This is some setup advice for those new to this platform and in need of setup help. After being on this thread, the D812 thread, the E817 thread and at the track, the common gripe that is frustrating to some people is that the rear end of this car is too loose, but praise it for a lot of steering. It usually starts with, "I put Ty Tessmann's 2015 DNC setup on..." Others will swear that setup is super stable and easy to drive. The better of a driver a person is, the harder it is for them to relate to a newer driver's complaint. The issue lies in the setup + the track condition + driver skill. Ty Tessmann has special skills and can successfully exploit maximum performance out of a weird handling car that lesser drivers (i.e. all the people complaining about it) cannot.

The first thing you need to do is evaluate your track. Your track is rather loose if it has independent particles of dirt sitting on top of the harder under layer that always continues to break up feeding a never ending supply of independent dirt particles back up to the surface which doesn't allow a clean racing line to form. If your track has a clean racing line it's probably medium or higher grip. This is generally speaking. Weather or watering can change the track's grip level. Concrete, astro turf, combination surfaces, grass, carpet etc I have no experience with. I'll get to clay later. Use the right tire with a compound matched to the temperature. This setup info isn't intended to get every last 1/10 second out of you and your car (because I can't do that from a keyboard), but it'll get you more satisfaction and less frustration out of your car.

If your track is of the looser variety, there is a higher probability that one of Ty's setup will seem to work better and be less tail happy. The reason is because there is a lot of body roll on the rear. You can liken this a loaded van with worn out shocks. You go into a turn and it leans a lot. On a loose track you need the lean to pressurize the outside tires down into the dirt. They will grip better. The 2015 DNC set up achieves this with light shock oil 30 front / 25 rear (car pitches forward and back and leans left and right freely, just like a loaded van with worn out shocks). Granted, shock oil is temperature dependent. If it's an 80*F+ day, this oil will feel light. The links on the towers are up quite high. The high links produce more body roll. The original D815 came with #3 rear camber plates which further causes body roll as compared to the #5 plates included with the D815 Version 2. The front link is short which resists deep roll, which under acceleration out of a turn transfers weight to the rear outside tire. The rear link is long which allows the rear to roll deeply. The rear hubs are all the way down which further causes more roll. The most critical area though, are the pills in the C and D block. 2 dots up on each means the hinge pin sits almost as low as it can go. It can only go one increment lower. The lower the hinge pins sits, the more the chassis will roll. The 124mm of rear droop allows the car to lean a lot before the droop screw stops the roll and the 2.4mm rear sway bar doesn't do much to stop all the leaning. So if you're on a loose surface, good. You'll have plenty of leaning to help force the outside rear tire down into the dirt to get traction. What happens when you're on a medium grip track and you're not super smooth on the throttle and steering input? Under ham fisted acceleration and cranking of the wheel, the weight very quickly transfers to the outside rear tire, overloads it causing loss of grip and the car spins. Coming out of a hairpin, this is probably where it'll end because you're not going very fast. If you're already up to a certain amount of speed, turning onto the straight and punch it, you'll still start to spin. If you try and correct by letting off the gas and counter-steering, the weight very quickly transfers (light shocks not damping much) to the front outside tire which bites hard (due to lots of caster and 2.2 front sway bar) and sends the light rear the other way. You correct left, you correct right. Next thing you know you're in a tank slapper situation. The light diff oil also plays a roll in this. 5k front and 2k rear gives the car a lot of steering off power. Basically the entire setup on a medium grip track will give you tons of front end steering into the corner and tons off oversteer on exit and that is what the newer drivers complain about.

What you need to do is control the amount of body roll to match your abilities and track's level of grip. Fortunately the 2015 DNC setup is a great starting point. The front end is mostly going to be fine. A 2.4mm front sway bar will make the car easier to drive though as it'll smooth out the steering. Remember I said the critical area for adjustment are the pills in the C and D block? Raise the hinge pins in them! They have a larger roll center adjustment effect than any other adjustment in the rear. Go straight to 1 dot up in the C block and 1 dot down in the D block. Don't forget to re-adjust droop and ride height. If it's an 80*F day, bump your shock oil up to at least 32.5 / 27.5 if not 35 / 30 (based on TLR oils). A 2.6 rear sway bar and lowering the rear upper link should be tried. I like thicker diffs (7k/5k/3k - Kyosho) and I feel they definitely aid in smoothness, drivability and ham fisted operation, but not everyone does. Try the first five adjustments first as they take the least amount of time to do. What you should notice now is that your D815 is smoother and easier to drive. The rear will be easier to control with the throttle. Smoothness in your driving is key to controlling how the car pitches around.

The original D815 setup at the back of the manual needs the carbon inserts in the rear arms, longer rear upper link, #5 rear camber plate and thicker diff oil. Kit shock oil is already specified at 32.5 / 27.5, but as stated above, the hotter the ambient temperature is the thicker the oil you'll need. The C and D block pill orientation (2 dots up / 1 dot up) raises the hinge pins higher than the DNC setup so you might be ok depending on how much grip your track has, but don't hesitate to change them to raise the hinge higher if the car still has squirmy handling. 2.4 mm front and 2.6 mm rear sway bars are already specified. Yes, there are still differences between the setup in this paragraph and the one above, but these changes matter the most.

The D815 Version 2 kit setup vs the DNC setup already specifies a lot of the stuff I mentioned like thicker diffs (rear is 1k thinner), carbon arm inserts, 1 dot down on D block (but C block pill hole should be raised), low link on the rear tower, #5 rear camber plate, long rear upper link, thick shock oil (40 / 35) for the temp they specify (20*C / 68*F) with their selected pistons 1.5x5 front / 1.6x5 rear and thicker sway bars. The D815V2 kit setup shouldn't need a lot of variance to get nice handling. C block pill change + rear diff oil and it should be stable and predictable.

The E817 kit setup looks mostly good, but once again the C and D block pills need the holes raised and diffs should be thicker. Make sure your shocks aren't too soft for the temperature you're driving in. Consider thicker front and rear sway bars, rear especially.

The lower grip your track is, the lower the rear inner hinge pins should be, the lighter diffs and the lighter the sway bars should be. The higher the grip, the higher the rear inner hinge pin should be, the thicker the diffs, the heavier the sway bars should be. Shock oil has to match the temperature. Do not automatically assume a loose rear end means the track is loose. Assess your dirt!

Lastly, after you get your D815 handling smoothly everything mentioned can adjusted to dial the handling in as can all the other setup parameters not mentioned. Setup can be confusing, so post any questions and I'll do my best to answer. Track types (very tight, bigger, bumpier, jump size, very high grip, layout style) can all warrant some changes.