Custom 5SFE Intake Manifold Project Options

[doory100]

Got this off a 97 3sfe rav4. I'm going to customize a intake manifold body for it at my work(custom sheet metal shop). this is the starting process should look close to a beams intake when in done. Ill be using 0.100" 5052 aluminum for the body with a machined 0.250" T6 aluminum flange. I will most likely make 2 when i take the intake form my 95 GT off. So I'll have one for sale then. Any thoughts??

This post has been edited by doory100: Oct 6, 2014 - 7:40 PM

[Bitter]

Yes, so no sense just hacking some stuff together and spending all the time to make it and get it leak free to find out you screwed up the plenum volume or runner length or both and have actually lost power. The stock 5S runners are very narrow, I know it's a pain but see about getting some mandrel bent aluminum tube or something and making fatter runners, ideally you want them to taper to the cylinders to compress the air column some so it 'pops' into the chamber when the valve opens and has a good turbulence and swirl to mix the A/F thoroughly for complete combustion and knock resistance.




Funny thing is, I don't even do this stuff or build this stuff, I've just learned this reading way too much and researching about things that interest me. If you do this right you can bolt on some nice gains with the rest of the porting and cams and see some good flow numbers. Remember to leave about a 1mm anti reversion lip on the bottom of the exhaust ports.

Anti-reversion Headers

In our page on cylinder head porting, Henry (aka Double H) explains that the primary pipes in the exhaust manifold should at match the exhaust port diameter on the cylinder head; but to reduce reversion, a primary pipe that is slightly larger than the exhaust port is better. Reversion is the flow of exhaust gasses back into the combustion chamber when the downward movement of the piston creates a vacuum in the cylinder. As we mentioned in engine tuning basics, the exhaust valves are still open when the intake stroke begins. This presents the potential for exhaust gasses to be drawn back into the combustion chamber when the piston moves down the cylinder. Any exhaust gases that are drawn into the combustion chamber will displace the air/fuel mixture being drawn in through the intakes valves and will increase the temperature in the combustion chamber, thus reducing the volumetric efficiency of the engine, as well as engine power. Preventing reversion will reduce the contamination of the air/fuel mixture by the spent exhaust gasses and will improve the efficiency of the engine. An anti-reversion header or AR header that is specifically designed to inhibit reversion would be your best choice. Anti-reversion headers have a built-in lip that restricts exhaust gas flow back into the combustion chamber.

http://www.custom-car.us/exhaust/header.aspx quick dirty explanation of things.