Just thought I would share my approach to setting up a touring car, specifically for the small club track at Chippenham (www.cmcc.org.uk).
I can’t emphasise enough how important it is to build the car well. None of these adjustments will make any difference if a bearing is binding or if the steering isn’t able to reach full lock. So take the time to make sure everything on your car is aligned correctly, that ever moving part moves freely, and that every stationary part stays put.
Once you have built the car up, you have to get it up to race weight – and get it balanced. BRCA regulations are 1350gm, and you want to get that weight even from left to right. The corner-weighting scales pictured above are a bit of an extravagance (most cars have holes in the shock tower so you can balance the car on a piece of string), but they demonstrate how well balanced my TOP Scythe is with just a little lead down the middle and the LiPo offset over the side of the chassis. Front/rear weight distribution is best left at factory settings to start with.
Bear in mind that different components have different weights. For that reason I always recommend running the same type of battery in your car throughout the race meeting. Throwing in an older pack for one race that is 50gms lighter will not only fail scrutineering, it will also make the car handle very differently – and a consistent car is essential if you are trying to understand setup changes or developing track conditions.
Generally, I would start out with the kit settings in terms of linkage positions and shock components, you may wish to tweak these one at a time but you have to be pretty confident/foolish to throw a completely different setup on a car and expect it to work.
Once you’ve got the car on the setup board at race weight, the first job is to set the ride height. Everything else follows from this. Bear in mind that different brands of tyres may have slightly different diameters, so the setup for one may not work for another.
I always set my car up with a 5mm front ride height and a 5.5mm rear ride height.
Next step is droop. This is the downtravel of the suspension beyond ride height. There are many ways of measuring it – choose the one that is consistent for you. I prefer the gauge method – but there are a few things you need to take into account. Most of them are numbered in such a way that a bigger number on the gauge is actually less droop. They are also only useful for measuring the position of the suspension arm relative to the bottom of the chassis – they don’t take into account ride height or tyre size or anything like that. So you need to do a bit of trial and error.
I usually start off by setting the rear droop at the point where the spring just starts to come off its collar when you lift the car off the ground. With my current car and the Sorex 28R tyres that works out at 5 on the gauge. I then set the front to have 1mm less droop (6 on the gauge in this case). I always check to make sure that the suspension is not pre-loaded – ie that the shocks extend a little when you lift the car off the ground. Pre-loaded suspension is edgy to drive and bad over the bumps. Never use the droop screws to adjust ride height.
The last basic job is the camber. I always set the car up with 2deg negative at the rear and 1.5deg negative at the front. This tends to give even tyre wear with a slight understeer balance. Take the measurement at a few points around the wheel to compensate for any warping. Don’t waste your time and money on a setup station, the only worthwhile measurements you will get are ones taken with the racing wheels on the car. A good quality camber gauge, ride-height gauge and flat board is all you need, although a droop gauge and a toe gauge can be handy.
Most modern touring cars have more adjustments than you could realistically make use of. I’ve had this Scythe for over 4 years now and there are settings I have never tried out – and I am one of those people that will change something on the car between every race if I have to! There are a few key adjustments that make a big difference when you are trying to get an ill-handling car close to what the track needs…
Tyres – most of us race on control tyres these days, but tyre prep (and the overall condition of your tyres) is a massive part of the cars performance. Check the gluing around the edge of the tyres regularly and re-glue if necessary. Have a consistent additive routine – for carpet on club nights, I clean with lighter fluid, and apply Nosram Carpet to the whole width of the tyres for about 5 minutes. You can try narrowing the application on the front tyres, or re-apply the additive, for different effects. A new set can do wonders.
Front drivetrain – Spools are very common outdoors, heavily-filled gear diffs are gaining in popularity, but on a tight indoor track, a medium-action diff makes the car a lot easier to get around and often quicker as a result. I currently have a tight ball diff in the front of the Scythe. The rear should always have a free-but-not-free-spinning diff in it.
Springs – probably the quickest way to get a big change in handling. Stiffer springs give less feeling of grip but more responsiveness.
Dampers – I generally keep the damping in harmony with the springs for a similar plush feel all round. Heavier damping will make the car feel smoother.
Radio settings – Something I find myself using a lot. Just one click of steering rates during a race can turn an understeering car into one with perfect balance. Resist the temptation to dial out too much steering to make the car easy to drive – you might not have enough to navigate the corners! My car is usually on 85-90% lock indoors.
There are a few more advanced adjustments on the cars, like roll centres and steering ackermann, but these are rarely quick fixes and need to be thought through. Best to leave them on kit settings unless there is a serious handling problem that springs and dampers can’t solve. I can recommend Elvo’s setup guide if you want to read about them in greater depth.
I briefly mentioned the radio, I should also mention the motor and speedo. Chippenham club nights now run to 13.5 “blinky” rules. For those that don’t know, “blinky” is a mode which stops the ESC adding timing to the motor electronically. It slows the cars down and makes the throttle feel more progressive – it is how brushless should have stayed all along. I run the Speed Passion v3 13.5 at a 5.5:1 ratio and could possibly go a little higher. Brushless motors have ample torque and can pull big gear ratios even on a small track. As far as ESC settings go, there is hardly anything to change. The Hobbywing Xtreme Stock I use has a “punch” setting which they call DDRS, and the only other thing you may want to change is the drag brake setting – the less you can get away with the better.
Let’s just say that “smooth is fast” and leave it at that!