The XUD Conversion

Summary

Peugeot’s excellent little XUD engine has been manufactured in either the earlier 1·4 litre or the later (improved) 1·5 litre capacities. The 1·4 XUD first saw service in the Citroën AX and produces 53 PS and 62 lbsft of torque (84 Nm). The later 1·5 litre engine produces 58 PS and 70 lbsft (95 Nm) of torque.

Either engine would suffice although the later 1·5 would offer better performance.

Performance & Economy

The 1·4 XUD is capable of truly impressive fuel consumption and the later Citroën AX 1·4 litre diesel has a combined cycle fuel consumption figure greater than all current modern direct injection diesel cars. However, the Ka is some 200 kg heavier than the Citroën AX so it would not perform anywhere near as well.

By studying similar cars with a similar power to weight ratio, I estimate that the Ka XUD models would have the following performance:

Engine	Maximum Speed	0 – 62 mph	Power to Weight
Endura-E	96 mph	13·7 seconds	63 PS / Ton
1·4 XUD	89 mph	18·3 seconds	58 PS / Ton
1·5 XUD	96 mph	16·5 seconds	62 PS / Ton

These acceleration times reflect the diesel’s typically tardy launching characteristics.

As far as economy goes, it’s reasonable to expect the 1·5 litre to be slightly less economical than the 1·4 under most conditions.

The 1·5 Ka XUD should be comparable to the Citroën Saxo in many respects, both being about the same weight (the Ka slightly heavier). I’d not expect the XUD Ka to be quite as economical as the Saxo, so I’m working with a combined cycle figure of 52 mpg for the Ka (versus 53 mpg for the Saxo).

For the 1·4 XUD, well it’s hard to determine what it could be. For the time being I’ve plumbed for a combined cycle average of 56 mpg.

Weight

The XUD is a notably light diesel engine although the 1·5 litre models are typically approximately 20 kg heavier than their 1 predecessors. Even so, the Endura-E isn’t the lightest of engine designs – the Ka should only be slightly heavier with the XUD onboard rather than the Endura-E.

Suspension & Braking

With less linear performance available and comparable kerb weight, there is no need to uprate the suspension or braking systems.

Servicing

Some XUD powered small Peugeots have notoriously difficult service items and that’s not likely to change if in situ in the Ka.

Cooling

Diesel engines can produce a lot of heat and one of the weaknesses of the 1·4 XUD is a headgasket that is more prone to going if the engine overheats. The installation of the 1·5 in the Peugeot 106, certainly, has an improved cooling system. Nevertheless, with the right sized radiator (perhaps the standard Ka item) I don’t envisage cooling being a major problem – certainly not in the same way as it might be with the newer TDCi unit.

Example Fuel Costs

Engine	MPG	Fuel Cost 10,000 Miles
Endura-E	42 mpg	£897
1·4 XUD	56 mpg	£673
1·5 XUD	52 mpg	£724

The above table makes the assumption that both petrol and diesel cost 82·9 pence per litre.

If the capital outlay for the conversion is £2,500, we will make up the difference over 111,500 miles for the 1·4 XUD and 145,000 miles for the 1·5 XUD. Ouch!