who knows stuff about spark plugs and turbos?

In news:4662a815$0$19249$ snipped-for-privacy@news.zen.co.uk, Doki wittered on forthwith;

Put it this way, my the bill for blueprinting the Rangie engine was >£4k, not including the low compression turbo pistons which were matched when the engine was first built.

It's an economic necessity, over the last decade the cost of mass production to these high tolerance levels has dropped dramatically in the same time the requirements for improved engine efficiency has increased equally dramatically. By manufacturing to tight tolerances it's possible to design in better BSFC companies that fail to invest in the improved tooling have consistently by the wayside. You could put the same argument towards manufacturing HDTVs why add the extra cost to a plasma of a HD decoder when

80% of Europe's HDTV owners don't have a HD source so they will not notice if it's not there. The average owner may not notice the closer tolerances but they do notice the effect that has.

They'll make themselves think they notice. You have to be sat rather close to an HD set for your eye to be able to resolve the higher resolution.

That is simply not correct. Specific engine output (HP/l) has increased but marginally since 1990. There are even quite some manufacturers where it has gone down.

We are talking here about NORMALLY ASPIRATED engines, not turbo'd or supercharged engines. Blueprinting on a turbood engine is rarely done and ever rarer for powergains. If more power is needed, the boost is upped.

There are but very very few NA-engines available off the shelve today who break the 100 HP/liter-marker. In bike-engine however the 200 HP/l- barrier is smashed.

You are evading the topic: blueprinting on ANY engine is possible and yields substancial bonusses in power and reliability.

The reason is that by blueprinting and attention to detail far beyond mass production, an engine will during its lifespan encounter less friction, perfectly sealing valves, a sutle modified valvetrain which allows higher top RPM, valve area optimized on the outside diameter, be balanced as good as possible and have a far better volumetric efficiency due to gas flowed channels.

If all parameters are optimised - I wrote a paper on that for the 2CV engine around 20 years back and there were some 50 points to be taken into account- power output can jump 50% to double on basicly the same engine. We had an student-engineer here who as part of his final year did the same for a newer high performance engine. It was no Toyota-egine but a Porsche 928 engine. His conclusions to the gains backed up by actually doing and measuring it, were almost indentical as on the "very modern" 2cv-engine.

Not all blueprinting is power related: very often -and personally found on Britisch and German high performance engines- cooling ducts and channels are partially blocked with excess material, not removed after casting. All engines and inlet lastings have areas not touched after casting. Those rough areas cause drag, obstruct smooth passage etc. That's also an area of major attention.

Just to make an extra point: most manufacturers sell the same engine in different countries but that very same engine makes less or more power depending on the countrie it is sold in. Very often this is done for fiscal or insurance reasons.

A compagnie who is asked to blueprint such an engine will find in no time what has been done to it in order to reduced power and free the "hidden" horses. It can be as simple as removing a holed plate in the inlet or exhaust path or as in case with some downtuned motorbike- engines modifying the carbs so that they can fully open. It is not always (even today) an electronic question.

Tom De Moor