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Porting & Polishing - Brera 2.2 JTS

I've just watched Wheeler Dealers doing up a Lotus Elise and the head was "ported and polished" to apparently improve the power the engine produces.

Now, I know that this program is really just entertainment but is there any beneifit in getting my 2.2 Brera's cylinder head treated this way, and if so, who offers this sort of service around the North London area??

I'm not looking for track performance but I always like to see what can be done with the standard engine without ruining reliability and mpg..
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There is a vast world of difference between a good and bad job!

A bad job can see you with less power, just because a company gets good results on say a VW head doesn't mean they will get good results on an alfa head, you need to make sure they have worked on and. Can prove results for your type of engine.

Ideally you want
T/b to inlet port matched
Inlet to head port matched
Head to exhaust port matched but so that the opening tapers slightly away from the head (smaller) to speed up the flow of gases.

Them you can get in to all sorts of extras like haveing the valve collers trimmed back etc.

You also need to look at things like gasket material between the t/b and inlet and head, these days it's common for them to be upgraded to ptfe as this has better thermal barrier protection and so cuts down heat transfer between parts, and in turn this reduces inlet temps and cooler temps etc better more powerful combustion.

Then you can look at the shape and design of the butterfly valves in the t/b , it's common practise and has being for many years to trim the spindle in half, fit counter sunk screw and machine a chamfer on to the leading edge of the plate.


Of course all this costs money although some can successfully be done at home, but couple it with a good cons air feed to the air filter a better less restrictive air filter in the standard housing and an exhaust should see you on the road to a few extra horses.
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also its usually best done when larger valves high lift cams and other things are taken into account..

porting and polishing is an art and unless done before on a certain head needs lots of time on a flow bench to work out what works on certain castings..

on its own it usually produces between 5 and 10% gains on average and costs between 300 and 500 quid..

but unless someone has previous experience of alfa heads the learning curve could cost loads and depending on the quality of the original castings provided minimal gains unless done with other modifications to improve the cars breathing
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What companies offer this sort of thing around the London area?
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I'd cam it too and then get a remap when you have the time/money.
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(Post Link) post #8 of 11 Old 03-02-14 Thread Starter
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I tried the two companies mentioned above but one said they couldn't do it and the other didn't get back to me.
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very odd.. will ask about and see if i can find a few more
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CFM Engineering Ltd

phoned a few others i use but most booked up for a while and nowhere near you..
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If you're serious about having headwork carried out, I'd suggest you watch this video;

NRE University. NRE Flow Bench. New X-Ram Manifold for LS Engines. NRE TV Episode 206. Tom Nelson - YouTube

If you're serious about having headwork carried out, I'd suggest you watch this video;

NRE University. NRE Flow Bench. New X-Ram Manifold for LS Engines. NRE TV Episode 206. Tom Nelson - YouTube

To be honest though, given the age of the engine, I would imagine there's little to be had in the way of gains from porting and polishing.

The intake trunking should be well matched to head and I'd hope that the valve seat angles are well optimised to produce a good spread of power. - by playing with them you'll probably end up sacrificing low end torque for high end power.

It'll also be tres expensive to do.

Last edited by Chris155; 10-02-14 at 16:13.
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