How do I improve my air intake and fuel system?

[dkerley03]

How do I improve my air intake and fuel system? Is it feasible to port and polish the E30 intake? This does not seem reasonable with the size and shape of the intake! Is it possible to replace the e30 intake with an intake off a newer BMW sixer? I know replacing the injectors with larger is a possibility, but would probably require more air flow. I know turbo charging is an option, but I would like to stay with normally aspirated and my factory engine and fine tune and improve its performance. Push it limits and see what can be achieved!

[jlevie]

Having the head ported and polished will make more difference than anything you can do to the intake manifold.

[lennon]

port the head and intake manifold and headers to match. dont polish. its pretty well accepted that a good porting with no polish is gonna be much better than one thats polished. it messes with the airflow and the fuel spray. you could go up 1 in valve size but i wouldnt bother with that. if you do all of this you might as well get a more aggressive cam too. and not to mention all the wear parts you should replace while you have the top end off.

[dkerley03]

Thank You for the advice.

I am planning and purchasing the parts I need to add am Eaton M90 Supercharger with an intercooler. I will also have my head ported and reworked at the time to improve performance. This will probably take six month or more collect and make all the parts.

[jeer]

yeah having the head off there is not too much room for bigger valves on the i head. you can but the cost vs gain there is minimal. best bet is to have the intake extrude honed then get the ports close to gasket matched even though you'll see that its pretty damn close to that from factory, then a more aggressive cam is almost a must to gain from the hard work and money put into doing all of this.

just my 2 cents from having the i head off a few times and looking at where i can improve using my die grinder :D

[jeer]

and let me know how that eaton m90 goes. i have one sitting on a bench at work that needs to be rebuilt and i was wondering about it vs turbo.

your personal input once its done would be great!

[sl0ride]

About the polishing, polish the exhaust with a fine flapper wheel. But leave the intake ports with 80 grit cartrige wheel finish. The exhanust you polish so carbon wont build up but you want roughness on the intake so fuel doesent pudde on a polished finish.

look up port and polish + bowl blend. Even if its a walk thru on chevy or ford heads the flow theories is still somewhat the same, dont mess up your short side or you ruin your heads. I would deffently have a junk pair of heads to practice on thou or just pay a pro. One slip with a carbide and your valve seats are gone