Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
Indeed. Unless it's a turbo where you can simply wind up the boost,
it's extremely expensive to get a meaningful power increase on most
modern engines.

Oh, no rechipping will net you lots..at the expense of dire fuel economy
usually.

Not on any decent car, it won't. Only those where there are identical
engines of differing power outputs where the power is set by the
electronics - and these are usually diesels.

Especially if there is a turbo you can screw the waste gate
down on

That's what I said above. Although you might well shorten the service life
of the engine.


Oh definitely...

I think the point I meant to make is that a commercial engine is
optimised for other things than raw power..flexibility, ease of
starting, fuel economy, emissions, noise and pure packaging concerns as
well as long service life may all be compromised by trying to 'extract
the max'

With fuel injection, you HAVE to remap if you start playing around with
alteration to the exhaust, valve timing and inlet tracts.

There is at least one installation - forget which one, which is 5bhp
down on an identical engine fitted to another model. The difference
purely being in the packaging of the exhaust manifold and pipework.

Every tuner knows that if you slap a nice trumpet without (much) air
filters on an engine, and put an optimised and really noisy exhaust on
it, shove in a high overlap cam, and dump as much fuel into it as
possible, a normal car engine can develop about twice the power, at the
expense of appalling idling, appalling noise, appalling fuel economy,
and a very short but colorful life.

If you also skim the head, and shove 5 star in it, it gets even better. :-)

I suppose your point, that there are no appallingly BAD installations
these days that can be EASILY upgraded by SIMPLE changes is also valid.

stuffing 5 star in, being the case in point.