Why can't you get performance cams for diesels?


Staff member
Deal, Kent UK
A3 1.4 TFSI 150 COD
They are not tuned as much as petrol engines so there is less of a market for them but there are also technical reasons why you can't get diesel performance cams.

Diesel engines are quite low revving, so a performance cam will not provide as much lift as it would on a petrol.

On petrol engines the gains tend to come in at 4000-8000 rpm, and most diesel engines just don't hit this level or are just about to redline.

The principles behind a compression ignition engine, as apposed to a spark ignition engine are very different when it comes to tuning them, so things that work well on a petrol do not always work on a diesel.

Interestingly a remap on a diesel nearly always gives better fuel economy, whereas on a petrol engine this is very unlikely to happen.

That's not to say there is no benefit from a slightly longer intake/exhaust duration, but most performance diesel engines out there are designed to a pretty high standard.