From Donington to MIRA: The Evolution of Data Logging with Haltech

0. Introduction

Data Logging... a 1950’s sportscar... Top gear... University?! All these seemingly unrelated things have come together for us lucky members of the Oxford Universities Motorsport Foundation over the last 2 months. My last report/update was written just after the Donington Historic Festival where the extremely kind people at Haltech and Race Winning Brands sponsored the team with a Haltech Nexus S2 and the climb up the Data Logging/Race Engineering learning curve began. The push to install sensors and study the produced lines has not slowed any. But I will pick up where we left off and even though this story starts quite similarly to the last one it definitely does not end the same.

1. Same ol’ Same ol’
After Donington, it was straight into the rally season, with the team heading to Abingdon for the CAR-nival and then on to the Big One: the Ypres Historic Rally in Belgium. Getting the Haltech into the Riley rally car will have to be a winter project due to the scale of the loom and the robustness it must have to withstand the rigors of rallying. This left me primarily learning about the VBOX and Racelogic software, particularly the wiring of CANBUS, which allows the VBOX to receive data from a secondary source. In the rally car’s case, these were our brake temperature sensors, which Racelogic had previously sponsored us with. 
One major issue we ran into was a Y-piece splitter that was supposed to allow the use of a serial OLED display alongside whatever CAN system was needed. When we discovered the Y-piece was causing problems, it dawned on use that it was also responsible for preventing communication between the Haltech and the VBOX on the Riley race car! As soon as we returned from Ypres, we bypassed the Y-piece and got the Haltech and VBOX to communicate, which finally allowed us to use Circuit Tools to split data gathered by the Haltech into laps and compare and contrast, just as any good race engineer would. This was a huge step forward.
Surely now, with a month until our next circuit race at the Oulton Park Gold Cup, we could get on with installing the Haltech/VBOX system into the Elva... or so we thought. We pushed ahead as before, trying to get the system dialled in while also installing superb new dampers supplied by Bilstein, springs from Eibach, and gorgeous, I mean drop-dead gorgeous, fixings from ARP. As the race weekend drew closer, we found ourselves in a very familiar predicament: the Riley Racer was ready to go, but the Elva was nowhere near tested enough and could potentially be unsafe to race. So, for the second time, we made the call to put the Haltech/VBOX system back into the Riley (now fitted with a new throttle position sensor and using an RPM opto-isolator, designed by our very own David Sellars, to avoid blowing up our new Haltech!). 
Oulton went brilliantly for us on the data-logging front — all systems worked, and we could finally practice finding lap time! That was until the gearbox decided Ding was not allowed to choose a gear... DNF.

OUMF Team at Oulton Park

2. Motor Industry Research Association and OUMF!
Back in March, at the Practical Classics Restoration Show, Ding was introduced to a chap named Andy Owen, a test engineer technician at HORIBA MIRA, a world-renowned test track used by most Formula One teams, JLR, and of course Top Gear! He mentioned there might be a chance for OUMF to have a day on their Dry Handling Circuit. This was an incredibly exciting proposition for a team who, in 25 years of existence, had never had the opportunity to set up a car in a controlled, non-competitive environment.
What a perfect opportunity for the Elva in particular, a chance to truly dial in our new springs, dampers, and suspension-related data acquisition system. To say we were excited is a huge understatement... we were practically jumping to get to MIRA as soon as possible. We promptly asked to go, but unfortunately, the track was closed on the day we expected the Elva to be ready. Still, this gave us extra time to get the car even more prepared for the big day.

New spring and dampers from Eibach and Bilstein

One area that needed attention was the wiring. Adding in all the Haltech sensors had turned our year-old loom (built before data logging was even considered!) into a bit of a rat’s nest. So our resident electrical guru, Ethan Wakeman, set about modifying his loom to make it data logger ready, carefully leaving pins free for future data logging ambitions. I was again tasked with the mechanical design side of mounting and integrating sensors. I had designed the throttle position sensor mount the first time we attempted this, so my new targets were steering angle and damper position.

Haltech Linear Potentiometer machined mounts

For steering, I CAD’ed up a belt-and-gear drive system off the steering column that spins a magnet in front of a rotary hall-effect sensor, 3D-printing the entire assembly. For damper position, I used the lathe to turn and tap mounts to fit on the ends of the damper bolts, milling flats so a 9/16" spanner could still be used. A stud was then threaded on, onto which a Haltech linear potentiometer could slide.
As the test day (August 30th) approached, Ollie Raja-Brown and I wrote up a first draft of a test plan to workshop with Ding and the rest of the team. But one major issue remained: the engine had a huge dead spot in the 3000–4500 rpm range, which completely killed Ding’s ability to balance the car in fast or constant-radius corners, exactly the kind of testing we needed to do at MIRA.
Luckily, carburettor specialist Tony Dwornik empathised with us and took on the challenge of figuring out what had changed with our previously untouched carb. We spent a day at his idyllic Oxfordshire workshop testing different jets and float heights, chasing the perfect air-fuel ratio. By the end of the day, the engine was pulling cleanly across the rev range, and all the testing allowed Ethan and me to dial in our new suspension pots and steering-angle sensor. It was all looking up.

3. “Its a science experiment not a pitstop”
Leaving the barn at 6am is never fun but remembering we were going testing and all that had led to it made waking up quite easy. We got to MIRA at 7:45 meeting Andy Owen and Tom Nichols at the proving ground and getting all of our phone cameras taped over! All very professional. We got to the track, unloaded, went for a sighting lap, warmed the Elva up and sent Ding on run #1 of the day to shakedown the car and data systems. The car came back green and ready to start the day on its Sustain GT40 development fuel. The first program would be the car on softer springs and getting data for understeer and lateral G as we changed bump and rebound throughout the new Bilstein dampers range. It was another huge learning curve for the whole team: Sam Cox and Amy Foster were doing fuel, tyres, and had to make sure the car was a consistent weight and that tyre pressures did not fluctuate from run to run. The corner mechanics like Edward Sheer and Luke Crutchley were having to follow a strict schedule and know what change was coming next. Myself and Ethan were figuring out new procedures of pulling data off the car and making sure we were not getting garbage from the sensors. I don’t know what we would've done if MIRA engineers Andy Owen and Tom Nichols were not around to guide and comment on how we were running the test. It was all learning, all the time, even for Ding who was having to adjust his driving so we could get consistent data.

OUMF MIRA test team and Andy

After a couple of runs, as things were just starting to flow, the diff started to make a suspect noise. The team took it out and inspected it, tightened the crown wheel bolts, and put it back in. Sadly though it seemed the constant radii corners were putting the LSD through hell and it came back with the same noise. With bad weather just over the hill we decided to call the day early. Very much a shame and we left with heavy hearts but lots to think about.
Everything leading up to MIRA has made both myself and the team better engineers, racers, and team mates. It has been one huge learning experience and promises to continue as while writing this we have confirmed our next test date for Sept 27th... 25 days! Massive thank you to Andy Owen and everyone at MIRA, Mark Luney at Haltech for the data logging support, Rob Fowler at Racelogic for answering my sometimes stupid questions, Bilstein and Eibach for the brand new suspension components that allow us to have a play, Sustain for the fuel, and ARP for supplying the fixings to keep it all together!

-Charlie Lemme
3rd Year BEng Motorsport Technology