Same capacity, different power - how?

fricatus

Just looking at the thread about the Seat Exeo, one of the posters listed the model variants that will be available, including the following:

2L diesel - 140
2L diesel - 170

(the latter figure presumably being BHP or PS)

I've seen this sort of thing for plenty of other cars too. From an engineering perspective though, how is the extra BHP obtained when the number of CCs is the same?

My understanding was always bigger engine = more power. I'm sure the insurance industry works on the same premise, charging you more on a 2 litre than on a 1.4 for example.

How does all this work?

Anan1

In a word, tuning. It can be either electronic (higher boost, different fuelling etc), or mechanical (ie bigger valves, different camshaft(s), higher compression ratio etc). Or indeed both.

Zube

Anan1 wrote: »

In a word, tuning. It can be either electronic (higher boost, different fuelling etc), or mechanical (ie bigger valves, different camshaft(s), higher compression ratio etc). Or indeed both.

...and tuning comes down to fuel. More fuel efficiently burnt, more power out.

Cookie_Monster

The increased power will have to be "offset" in some way however...

You can trade power for torque or more usually higher emmisions. The above 170 (BHP) has more torque and power iirc than the 140 but produces more rubbish out the back end

Pique

or bigger/more turbos

fricatus

Anan1 wrote: »

In a word, tuning. It can be either electronic (higher boost, different fuelling etc), or mechanical (ie bigger valves, different camshaft(s), higher compression ratio etc). Or indeed both.

The higher-powered engine would normally be more expensive though. Is this just a marketing thing (squeeze more money out for the same materials), or does the expense derive from a real increase in costs (e.g. engine needing to be built stronger for the higher compression ratio)?

Stevie Dakota

It's a money spinner for car makers. In the old days you made different cc engines to get more power which was costly. Now a simple remap on the one engine and you can charge on a sliding scale.

Pique

Stevie Dakota wrote: »

It's a money spinner for car makers. In the old days you made different cc engines to get more power which was costly. Now a simple remap on the one engine and you can charge on a sliding scale.

Wasn't that the case with the first Mini ONE ? Getting it chipped put out the same bhp as the Cooper, for a fraction of the price...

Anan1

fricatus wrote: »

The higher-powered engine would normally be more expensive though. Is this just a marketing thing (squeeze more money out for the same materials), or does the expense derive from a real increase in costs (e.g. engine needing to be built stronger for the higher compression ratio)?

Barrion certain low-volume, high-performance engines, it's just a marketing thing. I used to sell VW for a main dealer when the Mk4 Golf came out - the 1.4 cost more to build than the 1.6 (the 1.4 had a 16v head, whereas the 1.6 didn't), but the 1.6, being more powerful, cost more to buy.