hi

Scalliwag , very nice work indeed , what happen to post #69 pictures

cya

This is a stupid question, but once you have decided upon the port timing you want, how do you accurately translate it into dimensions on the rotor housing?

Degree wheel would be the best way.

wow great thread, i'm glad to see some of the experienced guys getting involved in this thread...

Jay7...

Is there any way to accurately predict the powerband based on port timing? I'm attempting to design a peripheral port for a boosted application that will only be revving to 8500, but there is very little information on RX7club and NoPistons about the subject.

I might just wing it based on what I personally think might work and hope for the best...

Depends on what you mean by "accurate". You can copy what other people have done and fudge here and there. Actual accurate prediction involves computer modeling.

I suppose just a general idea, like say X port timing should make peak power around 7-8k with a very good midrange.

The problem with copying is that very few people are actually willing to share detailed information about their setup and the results they achieved.

Pics to be posted after I take them, but finally buckled down and cut the S5 housings I have sitting around for PPort. Timing's about median between old style and new style MFR housings (that is to say, the numbers in that paper I keep bringing up) and looking at 1 3/4" ID on the tube. Which, yeah, may be on the smallish side compared to what some are doing, but I'm figuring on something roadrace/street oriented.

I'm figuring of doing a lot of dyno mule work on the intake/exhaust, as I'm fairly sure that's where gains are... hell, pulling my head out of my ass and looking again, on ye Maz paper, runner length and diameter played a lot larger part in shaping the powerband than timing. But hey, who knows.

Incidentally, I got sick of bottoming out the hole saw, so just chucked up a 1.5" end mill I've got sitting around and used that to make more room. Rough cut the hole with the holesaw, then used a boring bar to finish the hole to diameter, and open up the rest of the housing to tube OD. Made a nice press fit.

Did a bit of layout work to see how the port I was thinking of using would compare to the MFR port and to find out what the port timing would be.

The port I designed has almost the same port area as the MFR, would close at the same time as the MFR port, but would open 15 degrees later. I have been advised to increase the port radius's and open it earlier.

Any predictions for the performance of this port and advice to improve upon it to match my goals? Any thoughts on entry runner angle?



Finding port timing with degree wheel:
Attachment 699958




MFR port:
Attachment 699959




Square port I'm thinking about using:
Attachment 699960

Looks good. What is the characteristics of the square port vs the round port?

I have read Mazda used square port for qualifying as it flows more but must be kept at high rpm to keep velocity up.

Round port for racing as it has good overall power due to same timing but more velocity in lower rpms.

Turbo applications may be able to use a big square port and keep the rpms low enough for race reliability.

I am going to make some p-port housing for my 12a. It looks like the norm for 13b outer diameter is 2". What is a good diameter for the 12a since the housings are 10mm thinner?

This thread is friggen insane.



You guys are damn brave haha.



I would like to see a PP with custom irons, becuase really you dont need those thick ass irons if you have a PP intake.



=Ben

hmm. . . that's an interesting idea that I hadn't yet considered. Anyone know if anybody has done anything like apexFD just mentioned. . . thinner intermediate(s) and a shorter e-shaft.

Well- of course, you still have to cool the surface of the sidehousings somehow so there may be a limit on how thin you can go.

I believe the NSU P-port production engines cooled the housings with radial flow instead of Mazda's axial flow, so that is one possiblility.

It might help to use aluminum for its superior heat transfer with a sprayed on wear surface like early Mazda 10A production engines and its new 16X concept.

what do you guys think of this. i found the pic on the net. not this is back yard p porting.
http://www.geocities.com/izzmus/shotgun/shotgun.htm
http://www.geocities.com/izzmus/shotgun/shtgn03.jpg
http://www.geocities.com/izzmus/shotgun/shtgn04.jpg
http://www.geocities.com/izzmus/shotgun/shtgn10.jpg
http://www.geocities.com/izzmus/shotgun/shtgn23.jpg
http://www.geocities.com/izzmus/shotgun/shtgn24.jpg
http://www.geocities.com/izzmus/shotgun/shtgn28.jpg
http://www.geocities.com/izzmus/shotgun/shtgn31.jpg
http://www.geocities.com/izzmus/shotgun/shtgn33.jpg
http://www.geocities.com/izzmus/shotgun/shtgn36.jpg
http://www.geocities.com/izzmus/shotgun/shtgn42.jpg
http://www.geocities.com/izzmus/shotgun/shtgn45.jpg

It's probably already been posted in this thread, but I don't have the patience to traul through it, but where can I buy factory peripheral port housings for a 13B?

It's for an FD3S motor but I guess it won't make a difference if I get second gen peripheral housings?

that intake is an abomination. . .

thats the frist thing i thought of when i saw it. how about the door screen used as a oil baffle.

Wasn't that Peejay's setup? It belongs to someone on the forum.

iam not bashing it i just thought the screen was funny. wish he updated the web page and talked about how it went. the last thing on his page about it was ready to install.

http://www.youtube.com/watch?v=FR9hHHJKJA0

Friday, as it happens:

http://a384.ac-images.myspacecdn.com...c205ce0377.jpg

http://a958.ac-images.myspacecdn.com...104132a7bd.jpg

Goal is the next rallycross on the 20th.

