I am searching you *****...:p. I'm either spelling "peripheral" wrong or there just isn't a lot of easy-to-find really in-depth discussion floating around.

Anyway:



I'm cruising around and see that. It looks SO simple to me...simple to the point that I don't understand why there aren't more of them. Can anyone tell me?

From what I'm looking at, it looks completely like someone just simply cut a hole in the rotor housing, stuck a pipe in there, blocked the intake passages on the irons, and called it a day. Did I miss something? Do standard Apex seals hold up well against a peripheral port? Cooling issues? Do they not last long? Too stressed? Something that makes it just not that great of an idea? I KNOW that I have GOT to be missing something here.

Does a p-port work at all with the stock EFI? Just curious because I have a spare 13b, a shop, a hole saw, some pieces of pipe, and nothing better to do with my life. Of course I know I'd have to come up with a way to stage injectors and built an intake manifold but the previous statement applies here too.

another thing I'm curious about is that the standard ports on the irons are usually blocked by using a filler substance. This isn't safe and I don't understand why anyone would risk have an impropper mix or a section of filler break off from heat stress and destroy the rotor and housing? Why not just build a block off plate to mount on the outside of the housing?

 

Yes, its pretty much that simple.

There's a thread in the rotary performance section on building them.

Reason they're not run very much: limited by racing regulations and they are not all that streetable for most people. High idle, high power band, VERY sensitive to backpressure is there main drawbacks.

They will NOT run on the stock ECU. At all.

I've built and driven a couple PP's. They're fun, but I would not want to drive one everyday.

You can simply use block off plates for the intake ports if you want. I use devcon liquid epoxy to fill the irons and I've never had a problem with it.

 

What about cureting one? I've heard and seen that...what kind of monster would I be looking at fueling and what setups seems to work well?

High idle I understand, but I've heard stories about their astronomically placed powerband...any crank/balance issues with them?

 

Their powerband is not THAT high. Keep the intake ports relatively sane, and you can keep a power band below 9500-9600 (about the limit for 2mm steel apex seals).

Fuelling is up to you. Fuel injection is not all that hard... 4 fuel injectors would typically do it. Depends if you're able to make your own intake manifold, or not, really. There are manifolds that exist to bolt on a pair some FI Throttle bodies or a pair of carbs.

Not sure what you mean by curetting... a curette is a medical instrument for scraping the inside of something... like, your vagina.

 

yeah my PC is fritzing out...that's supposed to be "what about carbureting one".

I thought that the stock EFI wouldn't work due to the high power delivery but fuel cut can be defeated with the factory setup...an AFC and fuel cut controller would be useable, along with propper injectors, wouldn't they?

If I undergo this, it will be reletively mild as I don't have the means to cut a propper 2" hole...which is what I see most people do. It'd actually be closer to 1 3/4" id and the exhaust ports would just be de-sleeved, I think, if not left alone all together.

The manifold would be easy...mount a 90* elbow with a 6" rise into the intake cut and secure it, mount the throttle bodies on top, 2+ liter air box, plumbing to the stock air meter (if used that way). The fuel rails would be easy to construct...hell the stock primary could be kept and the acustom secondary just mounted to the new manifolds.

How do they secure the tubing placed in the intake cut?

 

OD of the pipe = ID of the hole. IE; 2.000" pipe into a 2.000" hole.
Heat the rotor housing to 100 degrees and freeze the pipe before pressing the pipe into place.
Then fill the rest of the rotor housing, surrouding the pipe, with epoxy.

The stock ECU will not work for fuelling. The injector timing is dependant upon the eccentric shaft position. PP's have radically changed port timing... The fuel injectors basically would not be firing for the majority of the intake stroke.

You could *probably* get away with using the stock computer for timing, but why would you bother? I would use at LEAST a megasquirt n' spark.

 

Check the nopistons site as I believe Scalliwag posted some setup info on cutting your own PP ports. Also if you can get to vintagerotaries.com you may find info on a fuel setup.

 

I've read a couple of posts saying that the factory ECU won't work due to injector timing but that doesn't make any sense to me. It shouldn't matter where the injectors are mounted as long as after their activation they're saturating the air with fuel. You can't really have an injector misfire, unless it just doesn't fire, because it's always going to be subject to air flow. Further, the P-port ports are at about the same area as the stock intake ports and suffer the same, if not less, overlap as a number of other variety of port jobs. I understand that the stock ECU may be the source of numerous limitations to the assembly, but not from injector timing and changes subject to the different manifold design can be countered by various other tuning devices or common sense...it seems.

Of course, I don't really know. All I see are pictures and they don't seem to match the excuses people give.

How to P-ports react to forced induction? That was the subject of some minor debate a few nights ago.

 

Let's look at an example

Mazda factory peripheral housings:
Intake opens 86* BTDC
Intake closes 75* ABDC

Mazda factory port timing for a turbo engine:
Intake opens 32° ATDC
Intake closes 50° ABDC

Peripheral port opens 118 degrees before what the stock computer thinks it should be opening at. In total, the intake port is open for 288 degrees of eccentric shaft rotation.
PP is open for 431 degrees. That's 50% more duration than stock. Doesn't exactly make a well-mixed intake charge.

