The charm of a budget turbo
Michael Gwyn bought a mk1 for £600 then turbocharged it himself using mostly secondhand parts that cost him about £1700
The BBR mk4 MX-5 Turbo was always destined to be one of our favourite cars of the year. Mazda’s fabulous sports car chassis teamed with 250bhp couldn’t fail to be a winning combination. Here’s a car with the ability to embarrass cars costing tens of thousands of pounds more. If only we had the spare cash…
That’s a common cry, of course. A lament you’ve probably uttered yourself at some stage.yet it is possible to avail yourself of turbocharged MX-5 performance for not much more than the cost of a secondhand learner car for your kids. Provided, that is, you’re prepared and able to do most of the spannering yourself and have the wiliness to track down good quality used components off the internet. And probably best to strike up a relationship with someone who has installed a turbocharger before.
Suffolk-based Michael Gwyn did just that. His turbo project began by accident, when he spotted a red mk1 for sale on the roadside for £600. Couldn’t resist.who could? The notion of fitting it with a turbocharger came a bit later, though, following a trackday when he was offered a few laps in ‘our’ Michael Cleverley’s mk1 turbocharged demo car: actually, it might have been more than just a few laps…
A man who relishes a challenge, Michael decided he wanted to install a turbocharger of his own, on a tight budget, and with the (freely and encouragingly given) help of Mr Cleverley and his crew. And so the project began.
The whirring, chuntering, wheezing heart of the conversion is a Mitsubishi-manufactured TD04 turbocharger, which despite its parentage was sourced secondhand from a Subaru Impreza Turbo motor. Crucial to the smooth integration of the turbo onto the stock 1.6 motor is a Megasquirt MS2 ECU supplied by Dimitri at MS Labs. Another crucial piece of electronics is a wideband Lambda sensor from Innovate.
An area in which you don’t want to skimp is the exhaust manifold, and Michael bought a welded steel unit, plus downpipe, from what is now called Revent but was previously, and more famously, known as Sturovo. Bigger injectors from a Mazda RX-8 help feed the engine’s newfound hunger for fuel, while an ebay purchase intercooler keeps coolant temperatures in check.
The Cleverley crew helped Michael with the ECU set-up and tuning, but as yet only on the road – a dyno session is on the cards for the near future to really nail down the mapping. Until that date with the dyno, a power output is a matter for learned speculation, but Mr
Cleverley is confident that there’s
BBR’S latest turbocharged mk4 MX-5 is a belter, but what if your finances won’t stretch that far? Well, there are cheaper paths to a boosted lifestyle… Words and photos: Brett Fraser
200bhp at least. And all for something in the region of £1600–£1700.
Michael has spent a little extra, though, uprating other areas of the car to cope with the additional power. The clutch has been uprated to an Exedy Stage 2 item, though if you’re not a really hard driver and stay away from tracks, the standard clutch should suffice. The original suspension has been swapped for V-maxx coilovers (as cheap as you should go, advises Cleverley), and the standard brakes uprated to mk2.5 Sport discs with EBC Yellow Stuff pads on the front, standard EBC pads on the rear.
This conversion may have been done at home, but there’s nothing homespun about the car’s performance. The turbo spools up without undue fanfare from about 2500rpm, helps build the acceleration robustly until 4500rpm, and from thereon up to 6500rpm thrusts the mk1 forward with thumping energy and verve. This upper-end punch is complemented by crisp throttle response and the elevation of fifth to an overtaking gear on open roads. Third is for angry attacks on tightly gnarled back roads; fourth is for chasing down sports cars worth 10 times more on twisting, flowing, cross-country secondaries.
And while modern turbocharged models barely alert you to the manner of their induction, Michael’s MX-5 shrieks and hollers and chatters and blows off its boost with all the maniacal musical accompaniment of the blown beasts of yore. It’s a visceral, engaging, enveloping experience that turns minor outings into major adventures. That said, it’s not unacceptably animal.you could just about use it as your everyday motor. If you didn’t live in a city or town: that would be frustrating.
But if you’ve got the skills and time to install a turbocharger on your own MX-5, it’s a magnificent way to go very fast, very cheaply.
Welded steel manifold and downpipe from Revent
Dump valve adds to the underbonnet orchestra