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Cylinder Head Work?


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hi there i have a standard 2.0 gte hatch and was wandering what kind of a bhp increase and sound does a ported head with a cam make?smile.gif

Depends on whats done,and this is usually controlled by how much you want to/ have available to spend.

A little porting work will increase flow, that is basically smoothing the sharp edges and rounding off the corners. Std valves can be replaced with raced spec type valves these will increase flow by a good chunk on their own, matched to a smoothed up head this increases quite dramatically.

Fitting the 45mm inlets, which means the valve throat/seat area has to be opened up. Fitting these will not see much of an increase unless the smoothing work has been done. If this is done correctly the heads will flow 100cfm with a valve lift of 400 thou (this is about the lift of the std cam).Std flow on a CIH 2.0 head is about 85 cfm, so you have an increase of 15% in the flow.

Different cams will give different power outputs obviously, BUT they also change the characteritics of the engine. Bigger durations will push the power band futher and further up the range.

A 214 kent will give you about 7bhp on a std head, a 234 will pick that up 16-18 bhp, a 244 could give you 25-30bhp but this is also dependant on the fuelling side of things. With a ported head and race valve you can get 15% ish more fuel in than a std head can so bigger bang.

Put your money into the head as this can reap rewards over just a cam. Remember that all the cams cost the same regardless of grind so you'll pay 300 plus for a 214, but you'll pay the same for a 244 which could give you another 23bhp for the same price. Don't be fooled into reshaping std valves as they are likely to make them weak, the result is the valve head snaps off = one dead engine.

Std injection will max out at 150bhp as this is all that the std injectors can supply fuel up to.

As a guide a 2.0 motor fitted with 234 kent cam, smoothed up head with std 45mm valves fitted, 40 dellortos, vernier timing gear, std pistons/bottom end, std exhaust manifold gave just shy of 160bhp(set up and measured on a rolling road)



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