Race Collective caught up with hillclimber and sprint racer, Ben Bonfield. By his own admission he doesn’t have the latest carbon fibre car or the biggest budget, but it’s fair to say with the trophy collection he’s gained over the years, he’s a bit of a dark horse out on track! Ben’s performances, particularly at Wiscombe with a 37.35 second run, have left some of the single seater paddock double checking the time sheets and wondering: “Did he really do that in a Jedi?”. A special thanks to Howie of 569 Media for the fantastic photographs.

Ben Bonfield Racing
Ben Bonfield Racing

Background and life in racing

“So to introduce myself, my name is Ben Bonfield, I am a product design and workshop mechanical engineer for our family run business and I own a 1995 Jedi Mk4″. Ben’s family have been involved in Motorsport for generations, his grandad started it off by organising rallies, hillclimbs and autocross events and his dad raced a classic Mini through the 80’s and 90’s.


“I was always a huge fan of close racing, be it touring cars, F1 or even rallying, with collections of classic events video taped to be rewatched over and over. Drivers like Ayrton Senna, Colin Mcrae and Steve Soper provided countless hours of entertainment. Motorsport to me has always been like family, you get together regularly, you can share many great moments together, laugh together, work together, compete together and go away from a weekend knowing that soon it will be time to get together again. I think it’s one of the reasons for keeping me tied to the sport.” he says.


Ben got the bug after his dad took him karting at a young age. “Karting was the first real time I got behind the wheel with Dad, he helped out at indoor events to earn vouchers so myself and my brother could kart in arrive and drive sessions. We quickly moved on to learning how to drive a manual car and started doing club auto tests on tarmac and on grass.” he says. 


At age 16, Ben and his dad prepped their classic Mk1 Mini for the 2004 hillclimb season. The rest is history and both compete in a double driving format to this day. The Mini is still the car of choice for dual driving and they have had some great success over the years, taking both class wins and podiums.

The Jedi

After years of driving the Mini, Ben wanted something that was a bit quicker and looked around at some single seaters. “I chose the Formula Jedi as it’s probably the best value for money out there, second hand value can be anywhere between 6-10k. Parts are readily available with good factory support, it’s easy to work on and it’s a proven chassis, with the first one made in 1984” he says.


Ben went on to say that the Jedi is actually cheaper to run than the Mini. “Even in terms of tyres, the Jedi would go through 2 sets of rear tyres a season, the Mini would go through 3 or 4 sets of fronts (28 single day events)”.


Ben found a Mk4 Jedi in Guernsey and went across to see it in August 2016. It was a circuit spec car and hadn’t been used in a few years, so there was a bit of work to do, but nothing Ben couldn’t handle being a mechanical engineer. Ben picked it up for £6,250 after and brought it back to his Taunton based workshop. 

The modifications and first few seasons

The first thing Ben needed to do was to get the car compliant with the blue book regs. “First thing we did was pop a new roll hoop on it, we took it to John Corbyn at Jedi Racing Cars and he sorted us out” he says. Being an early circuit spec Jedi, it was fitted with a Honda CBR900 engine, an open diff and was aerodynamically really basic. “We first upgraded the wings, wheels and tyres to bigger and wider spec parts, but for the first full season 2018 it was kept simple to settle into the behaviour and feeling of the car” Ben says. As his previous experience was in the Mini, the speed difference of the Jedi did take a little getting used to. “I did Gurston in the Jedi and managed to hit the limiter in 6th before the first corner (110mph), that was definitely an eye opener!” Ben says.



For 2019, Ben picked up a Suzuki 2001 GSXR 1000 engine, however, the chassis had to have new mounting points made and needed the diff mounts repositioned to get the chain to line up. Ben actually fitted the engine himself, along with a new set of electronics, a hillclimb tank (to save weight) and an ATB differential. This is all part of Ben’s cost saving approach which has meant he can focus his capital on purchasing parts rather than paying for labour. 



