will remain unaffected. The way I see it you want to prevent differences between how much the chassis twists in each end, BTW this is done after balancing the springs or the test is skewed.

*Edit
Just did the test on the 7.5:
- picking a rear wheel, the front dips and the rear opposite wheel and the same side front wheel lift off the ground at around the same time. The wheel I picked seems to transfer all the force to the chassis as the shock didn't compress visually (mind you 3.0mm rear sway bar);
- picking a front wheel, the same side rear wheel never leaves the ground, the shock compressed a bit as it should because the front RC height is lower than the rear.

Doing the test again in the 7.5 with the rear RC lowered and the same outcome as the XB9 happens, this time the rear shocks compressed on the wheel I picked. The setup it had was the last I used (exception for kick up which doesn't change the outcome) and it had all the traits associated with too high rear RC.

On the XB9'13:
- picking a wheel doesn't matter front or rear the opposite end same side wheel never lifts, a bit of bias towards the rear meaning picking the rear wheel the front is almost barely touching.


Instead of going by the last wheel to leave ground I think the truest sign would be how much the shock compresses when doing this test, remember I have balanced springs - none wheel exerts more force at CG than the other.


About the LV rear end setup, raising the inner hinge pins and inner camber link mounting points roughly the same amount and then levelling arms again is lowering CG by approaching CG to RC instead of raising RC closer to CG, you have now a stabler yet nimble car. If you end up with a lower ride height in the rear than the front don't be surprised.

JQ

I don't see how doing that demonstrates anything about the RC. What am I not getting?

30Tooth

iTrader: (1)

Focusing on demonstrating jacking forces, only that.

My ST-RR EVO

iTrader: (5)

It seems like the shocks, sway bars and the weight of the car would determine if another wheel lifts or not because if you took off the shocks and sway bars only the wheel you lifted would move. The r/c isn't a contributing factor. So if you do the test on a car and it gives you particular result, but then you change the pills in the lower suspension it'll give you a different result? Of course, i haven't tried this.

My ST-RR EVO

iTrader: (5)

As far as the LV rear end, that sounds like hitting the right r/c adjustment for the given condition?

On some cars, Kyosho's TKI3 for example, the rear inner hinge pin height was never changed by any pro on any setup sheet I've ever seen for any track condition. Looking at Hot Bodies, the Tessmann's move that thing around regularly to suit different track conditions. I'm not sure about other brands, but i think there is a mindset of, "Why move it? It works well everywhere." Or they're finding the set up feel that they're looking for other ways.

30Tooth

iTrader: (1)

Try it, it should explain more than I can the bottom line is that one wheel bumps cause a reaction and the force doesn't travel that linearly as I thought.

On the Kyosho some drivers are spoiling handling with inferior shock damping characteristics by using the same pistons front and rear, as you said drivers don't want certain things to change even if the change is for the better. Particularly the shock pistons, stock was a good setup (1.3f and 1.4r). Capping handling by running a so-so setup that works moderately most places is a sure way to stay behind the others and stall in a competitive racing environment, see the Tessmans - if he didn't pursue the best setup would he retain the advantage he has? Of course not, it would be the D8 all over again where the car had limited setup options and was ill-conceived (mainly the rear arm and shock length, the concept is sound though).
At that level there isn't good enough, or shouldn't be

inpuressa

iTrader: (10)

Hmm, really? I read from multiple sources that narrowing the inner hinge pins offer less roll resistance. As far as my experience with on-road goes, that's what the suspension blocks did...

As far as the new parts on the tki4 goes, I'm sure it has something to do with the upper arm height. Perhaps the upper arm needs to go higher = lower RC to negate the raised RC from the new B plate?

30Tooth

iTrader: (1)

Wide vs narrow pivot has negligible effect at ride height with level arms, but once it starts to roll it's very different. That's why I learnt to like that adjustment. Wide pivot plates/blocks the RC is high in average and narrow is low averagely. Both have constraints, because the RC height isn't bad per se but how the tires align with certain RC heights, for example the tires loosing camber because the RC sunk and the driver didn't cautioned the situation.

I think you are onto something here, I don't think the RC change wasn't that big but it certainly wouldn't hurt to raise the upper arm a bit. Also, the kick up angle changed big time but the upper arm angle remained the same? Or there was some change from the TKI3 I can't see in the setup sheet? It had to be changed, C hub cars don't run active caster.

inpuressa

iTrader: (10)

Not much changed other than the b-plate and longer arms. So the lower hinge pin angle changed quite a bit, but the upper arm pin angle didn't. Maybe this is where Kanai is trying to tweak.