I had a pint or three with a neighbour last evening who recently retired from his job as a development engineer for a UK motor manufacturer.
I was asking him why so many bugs find their way into the new cars after the extensive testing programme they carry out to engineer and develop a new model. He explained that very early in the development cycle the company will set a final launch date for a new model - possibly 12 to 18 months ahead. During the ongoing test programme various bugs will be found, a solution proposed and the required amendment channeled through the design, development, production engineering and tooling departments. More often than not this cycle will be repeated several times before an optimum solution is agreed. This process can take many months - even for a simple change.
Postponing a set launch date is a frightfully expensive business and for financial and marketing reasons cars are often launched onto the market with known problems - for which a solution is in the pipe-line - that will have to be resolved by the dealers when the fix becomes available.
He also chatted at length about how cars are prepared for motoring press road tests and for the government economy tests. I can't remember all that he said but a few points stick in my mind like :-
Fitting an "optimised" water pump, oil pump and alternator that use less power but are man enough for the planned tests.
A total engine, fuel system and power train re-build using finely tolerance matched components. This includes the optimal tensioning/setting of belts, chains and valve gear.
A very carefully mapped ECU - it is nothing for them to spend a couple of months on this aspect alone
Minimising oil levels to avoid churning power loss.
Careful choice of wheel bearings and drive shafts to minimise NHV (noise harshness and vibration)
Having the tyres ground on the wheel to achieve a perfectly circular tread - this reduces rolling resistance and NHV
Ensuring that all the components underneath the car are fitted such that the best aerodynamic condition is achieved - they are not modified - but he said that the exhaust system, aero panels and pipe runs under the car are "optimised".
I suppose that we should not be surprised by all this - after all - it's a competitive business.
