Race Engine Technology - March/April 07

CONTENTS: MARCH/APRIL 2007

Features

Inside: F1 POWERTRAIN 2007
Grand Prix engine and gearbox technology

Short Take: WET FLOW BENCH
Visualising the flow through the cylinder head

Preview: ENGINE EXPO 2007
Looking forward to the annual road/race crossover event

Profile: CORVETTE LE MANS V8
Exclusive insight into the GM Racing Small Block

Short Take: POWERTEC BIG BANG
Using uneven fire to gain tyre grip on loose surfaces

Motorcycle: ILMOR'S MOTOGP STRATEGY
Tackling the need for extreme precision at low throttle openings

Focus: VALVE SPRINGS
How the suppliers view current and future technology

Report: AETC
Highlights of the last Advanced Engineering Technology Conference

Supply Chain: AJPE
How Alan Johnson interacts with his Top Fuel component suppliers

Departments

Grid
The Race Engine Technology world

Expo
News from suppliers to race engine builders

IRED: Pro Stock Motorcycle
The NHRA engine builders

PS
Peugeot's last Le Mans winner

Ted Hurrell's Powertec Engineering, the engine division of the UK's commercially successful Radical racing car company, has developed a Big Bang Suzuki Hayabusa, initially for Autograss racing. Autograss is a popular form of motorsport in the UK, which is run on dirt track circuits primarily using specialist race cars. The 2006 National Champion was Anthony Ross using a Powertec V8 engine in standard 2.6 litre/ 380 bhp trim in a 'Class 10' (unlimited) single seater. He also raced the new Big Bang in line four in a lighter 'Class 8' single seater on a number of occasions, to very good effect.

The Hayabusa-based Powertec V8 may well be next for the Big Bang treatment, following the success of the four-cylinder project. Hurrell reports that each time the prototype Big Bang engine raced in 2006 the traction it gave the car made it the fastest vehicle in Class 8, in spite of a relative lack of top end power. Four different drivers including Ross took nine wins from 20 races against more powerful Class 8 cars.

The prototype engine was kept simple: it had a standard crankshaft and Powertec simply changed the camshafts and remapped the MBE engine management system. The revision fired two cylinders simultaneously, then after 180 degrees the other two, followed by a 540 degree interval. The exhaust system was unchanged on this standard tune, uneven fire Hayabusa.

The 1300 cc prototype engine outran 1350 cc 'full race' Hayabusas, in spite of giving away more than 50 bhp at the flywheel. For this season Hurrell has developed a Big Bang version of his 'full race' 1350 cc Autograss Hayabusa, having now proven the concept. This gives away nothing on the dyno while offering the advantages of Big Bang on track.

Hurrell says that Radical is keen to test the Big Bang engine in one of its sports-racing cars but he accepts that it may not prove so effective on tarmac and that there will be a question mark over its impact upon transmission reliability. Running on dirt, there was no issue of engine or transmission wear for the 470 kg, ARD chassis prototype racer through 20 (admittedly short) races.

The idea for the Big Bang conversion came jointly from Hurrell and from ARD owner 'Ant' Ross. "Ant came to us to discuss buying a V8 motor to run in a class 10 car and while we were talking the subject of Big Bang motors came up," recalls Hurrell. "Ant commented that he tried to get his previous engine tuners to look at trying it but they thought it would not work. I told him that we had already got an engine converted that we had dyno tested, etc. We had at that time only run it on carbs as it was easier to do than injection and we had just wanted to see how it worked.

"It was then that we struck a deal to try and win the two championships (National and BAS-British Autograss Series) with the V8 and then bring out the Big Bang at the end of the year."

Ross says that in wanting to try Big Bang he was influenced by MotoGP practice (as discussed in these pages on a number of occasions) and by having run an Autograss car equipped with pair of V2 engines very successfully against four cylinder machines of the same (total) displacement.

"We are effectively running this Big Bang Suzuki as a pair of twin cylinder engines," notes Ross. "We hit the circumference of the tyre twice in quick succession and then let it rest. It was a real eye opener when we took it to its first meeting, the way it drove away from the field!

"The thing you notice is that you don't have to wait to get the power down and its delivery is so smooth. There is no wheelspin and you get so much speed off the turns that you can easily overtake on the inside away from a corner. You get much better tyre wear, too."