SPENT-IT

iTrader: (15)

What would be the advantage or down fall to having a equal length semi-pp intake runner HP, Torque, topend? Good idea bad idea?
I think bridging the primary and secondary at the bottom as most are done would be a PIA and may not work out to well with the intake i want to use or can find.


My plan is to add a equal length runner with a plate on top for independent 52mm throttle bodys. NA for now, maybe boost later.

"Intake"
Online Store - Xcessive Manufacturing

"Throttle body"
SF Individual body parallel bore : SF 52-54mm Body. 2 inj - Jenvey Dynamics

lastphaseofthis

iTrader: (8)

i can't visualize your plan maybe a quick paint drawing would help..?

also shorter intakes make higher top end, vs long length lowers peak hp, but broadens the torque band.

SPENT-IT

iTrader: (15)

Hi
Yeah i know shorter intakes make higher top end. Will the added volume of the runner make up for that/ more flow, gain top end back?....that's kinda what im thinking.

Throttle body will be right on top on a plate/upper manifold to direct air flow, may set up a injector just for the semi-pp runner or just use the injector on the TB.



Here is a crude drawing.

lastphaseofthis

iTrader: (8)

so the 3 throttle bodies, in addition to the normal 20 upper? alot like logan( defines's) first version.

SPENT-IT

iTrader: (15)

No upper, just a mount for 3 TB's right on top of the lower intake.

What was his result with the semi-pp runners? Looks like his are longer then mine will be.

lastphaseofthis

iTrader: (8)

you mean 3 throttlebodies for the p port, and 3 for the side port...if not...
then you've missed the point of semi pp. its not that smaller port makes it semi. its that you have throttle bodies for side ports that do you idling/low load, and you stage a second set that go the the pport. that way you only use the pport when you need WOT power. peejay is telling me that it the p port even when closed is going to cause alot of exhaust gas delusion, however i must insist on doing it this way regardless.

defined's later setup is the record holder for n/a 20b at like 475 rwhp.
maybe someone else can chime in, maybe this is too uncharted territory..

BLUE TII

iTrader: (9)

Yeah, I agree that you want to use the Semi-P-ports for idle and low end and open up the side ports for more flow/later intake closing.

1) Appropriately sized P-port make more power everywhere than side ports so you will have more low end power. I have previously posted the dyno charts from rotary engine development that clearly show this. Semi-P-ports are tiny so are perfect for low end power.

2) You can close off side ports to late closing compression reversion (like stock 6 ports do) by closing the throttle body. Not so for P-ports, you close the throttle body and the compression reversion goes right around the apex seal into the exhaust stroke instead. Therefore, it is better to have early closing Semi-P-port and late closing side ports to extend the power into the higher rpm.

3) By using the p-port for idle/low load you will lessen the effects of the p-port overlap by establishing intake air flow through the p-port throttle body. When the p-port TB is shut the rotor creates vacuum sucking exhaust up from the p-port overlap. The more intake air coming from the p-port TB the less exhaust.

then you've missed the point of semi pp. its not that smaller port makes it semi. its that you have throttle bodies for side ports that do you idling/low load, and you stage a second set that go the the pport. that way you only use the pport when you need WOT power.

Well, that is the usual thinking... so that is how most people do it.

Mazda did it both ways.
The first Cosmo 10A had auxiliary peripheral ports, but they later reverted to just side ports as it didn't really work.
The R.O.S.C.O (ROtary Stratified COmbustion) engine used a small peripheral primary port and high pressure semi-direct injection, but it was not a production engine.

lastphaseofthis

iTrader: (8)

OH snap. now its very clear why pee jay was saying to do it opposite... there will always be
intake draw, or vacuum, pulling in exhaust because of the back to back combustion cycle when the apex seal is passing over the port.
my concept is flawed. i need to reduce the size of the pp to get away of the EGR effect.
thank you thank you thank you blue!

SPENT-IT

iTrader: (15)

Im not new to rotarys and lastphaseofthis post is confusing and wrong.

