Posted by DYezak (dyezak@riskmgt.tamu.edu) on June 02, 1998 at 10:34:30:

Could one of you please tell me how to determine the following for a custom sheet metal intake:
Correct plentium intake.
Correct runner length.
Correct runner cross section area.

Am I forgeting anything? Information about my engine/car:
2200lbs with driver and liquids
1.5L SOHC Mitsubishi
5sp
Custom intake, exhaust, and shifter.

After 5pm today these things will be added:
Advanced cam and timing and tighter valve lash.
 

Posted by NITRO on June 02, 1998 at 19:54:31:
In Reply to: TOO, NITRO...Sheet Metal Intake Questions posted by body on June 02, 1998 at 10:34:30:

All the things you're asking are good and answerable questions, but in order to provide correct answers, the rpm range from bottom to top is a necessity as is the throttle body diameter, and space limitations. The plenum volume is critical on N/A engines, and a basic rule of thumb is: The smaller the plenum, the lower the rpm range, and bigger means higher rpm. The throttle body size and flow rate also affect the plenum size: Bigger TB, smaller plenum, small TB, larger plenum.The runners work very much the same way. This is why you see so many sheet metal manifolds today in racing. Technology is moving so fast that tooling up and casting a manifold would be a really bad mistake, because, before you'd sell "any" the engines will want a different configuration, and you'd be out considerable money.
I need the info from above, and your cam specs/ comp. ratio, and intended use. The last thing you need to do is spend a shit load on a cool looking intake, and have the thing do nothing......except look good when the hood's open. Write back, we'll give you the specs.

Posted by DYezak on June 03, 1998 at 11:09:07:
In Reply to: Re: TOO, NITRO...Sheet Metal Intake Questions posted by body on June 02, 1998 at 19:54:31:

OK, I know how to, and can get everything you asked for except the cam specs...how do you go about getting those? It's a stock cam. And the RPM range...is that the range I want it to be most effective in? I want to bring the power band down as far as possible (is 5000 peak to low for a 4cyl)...so hear are my plans so far for achieving this: Advancing cam, Bore TB, Small Plentium (am I on the right track). My Comp Ratio is 9.0:1 (I'm going to bring it up with milled heads, probably 9.5, try for 10). I intend on using it in street/strip (60/40) and hood clearance is no prob...I work in a custom speed shop and we do custom hood scoops on v8's all the time (you should see my Studebaker (sp.)). I've raced large 8's mostly and this is my first 4...kinda fun to tinker with. I've never constructed a Sheet Metal intake before...but I have a coworker/friend who has. I'm not really shooting for the moon with this car. A juiced (40hp) mid 14 run down the 1/4 would have me grinning from ear to ear. I'm taking it next weekend to see what it runs now. I appreciate the help. (I'll have the TB size tomarrow...I'm away from my car)