I’m keen to fit a supercharger to my MX5 mk2 2.5
i like the look of the TWR superchargers and I’d really like to get it to 300bhp.
Appreciated it’s a lot of extra work I.e brakes, clutch, suspension etc
Has anyone managed to get this power from there Mx5?
Any tips? Good suppliers etc?
Any turbo fans fancy telling me not to bother? Haha
I had a nervous breakdown a year or so ago and I’m now going through a list of things I want to complete!
Bobby
Bobby,
It’s good you are aware of starting with the chassis first. Many don’t as I’ve witnessed over a few years.
The core issue is before doubling the BHP…the old clutch & gearbox will be a main consideration, as will the general fitness of what is also an old engine.
I can put it this way…as I also have a Mk2.5 with 105k on it and it is oil tight and perfectly fit for purpose…and if I was going your route I’d be prepared to kiss goodby to reliability.
TBH, over the years I’ve had a passenger run in an SC’d Mk2, and a turbo…which was done by an engineer in Fife I know on his own car who had steel bullt the innards himself…crank, rods, pistons etc and at 240/250 bhp (from distant memory) He instinctively knew the old engine would lunch itself unless he did. It had done around 140000 miles.
Suffice to say it was ballistic and just about useable sensibly on public roads. It chirped it’s rear tyres through the box in the dry…with Toyo R888 sticky rubber. He reckoned that was as much as the gearbox, diff etc would reliably take. Naturally, it had some sort of upgraded clutch.
I’d say turbo anyway…much as my personal preference being old school is supercharger.
It could, and should take up to 5/6k at least if you starty with the chassis and work your way up.
And let’s face it, even “just” 200bhp gives what the mental dingbat Sierra Cosworths delvered back in the day.
In a Mk2 Mx5 5…200bhp in my view is more than street-adequate.
Most of the time…finding the chance to use 300 bhp will be rare…legally!
Is it worth it?
I went the supercharger route on my mk1 1.6 Eunos ( I know it’s not a mk2.5 ) I was very fortunate to obtain the last ever Jackson Racing kit, a few years after they stopped producing them for the mk1’s. It had been sat on a shelf gathering dust in a branch of Moss Europe. Anyway, suffice to say, the the best thing I ever did IMO. Went from factory fresh 114bhp to 190bhp on only 8psi of boost in less than a day of DIY spannering. Superb and linear power delivery using just the supplied power card for fuelling, piggy backed onto stock ECU! and a boost controller to retard the ignition when on boost. No manifold to swap out, no replacement ECU to install. The initial conversion worked out at around £30/per 1 bhp increase. Exponentially, upping the power further, increases that ratio massively! On my charger (MP45) not a lot of ceiling anyway for big power increases beyond what I had? Crank overlay, reduction pulley to make it spin beyond its design rpm, refusing reliability and longevity in the process.
OK, old skool stuff but then so am I OEM reliability too! It was enough power for me I admit. I did upgrade the clutch as the stock one did slip sometimes. 300bhp is a massive increase from stock? It has been done though but would you need a forged engine to cope? Can get quite expensive, chasing the horses
That car is no longer with me but from what I understand, the charger set up is still providing excellent service after 6 or 7 years since installation.
Good luck whatever you choose to do!
Barrie
The Mk2 (BP) engine is often quoted as being quite safe up to 230 hp, which is probably an increase on what the BPT (turbo) version of the engine produced in standard form. Any more than that and you must accept some increased risk on a standard bottom end.
My son has a turbo conversion on his Mk2 1.8iS. The parts were sourced by himself then fitted and set up by “Blink Motorsport”. That car was acknowledged by Blink as surprisingly powerful and went on to take the “fastest Mazda” trophy at the Jap show when he took it to a Santa Pod meet a couple of years ago. Despite that, it actually produces a bit less than 300 hp!
However, the advantage of a supercharger is the instant increase in usable torque it provides, even from low revs, rather than out and out horsepower at high revs.
It has to be said that it would take quite a large supercharger to produce 300hp from an engine that produced half that in normally aspirated form. Even so, the increased torque from a supercharged engine can be very usable on the road. I fitted my own experimental designed/built Eaton supercharger conversion to my other sports car. That one has only a sub 1 litre engine but the conversion almost doubled the torque output and because it only weighs 630 kgs it accelerates noticeably quicker than my Mk2 1.8i does. It has about the same power to weight ratio that my old BMW 330D had. It’s quite “interesting” to drive it on it’s 5.25 x 16 inch crossply tyres.
My next project might well be to fit a brand new Eaton supercharger I bought some years ago to my Mk2. There’s no way it would produce 300 hp because it’s not big enough but even so I know it would give a large increase in torque and “fun factor”. I would not want to run more than 230 hp anyway.
Hello everyone,
thanks so much for all the replies. I am in agreement that chucking 300HP out of one of these engines is probably a little daft however Im one of those people who likes to set challenges otherwise i don’t really see the point.
I decided last year to change career and googled toughest jobs in the world. Commercial Diver came up. Thats now what im doing. Its hard haha! Why not spend the wages on a car project! Im not married and have no kids so i can still do this!!
The current engine is in pretty good condition. Its been driven gently from what i can gather; previous lady owner who test drove it with me wouldn’t go on motorways and drove it 3.5 miles everyday. Its currently got r.e. 90,000 on the OD.
The gear box currently has an issue but im getting the guys at Skuzzle Motorsports to rectify that.
The big question is wether its worth doing. That i will never know. Im looking for the long experience and im prepared to spend on the project, so brakes, suspension, wish bones, racing flywheel, racing clutch, wheels, upgrading of engine parts, exhaust etc etc are all things which will be getting done.
I like the idea of the SC as already stated its torque from the word go.
I think in essence if i get it going in a year or so then the plan is to get it to Germany and get my Dad and I around the Neurbergring. If it blows up then that’s that!
Am i right in thinking that you can put Rx8 brakes on MX5’s? Is this a good idea when looking at break upgrades? I also want to start looking at the suspension system. Has anyone got suggestions for good brands of suspension to put on them?
Regards
Bobby Bird