Thread: Blox intake velocity stacks?

i prefer to vaseline on my flow stack

Thats what she said!

Let me provide some clarification and some back ground. First polishing is typically performed downstream of fuel injection. This is to prevent any "micro" hot spots that could cause pre-ignition. Upstream a head porter will typically leave a "rough" ported surface finish (ie. 220grit, varies in the industry) to improve flow rates. BPi flows stacks are intentionally surfaced finished for the very purpose of improving flow rates and preventing boundary layout seperation. As for Blox, I do not know what their copying, innovation killing selves did.

The "rough" surface keeps the boundary layer height small and "high-energy" so that is less likely to seperate.

So that said, polishing the BPI Flow Stack will yield negative consequences. Not very significant, but a step in the wrong direction.

Interesting. What I've read about port and polishing is, you want to do it up to injectors, after that you want to leave it rough otherwise fuel might puddle.


Welcome to the SE-R club nice looking lemon . Also fixed your first signature link (it led to an unknown page "http://www.bpinitiatives.com/site/24hrlemonade/").

Hind sight, I should have not brought up headwork. That is a "black art" and everyone has there own theories, techniques and practices.

Basically the the textured surface is analogous to dimples on a golf ball.

Yeah head porting/polishing is one of those items that everyone has their own opinion. Would be nice to see actual airflow data on different porting styles .

Though I can't say I understand how the grooves help at the intake level. I'm tempted to get a Blox intake now and dyno side by side .