Rubbish as if you ask any mapper or head tuner they will tell you the significant gains to be had from porting a head. A fully forged engine with 3 angle valve seats and 264 cams went to be mapped with a GT30 turbo and produced 452 BHP at 1.7 Bar and 448 lb torque... the same engine had the head ported and skimmed and then went back to the rollers and produced 467 BHP with 492 lb Torque. Any 2.3 Stroker needs porting done to expel the gases faster from the head. It all depends on your turbo and spool. A stock turbo and head will benfit nothing from porting for the price of porting a head.
Does Cylinder Head Porting Contribute to Better Performance on a Trubo Charged Engine?
Which will fill a 5 gallon container the fastest?
A: A one inch water pipe at a pressure of 15 PSI, with a 1/2" restrictor at the outlet.
or
B: A one inch water pipe at a pressure of 15 PSI, with a 3/4" restrictor at the outlet.
If your answer is “A “you should not be giving nor have an opinion on porting cylinder heads on turbo charged engines.
If your answer is “B “then you will understand that all turbo charged engine will benefit drastically if cylinder head porting is done correctly.
Cylinder Head Porting or Port and Polish is the art form of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. Cylinder heads, as manufactured are not optimal due to design and manufacturing constraints. Porting the heads provides the finely detailed attention required to bring the engine to the highest level of efficiency by an increase in volumetric efficiency. More than any other single factor, porting technology is responsible for the high power output of modern engines.
This flow porting process can be applied to a race engine to optimize its power output as well as to a production engine to enhance its power output for daily use or to alter its power output characteristics to suit a particular application or to turn it into a racing engine.
Daily human experience with air gives the impression that air is light and nearly non-existent as we move slowly through it. An engine running at high speed experiences a totally different substance. In that context, air can be thought of as thick, sticky, elastic, gooey and heavy. Pumping it is a major problem for engines running at speed. Flow porting helps engines deal with this problem.
More boost equates to more induction heat and induction heat can equate to a multitude of problems therefore it should be the engine tuner or engine builder's main aim to make the highest level of horse power at the lowest level of boost.
