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[BazaJT]

Only asking out of curiosity/interest.Watched the lastest Wheeler Dealers tonight,they did a Lotus Elise.The head was taken to an engineering company for polishing,porting and skimming which apparently upped BHP from 118 to 150ish.Now I'm sure I've read somewhere that having this work done you should also slightly tweak the inlet/exhaust manifold gaskets to match,also possibly the manifolds themselves,does anyone know if this is correct as no mention was made of such in the programme?Also in going that far would it not also have been as well to change at least the exhaust manifold if not the whole exhaust for better extraction or is the standard Elise manifold up to the task?As said just curious.

[henryd]

You often see stuff like that on wheeler dealer,they don't list everything done as they would look out of pocket at the end sale,wouldn't make good telly would it?

[albitz]

I watched that too. A load of crap imo. He put it on a flow bench after opening the ports out (1mm iirc ?)which apparently told him the bhp had gone up from 120 to 150.

[BazaJT]

Yes it was something along those lines,I must admit I didn't know it could be done in that way,I thought you'd have to rolling road it-but then I'm no engineer so what do I know?

[albitz]

Im no engineer either,but Im pretty certain that you cant (accurately) do it that way.

[Marks DTM Calib]

Utter bull.

If a gas flowed head could yield that sort of gains then it was a bloody terrible head in the first place!

The Rover V8 has one of the worst head desgns going and even that does not see improvements of that scale and it has twice the cylinder count.

When porting you go through a number of steps, the usual is to open adn smooth the inlets as much as possible and check the flow rates with a flow meter rig. Once done you would then need to match the inlet to your modified cylidner head (plus gasket potentialy) to ensure there is no steps in the system.

You can do similar on the exhaut although the gains are much less.

You certainly cant work out the bhp from the flowbench result, there are WAY more factors in the equation than that!

[Kevin Wood]

Yes, assuming it's a 1.8 K series you need to do quite a bit of work to up the 118BHP variant to 150... like change most of the induction system and the cams for a start. Guessing if they'd included that work it would have showed them making a loss.