Tuning tips: Port matching an engine

[obi_waynne]

The ports on the engine allow the air into the engine and the exhaust gases out. There are typically 2 per cylinder, an inlet and an exhaust. The inlets or ports are joined to the manifold or headers via a gasket. Whenever you get a join between two surfaces there is typically a step or [...]
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What do you think of this tip then, read the article and post your comments in here.

 

[picassoonwheels]

Well IMO, this article is pretty basic and though it would give an insight on air-flow to beginner DIY enthusiasts, and novices, it may, or may not help them in practicality, since, most probably, either they would not be deft or mechanically inclined enuf to do it, or if the do attempt it, chances are, they would right mess up the job, and would then require professional help, (in both issues pun intended).

There could be exceptions though, who manage to get it right on the first attempt.

Those who would be capable of doing this, would already know about it. It reads like some of the Car Mechanics article I used to read when I was 7, and started spending time in a garage owned by my friends dad.

Sorry, a bit rude, but hey, you asked for my opinion now. didn't you..?

 

[obi_waynne]

That is great. What would you add or like to see included in the article?

 

[HDi fun]

Port design is a black art in my opinion. Sometimes what initially appears to be an obstruction can actually be a designed in feature to increase turbulence or swirl as air/fuel mix (plain air in the case of derv engines or direct injection petrol engines) is drawn into the combustion chamber.

But in general polishing of ports is a good thing. Clearly an engine that's been crudely built in the first place will benefit more than one which has been designed with outright efficiency and performance as a primary goal. I can't imagine there being much point in playing about with the heads and manifolds on a V10 BMW M5.

 

[obi_waynne]

I was amazed when I discovered that a narrower port can actually under some circumstances flow better than a wider one!

 

[pgarner]

what causes that? increased in the airflow speed

 

[HDi fun]

what causes that? increased in the airflow speed

Basically yes.

It's also about creating turbulence and 'swirl' so that fuel is well mixed and distributed in the combustion chamber charge before ignition.

The same applies to dervs except that the fuel is thrown in as the piston approaches TDC.