Supercharging a Diesel

[Ferrer]

Really? In the Mini One D (Toyota-sourced 1.4 turbo diesel with a BMW 6-speed manual 'box) and the new Cooper D (same 1.6 common rail diesel as my car but again with a BMW 6-speed 'box), you can select 1st anywhere below about 10mph with zero reluctance. They're brilliant gearboxes and I wish I had one in my car.

In fact, I had a test drive in a C4 diesel with the EGS paddleshift gearbox and it was much better to use in everyday driving than my manual. I think auto/DSG style gearboxes suit modern diesels better anyway - the good ones use electronic trickery to keep the engine revs where they need to be - there was no issue with lag in the DSG or VAG 'boxes I sampled.

Oh no, you can do it just that car jerks about and it's almost impossible to do it smoothly. Not that you need to anyway since most of the times you could start in second or sometimes even in third easily.

BMW gearboxes are good, but work better as you increase speed. The Lancia's is the complete opposite, works well at moderate speeds but it protests as you up the ante (as most of the bits and pieces of the car actually, but that's another story).

As for autos, DSG and the likes, yes they are comfy but as for performance you can achieve the same effect if you work a manual gearbox. In ym opinion it all depends on preference and for me it's clear which one I prefer.

[LeonOfTheDead]

I've driven my friends '99 Ibiza 1.9TDi (I think it's a 90bhp unit) and it picks its self up really well, still at 150,000mi. It definately feels alot more brisk than my car and there is a noticeable shove in any gear when floored, something that's not always felt in my car, it will also pull itself up big hills in 4th where my car would need a little bit of a run up in 3rd. The engine is very rough, noisey and wobbles the car though

being a 10 years old car helps a lot. Lighter, and a less controlling engine's electronic.

[walterGT67]

turbo diesels are much more effiecient. its easier to use a diesels exhaust as opposed to its crankshaft. also diesel's don't have high rpms to spool the supercharger fast

Ya diesel can make much more power w/ FI

[CapnBoost]

Positive displacement superchargers are driven from the crank. If you wanted to deliver the kinds of boost pressures offered by turbochargers (as has been noted in the 20psi+ region) you would have to gear the supercharger such that it would be such a parasitic draw as to be useless.

I can't seem to find it now, but I recall a show saying that the supercharger on the SLR Mclaren is responsible for about 200hp worth of parasitic draw. (It more than makes up for it in boost, of course)