Some of you may remember last year, that we spent several months working with an experienced engineer who’d worked on large V12 engines to see what could be done with some modest changes to the 1.8 MX5 head.

The first head with revised cams, reprofiled valves, skimming and some port work gave an impressive 20lbft increase in the mid-range, but with a rather lumpy torque curve and less impressive gains at the top end. It was a learning experience for us with the MX-5 engine. So at the end of last year, we looked for someone with a proven track record with small 4 cylinder engines to collaborate with and build upon what we'd learnt last year in a new project.

In fact 2007 saw the start of two new engine projects. A new moderately modified normally aspirated head, which is near completion and the recently completed 9000rpm red line high compression custom built Mazda road-race engine, based on the 1.8 mk2 engine. Developments from this engine are designed to feed into all our engine work.

Last Monday we took the new road-race engine to the rolling road for tuning. Managed by the new Emerald K3 ECU in sequential injection mode, on it's first outing it made 214.5bhp at 8694 rpm and 146.2lb ft torque at 7244 rpm. There's still work to do on the exhaust manifold and throttle bodies, but even at this stage it gives 202.7bhp per tonne in a nimble handling MX5 (mk2). Compare that to the relatively larger and heavier S2000s at 186.77 bhp / tonne and you can perhaps see the potential.

As a race engine, it would be possible to get quite a bit more horse power from it by running full race cams, but in it's current form we've been pleasantly surprised how flexible it is as a road car. At 3,500rpm it's making around the same torque as a standard car, so can cruise comfortably in traffic.

At full throttle, it's like nothing we've tried before. Burbling and Screaming throttle bodies with the snappiest possible response pull urgently all the way to 9000rpm. We're also working on cold air box options to reduce the volume to more modest levels.

The new car will be making a feature at our open day this coming 14th October at North Weald airfield and passenger rides will be available for those that want to experience it first hand.

The specification list for the engine is lengthy but includes our new billet steel crank 3kg lighter than standard, forged rods, high compression pistons, chrome bearings and extensive head work including a custom valve train, which is not available off the shelf for the MX-5 and is where much of the power is derived.

Don't get us wrong, we love the turbos and superchargers, but there is nothing like this in forced induction. With no hot compressed air to deal with, ignition timing is aggressive across the whole map and four individual throttle bodies near the head gives for the snappiest throttle response available on the MX-5 and then there's the noise...

You can see the dyno and some photos of the project below. If anyone is interested in their own normally aspirated built engine, we'll be putting together some staged options soon, please contact us.

Dynograph, care of Track and Road	The car on the rolling road
Billet crank in place in the block, with forged rods & ARP studs. Available now and at 3kg lighter than stock and many times stronger, the billet crank gives many advantages for a high revving or turbocharged engine.	Engine bay. Less is definitely more with this one !
Woessner pistons and ARP studs