Belgian Nationals Rd5 MRCZ, Florian Joos T4 2018 low grip settings

After almost a year of racing the Xray T4 2018, we are getting quite familiar with the range of different setups that are needed to get a lot out of this chassis.

Most of the time, we race on high traction surfaces. Last weekend however, Florian Joos participated in round 5 of the Belgian nats. This race was held on the track of MRCZ in Zwevegem. This non permanent technical track is laid out on a parking lot. Even though the club does an amazing job to build the track and to clean it, the grip conditions are quite low.

In this small article, I will guide you through the setup changes I did to make the car competitive throughout the different track conditions.


MRCZ is a small and technical track that Florian likes a lot, although he had some mixed emotions here in the past. This track was the scene of his first ever victory in the Belgian nationals. Back then he was running the Tamiya TRF419 with TheRCracer low damper mount conversion. In 2017 he could have won the title in the stock class, but he got hit a couple of times, which ended his title aspirations.

This year, we run the Xray T4 2018 in the modified class. This class is dominated by Belgian ETS front runner Olivier Bultynck for 10 years now. Despite the fact that he was challenged by some serious competitors, Ollie has always kept them at bay to become overall champion. By being such a good driver, he is a serious benchmark for the other drivers, including my son Florian. Here is what we tried to close the gap to Ollie:

Pre race

This is perhaps the most important aspect of a race. A race can be won on the track, but you can easily loose it due to a bad preparation. Before the race I checked the drivetrain and completely overhauled the car. I looked at old setup sheets and decided to adapt these things to the car:

• The T4 2018 has ultra low shocks. These work ideally in high grip conditions but are not so suited to low grip conditions. I put the longer shocks on together with the shock towers from the 2017 car: #302085 and #303086.

• I also used the central torque link, just like the one that was pioneered in TheRCRacer here. I used Xray parts #302663, #303212 and #362650 for it. I shimmed it at 5 or 6mm so that you get enough lateral movement. 

• I used 5mm hexes in the front and the -0,75 hexes in the rear to get some good rotation out of the car. 

• For the diff I only used one with 3000 oil. This may feel soft, but it actually works when there’s not a lot of traction. 

• Perhaps the most important was the droop setting. I used 5.2 in the front and 4.2 in the rear to get lot’s of chassis roll. 

• I used the Bittydesign M410 Ultra light weight body. It combines enough steering with a stable rear end. I chose the ULT version because it’s a bit faster in the chicanes. 

• Quite important is the rotor in the motor. Florian always uses Hobbywing and he swears with it. While we were at the Worlds in South Africa, we spoke with Salton Dong, the Hobbywing engineer, about low grip conditions. At first, I wanted to use a lower wind motor (5 or 6.5) and give it more boost. Salton told us we should just swap the rotor with a thinner 12.1 rotor (instead of a 12.3), as this would make the car much smoother. I thus kept the 4.5 motor but installed the 12.1 rotor. 

Attached you can find the setup we started the race with. I also used 2.3-2.6 springs in the front and 2.5 in the back. With this setup Florian set the fastes time on Saturday, with a 14.1. He was .1 faster on a single lap than Ollie and .2 than the other drivers.

Sunday

We started with Q1 on new tires. Each driver can use 2 sets of Volante 36R tires in modified. Some drivers decided to use 2 sets of new tires, whereas others only used one or a mix of new and old tires.

In Q1, Florian drove quite well, but was not on the pace. It seemed that his car was struggling a bit to find grip. In order to improve the car, I made the following changes:

• Increase the springs to 2.5-2.8 front and 2.6 rear

• Decrease the shim underneath the torque rod to 3mm

• Decrease the drive frequency from 12Khz to 8khz and increase the turbo timing from 20 to 25 (it was a very short straight).

• Use -0.75 hexes in the front to get more steering and make the car more responsive.

• I changed the body from the Bittydesign M410 to the Montech Racer leggera. In Q1 our lightweight body was rear ended, and this impacted the height of the body. We therefore decided to switch to a different lightweight body.

These changes helped, as Florian improved overall time by 2 seconds and shaved a tenth off of his personal fastest lap. More importantly, he was only 3 seconds behind Olivier and claimed the overall P2 spot.

Before the start of Q3, I increased his diff to 5000 instead of 3000. From the start, Florian noticed the car was better. He could accelerate much faster and carry more speed in the long left hand corner after the straight. He shaved another 1.5 seconds off his time on 5 minutes and finished only 1.7 seconds behind Olivier this time. Despite Mitchell Van Es who was already in 3rd place improving his time, Florian kept the overall P2 position.

Finals

We decided to use our second set of new tires for the finals, just like Oliver. Mitchell in P3 ran on the same tires as in the qualifications, whereas Athan De Witte already ran his tires in. Thomas Stockman in P5 also used a new set of tires.

In A1 and A2 Florian drove extremely well. He finished A1 3 seconds behind Ollie, which is the closest he ever came to him in a modified race. In A2 he finished 6 seconds behind and couldn’t keep up with him. For A3 I decided to take a gamble and use the tires from the qualifications. It paid dividends as he was in a league of his own (Ollie didn’t run) and set his best time of the finals.

Overall it was a great weekend and we were really happy with 2nd place.

You can find the final set-up here.

Thanks to my sponsors :)

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