SuperKa ‘v’ SuperCinq

Statistical Analysis

Study the power and torque outputs of both the SuperKa and the SuperCinq, and you would think that the smaller Cinquecento would be quicker. Then check the kerb weight, and you’d expect the Ka to be eating the Cinq’s dust from rest.

The Ka produces less power, but its peak power is produced at a lower engine speed than the Cinquecento and - of more significance - the torque is also produced lower. The Ka also has a flatter torque curve than the Cinquecento. The Ka has useful torque from just 3,000 rpm, whereas the Cinquecento has little below around 4,500 rpm.

	SuperKa	SuperCinq
Power	174 PS @ 6,600 rpm	187 PS @ 6,900 rpm
Torque	212 Nm @ 5,100 rpm	213 Nm @ 5,500 rpm
Weight	780 kg	656 kg
PW	223 PS/t	285 PS/t
TW	272 Nm/t	325 Nm/t

Off the line, the SuperKa and SuperCinq are quite the opposite of these figures. The Ka accelerates very well through the lower three gears, whereas the SuperCinq gets bogged down below the peak torque level. Indeed, the SuperCinq only gets into its stride in third, fourth and fifth gear.

0-400	14·514 s	14·869 s
@ mph	95 mph	94 mph
0-1000	26·775 s	27·385 s
@ mph	119 mph	120 mph
Vmax	141 mph	150 mph

So the SuperKa is quicker off the line, but by the time the 400 metre mark arrives, both of these cars are going up into fourth gear. Once in fourth, the SuperCinq starts to out-accelerate the Ka. By the time the 1,000 metre marker arrives, the SuperCinq has slipped further behind, but is accelerating better than the Ka. It has a lot of catching up to do, but the SuperCinq has much better acceleration above around 110 mph compared with the Ka.

The SuperCinq has a full 9 mph top speed advantage over the SuperKa. On a long strait, this advantage can be significant.

Car Set Up

Before I study the suspension and brake settings, first a note about gear ratios. It is quite by chance that both the SuperKa and the SuperCinq have remarkably similar gear ratios, despite the big differences in the power delivery characteristics.

Gear Ratios (MPH / 1000 rpm)
First	6·21	6·31
Second	9·65	9·74
Third	13·82	13·91
Fourth	17·99	17·90
Fifth	22·39	22·44
Reverse	6·86	6·96

The Ka has slightly lower first, second and third gears. This, combined with much more useable low down heave, is what gives the Ka it’s immediate advantage off the line compared to the Cinquecento.

So why not use lower gearing for the Cinquecento? Good question! If we lower the gearing for the Cinquecento, we should get slightly better acceleration (and lets face it, it only needs to be slightly better to be quicker than the Ka). If we lower it too much, we get rampant wheelspin from rest, which is not a good thing.

Why have you lowered the SuperCinq’s fourth gear? Another good question to ask. Actually, I’ve not, I’ve raised fifth. This is primarily because I in most races that a sub-200 PS car will enter, acceleration up to around 120 mph is more important than top speed. It’s not often that the speed will creep up much above this level - it’s not often that these cars will use fifth gear. However, we want to retain their long legs for the few races where this will be used. In essence, it’s more useful to have a lower fourth gear.

Why don’t you lower the Ka’s gearing: it hits top speed at 6,300 rpm in fifth? Yes, it does. The ratios used in the SuperKa have been finely adjusted to make the most out of the engine’s power delivery. Although the 1·3 litre engine redlines at 6,700 rpm, and produces peak power at 6,600 rpm, the engine is getting past its best much over 6,000 rpm. By lowering the gearing, we actually reduce high speed acceleration and the top speed! If we reduce third gear, we will need fourth to complete the 0 - 400 dash (a Citroen Saxo VTR trick, I appreciate).