Outer Limits 4x4 Board

Since the heads gone on the zook thinking of getting this done.

Anyone done it and what gains did it yield.

Also anyone else post up any mods that can be done to the sierra heads once there off.

I believe 1.6 exhaust valves fit in but what does this do for the head.

cheers

http://www.suzisport.au.com have swirl polished stainless 0.5 mm oversize valves

280 or so but

bump

someone must know.

cheers

I'm pulling mine off (hopefully) to give it a bit of work soon, I'll keep you posted on whatever I find or end up doing.

nicbeer wrote:bump

someone must know.

cheers

They imporve response in the motor especially noticable in low RPM, the smaller inlet keeps air speed quite high making for better atomisation of the air fuel mixture, so you get a good burn (There for good power) and the larger exhaust valve (if you have a better breating exhaust ) allows for better scavanging of the exhaust gasses from the combustion chamber..
This means that there is more room for air/fuel instead of burned gas's so you get a bit more bang per cycle.

This is most effective if there is a proper valve job and the area above the valve is properly blended allowing good flow..
While your at it, they can do some cool stuff with cams as well to allow a bit better mid range and top end without sacrificing bottom end torque.

i got a price sum time ago to port and polish and flow the head for max power for around the $400 mark so dont expect to get out of it cheaply.

Whered ya get the quote from bazooked.

cheers

high flow induction, dont no if they r still around.