View Full Version : S13 SR20 Head porting questions

06-18-2005, 08:00 PM

T3/T67, .82 A/R Hotside, Stage3 wheel
Custom or Greddy intake mani
Tubular, equal length exhaust mani
Autronic SM2, 1000cc injectors, etc
86.5mm, 9.0:1 compression
HKS 272 cams, 8500-9000rpm shift point

What kind of porting needs to be done to SR20 heads to get them to flow for about 550-650whp, on the turbo alone? We have had several MR2 and DSM heads ported with excellent results, but this will be our first SR20 head. Are oversized valves recommended for this kind of power? At the very minimum I'm going to have the ports cleaned up and balanced, along with the valve throat divided knife edged. Similar work for the exhaust, and the combustion chamber polished.

Any thoughts, help, ideas?


06-19-2005, 02:40 PM
if you are spinnning to 9K you better be going solid lifter or you will be breaking rocker arms. Talk to hugh and enthalpy, both have shattered rocker arms before. Over 8K is just not safe with the hydraulic setup. At the very least you will need 0.5mm oversized on the intake with alot of port shape work. remember that you will need all new guides if you want to run bigger exhaust valves too. search FA for a post on which valve guides are needed to run oversized exhaust valves. The guide are from a toyota i believe. I would also clover leaf the combustion chambers.

Remember this though, plenty of people have made 550-600whp on a stock head with no porting. Enjuku,enthalpy, Glen, and i made 530whp on 24psi with a consertive tune and smaller turbo than you. All stock heads

06-19-2005, 03:21 PM
I will definitely be going solid lifter. I'm not necessarily going to be spinning to 9k, but probably at least 8500rpm. If that kind of power is being made with stock head porting, I'll probably just get the casting cleaned up and balanced. Thanks for the info.