Grizzly

I just want to make sure i've done my porting right before i bolt it all together?

Ok i'll start with the Primary ports, i have opened them up to the same size and shape as the stock secondrys on a Fc. As for the runners all i have done is smoothed them out maybe 1-2mm bigger (I duno if this is big enough?).

The secondrys are quite alot diffrent from the stock Fc's. I've used Cosmo Re plates extended the port its self about 5mm and have made a smallish bridge that i've cut at about 45% to the plate so there is a good amount of metal left in the Bridge (and they are about 7mm wide). I've also cut out the housing for clearance for the extra port. The Runner have been opened out but i've not gone to big, I have tryed to do it this way to try to keep the air speed up at low revs?

The Exhaust is the next one that i spent alot of time cuting out, i'll be fitting stock 2mm Mazda Tips so i've left the Primary side of the Exhaust Port and made the other side about 10mm wider, to keep the over lap down i've left the top edge and moved the lower edge down about 10mm, then trumpeted the Port to the SS Runner (which also got opened up a bit).

I have matched all the manifolds and everything has been finished in 80's grit cones (quite smooth).

I hope i will get into the 500bhp band with the right Turbo, Does all this sound ok? or do i need to open the Runners some more?

Thanks......Chris

Grizzly

No one?

RETed

A picture is worth a thousand words...

I basically just cut "upwards" on the intake port.&nbsp Downwards creates more overlap - something I don't like doing.&nbsp You cannot go "in" towards the center, as this goes into the oil control ring area - porting into here will cause a lot of oil smoking due to excessive blow-by.&nbsp Porting "back" is something most port templates will do...about 2-3mm.&nbsp I just got through porting a Kouki turbo engine and happened to measure the corner seal area in relation to the port - there really isn't any space to port!&nbsp I'm going to stop porting back from no one, as this just stresses the corner seal unnecessarily - all this does is add overlap anyways; with a bridge port, you create huge amounts of overlap anyways.

Watch out with 13BT irons, as you cannot port "straight down" on the "upwards" side.&nbsp The water jacket is VERY thin in this area and will not tolerate lots of metal removal.&nbsp Check out the Mazdatrix site for some really good pic on this!

http://www.mazdatrix.com/faq/cutaways.htm


-Ted

qwck10th

These pics might help some. They were done using RacingBeat's bridge template.
s

RETed

Ouch!&nbsp Try and see if you can get that housing welded!


-Ted

tims

fill it with epoxy and make it a peripheral port. easier to port and makes more power. my own engine builder will charge double the money for a bridge compared to a PP, plus PP water seals will last much longer. for a turbo application porting seems to be a debateable issue. I have done it and not done it and results with the same turbo and intercooler were basicly the same. want 500HP match turbo and intercooler and tune engine properly and this should not be a problem porting or not.

HWO

port the back of the primary intake ports to have the same opening timing as the secondary ports. You can go back about 3mm on the primaries to match it up, just make a template of the secondary port's back edge and overlay it onto the centre plate's primary ports