So, the move has now been completed, and as is my way I’ve made quite a few racing trips to local tracks already… in three weeks I’ve been twice to both Illawarra Model Car Club (IMCC) and Sydney Model Autosports (SMA). Both offer pretty tight and technical layouts, so getting the car to perform in the twisties is a requirement over pure horsepower.
First up, IMCC. The two meetings I attended were Sunday morning meetings, and thankfully warm and dry. Not many runners, with just the two of us in mod mixed in with the stock drivers. I started out with my previously posted Logan setup, and worked through quite a number of changes, including wheelbase, shock positions, diff oil, ackerman and motor mount screws. I also gave the complete MR ETS rear end setup a try, just for completeness (Whhaaaaay too loose!). By the end of the two separate race days, I pretty much ended up back on where I started, with just a couple of small changes;
- 5000wt rear diff
- two screws in motor mount
- 1mm shim under rear inner camber link
Pretty much these changes were aimed solely at improving the rear end grip and feel. There are a couple of quick direction changes, that require the rear end to be tied down, which both the second and third changes helped with. The heavier diff was helpful as there is a lot of part throttle turns, so having good and responsive on-power steering seems to be key to good lap times. It also helps to stabilise the car into the tighter corners on the brakes.
Overall, after the two day meetings I was getting much more comfortable with the car, and it was clearly responding well to small changes in the setup… and that was proving really useful in improving my own setup knowledge base. Wheelbase is one of the biggest things I have been playing around with alot, as it was something I set and forgot on older cars (and wasn’t even an option on the Mi5’s!).
However, there did seem to be a bit of pace lacking, so whilst the balance felt good, I wanted to try and increase the overall grip of the car. The key to solving this puzzle came from looking at some photos a friend had taken of my car on track. It was pretty clear to see it was rolling… a lot! This set my mind in motion, and I pumped the setup into RC Crew Chief, and checked the roll stiffness vs other cars and setups. This showed up that with the shock positions setup in the kit, coupled with the low roll centre of the setup I was running, was giving quite a low roll stiffness, hence the excessive roll. To combat this, I went to SMA for the first time since arriving with a plan of attack!
The two SMA meets were tuesday night meets, so a bit different too the IMCC day runs. All the same, I started out with the IMCC setup… but the first change was standing the shocks, to both hole 4 front and rear. Straight away, overall grip improved, whilst still maintaining the good balance.. and a 2/10ths laptime improvement! The rest of the first night, I pretty much spent again experimenting with things I had tried at IMCC. with camber link shims, wheelbase and motor mount screws all coming under the spot light. One other big change was dropping back to a 3000wt rear diff, as more initial steering was needed. To help bring back the on power, I dropped the inner link shim back to 0mm, and also went back to the four screw motor mount option… or in other words, the Logan setup with the shocks stood up!
For the second meeting, I tested out more wheelbase and ackerman changes, learning quite a few things along the way. Basically, going to a longer front wheelbase (going from 2mm to 2.5mm) did give more steering, but lacked a bit of rotation. A shorter rear was actually more a step in the right direction (2.5mm to 2mm), although not sure on the laptime difference. I did make sure to combine the front wheelbase change with an increase of ackerman shims (going up to 1.5mm), but the best feel and lap times to me came from the shorter front.
A quick run through the shock mounting positions also had some interesting results. Hole 4 on both towers was given a decent balance, but I given I wanted a bit more rotation on the older tyres, going to 3 on the rear tower helped in this regard.Initially I had tried out going to the TRF team setup of 3 front, 4 rear… but this just turned the car into a push monkey in the longer sweeping turns, with the front washing out. So F4/R3 it is then! Overall, the balance now as close to being spot on, with good all round grip, and a really nice balanced feel.
And that is pretty much the update done. The car itself is fulfilling everything I wanted in a new chassis, being easy to work on, and reacting so well to small changes. It’s also been totally reliable, with five meetings under it’s belt and only a stripped servo gear being the only issue! The ProAmps motor (review here) has also been working well, is smooth and has a nice power delivery. I’ve run a couple of further back to backs with the Hobbywing V10, and there really isn’t a lot too choose between the two, both are quality motors.
I guess you could say I’m enjoying my racing again… 😀 Till next time…