Gas Flowing

[jeffrosie]

Anybody tried diy/home gas flowing their heads. Basically smoothen the runners and remove cast marks. Should be a fair few horses in there. Maybe even increase compression??

[Ollieh17]

Polish exhaust ports, gasket match the runners and remove any cast marks.

[jeffrosie]

Yeah that's what I'm talking about. Use the vacuum cleaner on blow low pressure to see air flow with pingpong ball.

[AdamB]

Not worth it really, will likely just make it even worse. Stock heads flow rather well, all you'll be doing is shifting the powerband upwards of where the cams don't make any power and will have poor gas velocity at low valve lifts losing mid range punch as well.

[Mickey The Fish]

I tried this about 3 years ago when I just had mine N/A, AdamB is right if you mess with the intake it makes next to no difference on the dyno, it didn't even move the power band. However polishing the exhaust side of things (mirror polished) did give a slight increase in bhp (about 2bhp) and a smidge of torque. Once again the power band didn't move. If I can find them I may still have the dyno prints which I'll post if I have them. Please keep in mind I'm no expert like AdamB and the polishing was done at home with a cheap die grinder and a port and polish kit from Frost Auto Resteration off the internet. I removed minimal metal and measured all the ports were the same when I'd done by filling with silicone let it set, pulled it out and measured with digital verniers. To be honest a lot of work for not a lot of gain. I've just redone the same head but mirror polished both sides and knife edged the port splitters and put it back on my turbo'd N/A which I'm going to get mapped again soon to see how far I can take the 4efe with a turbo on it. If your just keeping N/A I honestly wouldn't bother because like I say a lot of work for not a great gain.

[jeffrosie]

Cheers guys. I'll take that as said then