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I drive BMW X5 Diesel Power and Mazda RX-8 2jz 4wd robot trans
My former car - Toyota Mark II Gangsta...
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Deep Head improving

On this installment, we will peek into the inner reaches of modified cylinder heads to find out just what is involved in modifying one. There is a lot of work to be done and many choices you can make. Part four of our series is intended to help you understand some of the more common tricks so you can make the appropriate decisions when it comes to modifying your head for maximum power.


Achieving good airflow through the cylinder head is essential for creating big horsepower. How does increasing airflow get you more power? To start, an engine is basically an air pump. To create the most power possible, it is important to get the maximum amount of fresh air into and burnt exhaust out of the engine with the least amount of mechanical effort. Excess intake and exhaust port restriction makes more work for the engine--work that is not used to turn the wheels. This extra work is called pumping loss.

Port work on most modern, high-output engines is usually limited to detail work, but this

Imagine sucking a thick milkshake through a small straw. This takes a lot of sucking effort on your part. Now drink that same milkshake through a larger straw; it's easier isn't it? The extra effort you are expending to drink that milkshake through the smaller straw is a pumping loss. The more work it takes to get the various gases into and out of your engine, the less power will be available to spin the crank and the wheels.

Another major factor is volumetric efficiency. Volumetric efficiency is the percent of an engine's displacement that is filled on each intake stroke. To make things easy to understand, let's imagine that you have an engine that displaces 1000 cc. If the engine can take in 800 cc of air on the intake stroke, the engine has 80-percent volumetric efficiency. Eighty-percent volumetric efficiency is typical for a modern, production-based, naturally aspirated engine.
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Posted 20 December 2010
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Zayac 4 years ago
Jonathan Shelby, 32 years old
I drive Toyota Sprinter Trueno Drag car
Sydney, my city

will think about porting of my F20B head!
thx!

Posted 08 January 2013 at 10:56
Napster 3 years, 12 months ago
napster smith, 35 years old
I drive Ferrari 458 Italia red devil
Sydney, freedom!

Some times less___))))

Posted 29 December 2012 at 04:26
Petrovich 4 years, 2 months ago
Peter Clarkson, 31 years old
I drive Toyota Supra lovely!
Sydney, speedlimits

This is the way to get 10% extra power

Posted 06 September 2012 at 07:40