kahren

[quote name='Maxt' date='Jul 24 2005, 09:37 AM']In terms of a true peripheral port, it wont work with a pinch of **** to put it bluntly..


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i dont think its the ems, it dpeends what the porting is and what rpm you are tryign to target the idle at with what size injectors. if the injectors are way big u just cant time them well enouf to idle sometimes no matter what ems. there is more to a steady idle then just injector timing.

ColinRX7

[quote name='j9fd3s' date='Jul 24 2005, 03:02 PM']keep in mind the mazda race p port motors are designed for maximum power, there are other motors, like the mercedes, with the port timing setup to make power in a more "streetable" power band/rpm range. if you make the port timing more "sane" then its gonna run better at lower rpms, although i doubt its gonna idle as well as a side port no matter what you do. the nsu primary is maybe 10mm and the car idles like poop


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10mm? That's awful tiny...



A brappy idle is still streetable IMO... What's "idles like poop".. hardly runs at all or just idle bounces annoyingly?







I'm not looking for maximum power, I'm looking for a solution to the bridgeport.. It's been proven (obviously) already how much power is to be had N/A from a bridgeport, and still run around on the street without too much drama.. My question is why can't this be done with a peripheral port..

ColinRX7

Oh yeah and does anyone have any comments on the 10a pport motor?



I heard something a while ago about a factory p port motor called the 10a from like eons ago...

BLUE TII

If you want a cross port motor that is very streetable I think you should make a smaller peripheral port primary w/ conservative timing and a BIG early opening streetport 2ndary port and a beveled rotor.



You can set up the smaller higher velocity p-port primary to blow accross the larger streetport and speed its flow in the way a siphon works.



Added benifit is better mileage as your high velocity primary blows the charge over the rotor top to the rear of the chamber reducing fuel condensation on engine surfaces.



You can also close the big sideport effectively w/ a throttle body for low rpm power and throttle response.



Mazda made an experimental motor that used this crossport technique and semi direct injection (where oil metering hole is) to make very lean burn motors. Problem is rotaries running lean produce lots of oxides of nitrogen that are hard to reduce and were later added to emmisions standards.



Sideports can flow very well, they just usually lack the early opening that you need for high rpm power. When the P-ports were outlawed from competition Mazda responded with the bridgeport motor the next year that was only down 10hp and hp continued to rise w/ its development the next year.



What sideports usually lack is early enough opening this can be remedied in a streetport by cutting into the cornerseal track enough to drop the top sideseal but not the lower (~25 deg opening) and making the top of the ports sideseal friendly so it lasts and then beveling the edge of the rotor (~5 deg opening now).

ColinRX7

Rotarygod PMed me and I intend on replying to him here shortly when I have time (I am at work currently and don't have time to make a lengthy reply)



But before I do I encourage him to post his reply publically, and that nopistons is a much more laid back and open minded community than the other communities out there..



He has some great ideas, and we are suffering a bit if we don't involve the other gurus around here with their thoughts on it..



Just a thought while I'm rushing to click "add reply" while I'm at work.. lol..

j9fd3s

[quote name='ColinRX7' date='Jul 25 2005, 04:44 PM']10mm? That's awful tiny...



A brappy idle is still streetable IMO... What's "idles like poop".. hardly runs at all or just idle bounces annoyingly?

I'm not looking for maximum power, I'm looking for a solution to the bridgeport.. It's been proven (obviously) already how much power is to be had N/A from a bridgeport, and still run around on the street without too much drama.. My question is why can't this be done with a peripheral port..


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it has a tinny, brap miss miss brap brap brap miss miss kinda idle. i should take some fresh pics, the nsu has 2 ports per rotor, one teeny primary port and one decent sized primary, thru a 2 barrel progressive carburator.

heretic

The 10A was just a smaller 12A. Or, correctly, the 12A was a larger 10A, and the 13B is a still-larger 10A.



All production 10As were four side intake ports just like all other Mazdas from the late 60's and the 70's.



We in the US only ever got the 10A in the R-100, but in many countries they were also put in RX-2s and RX-3s, and the 12A was an up-option.



The NSU primary ports *were* tiny. They were about 10mm... the secondary ports were quite a bit larger. Primary and secondary peripehral ports, stacked over/under. Very interesting. The Ro80's engine was the size of a 10A, which is where your confusion may lie.

BLUE TII

Oh yeah and does anyone have any comments on the 10a pport motor?



I heard something a while ago about a factory p port motor called the 10a from like eons ago...



Mazda sold a "sports kit" over the counter to customers that converted the production 10A to a 200hp p-port race motor. This allowed them to use the P-port in production class racing untill it was banned for power reasons.



They got by using the aluminum sidehousings in the factory R100 race cars from the Cosmo Sports 10A instead of the cast iron units (like all later Mazdas) that came in the R100. Perhaps you could buy those over the counter as well at the time???



Would have been a nice dealer option to get a R100 w/ sports kit! Wonder if that was ever done.



Edit- Mazda did try cross/combo ports in the preproduction Cosmo Sport 10A, but there were no real gains over sideport in production trim (legal exhaust ect.).

Maxt

[quote name='kahren' date='Jul 24 2005, 04:46 PM']i dont think its the ems, it dpeends what the porting is and what rpm you are tryign to target the idle at with what size injectors. if the injectors are way big u just cant time them well enouf to idle sometimes no matter what ems. there is more to a steady idle then just injector timing.


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Ummmmmmm. not really... thats about all of it...

j9fd3s

[quote name='BLUE TII' date='Jul 28 2005, 11:53 AM']Oh yeah and does anyone have any comments on the 10a pport motor?



I heard something a while ago about a factory p port motor called the 10a from like eons ago...



Mazda sold a "sports kit" over the counter to customers that converted the production 10A to a 200hp p-port race motor. This allowed them to use the P-port in production class racing untill it was banned for power reasons.



They got by using the aluminum sidehousings in the factory R100 race cars from the Cosmo Sports 10A instead of the cast iron units (like all later Mazdas) that came in the R100. Perhaps you could buy those over the counter as well at the time???



Would have been a nice dealer option to get a R100 w/ sports kit! Wonder if that was ever done.



Edit- Mazda did try cross/combo ports in the preproduction Cosmo Sport 10A, but there were no real gains over sideport in production trim (legal exhaust ect.).


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ive seen the competition prep manual for the r100, its neat goes thru the whole car. slot this, beef this up add flares here.