Budget 12A SP build

NoDOHC · 12-21-2010, 12:01 AM

Those pictures reminded me, you have to keep the rotors separate on a 12A (they are different). I had forgotten that.

Let me put the porting to you this way, you can always take more out later. You can't easily add it back. Small porting is your friend.

Intake port cross section should not exceed cross section of intake runner feeding it.

Later close is only better if it greatly improves flow, don't dig a corner upwards just to match the majority of porting templates on the market today. I prefer the port to follow the shape of the rotor (quicker close = optimum dynamic charging, maximum port area without expense of compression displacement).

Exhaust port should increase in cross-sectional area.

12-21-2010, 12:01 AM	#12
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 18	Those pictures reminded me, you have to keep the rotors separate on a 12A (they are different). I had forgotten that. Let me put the porting to you this way, you can always take more out later. You can't easily add it back. Small porting is your friend. Intake port cross section should not exceed cross section of intake runner feeding it. Later close is only better if it greatly improves flow, don't dig a corner upwards just to match the majority of porting templates on the market today. I prefer the port to follow the shape of the rotor (quicker close = optimum dynamic charging, maximum port area without expense of compression displacement). Exhaust port should increase in cross-sectional area. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)