I spent a while deliberating on various ways of increasing engine power, and must have settled upon every conceivable idea going. As is the way with me though, eventually a plan sticks.
I’d quite like some more power, but at the same time keep it naturally aspirated. That’s not a common way of tuning MX5s and whilst kits are out there, you tend to have to research it all yourself. The exception to this is the Blink Motorsport 160 package, where for £1,500 you’ll get a modified cylinder head (exchange), regrind your existing cams, MegaSquirt PNP ECU, wideband lambda sender and some gaskets. Unsurprisingly, this should net you somewhere in the region of 160bhp with a 1.8.
I nearly opted for this, and I still will I suspect, but there’s something I’d like to get out of the way first. That is, building the best base I can without spending silly money. To that end, I’ve sourced two more engines…
2000 Mk2 MX5 1.8
I’ve bought this engine for the top half. The mk2 head flows ever so slightly better than the mk1 head, and has solid lifters. Unfortunately these have the shims on top of the lifters so that doesn’t translate to instant revability. I think I read that Blink tested it at the head flowed 4% more or something equally pretty small. With MX5 engine prices pretty low, it made sense. The mk2 engine had 9.5:1 compression against the 8.8/9:1 of the mk1 engine and around 140-143bhp from the factory.
2003 Mk2 1.8 (SVT)
This is the engine with the highest output (Mazdaspeed turbos excluded). It had VVT above the previous generation engine and a higher compression ratio (10:1). Unfortunately, due to the height of the VVT solenoid the engine doesn’t fit in a Westfield, else that would have been an easy 146bhp. I’m still intending to realise the benefits of this engine though by using the bottom end of it and fitting the head from the earlier engine.
Most of all though, having built the car I’ve still never stripped down and rebuilt an engine. This little project gives me the opportunity to do that,