Month: December 2025

Returning to the track

The time had come to take the Swift back to the track.

Last Monday, 15/12/2025 I participated in an open pit lane day at Winton Motor Raceway here in Victoria, Australia.

The car performed really well, oil temps hit about 110C after a few hot laps but appeared to stay consistent. Water temp hardly hit 90C and fans worked as intended via the Link.

The car will take some time to get used to with the new power but gearing feels a bit nicer now at Winton. I think it’s faster keeping the car in 3rd in some corners rather than shifting from 4th to 2nd, which I struggle with.

I am starting to learn the AD09’s a bit better too. They’re definitely not as grippy as my previous RE-71R’s but are wearing far slower.

The day was cut short by a rather large fuel leak, I lost about 5L into the engine bay, a miracle there was no fire.

My 3D printed injector rail spacers got hot and went soft, causing the rail to sag and unseat the No. 4 injector (closest to the rail feed). Unlike the original post, I did print them again in ABS however the infill/density was low. I think this was the main factor as the engine bay doesn’t feel like it’s getting hot enough to reach ABS melting point. Thankfully, by the time it had fully let go I was close enough to the pits to kill the car and coast in.

I had to remove the bonnet liner as it was drenched in fuel. It was dripping for fuel for over 10 minutes with the bonnet up. Maybe I should’ve bought a lottery ticket…

Thanks to some fellow Suzuki enthusiast who had some spare round bar, we were able to cut some makeshift spacers down to get me home. It was about 1PM at the time of the fuel disaster and almost 2PM by the time I had fixed it. I elected not to return to the track, opting to leave the car in the sun to let the excess fuel in the engine bay to evaporate.

Overall, a successful shakedown. Despite being 0.5s off my NA PB, I was improving by over a second each time I went out and having a brief look at the data a 1:40 should be very achievable… Once I grow some balls and regain some confidence after my crash in the Galant a few years ago.

Best lap of the day (delta to PB [NA]):

Fans

As mentioned in my previous post, my radiator fan did not work after installing the Link (same with A/C). After doing some googling, I suspected the fans could’ve been locked out due to no A/C gas.

Looking at the wiring diagram for the fan setup on an earlier model Swift Sport (ZC31S) I decided this was unlikely. I had the A/C gas reinstated and there was no change. Notably, the A/C compressor requires jumping to trigger.

Reviewing the diagram, I believe there is something internally inside the ECU that is unhappy with the “IGN ON” state. Refusing to trigger (pull down) the outputs to the radiator fan and A/C compressor relays. – refer green “fucked?” circles. I discuss more about it in this post I made on the Link Forum.

Above image is how I ended up wiring the fans via the Link, it works perfectly! On low speed, at idle the fan was able to drop the temp nicely. As we enter the depths of Summer it will be good to see how high speed goes. My logic for fan control is below. Note, the image of the laptop below doesn’t show current settings.

LOW: Coolant temperature > 93C (3C hysteresis)
HIGH: Coolant temperature > 100C (4C hysteresis)

Unfortunately, I am now out of aux outputs and will require one to get A/C working via the Link (if I choose to do so).

I have a few options for triggering the A/C compressor. The factory ECU appears to trigger the compressor relay output when receiving a CAN message from the press of the A/C button in the car.

From my research, I believe the car (and most late model Suzuki’s) runs the bus on 500Kbp/s. As I have the CAN lambda installed on 1Mbp/s, I would need to drop the bus to 500 Kbp/s and sniff out the A/C request in order to get the Link to control the compressor output. If I go with this option, I will make the Link fan output be single speed, HIGH (Aux 4) and the LOW speed would become the A/C compressor (Aux 5).

The alternative is run a secondary CAN device, such as the Canny C7 which could control the compressor relay output as a standalone device. This could be preferable as the Link CAN bus would be completely separate to the OEM ECU.

Updated wiring table is below.