I'm going to be starting an engine build project/experiment. I want to build a semi p-port and I was wondering if S5 6-port irons would be able to flow enough to keep up with an 1" inch or so p-port? I figure, i will probably have to port the primaries but do you think the secondaries and aux ports will flow enough?

 

what do you mean flow enough to keep up? they will all work in conjunction - just at different degrees of eccentric shaft rotation.

 

I think the aux port plates may not give as good of results. The 5th and 6th ports close during the compression stroke. So any extra incoming air from the 1" pp's, may be lost through those ports on the compression stroke unless the rest of your intake design is designed to take advantage of it. However, since your experimenting, test the engine with both plates designs and see which one gives you the best results.

 

Well, I though i remembered reading that an engine would only flow as much as it's smallest port. But now that i think about it, I think i am thinking of velocity, maybe? I was thinking of putting them right at the top even with the aux ports, That way it would keep the overlap down too, but it might put my powerband too high.

 

I also was thinking what if I just closed off my secondaries, and just used my primaries with a little bit bigger p-port? I don't know just throwing ideas around to see what you guys think.

 

Ive had thoughts on this subject before. What I think would be very interesting to try is to street port the standard ports and do a full sized peripheral port. Then create an intake manifold with 4 individual throttle bodies, i was thinking barrel style throttle bodies because they could seal off completely. Two large ones for the p-ports and two small ones for the street ports. Then it should be possible to create a linkage system that will only open the street port tb's up until a certain throttle position, say 50% for example , where the street port tb's will be wide open, then as the accelerator is depressed past this 50% the street port tb's will start closing (barrel style so will keep rotating past WOT and start closing) at this point the larger peripheral port tb's will start opening and their injectors will start firing, with some time and effort on the transition between street port and peripheral port it should be possible to get it fairly smooth.

So at anything below 50% throttle position the p-ports will be closed off and all control will be via the street ports and from 50% to 100% will be a transition between the two , and at 100% will be only peripheral ports.

So for street driving you would have a street port, or even standard port, but when you want it and go WOT you will have the power of a full peripheral port. Could be very interesting, i think it would work even better with a Y-pipe in the exhaust that opens at a certain throttle position, allowing a quiet streetable exhaust that will become capable of handling a peripheral port when you floor it.

Would be very intricate to do but just a thought. Think a problem would be fuel control, as the injectors for the street ports would have to start firing less and less after 50% whereas the p-ports would have to start firing more and more.

Anyways just a random idea, havent put loads of thought into it so there are probably huge holes in it.

 

Well one "Hole" is the exhaust. You can't really have something that can sort of handle a PP, you have to make the exhaust specifically for the PP because PP's are touchier w/ exhaust tuning. And a SP wouldn't really respond well to that huge of an exhaust, no velocity, loss of torque.

 

With enough planning anything is possible my friend. I've actually been in the development stages of the above ideal for the past 3 yrs. Sit back and see what happens.

 

Well I hope you don't mind that I'm going to completely steal every possible facet of the design and use it on an engine of my own

 

has any one done a semi-pp on a Renesis yet. Put small p-ports in the housing for intake and exhaust, but keep them small and seperated so that overlap is at a minimum? I would think it would flow really good with the p-ports and still have the streetability of a stock non-renesis rotary with the low overlap.

 

oops

 

Is it necesary to use an aluminum tube for the insert or can I use a steel tube?

 

This is when you purchase you some used beat up housings and experiment with both metals. What's best is what's easiest for you and what you have available.

 

Here's a practice housing I've been working on. I used a Hole saw and smoothed out 1/4" bolt.

 

Seriously though does anybody know anything about the Renesis idea? I really wanted to try it instead, but I didnt have the funds for the Renesis side Housings.

 

if you go over to rx8club.com, there is a project that involved a peripheral intake port over there, but it was a full-sized port. i can't remember what the results were.

 

It would defeat the whole purpose of the Renesis.

 

Nice that's how I did my experiments but I had to use a cordless hand drill cause I don't have a drill press. LOL! It still worked though. Anyways, the more you experiment with things, the more you find how easy it is to do certain things you thought you couldn't do.

 

Not completely, the renesis has no overlap. Really small p-ports that were far enough apart would increse the flow quite a bit, but still keep the overlap to a minimum. The overlap would effect the idle quality, light load power, and emissions, but it would be built for more power so i wouldn't think that these would be very important. It might need to be reved quite high to see all the potential of all the port area though.

 

well, yes and no.

if you're Mazda and you have to satisfy thousands of customers and federal regulations and such, then yes. if you're a rotorhead that just wants to build something to satisfy your desires/needs, then no. you'll use whatever knowledge and tools you have at your disposal.

 

pretty much how mine came out, too. yours are a bit cleaner though.

i know what you mean. i had originally tracked down a machine shop local to me to do it, but i think they shelved my job because they had bigger fish to fry - anyway, i had to go out of town on business so i decided to take my housings back with the intention of returning them to the shop when i returned. however, while i was out of town i decided to get a couple of hole saws and try it for myself when i got back home and that's exactly what i did. it came out better than i dreamed i could have done for myself.

i still need the sleeves to be welded (which i can't do), but so far my timings are spot on. i don't see that changing when the sleeves are in and i do my final clean-up machining. not bad for a regular drill and Dremel, eh?

 

If you want to look at it this way, the stock exhaust ports on the Renesis pretty much cannot be ported, how do you plan on getting the extra air from the semi pp out of the motor?

 

"pretty much how mine came out, too. yours are a bit cleaner though."

Thanks, I've noticed that there are a few small gaps between the pipe and the outside hole of the rotor housing. Devcon aluminum putty would fix this wouldn't it? My uncle is helping me with it a little bit and he's know a guy that pours molten aluminum and thats how he wants to seal it up. I would think that would warp the housings!?

"how do you plan on getting the extra air from the semi pp out of the motor?"

By adding a small peripheral port exhaust also. The side exhaust is good, because of it's quick abrupt timing and zero overlap, but the peripheral exhaust I think would definetly outflow it.

 

i recently came across a gel that's supposed to absorb heat when you weld aluminum, to keep it from warping. i saw it another thread here on the board. i guess if you're going to fill with molten aluminum it'll be exposed to extreme heat for a longer period though, so maybe using the gel might be futile. i don't know, but i figured i'd toss it out there for consideration.

yeah, mine has those ugly gaps and those are what i want to have someone weld up. to be honest, if i can get the sleeves machined to the perfect contour of the housing, then the gaps would disappear (because i cut my actual ports to the inner diameter of the sleeve), but i don't have the means to do that, so either way i'll need help when it comes to securing the sleeve and filling any gaps. the Devcon stuff should be relatively easy after i get that done.

 

Then why bother with the Renesis? Pre-Renesis already has peripheral exhaust. That's my whole point. Once you add peripheral intake and exhaust ports, regardless of the size, you've introduced overlap. This negates the fact that you have Renesis side ports or not. I don't want to steer you away from your project, I just think it will be far easier with a pre-Renesis base. That's just my opinion, which doesn't really mean anything, because we all know opinions are like ********...