1" port in the housings and the use of the side ports "is" a SEMI-PP. It doesn't matter what intake configuration you use....and WOT is WOT, either way it's max for max power.

First off i don't care about noise,emissions, or mileage.
I want to use SEMI-PP because of better drivabilty longer engine/apex life and the power will be like a Full-PP.

My idea behind my setup is like the oldschool Weber IDA SEMI-PP intake style but with a longer runner just like the way i have been trying to describe, i thought the idea was pretty simple. I tried to find a picture of a old school SEMI-PP intake for lastphaseofthis with no luck.

So far this thread has gotten off track with no real input about my question...It's about SEMI-PP runner length.

Any input about my idea would be great......What would be the advantage or down fall to having a equal length semi-pp intake runner HP, Torque, topend? Good idea bad idea?

Thanks

lastphaseofthis

iTrader: (8)

semi-pp can mean what ever you want it to mean. if you want semi-pp to mean, a smaller then normal PP that uses side port in conjunction then fine.

but the semi-PP that actually has benefit is more defined as a pp that is staged. a "sometimes PP, sometimes PP and side port." like a honda with vtec. the PP is one cam profile, and the side ports are completely different profile.
good luck with your thread. i'm out.

t-von

iTrader: (8)

I'm general, your runner lengths determine your torque peak. Longer moves it to the left, shorter to the right. There is no good or bad with experimenting with runner lengths as mostly you have to experiment to see what works when it's actually up and running. Build your intake to add or subtract length as neccessary.

diabolical1

iTrader: (3)

i think i know what you're trying to ask because i am sort of going through the same thing right now with my semi-pp (mine is a 13B though). many things to consider and you want to get the best result you possibly can within the confines of your ability (whether that means fabrication skills, budget or both). however, the way you asked the question is kind of awkward.

so just to be clear, are we talking about a total of 3 throttles to service all 9 ports, or are you making the top plate to run a total of 6 throttles (3 sides + 3 peripherals)?

adding the runners to the manifold will work just fine. it's been done.

is it ideal? probably not.

based on my limited understanding of it all, you'll probably be giving up some torque, but will likely have a somewhat decent increase in power. i think ideally, you would want to do something similar to Logan or F1Pilot. as T-von suggested, i think you'll want to have a situation where you can play with lengths and having your runners fixed in a pre-existing manifold doesn't really give you that luxury.

how are you planning to stage the ports, sides first or peripherals first?

SPENT-IT

iTrader: (15)

One TB per rotor just like a old school Weber IDA setup, but the Semi-pp connection will be at the top with a long runner instead of conneting them at the bottom. I wish i could find a picture of the oldschool semi-pp connection. I can do anything as far as fabbing my idea behind using that manifold is for simplicity, less fabbing for me. Injector bungs and rail are already in place. There are not many options as for buying a 20B intake especially a semi-pp one.

There will be no staging, i would never do independent TB for the semi runner why block flow?.... rotarys don't like that. I cosider both of the intakes lastphaseofthis posted to be junk, bad flow and not good for boost if anybody wants to. The blue one on the left has potential if he would have connected the semi-pp runner to the main intake runners.

To anyone learning about PP vs Semi-PP disregard what lastphaseofthis has said, the info is wrong.
One big port in the housing and blocked off side ports is Peripheral Port, AKA PP
A port in the housing no matter what size generally 1" plus the use of the side ports is a Semi Peripheral Port, AKA Semi-PP
Cut and dry, black and white, that's what is is.


I guess what it comes down to is what im doing is experimental...like most things i do LOL....any more input is welcome.




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lastphaseofthis

iTrader: (8)

ya its junk..the one on the left is..
where's your proof that it's wrong? cause all i have is logan's work that backs up what i claim to be CORRECT, which is DYNO PROVEN.

SPENT-IT

iTrader: (15)

LOL in my post #5 i asked you about the result of the intakes and now you say something post#14...LOL

I will get my pop corn also..LOL

I like how you only quote part of what i say when you do. LOL

and what he did is not what im doing. I guess i should have said they don't work for what i want to do...not say it's junk...but if you would read and quote the whole part of what i said you would have a better understanding of what im looking for.


