I saw a thread similar to this one but it has been discussed on 0... I'm really curious about it and it may be a plan for my 7 but I doubt it.

Is there anyone running a P-port engine and with the stock ports open at low rpm with the P-ports closed and then over something like 5k the p-ports open and the stock ports closed. I'd use butterfly valve in the intake manifold. Since I would focus on the p-port power, The intake and exhaust system would be configured for a p-port engine.

It's probably stupid but since the pport would open before the stock port, could the butterfly broke under the engine vacuum?

What would be the draw back of running 4 NGK R6725-11.5 while daily driving with the stock port?

I mean, would this be possible? Since I've search and didn't find much about that I'd like to know.

I Know that the engine under 5k would make horrible power but atleast it would have a smooth idle, and a good fuel consumption.

The Intake setup with the butterfly maybe hard to do, but If you look at the racing beat housing, the port is higher so it would give some space.

 

yeah, i feel your pain. it's been really hard finding any support/assistance or information regarding semi-peripherals, so i've decided to keep trying and make ways to do it myself.

from what you wrote, it sounds like you're planning to use full-sized peripherals in conjunction with the side ports. obviously, anything is possible, but it's problematic for a few reasons. so you may want to reconsider that. semi-peripherals usually utilize much smaller ports cut inline with the stock side ports.

the butterfly idea has been proposed, but i can't remember actually seeing one in use. i'll defer the question about the plugs to anyone that has actual experiences with them, but good luck in getting an answer.

you may want to search for Judge Ito and GtoRx7 on the board. it might be useful, it might not.

 

Yea there isn't many info about the semi p-port

With the butterfly I want to Use the stock port only at low rpm and only the p-port at higer rpm so the stock ports ans p-ports will not work at the same time.


as for my question:It's probably stupid but since the pport would open before the stock port, could the butterfly broke under the engine vacuum?

Forgetting I was out of my mind I think... and Gtorx7 runned or run Is P-port caped off so shame on me



diabolical1, what are you planning doing for your semi-port?

 

You would have to have the butterfly AT the pport opening to be effective. A slide throttle would probably work better since you could get it closer to the port opening, but it will still communicate with the exhaust port so you will more than likely have the same choppy idle and poor low end(light throttle). I'd still like to see whether or not it's possible.

 

I have been considering something similar recently. I base the side port/p-port decision off of throttle position though, and figured I would just trick the ECU into thinking the butterfly valve was another throttle body.

Would need a very complicated intake manifold with runners to both sets of ports, and the exhaust would have to be tuned for the PPs because you probably won't gain anything from a PP running a streetport exhaust. That, and even with a Pport exhaust you'll have no velocity at low revs so low end will still suffer. You literally would need two, seperate, independent intake, exhaust, and tunes.

It could probably be done. Weight, space, and tuning would have to be figured out though and I haven't.

 

drewski86:I know that I should put the butterfly as close as possible to the port but I never knew why! Can anyone explain it to me?

About the intake port communicating with the exhaust one, I tought that since the RB P-port housing port seems to be higher it would reduce the rough idle and light throttle bucking. Please tell me if I'm wrong about this one.

Falken: I was planning on starting with two itbs, then it would split in 2 the stock port and the p-port. The stock port tubing would split in two again to go to each side port. The intake tubing length for the p-port would be callculated for hi-rpm use as the stock port tubing would be calculated to give as much low end power as possible.

The exhaust would completly calculated for the p-port. I'd probably using 2 axle back, one for the street and one for racing. The street one would use a silencer and probably one of those Apex'I ecv thing to make it quieter.

I don't want 2 exhaust, intake, map and etc...

In fact the car could be 110 hp under 5k and it wouldn't bother as long as it would be street driven and idle smoothly. When I say idle smoothly I mean something like a street port or 1k with little brap brap But I wouldn't like any pp bucking style between 2 and 4k.

Anyone knows the port timing of the RB pp housing?

 

I don't remember what the Racing Beat PP timing is, but the Mazda PP opens over 100* sooner than most streetports. The Mazda PP has over 140* where the exhaust port and intake port are both open whereas most streetports have less than 30*.

Even though you will have a throttle closed in the intake, there is still a good sized hole for exhaust gas to move into the intake charge. This is why you want the throttle as close to the port as possible, to make the hole smaller. I don't know how much of an effect it will have as no one has done it, or is talking about it.

You're exhaust will be based strictly on your exhaust ports and where you want power, intake will have no effect on the exhaust.

 

Well yeah, if you feel like fabbing up that type of intake system, go for it, but that's where I scrapped the idea when I was considering it.

 

Why not accept the slight flaws of a small semi peripheral port (1") in trade for the power gains? A properly done SPP has more bottom end than you would think. Peejay swears that his full p port makes more torque than his street port at any RPM above 2000 and i believe him. If you don't mind the idle and fuel consumption i say go for it.


The butterfly idea is sound in theory but i think all will be lost in the execution. If you could have your cake and eat it too don't you think Mazda would have tried it already.

No disrespect, just my $.02

Also, the plugs won't cause any problems as long as your not fouling them. If you have them run em but i wouldn't buy them just to run on the street. There are much cheaper plugs that work just as well.



Hey Falken, any vids of your DIY turbines? I have made a couple as well

 

sounds like you're making things way too complicated for yourself. i, too, think it prudent to consider using smaller peripherals in your combination and just try to play around with port timing with respect to your side ports. that's what i'm doing with mine.