You're welcome to try it. It *will* run, just very, very poorly.

 

They do NOT react well to backpressure. Size the turbo large enough and you're going to make gobs of power. Choke off the exhaust flow with a small turbo and you pretty much just end up pumping exhaust completely into the intake charge.

 

It just seems really odd thinking about it because I don't understand why you can't place the peripheral port in the same area as the stock ports in relation to the crank...looking at pictures, it really seems to be in the same general location. Does it have to do with the rotar's "wobble" and curved face? Even taking that into consideration I have a hard time seeing the problem, maybe after I go home and play with a housing and iron for a little while I'll see it.

Why not move the intake port closer to the exhaust port, then?

I didn't think they reacted well to turbocharging, I was thinking supercharging.

 

On a side port, the port opens by the sweep of the side of the rotor.
On a PP, the port opens by the sweep of the apex seal.

 

The stock ECU fires the primaries all the time, right? Why not use an AFC and 1200cc primaries, then?

...just letting my curiosity ask the questions...lol...

 

No, it fires them in relation to eccentric shaft positioning.

 

yeah...duh...fires them into the same place...and you can't really just move the intake ports closer to the exhaust because you're not going to get the clearance you need...the concept is awesome, but If I get bored enough to build it I'll just have to sell it because I won't be interested enough to further it along I don't think unless I just carburate it.

<~hates aftermarket efi...for some unknown reasoning...

 

Yeah, you can't really go down any further as it increases the intake timing (and overlap) even more, and it would cut into one of the tension bolt holes.
Hate standalones? geez, I think they're one of the first mods a person should do. HELLO idle quality and throttle response.

 

Bad experiences leave bad tastes...I wasn't impressed the first time around and it cost me a small fortune to get things done and I ended up with nothing to show for it. It was like paying $250 a month, plus full coverage insurance, to lease a car for 2 years and give it back...

 

Just curious, but why don't people use the PP and the stock ports for airflow, that would be a shitload more air than just a PP and closing up the stocks. I mean if your creative, you could make a manifold that could put all ports to use. Is it becuase we can't make the exhaust ports really any bigger? and it acts as a bottleneck to airflow?

What about boosting PP engines? I would think that during the intake cycle, wouldn't there be a small degree to wich boosted air will leak out the exhaust ports due to the position of the rotor?

 

Its been done. The "combo-port" has both its good aspects and bad aspects.

You can boost a PP, no problem. You just really have to keep backpressure to a minimum with a large turbo. See if you are making 25 psi, you have at LEAST 25 psi of exhaust backpressure, usually more. With a PP, the exhaust and intake are open at the same time for an EXTREMELY large duration... so the higher pressure exhaust flows into the lower pressure intake charge and dilutes the intake charge. To keep this effect to a minimum... we need to keep the exhaust pressure very low until the engine speeds come up and give the charges less time to dilute.
So we need to put a very big turbo onto a very high-rpm engine.

BIG power, very little usable powerband outside of flat-out drag racing.

 

I had not thought about that...that gives a slightly different angle to think with.

 

Overlap.

This is the main reason for the increased idle.

 

Whats the good and bad for the combo port? was I semi right?

 

That's a whole 'nother topic, one that I don't feel quite up to getting into tonight.
You can search if you wish... if not, I'll bring it up tomorrow.

I'll grab those OPR pics tomorrow too.

G'night.

 

The reason you've seen so few of these is that they are a race only engine. Anybody how tells you they're streetable is talking out their ***. Simply being able to drive it on the street does not mean streetable! The power is concentrated very high in the powerband, making low-speed drivability terrible, and the effects on noise and emissions make them totally illegal.

You should not even consider the stock EFI system. Don't even give it a second though. Injection timing is critical for PP's due to the large overlap, so this must be adjustable. For a carb you'd be looking at a Weber 51IDA with extended float bowls as a minimum. A 48IDA will restrict you to power levels you can achieve with a bridge-port, making the whole exercise pointless. An aftermarket EFI set-up will give you much more scope for both power and widening the power band. 50mm or 55mm throttle bodies on a Weber manifold would be the way to go.

In the old days a PP with a big Weber would get ~300fwhp. AFAIK the most power extracted from a NA rotary is 175hp/rotor (R26B), but that engine had every trick in the book applied to it, so that's a slightly unrealistic target. You can have a reasonably quiet, drivable and legalish 13BT that makes 350fwhp and more torque, so you wouldn't even consider a PP unless you were racing in a class that does not allow turbos.

Mazda tried the "combi-port" in the early days and gave up on it. Too many of the PP disadvantages and not enough of the side-port advantages.

 

i may be only 13 but i know that you have to vut through the water seal and then block off some of the water galleries and eventually the galleries you blocked off give way( heat,wear ect) coolant leaks into ur motor then da motor ***** itself. you also have to get away with overlap somehow