Boost ports - best arrangement

[olliewtf]

Hi all,

Marking up ring pegs for boost port cutting.

I have the option to either cut one large port between the pegs (easier to cut, more stress on ring)
or 2 ports (harder to cut, less area, more support)
or 2 ports, one inside ring pegs slightly over to one side, one with the ring peg running exactly in the middle of other peg (better as then boost would be more opposite the exh port, easier to cut as the space between ports is bigger, harder to cut to get the width and position of the port right for the ring peg support (for one of the boost ports)). This option would also see the inlet widen for the port to be properly fed.

Exotic option 3 could be 3 ports, but i think thats out of my depth.

One big thing is the gap between the pegs is not directly opposite the exh port. Though maybe Im left with a 'as good as' scenario.

I wouldnt say im great with the dremel (I have no fine handpieces for intricate work), so whats my best option considering i may stray 1mm too far and to gain best area / reliability considering previous point? cheers everyone!

ps. how wide can i go on inlet? 60%? ta

[olliewtf]

Having had another look and marking the pegs properly, ive gone for on single port between the pegs, 5mm either side.
Port will be approx 18mm wide, which should give pretty decent area all things considered.

For anyone interested I can update as i progress.

[fairspares]

yes please keep us updated and add some photos cheers.

[coaster]

I don't think you mentioned what cylinder you are working on? When I had a go at home porting a few years ago, I was working on a steel lined Indian Ally 225 barrel and cut a boost port around 20mm wide but managed to break through into daylight between the fins Fixed it by gluing in a small piece of ally using JB Weld which held up ok.

[olliewtf]

Yeah ive seen that thread aha. For that very reason Ive been very careful; Im about half way with cutting the boost port. Seems kinda hard to judge how deep to go, just plenty of stop, look, look again etc etc. I'd hate to break through.

I am working on a smallblock ally barrel. Going well so far! Will try and post pics when its a bit cleaner as right now it looks bloody embarrassing haha.