350bhp/tonne Sylva J15 'Busa build

350bhp/tonne Sylva J15 'Busa build

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padrc66

Original Poster:

38 posts

137 months

Saturday 5th October 2019
quotequote all
Following on from my post about getting the car on the road (chuffed to get readers car of the week!):

https://www.pistonheads.com/gassing/topic.asp?h=0&...

I promised to upload some pictures of the build. This may take a while but here goes:

The kit was originally bought from Jeremy Philips (Sylva sports cars) in 2010 with a one-off chassis. The original R1OT (like the J15 but open wheels and mudguards like a caterham) was designed around the Yamaha R1 engine which is very short fore-aft due to having the gearbox shafts stacked vertically. Many Riots were then built with Ford Puma/Fiesta Zetec SE engines and when the J15 was launched with a wider chassis and full bodywork most were built with Zetec SE engines or similar.

It is difficult to fit a motorbike engine and chain drive diff into the car as it becomes quite long compared to a transverse engine and gearbox from a car. I know of 2 other J15s with bike engines, Tim Hoverd's Fireblade engined car which competed in 750MC and another Hayabusa engined car built for the importer in the USA. Both of these had a longer wheelbase chassis to take the length of the powertrain and they both had to have the body stretched to fit.

The original buyer of my car didn't want to do this so Jeremy built a chassis with additional length behind the rear suspension attachments to allow the diff to move back with angled driveshafts to the original wheel location.

Unfortunately the original purchaser passed away before he was able to start the car so the kit sat around until 2015 when his son decided to sell the kit and engine. The engine is a 2010 Gen2 Hayabusa bought from Yorkshire engines and listing the engine as new although i think it was from a crashed bike and probably had a few hundred miles on it.

The kit and engine was listed on ebay but, being in deepest south wales, didn't attract much attention so, being just up the road, i was able to get it for a substantial reduction on what was originally paid.

Here's what I had when we got it back to my garage:









Of course I soon had to offer the bits up to see what I had:



It was at this stage that I started to realise the size of the task I had taken on. Where the engine and diff were due to fit was just a big open space - the original purchaser had planned to make his own framework to mount the engine and diff. Time to buy a welder and teach myself to weld again, something i hadn't done since at Uni 30 years earlier!

Engine and chain drive diff (from West Wales Trike Shack) offered up to start working things out. I wanted to keep the standard airbox if i could as my background is in vehicle development and I know how much work goes into developing these and how much power can potentially be lost by changing to a foam air filter with no plenum. I followed a tip from the locostbuilders forum that the throttle bodies and airbox could be reversed to bring it a bit lower. There was no way it wasn't going to stick out through the engine cover somewhere though!





to be continued.......