So, Back from my first big meeting with the 416.... Started off very ropey, but by the end of the day... awesome.

Had problems before the weekend even started, in that my spare C-hubs had arrived in time. Rigged up a fix with 415 C-hubs, and HPI steering knuckles, as mentioned above. Thankfully, this combo kept the axle at the same height, and the kingpin ball joint at the same height as the 416's parts. Only difference was with the steering ball joint position, with it being slightly further forward (effectively mid way between the tamiya holes), and slightly inward. There was also no need to run the 0.5mm shim under the ball joint, as the HPI hub is lower anyway. So with that sorted... onto the meeting.

Track for today at the wars was quite wide and open, so corner speed and a smooth car was really important...more so given that I was running stock...

Started out with the setup I posted above, except for kit setup on springs and roll bars. Quite simply, car was just, erm, awful.... Brought it off the track after practice, and a number of fellow racers noted how poor it looked, so not a good start. Snapping round, and had no confidence in it..

For the 1st qualifier, decided I needed to go drastic, so moved the setup towards what I had seen the TRF guys running at the DHI (wireless internet is so helpful)... so D/D on the front (using the 416 D on the front rear block, so only 3mm of shims), longer front link, A/E on the rear (running stock, so 2° toe in only), and 3mm under the inner and outer ball joints on the rear links.

Next run, sorted. Car much better, but felt a little sliddy, and not locked into the track. So for the 2nd round, moved to Tamiya White/blues, and with just a soft front roll bar. Felt better, but I hadn't predicted the track rubbering in so well, so now lacked a little mid-corner speed... balls.

3rd round, raised the roll centers all round, by placing some 0.5mm shims under all the suspension blocks, as well as going up 2teeth on the spur to lower the FDR a little (keep the revs of the motor up mid corner)... better, corner speed was up, and balance really good.

Final round, went "sod it, need the corner speed", so put the stock roll bars back on the car. Much improved, and put in a good improvement... unfortunately the pack was really close... was 10sec off TQ, and ended up 15th! Crazy... if I hadn't made two unforced errors and lost ~3sec, would have been the in A. Track really punished mistakes... oh well.

For the final, thought I'd try moving the rear shocks back to their stock position on the tower, to aid a bit of mid corner steering. Worked really well, and couldn't believe how good the car felt to drive. Rear end was really stable, but still had loads of steering, and corner speed.... all it need was a driver who could hold a line more consistently.

So overall, really impressed with the 416. Needs a little work on the setup to get it carpet ready IMO, but it is awesome when hooked up. Never had my 415 as handle as well. I now need more track time with the car, so I can get used to how the car drives... otherwise, no complaints, despite the poor start this morning

Ed

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I would like help with spacers though ?? looking at some of your setup sheets i understand most of it but am not sure what spacers i would need to get to help tune my car when it comes are they tamiya parts if so could you tell me the number so i can get some ready I have circled the one i mean on ed's carpet wars sheet below hope you don't mind ed. Also what is difference between arm spacers and mount spacers they seem to go in the same place or am I having a blonde moment ??

Suspension mount spacers go under the blocks. This basically is the coarsest method of changing the roll centre of the car. More spacers = higher roll center. Also allows the adjustment of kick-up/anti-dive on the front, and anti-squat on the rear.

Wheel spacers are the shims that go outside the wheel hex. Help to alter the track (width) of the car.

Suspension Arm Spacers are used to alter the wheel base of the car, so are on the hinge pin. By moving the shims around you can lengthen/shorten the wheelbase, or change the weight distribution by moving both F&R arms the same amount forward/backward. Keep it as kit for now though... or if your running D/D blocks on the front, 0.5mm back on the front (2mm behind the arm rather than 2.5).

The little spacer pointing to the rear hub (just labeled Spacer) is another wheelbase adjustment, but on the outside of the arms. Not played with this setting yet.

Steering spacer; used to alter the Ackerman of the car. More shims = less Ackerman (wheels turn more parallel), I believe, though I could be wrong. Someone on here will correct me other wise :P

As for part numbers... any 3mm spacers will work for all but the wheel spacers. Tamiya do offer a set with a range of thickness' (Part #TAM53539 I think), so maybe worth grabbing a couple of sets.
Wheel spacers I wouldn't worry about too much, the 416 comes with 4 of both 0.5 and 1mm, which is all you really need.

However, Tamiya do offer some suspension block spacers to make it easier to change the shims under the blocks, as they just slide in. Part# are TAM53932 for the 0.5mm, and TAM53933 for the 1mm spacers.

Ed

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What difference would it make on handling if we shimed under the balljoints as compared to under the suspension mounts for roll center?

Shimming under the ball joints affects both roll centre, and camber change. The roll centre change is less for the same amount of shims than for under the suspension blocks (on the 415, 0.5mm of shims under the suspension blocks resulted in a 1mm change in RC, 0.5mm under the ball joints changed it by 0.4mm). More shims = lower RC, but also less camber change in the front end (link is flatter). Less shims = higher RC, but also more camber change (link is more angled). In all honesty, I tend to ignore the camber change affect (that can be tuned more effectively by the camber link position on the bulkhead), and just use the shims as a fine tune for roll centre.

What would Kick-up/Antidive setup & also anti-squat gives on car handling?

Anti-dive resists transferring the weight forward, which helps the car corner flatter (this has been covered in more detail.post #1069 by Apex) It also reduces the castor of the car, improving inital turn-in.
Kick-up is the reverse of anti-dive (in affect, pro-dive if you will). It also helps the car cope better with bumps on a track.
Anti-squat is similar to anti-dive, but it works on the rear, resisting weight transfer backwards, and makes the rear seem to corner flatter.

Changes on the Steering Ackerman would need me to adjust the shims behind the balljoints on the steering rack or the ball joints on the steering knuckle? What would more/less Ackerman give?

Shims on the steering rack. If you add shims on the knuckle, then all your changing is the bump steer characteristics.
Ackerman, for me, is something I'm still trying to fully figure out, but having asked a number of top racers over here regarding the change (and played around with it myself), more shims (link further forward) seems to give the car more steering in general. One thing I have noticed over the last few years, is that the succesful cars indoors on carpet all seem to have very flat steering links, with minimal angle, so less Ackerman.
On the 415, I did play with moving the link on the steering hub. Indoors I preferred the feel with the link in the back hole, as it seemed to smooth out the reaction, whereas outdoors I favored the front hole, as it seemed to make the car more reactive initially to steering inputs.

Ed