Kenku

I'm going to be nicer. You posted a general basic question about a turbo car with no mods in a forum section dedicated to built non-turbo engines, and specifically as a response in a thread about peripheral ports.

There's like, 5 forum sections where that would make more sense to ask. In what aspect is that relevant to naturally aspirated builds in general, or a peripheral port in specific?

peejay

What he is saying is you would be doing it backwards. Idle on the peripheral port, come in on the side ports with more load.

The trick is, side ports are okay with high vacuum, peripheral ports just pull up exhaust gases when they have vacuum in them. (Physically put a rotor in a housing and VISUALIZE what is going on at various points in the cycle) Which makes for bad low load drivability. So you idle on the peripheral ports while keeping the side ports shut, because the side ports can be shut without hurting drivability and you keep air flowing through the peripheral port to minimize how much vacuum it has. Likewise at low load driving you want to be running through the peripheral port so it doesn't see as much vacuum.

If you kept the peripheral ports shut all the time, they would see vaccum/no flow all the time and they would act as a kind of pulse pump to pull exhaust gases up during overlap and the engine would choke on exhaust gases all the time that those ports were shut.

rcpython59

Ok sorry,didn't think it was thread worthy and was hoping it was okay cause it was my own thread.

Dak

Thread worthy or not you took your own thread way off topic hence the full retard meme. Post the question about the TII over in the 2nd gen section. It's the proper spot and see's more traffic anyway.

peejay

Here, this isn't naturally aspirated or peripheral ported or a RX-7 or a rotary or even a car.

Mazderati

iTrader: (3)

I reposted hoping the kid would get the hint everything doesn't have to be so serious. It's OK to laugh.

lastphaseofthis

iTrader: (8)

i must have missed something, here's some images i found of it done the way i intend... so i am not alone in this idea...


the one above clearly runs the pp only when the secondary throttle plates are open...

i understand what you're saying, but having the valve to the p port, at the rotor housings, or maybe even inside it, will only have a small amount of area to be under vacuum...

and its just an area that for a moment during the cycle can be considered to be part of the exhaust system. with the correct tuning the vacuum of the close p port will help flow balance, like a two stroke cycle were the intake charge goes out the exhaust then back in at the last moment...
which in my case is solved by my ultimate secret weapon.. a closed loop back pressure feedback controller, via flapper in exhaust. always the perfect amount of back pressure at the right time. .

remember exhaust first expands, and then contracts, i want that contraction to pull on the pp port as the rotor is about to close passed it. this is all theory, but what im visualizing works.
the way i see it.. to take full advantage of a Pport is to have a really free flowing exhuast, but at low loads this causes very low back pressure, and the intake charge mostly goes out the exhaust, at high loads there is more volume of exhaust pushing the intake back into the chamber. to overcome this lack of volume/back pressure, a flapper would provide an adjustable restriction that when tuned to a "back pressure curve" would result in the chamber being filled by an intake charge from the intake, and the exhaust being pushed back. the only thing im unsure about is having the two housings NOT cross. and completely independent, i think by having the correct cross over length, the result is the exhaust port being under vacuum from the opposing housing right before the e port opens.... i need to run many tests.

i look forward to your input.

Jager

iTrader: (10)

Cool thread!

Taking notes.

j9fd3s

iTrader: (3)

after having lived with the P port for quite a while now, i've learned its a balancing act between what I want, what the engine wants, and what the neighbors want.

i would suggest that you are prepared to set up the thing so you can give the engine what it wants, hence the suggestion to open the P ports with load, and not RPM.

PJ might be right too.

the Japanese do the cross port sometimes, however they tend to run a smaller PP, here are some pics from 1999, with the 3rd plug just because. car is from Revolution, and i'm not sure if its the same one he's got now, but his current semi PP car is ~800ps on pump gas

lastphaseofthis

iTrader: (8)

that pic shows that my closing timing is almost the same, in relation to the oil injection hole. sweet, cause i eye balled it however i have much larger ports.



this is the steel version, kinda practice housing that i may try to use... also used alum on another pair i made. turned out much cleaner.

peejay

Sure. The secondary throttles are going to be able to flow more air, an important consideration.

