Malcolm Roach’s Fiat 500 isn’t really his car. He actually has to ask permission to borrow it from his wife, who loves it a lot (far more than she ever did the Volkswagen Fox that preceded it)
Now you might think that an off-white Fiat 500 with red leather upholstery is a bit of a girlie car, but, after Tunit got their hands on it, I assure you that its performance was far from girlie! Malcolm headed from Cheshire up to Chorley to have a Tunit fitted to the 1.3 MultiJet engined 500, having been promised some test runs on their rolling road dynamometer in order to see what figures their conversion could produce on this, their very first Fiat 500 conversion. The 1.3 MultiJet engine is a well-proven and very robust little power unit, and one that has previously produced as much as 95-96bhp in various Puntos in the hands of Tunit. But the 1248cc engine comes in a lower level of tune in the 500, with factory figures of 75bhp and 107lb ft of torque – 33lb ft down on the Grande Punto MultiJet 75’s engine, and 15bhp and 41lb ft down on the Punto MultiJet 90’s. One can only presume that Fiat feel that this engine offers adequate performance in the 500, which it does 0-62mph in 12.5 seconds and it probably helps to keep insurance ratings low, at Group 3 or 4, depending on trim level. Starting, as they were, at a lower base power level, the target that the Tunit boys had in mind was something in excess of 95bhp, and torque figures of something around 140lb ft. After setting up the little Fiat on the dyno rollers and taking a few calibration settings, fitting the Tunit itself took only a few minutes, all the vital electrical connections being surprisingly accessible in the somewhat crowded engine compartment. So now for a few full power blasts on the rolling road! Well, it didn’t take too many runs, with just a few minor adjustments along the way, before the Tunit technicians decided they had optimised the performance settings. The good news was 102bhp at 3,900rpm, with a torque peak of just under 144lb ft, at 3,650rpm. Whilst the standard engine was a pretty healthy specimen, recording figures of 79.4bhp at 3,980rpm, and 112.4lb ft at 3,600rpm, everyone was more than happy with those power and torque boosts of around 28 per cent!
“The good news was 102bhp at 3,900rpm, with a torque peak of just under 144lb ft, at 3,650rpm.”
That doesn’t tell the full story of the remarkable torque curve of the little 1.3 MultiJet engine, which both as standard, and tuned, shows a nice flat plateau from just under 2,400rpm right through to over 3,600rpm. These are great characteristics to have in a diesel engine, as they mean strong pulling power through a large part of the engine’s normal operating speed band. Good though the standard engine is, the Tunit conversion had made a big difference to the figures, and it was no wonder that Malcolm could feel a huge difference as soon as he took the car out on the road! I went with him (adding a not inconsiderable 90 kilograms to the all-up weight, I might add!) and the transformation in the car’s response was immediately hugely impressive. It felt like a snorting little car and yet one still totally lacking in temperament, and more than happy to trickle along at as little as 1,200rpm, without any suggestion of transmission snatch or uneven throttle response.
Malcolm allowed me a few miles at the wheel, and what impressed me most of all was its dual character. Pootling along in 30mph limits it was totally vice-free, and yet you could feel a latent willingness, even eagerness, to take on some more demanding work. Stroke the accelerator somewhat more firmly (it doesn’t need flooring) and you can feel that extra lump of torque coming in strongly, and the happy little MultiJet engine then spins eagerly up to over 4,000rpm with great enthusiasm, and yet admirable smoothness and refinement. Catching up with Malcolm a couple of weeks later, he was still ecstatic – “sensational” was a word that he used about the conversion, and his wife reported that it was “much more responsive” and “a lot smoother.” She also says that the improved pick up and flexibility is often saving her a downwards gear change. Add to that a confirmed economy improvement from 51mpg to 54mpg and you can guess that we have a very happy Tunit enthusiast – and one who says that this is the best of the three Tunit conversions that he has had. You can hardly ask for more than such praise from a three-time Tunit customer!