View Full Version : Cylinder head porting on single

15-07-09, 15:09
Hey guys
Does anyone know how much a full port one polish costs and what sort of power gains can be expected on a big single from this.
Many thanks

15-07-09, 16:01
Price wise have a look on the Whifbitz site as Paul has all the stages priced up. Think the Stage 2 is arround the 1000 mark. Its hard to quatify what gains its made on mine as it was done as part of the engine build.

15-07-09, 16:07
Price wise i don't know, but as to whether you will see much gain will depend on how well the std head flows, and how good the porting is, you need before and after flow bench graphs to quantify the porters work, its easy to smooth out ports and head etc and say there you go that will give you another 20BHP;)

15-07-09, 16:13
I'd like to think for a grand I would see more than 20hp.
I'd be better off turning the boost up another.2bar LOL.

I did my own on the engine I have in mine but for my next project I'm considering getting it done by a machine shop/ engine builer

15-07-09, 17:12
I have done my own porting on some N/A engines in the past, and also had it done by professionals, and IMO unless you want to squeeze every last BHP out of a motor, its not worth it in real terms.
Most modern head design (last 15 years or so ) is pretty good, not like an old cross flow Ford which could pick up 15-20BHP from porting well.
IMO i think you would be lucky to see 20BHP from a flow job on the Supra head, but i'm sure there will those that say you can get more.

15-07-09, 18:13

Have a look at this. It's not worth doing the head unless you're building a 1000BHP monster and are taking competition seriously. Toyota did a great job on the head.