Oh and i will repost this for people who are new to rotarys.

To anyone learning about PP vs Semi-PP disregard what lastphaseofthis has said, the info is wrong.
One big port in the housing and blocked off side ports is Peripheral Port, AKA PP
A port in the housing no matter what size generally 1" plus the use of the side ports is a Semi Peripheral Port, AKA Semi-PP
Cut and dry, black and white, that's what is is.


---------------------------------

lastphaseofthis

iTrader: (8)

go back and read post #6 dummy. you missed my answer! i did answer you.

i only quote the information i am replying too. i certainly don't want to repeat you saying my info is wrong, when my info is based completely on the RECORD HOLDING SEMI PP DESIGN, don't you get it yet? you're wrong. semi PP is just a name that gets thrown around for various designs.
some dummies that completely miss the big picture just see it as a smaller then normal PP that runs side intakes instead of blocking them off. you can't see the forest for the trees.
hmm this popcorn is tasty.

BLUE TII

iTrader: (9)

View Post
My plan is to add a equal length runner with a plate on top for independent 52mm throttle bodys. NA for now, maybe boost later.

Why equal length?
There are a bunch of things going on inside the manifold and equal length between side ports and peripheral ports isn't going to help anything.

Since the peripheral and side intake ports have very different port timing the required lengths for tuning to the dynamic pressure waves will be different.

What peripheral ports want-
It is probably a good idea to isolate the peripheral ports from the side ports though you show disdain for it.

Reason- I have only ever seen peripheral intakes using Helmholtz resonance effects. That is, I have only seen uncollected peripheral port runners on race engines where the pressure wave exits the velocity stack changing from a positive wave force reflecting back as a negative wave force and vice versa.

That is intake 101 stuff, I am sure you are familiar.

What side ports want-
Now, side ports want something different. You can certainly just use the Helmholtz resonance effect with side ports and make great power by having a clear flow path (like Holley 4150 style manifolds) but you are leaving some power on the table as Mazda and the aftermarket found.

You will notice that later Mazda engine connected the primary ports together and the 2ndary ports together to take advantage of the "tournament effect" of reflecting the pressure waves from one port directly into the opposing port without losing energy by changing wave force value from positive to negative.

Mazda used the primaries together and 2ndaries together so they could stage the throttle body opening (primaries alone, then 2ndaries) for best intake velocity/power under the curve/response/driveability.

If you look up Mazda Dynamic Effect Intake you will get SAE papers, etc on the intake tuning.

The aftermarket side port race manifolds use the same "tournament effect" but for a shorter runner length conducive to high rpm power and simplicity/high flow potential they tie the primary to the 2ndary on each rotor together.

Formula Mazda, RE Amemiya GT300 20B and most NA side port race engines you find will have this style intake manifold over the independent runners leading to a plenum so they can take advantage of the Dynamic Effect Intake pressure waves and the Helmholtz resonance pressure waves.

Well, what I just described was the intake manifold shown to you (without the plenum) that made 475rwhp.

He did not have injectors in his semi-p-ports so he couldn't try staging it p-ports first as I suggest for better driveability, but as you say- you don't care you want max power.

lastphaseofthis

iTrader: (8)

i see injectors on the back side feeding the peri ports
i see three orange injector connectors facing upwards.
which begs the question why not periport as the primarys like you suggest... i think there is something we're not seeing.

BLUE TII

iTrader: (9)

Saying all that, there is one style semi-p-port intake I have never seen used that I would like to experiment with myself.

Picture-
A simple short runner from peripheral intake port to a large velocity stack transitioning into an inline (cylindrical) plenum with a large throttle body at the end.

Now, primary and 2ndary port runners curve 90deg into the walls of the cylindrical plenum so that they are facing each other directly just behind the throttle body as in the stock 3rd gen RX-7 2ndary ports.

A sleeve in the cylindrical plenum rotates to close off the stock primary/2ndary side port runners for higher intake velocity to the p-port at lower rpm (more engine torque).