There's that, BUT you are also opening communication between the exhausting chamber and the intaking/compressing chamber. Under light load, the pressure in the intaking/compressing chamber will still be a relatively high vacuum at the point where the apex seal finally closes the intake port. You'll be sucking exhaust gases up the whole time.

False premise. You don't want backpressure ever.

That works fine at WOT. Not so much at high vacuum.

That never happens except maybe at WOT. If that were happening, the intake change would be flushing the rest of the exhaust gases out, and the engine would be running smoothly instead of misfiring all the time.

j9fd3s

iTrader: (3)

yeah its actually the other way, the engine is sucking up exhaust gasses most of the time.

peejay

2 strokes really do have a problem with blowing intake out the exhaust, because the cylinder's intake and exhaust ports are both open at more or less the same time, the intake air is forced into the cylinder by the underside of the piston, and the only thing keeping the intake from being pushed right out the other side is a combination of clever cylinder shapes (loop scavenging for example) and timed exhaust pulse reflection to slam the door on the cylinder.

There is no analogue in a rotary, the airflow going in is strictly due to 4-stroke filling characteristics, exhaust flow is strictly by 4 stroke exhaust characteristics. The intake and exhaust ports open and close at separate times and the air charge is not mechanically pushed into the engine from a separate chamber. This is why 2 stroke exhaust theory generally falls apart when you try to use it.

lastphaseofthis

iTrader: (8)

i think you're totally right. i'll have to make changes in my plan. which saves alot of time and cha ching as right now its just a plan.

also i want to be clear i will have 3 throttle plates, one for the primarys on the center housing for idle/low load, and 2 for each pport. the exhaust port is closed right before the GSL-se primary port opens... so the exhaust port i will talk to the closed p port, but not the primary... i will have exhaust gas dilition from the area inside the closed pport, but thats were balanced tuning will come in.

RX200013B

Just to share, this is what I'll be hopefully running by the end of the month.

j9fd3s

iTrader: (3)

nice, couple that with some low compression rotors and a big turbo and its a really high hp setup

RX200013B

I'm gonna run it N/A for a while.... more my style.

j9fd3s

iTrader: (3)

well if they make 800hp @30psi, you should make 266.66hp without the turbo, just based on the pressure ratio change.

30psi = pressure ratio of 3. divide 800hp/3 to get hp@pr of 1, which is 266.

RX200013B

yeah, that would be sweet!, I'm shooting for 225rwhp.... fingers crossed..

lastphaseofthis

iTrader: (8)

i have a turbo LIM with the p port tied to the secondaries as well, but its being shelfed unless i actually need it for turbo clearance.. that manifold stinks for flow because of the sharp bends, I'm remaking my entire intake from scratch..

i think you will hit your goal of 225 though. but it could very well be 275-300 with a better flowing one. man i can't wait to get started...

RX200013B

^^^I agree... I'm planning on doing a ITB set up in the future..

lastphaseofthis

iTrader: (8)

yours isn't too bad. my pport are much larger, and the manifold is matched to it, and it started life as a FC LIM so the runners are small, and then split to way too much area for the size of the pports. the upper flange on my is a huge bottle neck, thats the main reason im shelving it.

RX200013B

I only did a 7/8 I'd. What you do?

lastphaseofthis

iTrader: (8)

its the size in the above pic, i can't remember but wanna say 44mm or 1 and 3/4... when i started drilling holes i didn't think it was going to turn out so well, and one thing lead to another, sort a of like dating and then marring a hooker after just trying her out for a night.

i don't think i could weld the inside of 7/8 alum pipe, but 44 was able to be done. and now i'm working backwards to smaller sizes, or maybe i'll just run what i've done and build apon those results.

rcpython59

A while back I was doing some research on semi peripheral and something I read made me think that a semi peripheral isn't gonna work out for me. But now I'm thinking it's a possibility after hearing some of you guys talk about it. Is it possible to use a semi pp without some actuator? I realize it wouldn't have very good low end drivability,but I'm willing to make sacrifices Lol. But the real question is if it will be beneficial without an equally elaborate exhaust system that can compliment the better flowing intake system. Would it be possible to Build a semi pp exhaust without using renesis parts? sorry if these are "dumb questions" but I couldn't find any info and I gotta learn somehow