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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Fri Mar 25, 2011 3:42 pm 
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Dr Wankel Himself
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Rota Ash wrote:


rofl, was thinking the same thing :laugh: :laugh: :laugh:


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Mon Mar 28, 2011 9:40 pm 
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BO0557 wrote:
have started the porting on the new 12a plates ive got.

Front plate on left is a little bigger and squarer than the racingbeat large extend - Stock s3 12a ports on the righ

Image

Im also in need of some long like 100mm carbid and stones for my dremel.. i dont have a compressor here in the UK which is shit so if anyone knows of a place that sells longer 3mm shank stuff..


getting nice and large.excellent.

have u done seal trace,dont think there will be any issues but are u 100% happy all seals pass over all ok? if so then great.

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Tue Mar 29, 2011 2:43 pm 
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whats the extra fuel consumption you can expect from a 12A EP with 3 inch pipe all the way through and a stock carbie?

whats the expected HP with a setup like this and if i did get a nikki or a weber how much more power would i get?

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Tue May 24, 2011 10:08 pm 
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bumpstart wrote:
Quote:
Rota Ash wrote:
i thought the idea of porting the runners was to direct more air into the path of the rota, also wouldn't u want the runner to go from big to small to increase air speed, obviously u would have to


in NA, every poofteenth of restriction counts
and there is WOT gains ( at expense of quite a lot of effort ) in opening the bowl, removing runner restriction and smoothing the airflow



is the filling efficiency of the runner at NA even proving a filling restriction ?
is it being a hold back compared the port area that's available to be cut from s4/5 and even bigger cosmo / FD plates ?


Are you saying a cosmo or S6 block would be a good basis for a good bridgeported N/A engine, and that the larger runners and ports would not affect power loss due to lack of air speed.


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Wed Jun 29, 2011 7:59 pm 
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My way of porting a sixport...
The pics of plates behind my porting is done by someone else, don't know who!
And as you can se, it where to close to the waterjacket.

280hp :P

Image

Image

Image

Here is the one in the background my plate...

Image


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Wed Sep 14, 2011 4:26 pm 
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Noob question. On a stock unported 12A, how do the sizes compare from the centre plate ports to endplate ports. I've never opened one up. Any pics? Cheers


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Wed Sep 14, 2011 9:25 pm 
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Rotor Junkie
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There's a few port variations available on 12a's, which one in particular are we talking about?

Some have quite a sizeable difference like N0/R5 jap import combinations, others are more similar in size like R5, N and Y combinations.

If you let us know what plates we're dealing with, I'm sure we can dig up some photos to show you the difference. Hope that helps.

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Wed Sep 14, 2011 9:55 pm 
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straight off top of my head -

depends on which engine it is

lots of confusion lays in the ID of japanese import engines from the late 70's early 80's
IE there is japanese variations of N and or r5 grey ( nitrided ) plated engines that use different middle plates to the australian versions
it is best to compare apples with apples by taking the code cast near the oil filler neck on the middle plate

70's oz engines usually have primary ports very similar to the secondary porting if not the same, some with and some without the tall port runner
the secondary porting on these engines can be 42 to 48 mm high depending on the plates used
( 3B,R5,X )



talking 70's oz primary plates
R= 42 mm port,, tall runner
R5= 42 mm port , short runner,, suspect 3B is similar

later oz rx7 engines,, if fitted with the Y middle plate also have the ( 42mm? ) tall port, and tall runner

however many japanese s1 engines bring an N0 middle plate,, also with small runners and small port


the 6p 12a and the 12at middle plate is a K and these have a tiny port
( the K plate is easy to ID as it has the provisions for engine mount on the exhaust side, ie it was intended for fitment into a HB cosmo )

ie
R ,Y middle plates have the tall 42 mm ports with tall runners
R5 middle plate ( and i suspect 3B ) have the 42 mm ports with short runners
N0 brings a small port not unlike that seen in s4 turbo
and K brings a tiny port the size of a 5 c piece

the philosophy differs because 4 x big ports is designed for high speed highway driving ( US, oz )
while mixing small and big was for bringing TQ gains down low for city use ( japan )

some of the early engines with 4 x 42 mm ports where intended for reversed inlet manifold so the long runners to the outer plates are actually primarys
( the US version of the rx5 13b is one example )

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Sep 15, 2011 12:02 am 
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NO centre plate and R5 end plates. So from what bumpstart wrote, the NO centre plate ports would be smaller than the R5 end plate ports?

I'm just curious as I want to make up a custom manifold for my own Nikki setup. I read in another of bumpstart's posts about the manifold with reversed runners, and am just wondering whether this would be beneficial with these ports. Having longer primary runners feed the end plates and shorter secondary runners feed the centre plate. What do you guys think?


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Sep 15, 2011 12:16 am 
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Yep, N0 plates have a much smaller port than R5,

Not the best pics I know, but your ports should look like these.

R5 ports (front and rear plates - secondaries)
Image

N0 ports (centre plate - primaries)
Image

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Sep 15, 2011 12:46 am 
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i see no advantage in having the short runners to the smaller ports

the motors used thus in the US have 4 x 42 mm ports
so the short runners to a decent port compliment WOT power and the long runners compliment low speed TQ
( without having to kill the port timing to increase airspeed )


i would think you need the ported Y centre plate to get the inlet timing of the new "secondaries" to be same or later close than that of the new primaries to get the best of the principle

however many of the early aussie engines,, and the s3 12a would be ideal candidates to try the theory on

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Sep 15, 2011 1:08 am 
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Alright fair enough, thanks for the info! :)


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Oct 20, 2011 3:38 am 
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how does these port look?

Image

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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Oct 20, 2011 3:51 am 
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they look alright to me, though you could open up the bottom of the main port a little looks like that hasnt been touched.

remember guys the exhaust port is paramount to getting the engine to make good power. so often overlooked by the inexperienced.


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 Post subject: Re: Everything You'd want to know about Porting on a Rotary
PostPosted: Thu Oct 20, 2011 7:59 am 
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Definately some interesting port work in this thread!!

Munch Munch wrote:
remember guys the exhaust port is paramount to getting the engine to make good power. so often overlooked by the inexperienced.


Munch you are 200% correct. The exhaust in many ways is MORE important than the intake as it allows both the timing and scavenging of the incoming mixture.

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