I theorize the P-port will only see the effects of the Helmholtz resonance as its pressure waves will travel the direct path up and down the p-port runner/cylindrical plenum.

However, the side ports will gain the advantages of the Dynamic Effect Intake by opposing each other across the plenum and gain the Helmholtz resonance effects from plenum to throttle body.

I don't know if you could work the proper runner lengths needed into this scheme.

Here is a crude drawing of half the proposed intake manifold (1 rotor)

lastphaseofthis

iTrader: (8)

since we're sharing crude drawings... here is my plan to maximize side port low rpm torque and all out PP peak power. i've notices there isn't alot of room for air to go around the apex seal with my p port location, not as long as the exhaust doesn't have any back pressure...

SPENT-IT

iTrader: (15)

This tread has gone completely crazy.

lastphaseofthis
You posted a picture of someones intake maybe from a build thread that i have never seen. I asked you about it all you told me is how much HP it makes and absolutely nothing about semi-pp intake runner length.That's what the thread is about, read the title. Three times i told you that the throttle bodys will be on top i showed you a picture of where i want to put the runners. In my first post is says i may boost later.
You post misinformation about what a Semi-pp is, it has "nothing" to do with wether the intake has indepentent throttle bodys for the semi-pp runners to make it semi-pp or not. It's all about the holes in the keg/engine.
I will quote you from post #6 "its not that smaller port makes it semi. its that you have throttle bodies for side ports that do you idling/low load, and you stage a second set that go the the pport." This is what im saying is wrong ,not that the intake you posted didn't make 475HP. If that guy made 475HP that is great im happy for him but drilling his HP numbers into my head does nothing for me..no help and his setup it's not what im doing.

You brought someones intake into the thread and have not said a word or any good info about what im asking, just a bunch of nothing and confusion. This thread is about what "im" looking to do.
If you would read the title and read this entire thread over again you will see what im talking about.
Now time to move on.
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Blue TII
Yes i know there are a bunch of things going on inside the manifold that's what the thread is about.
You asked Why equal length? because that will be the end result if i just put TBs on top of that lower intake with a plate with taper/chamfer to direct air flow to the runners.

The reason i show disdain for isolating the peripheral ports it's not needed and has been done a lot in the past, but the runners are joined at a lower point. If i could only find a picture of a Weber IDA intake that has been modded for semi-pp i could show you what im talking about it's driving me nuts that i can't find one.
Some guy with a real nice red RX3 SP and many others have that style of semi-pp intake and that's what i was planing to do on my 13B build. I bought a 20B now im looking to do the same thing with a twist...longer runner because of the style of intake availability makes it hard to join at a lower point.

At this point and the way this thread went i realy don't want to bother talking about it anymore. I just may go ahead and do it, then maybe someday just show my results. Im not looking to break any records or build a dyno queen. I already know that the intake im looking to buy will have a little limitation with NA flow vs a full custom smooth flowing intake....but boost can over ride that.


Thank you to everyone that has posted useful information.

lastphaseofthis

iTrader: (8)

you asked people from another thread to come here.. didn't you read what happened in the other thread.. some dummy asked about building a $1k Pport engine, and while we answered his dumb questions he continued to show he didn't grasp the material, and eventually we ignore him completely and continue talking about REAL Pport building and design.. despite it was " his thread " kinda like how this thread has gone..

you mad bro?

now blue, to keep the information coming, is your drawing a design for a single rotor engine, or just for the sake of your drawing you only illustrated one rotor?

SPENT-IT

iTrader: (15)

If i wanted to talk about what was going on in that thread i would have posted in it....that's why i did what i did because i didn't want to derail that thread,because it's rude.,..wow you don't get it do you.

Are you mad?..no..bye

lastphaseofthis

iTrader: (8)

Bye.

TonyD89

iTrader: (10)

Thanks for the info Blue TII. Very goods conceptual information. I had planned on using motorcycle ITB's and thought, wow, I could have a semi PP too! After reading your post, I don't think it's really possible.