[quote name='BDC' date='May 6 2005, 06:30 PM']

It does not take into account the position, angle, shape, movement, speed, or anything else of the engine rotor, it has no knowledge of overlap, and knows nothing at all about combustion chamber shape, compression and exhaust stroke degrees, and the like.



A part of me says that there's no improvement on ramping the closing edge. After all, the charge entering the runner may have to make two turns now instead of just one as it transitions from the runner to the outlet. I've seen no actual, proven improvement on it. I believe the only real reason people harp on it now is because of the info Judge Ito brought up dealing with side seal integrity when taking iron out of the short radius all around of the port outlet. I know it's a common staple for people who "port" to hog out the closing edge in that manner, but does this really yield more power? I am not convinced at all. I think more power is yielded out of earlier opening (among other things); not later closing.



1Revvin man, I think what you've got will work. Keep the port outlets the way they are.



B


[/quote]





for the first part, all other things set aside, air flows better across a radius.



i'm not talking about the type of ramping to soften the edge for an unsupported side seal, i'm talking about giving the closing edge a radius. the purpose isn't to extend the port timing, but to get rid of the sharp edge.

if you look at the renisis port timing, it closes about the same but opens eariler, the side exhaust lets em do it without having "too much" overlap

^ zero overlap.



but the renesis has its own demons. side exhaust is really restrictive and beats up on the side seals. i'm looking into dinding a company that will coat the side seals with something for more durability.

[quote name='guitarjunkie28' date='May 7 2005, 11:03 AM']

but the renesis has its own demons. side exhaust is really restrictive and beats up on the side seals. i'm looking into dinding a company that will coat the side seals with something for more durability.


[/quote]



how many failures have you seen due to this? do you have any proof that this happens? any pics of the side seals?

[quote name='j9fd3s' date='May 7 2005, 10:58 AM']if you look at the renisis port timing, it closes about the same but opens eariler, the side exhaust lets em do it without having "too much" overlap


[/quote]



in this case opening the side ports earlier only adds to the amoutn of air entering the engine. since it still has zero overlap it cant really be compared to the regular side port with pport exhaust.

[quote name='guitarjunkie28' date='May 6 2005, 06:40 PM']for the first part, all other things set aside, air flows better across a radius.



i'm not talking about the type of ramping to soften the edge for an unsupported side seal, i'm talking about giving the closing edge a radius. the purpose isn't to extend the port timing, but to get rid of the sharp edge.


[/quote]



That's true, but that still doesn't answer my question -- how is the sharp edge on the stock port's closing edge detrimental to how the charge flows into the chamber?



B

brian,

when the rotor gets to the point where it's closing the port, the radius makes the air turn and shoot almost straight up--adding swirl and mixture.



kahren,

these are from a stock renesis i got to take apart with 26k miles on it. i fear for the future of these engines.



what caused it? all the intake ports looked fine around the edges--no signs of impact whatsoever. the exhaust ports on the front and rear side housings, however, did show some signs of either impact or scraping. maybe it's from the extra expansion of the side seals because they're in contact with the exhaust gas??? i'm not sure, but that'd be my best guess for the time being.



i think if mazda reduced the exhaust port size about .3-.4mm from the wall, it might eliminate this.[attachment=30678:attachment][attachment=30679:attachment]

i talked to jhb about coating the side seals and they said they weren't sure if they had anything that would be totally appropriate, but they could try experimenting with coatings.



that may be a good idea for the rx8 guys.

i dont think coating them would help much, the coatings may wear out after a while most likely sooner then later. if anything you should try treating the seals.

do you have any better pictures of the side seals?

i'm not a photographer.



my idea of coating isn't so much for the wear surface, but heat rejection, to lower expansion. i dunno if it'd work all that well, but it'd be worth a shot.