BOB KOTMEL STAGE WRITE

NEXT TIME MARK BUSSCHER’S TONNER HITS THE TRACK, HE WILL SEE AT LEAST AN EXTRA TWO-TENTHS AND 2MPH FROM A SIMPLE FUEL SWAP

AS OF 1 July 2019, leaded racing fuels are banned in Australia. They’ve been banned in most forms of motorsport in Europe for many years, and as a result the European fuel manufacturers’ main focus has been on developing unleaded racing fuels. The French-made ETS unleaded race fuel, for example, has powered cars to 50 world titles and national championships across the globe, and this unleaded technology has never before been available to the Australian market until now. So I decided to give Mark ‘Bushy’ Busscher (MB Performance Competition Engines) and Simon Ingram (International Motorsport Solutions) a call to ask about the ETS fuel.

Mark is an engine builder with over 30 years’ experience in endurance engines and drag, circle-track, road and boat racing. He also raced his nine-second Ls3-powered Holden One Tonner in last year’s Street Machine Drag Challenge, where he finished second in the Tuff Mounts Outlaw Aspirated class.

Bushy doesn’t have a vested interest in recommending the ETS unleaded fuel; he simply approached Simon at International Motorsport Solutions about a fuel recommendation for his LS3, which coincided with Simon’s desire to conduct some R&D with some prototype unleaded fuels in a pushrod V8, designed to replace the leaded fuels in the Aussie market. So a selection of ETS unleaded fuels were tested with Mark’s LS3 on Racecomp Motorsports’ Superflow 902 dyno.

We detailed Mark’s 13.8:1-compression LS3 in his Holden Adventra tow car in the April 2017 issue, and this same engine has had an update to 15:1 compression after competing in

the Tonner in DC 2018. The stock-block 416cube mill has run a best of 9.63@142mph in the 3495lb Tonner on ETS P14 fuel. The same Crane hydraulic-roller cam (236 intake/246 exhaust at 50thou; .790in lift; 119-degree separation angle) was used, but the factory EFI manifold and throttlebody have been replaced by a single four-barrel Ray Edwards five-circuit Pro Stock 1390cfm carb and CID manifold. The heads are the stock LS3 items that have been ported in-house, while exhaust gas exits via Di Filippo 1/ 78 -inch headers. The ignition is a fully programmable LS MSD (part number 60143).

The high-compression LS3 is backed by a Rossler Pro Mod TH400 and a Dominator 6000rpm eight-inch stall converter with three per cent slip on the top end. The chrome-moly fabricated nine-inch is fitted with a Mark Williams Pro Series aluminium third member with 4.22:1 gears. It cruises on the street at 3100rpm at 100km/h, rolling on 31.5-inch Mickey Thompson SS Street rear tyres. For racing, Mark uses 315x60x15 Radial X rear rubber. The One Tonner levitates the front wheels using Caltracs with mono-leaf slide suspension, on its way to 1.24-second 60-foot times. If you get the Moroso calculator out, the 3495lb Tonner is making 770hp at 142mph and is a mere 0.15 off perfect hook-up. That’s a lot of real weight-shifted neddies for such a tiny little hydraulic-roller cam!

Now to the testing. The 15:1-comp, 416ci LS3 did well over 40 dyno pulls testing different fuels. Each fuel tested required different jetting and timing to get the optimum results. The best ETS fuel tested was 28hp and 23ft-lb better than the P14 11 per cent oxygenated fuel that Mark was using.

Octane rating has long been viewed as the be-all and end-all of race fuels: the bigger the number, the more compression, the more horsepower. This is not necessarily the case according to Simon. Chemical engineering has improved racing fuels to a point now where a 102-octane unleaded will outperform 114-octane avgas. Hard to believe, but the results are there. Many of the ETS fuels have a higher density/specific gravity, and therefore contain more energy, which means a more powerful combustion when burnt. The ETS folks also use 98 per cent pure molecules to blend their fuels, which, combined with other special additives and exotic chemicals, provides thinner fuel spraying and therefore much better combustion. You can find more info on the ETS Racing Fuels Facebook page or website.

To get the maximum benefit from any brand of new-technology, high-performance unleaded fuel, the jetting and timing changes required are best performed on a dyno. Next time Mark’s Tonner hits the track, he will see at least an extra two-tenths and 2mph from a simple fuel swap. It’s almost like bolting on a small 20hp nitrous kit.

I asked Mark about the shelf life of ETS fuel; as many of us know, some unleaded fuels have a very limited shelf life. He said that the ETS fuel is very stable and has a long shelf life; the drums are sealed with nitrogen. Even when opened, the fuel doesn’t go off, and dyno results are consistent with the same drum of fuel months apart.

If you want to give some of the European race fuels a go, contact Simon via the International Motorsport Solutions website: ims-racing.com.au.