Late last year, Ben smashed out a 37.35 second run at Wiscombe, which would have earned him a spot in the Top 12 British Run off! “Wiscombe is my favourite track, it was the first ever hillclimb that I competed at in 2004, the twists and turns make it really exciting and it feels great in the Jedi. Our Jedi was the 6th fastest car up Wiscombe in 2020, being beaten by Paul Haimes (Gould GR59 36.23), Ed Hollier (Pilbeam Mp62 1600cc), 36.24, Andrew Forsyth (OMS CF04 1400cc 36.80), Andrew Short (OMS CF07 1600cc 36.85), Andy Greenen (Empire Evo 2 998cc 37.19), and then my time with the Jedi” he says. All those cars have significantly more aero and a lot more power. Ben has also had a lot of success at Werrington hillclimb and at sprint events such as Clay Pigeon and Abingdon, usually picking up 1st in class and getting in the top 3 fastest time of day. 

The home built engine for 2021

From an engineering point of view things start to get really interesting here. Ben wanted some additional power and went in search for a cost effective engine, with the K7’s and K8’s going for around £3,000, Ben decided to build his own hybrid based on a GSX-S1000. “I wanted to build a new engine, but also keep the costs really low, I did countless hours of research on pretty much every bike engine related forum” he says. Ben decided on the GSX-S1000 engine, which he says was based on the GSX-R1000 K8 block which is popular with the front Formula Jedi/ 1000 runners. In 2018 spec, these GSX-S engines can be picked up for between £500 to £800 which is an awful lot cheaper than the R variant. “I found out that the post 2017 units had windage holes drilled into the block, which equalises the crankcase pressure leading to about a 10BHP increase” Ben says. He also explained that the GSX-S engine had a detuned head, as these engines were used in touring style applications. 


“I then bought a GSX-R head from Germany for £200, had the head ported and polished by a well known tuner Mark Shillaber. I then rebuilt the head and shimmed it up to spec ready to go on the new engine. I also converted the timing trigger wheel to a 2001 spec GSX-R rather than the later management type and set it up to run the early type sensors along with the 2001 16 bit management system. This allows me to swap the engines and return to the old engine if we ever have a problem. Less sensors and emission restrictions were on the early ECU’s and it was also cheaper than a standalone system.” he says.  A Power Commander 5 to manage the fuel and ignition and a flat shift system for quicker changes was added to the car in the new year. There are high hopes for this engine and Ben is set to dyno the car in late March, he thinks it could reach the £200bhp mark!



For the 2021 season, Ben has also replaced the old aluminium wing with a bigger carbon fibre version thanks to the help of Andrew Dinner at the Fragile Workshop. This should help with front end grip and reduce weight on the front end. We can’t wait to see what times Ben can get out of this near 30 year old car.

Keeping costs down

“When it comes to costs I try to do as much as possible in house, engine rebuilds are normally done by myself, along with electrics and general repairs” Ben says. When looking to purchase anything Motorsport related, Ben does a lot of research. “I’ve found that researching online yields some good discounts, the helmet I bought a few years back cost me £300 instead of £450; I purchased it from the abroad and the shipping was included in that price. If you look up the FIA numbers you can really find some bargains, lots of the products are made in the same factories as the really pricey stuff. My new suit for 2021 is new old stock Oreca which came in at £160 brand new again a considerable saving as the new model comes in at £315″ he says. Those are some good tips for those of us who go straight to the highstreet vendors.

2021 and shoutouts

For 2021, Ben is going to have a crack at getting to the top of both the ASWMC Hillclimb and Sprint Championships. He will also be signing up for the ACSMC Championship, along with the Cornish Speed and HSA Championships. Sounds like someone has been missing their racing! We wish Ben the best of the luck in tearing down the times of those set by carbon single seaters. Who doesn’t love an underdog.


Bens shout out list is below.

  • Specialist Components who for many years supported and helped us out with the Mini.
  • At Power throttles who have bailed us out in the past when we’ve needed replacement parts.
  • Bridgwater College Motorsport for the fantastic work put in to setting up the cars over the many years. 
  • GB Enterprises who will be running and mapping the new engine on their rollers.
  • Jedi Racing Cars for their support and advice in moving forward with the developments.
  • 569 Media for the fantastic photography over the years
Mk4 Jedi



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