 

Here is what R-magic does. They use a medium P-port and then use the center housings intake ports. End housings are plugged.　They call it a sequential port.

http://www.rmagic.net/parts/engine/img/fd_engine_01.jpg

Revolution however does a cross port.
The cross port they use is small p-ports with stock intake ports. The sell a kit with manifold and housings or adapters for housings.
Nobody has any huge success with these semi P-port set ups but it is always interesting to see and hear about.
Here is a pic of the revolution kit.

http://revo-tune.jp/catalogue/detail.php?id=105

 

they did do it in the late 60's. they ran a variant of the cosmo 0810 engine with a semi PP fed by the secondaries of the carb.

 

Fabing an intake manifold does not scare me and I know two good TIG welder that could help me with it.

13B-RX3: Yea I've read about it and it seems that many P-ports make good low end power too. It's more the heavy ''brap brap'' idle and the sound that I fear since cops in my area are very strick about noise... so this is why I tought of the butterfly. I wanted to know if it could work but I didn't think there were more than 100* of overlap...

I also tought that since PP make an extremly loud sound and that they make hi-emissions, Mazda wouldn't try to make a car like that but I knew inside of me that there was a reason I didn't heard of that

drewski86: Thank you, I wanted to know the Rb duration and * to know the overlap.

Are the semi-pp with the 1'' port making good power? And how does it idle?

 

More than you could ever imagine in turbo form. I don't know about N/A.

IIRC Ito was making good power with a half bridge/semi p port combo.

How much power are you wanting to make?



I know it's a turbo but you get the idea.

http://www.youtube.com/watch?v=zkMdKPeiF4w


Sorry about spewing my turbo propaganda but 95% of what your going to find on semi p ports is gonna be from the turbo guys.

 

Yea moslty all info are about turbo engine but I don't care that much about the power it's mostly Idle and sounds while cruising.

I'm looking for +/- 250 whp so it's almost a waste to use a 20b. I always loved n/a engine and I drove my stock twins fd for about 2 years and now I want to try something else and I'm not a power freak.

The engine sound is awsome

How is reacting an semi-pp under light throttle? How high is your idle?

 

This is one of those projects that you will absolutely have to have a sound understanding of how a rotary works. Especially with intake runner design, length, and operation. Once you've done that, then you will need to find an ecu capable of running it properly. Think about what your asking. Your talking about running of the side ports at lower rpm's and transitioning to PP's in the upper rpm's while also closing the side ports. In this transition you will also have to cut fuel to specific ports as well since your basically cutting off air flow. Then what are you gonna do if one of the specific ports throttle butterfly's stick open with no fuel flow? This is a lean condition waiting to happen. Good luck finding specific info around here. Realistically you will have to do years of research to get even close to having a design that may actually work. My advice is start researching everything related to NA rotary's and how power is made. I've personally been researching this very same idea for the past 4 yrs. Trust me it' ain't easy but it is very possible. I may however have something worked out early next year.

 

they fired up the speedsource rx8 as well as the 797, the imsa 1st gen, and a 4 rotor 626 at sevenstock.

the speedsource car actually idles quite nicely, and it wasn't loud at all.

a PP doesnt idle as rough as a bridge does, they dont brap as much

 

last i checked, Ito made 310 tuned without the nitrous and his look like they're about an inch. i haven't looked him up in long time so i don't know if he ever improved on that power figure, but that's just to show that power can be made. i don't know what the torque curve looks like either. however, consider (1) his experience, (2) his custom intake, (3) the car's purpose ... AND (4) did i mention his experience? before trying to completely replicate (or exceed) his achievement. i'm sure there were other little tricks and things that were not obvious as well. i have no clue as to how the car idles, but most of the ones i've heard in real life idles well - relatively speaking. the only issue of course is noise - they were all racecars and dumped the exhaust either just behind the front wheel or somewhere mid-chassis. i've never heard one with an exhaust even trying to be streetable.

 

Quite and Pport don't go together very well

 

ITO'S engine had full bridge ports and 1" PP"s. 4 separate TB's for each primary and secondary port. The 1"PP's where joined with the secondary runners. All runners where perfectly straight mimicking the 787b setup and was designed for top end power. Given all the internal overlap, torque below 3k would be terrible for economical street driving. Anything above that would be completely a different story. ITO most definitely knows his **** when it comes to making power.

 

i know. i studied as much as i could from photos of his setup. it's phenomenal and it's what inspires me most. to be honest it was his setup that got me thinking about building one for my racecar and i've been using my time on-and-off since then, between projects, to sketch and iron out my own plans. i'm finally at a point now where i can start trying to actually work.

i only mentioned his setup for illustration of the potential since Pic seems so hell-bent on using full-sized peripherals instead of the smaller diameter ones. as i implied in my response, Ito's setup was built for racing, not the street.

 

Thanks guys for all the great info! I wanted to know if this was possible and I got my answer.

And I'm not hell bent on the Full p-port it's just I asked about it and wanted to know if this would work.

I got all winter to think about the next engine and I'm just trying to find the perfect setup for me.

 

two things just came to mind

1. i wonder what mazdas port timing was like when they tried this?

2. i have a whole jdm rx7 magazine from 2001 with all kinds of na and pp's in it, anneversart racing factory, among others have had kits