Did it start? Howz it run? That's a big squre port you've got there.

how did it go

http://www.youtube.com/watch?v=Tr7vU3cbH6E

I should explain the screen. I had two reasons for it: first and most practical, I removed the screen on the pickup tube and bellmouthed it, and I am somewhat paranoid about random junk getting sucked into it and mangling the oil pump, so I figured the screen would protect against that sort of thing. Second, I was hoping that any air bubbles would get broken up and/or stay above screen level, to help ensure that the oil the pickup saw was "solid".

It was a lot of fussing around. This time, I just used an unmodified pickup. I'm not winging the engine up real high, the stock oiling system is good enough.

The problem I see with the screen is it will actually preserve the bubbles in the frothed oil in the void of the screen.

You want a smooth flat sheet for the baffle so that the surface tension draws the oil in each bubble down to the sheet of oil film on the baffle plate as fast as possible so you have more liquid oil and less froth.

You can paint your porous cast oil return surfaces with Glyptal as well to serve the same purpose.

What ID are the 12app drag racers using?

DelSlow,
referred to the photo above, the front rotor is exactly at it's TDC? is the e-shaft's lobe at it's highest point pushing toward front rotor when it is on TDC?
i am having problem finding true TDC without gettting the engine dismantled

just wondering on the port timing and if you could give me some info on how you marked it out on the housing ?

any help would be much appreciated

This is an awesome thread!!!

///////////////////////////////////////////////////////////////////////////////
"Most NA/PR rotary builders don't do it."

***how do you know... PR/we were doing it when we started building turbos back in 1982, most of you were not even born yet...

Umm... the post you are responding to is 7 years old.

Very useful info on this thread...Thanks:icon_tup::)

just making sure things are said right for the record here!

Bringing some new life into this nice topic..

I'm thinkering about making such engine in a year or so.. I have a good 4port rx8 engine, and because it has 10:1 CR and lighter rotors it will be quite good.. engine will get telescopic intake like mazda did for the 787b..

now I could use rx8 rotors in s5 TII engine, or I could use complete rx8 engine with TII rotor housings.. question is, what effect will it have when I both have pheripal and side exh ports?

engine will be for a circuit racing and power band from 6000-9500rpm; need 300hp at least

I dont think you're power band will start till about 7K or above, even with fuel injection. But it should definetly make more then 300hp.

If I look at the lemans engine they had quite good torque at 6000 rpm (around 300Nm for 2 rotor equivalent).. I will try to keep overlap as low as possible by making it almost D shaped port (flat side on the bottom offcourse), offcourse most of the torque lies in the resosnace tuning of the intake manifold, but it will be quite straightforward to control the trumpets by PWM signal with the microtech I'll use..

Unless the exh velocity will be too low to start comin in the powerband at reasonable rpm due the huge port area with both pheripal and side ports

Search Rotary Aviation's website. The used to have a dyno graph of a Renisis engine with both peripheral and side exhaust ports. The torque was awesome!

Here's the dyno sheet of the p-port renisis,although some people bitch about the H.P but keep in mind that the power band almost peaks a 7200rpm. which is great for reliability compared to a regular p-port engine that has to rev at close to 10,000rpm's for that same power band.

http://www.rotaryeng.net/RX8PP264a-Stock-RX8.jpg

is this with only side exh ports or both side and P-exh ports?

might make close to 300hp with a shorter intake at higher rpm.. advantage is that yoo can have diff lengths for the runners for side and peripheral exh boards to widen de powerband a bit more

Probaly just end up using the renesis rotors in the S5 engine.. :nod:

I also looked on rotary aviation but couldn't find the dyno mentioned :/

I'm having trouble reading what you said but if i understand you, If you add peripheral exhaust it will no longer have the low overlap that makes it have a low redline. If you are not talking about adding PPort exhaust, the exhaust runners are so shitty that changing exhaust tuning has almost no change in power.

A variable runner intake will help but most people are to lazy, to obsessed with peak HP or to obsessed with weight to make one.

Side ports only

Thank you for answering it for me:bigthumb: Not sober enough for me to answer:beer:

I agree that with this kind of setup,a variable intake runner efi intake would increase the power band by 20 to 40 hp?? more than whats on this dyno chart.

But the side exhaust port could use a little work,ie ported for a smooth transition or port it for an early opening.there is about 1 inch of port material that that can be ported downward for an early opening, you do that plus the intake that you have just described,should yield you about same h.p as regular p-port but more reliably..:icon_tup:

i thought the manifold control the peak power

what was the weight of the rx3 with driver just curious i have a first gen drag car pport g-force trans and chevy 12bolt rear end best time 10.48 at 126mph and it has carb on it trying to get the car in the nine second zone i am in ca name eric darby second fastest all motor rotary in ca

Wow, this thread is cool because you can learn many things by reading the post and you get some tips that might help us in our daily activity.

where did you find out where to put the hole did you have a template or a spec you could give me or tell me where to get the template thanks

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Excellent work!!!!!!

Revive to keep the P-Port Alive!!