S5 UIM does not add RPM, the lighter rotors added the extra RPM.

The S5 UIM swap is not a super easy one though.

 

Sorry I mean the s5 uim allows the power curve to continue to the higher RPM allowing for the 10-15 HP. I don't know about the whole ligter rotors bit. O.o

 

Ok, I stand corrected. Admittedly, I was thinking about the primaries, but I didn't realize they had that much different timing.

 

Most of the vendors offer 6 port porting templates. It's the best place to start for someone not familiar with porting.

You'll find that most of these templates are fairly mild with only a few changes in timing (generally opening earlier) and a small enlargement of the port size. The reason for this is to maximize the low end and midrange by keeping velocity up and minimize overlap to keep mileage and drivability decent.

It's unlikely you will get 200 RWHP at 4 PSI without a standalone and a good tune. The stock turbo just isn't pushing that much air.

An RTek is not a standalone.

Not for a turbo application.

 

Ok, thank you for clearing all that up. I shall continue my research.

 

this question really isnt answered. i think that the stock 6
ports close too late for turbo cars compared to a street ported 4 port. but i would like to know the reason for this also. because the 6 ports would be superior on the turbo cars if this wasnt the case.

 

Late closing on a turbo application is not an issue.

 

dont forget the stat gears can also keep this load. try going to s5 rpms without the stat gears.

 

plz explain cause im all ears. what is the issue? (no sarcasm)

 

Unless you start to intrude upon the compression stroke, the turbocharger will continue to pump in air.

 

isnt that what the 6 port does?

 

intrude upon the compression stroke^^

 

Not in a stock config.

 

the right person just answered u

 

from rob at pineapple racing...
http://www.rebuildingrotaryengines.c...rting_overview


...i just want to know if its a superior port for turbo application. why and or why not??

 

* warning I know nothing *

But based off that video ..... it could cause a little pulse to go the the other rotor... That sounds good... I guess....

My question is... In the video you can't port the left of the port or else the side and corner seal will fall out, and you cant port the bottom of the port or else your intake will be open when your exhaust is open and that can't be good for trying to spool a turbo, you can't port the right side or else you are going to clip your oil seal and have a smoke screen behind you......... The only spot I can see you can port for your NA is to either make the little strip between the ports smaller, or to take it away. According to that video .... I don't see why that would cause your intake air velocity to be ungodly slow. The rotor opens up from the side, not from the bottom to the top. (could you explain why it would kill the air speed to take out the middle section? It seems so small to me)


*end warning that I am a dumb a$$*

 

^ As I understand it more air coming in at the same velocity doesn't help until the engine needs more air quicker, higher RPM, and less time to "pull" it in. Think about 310 duration cams in a DOHC motor.

 

Sorry, for some reason I thought you were referring to the 4 port engine. I guess I need to lay off the crack pipe (or hit it harder?).

In theory, keeping the intake open as long as possible in a turbo application will promote better chamber filling. Of course there is a point at which the compression of the rotor will be greater then the intake pressure and you will start forcing the charge back out into the intake.

If you look into the lower intake in an NA engine, you can see how the secondary runners are full of carbon and junk. This is caused by the deposits left by intake reversion as the S4 and S5 NA intakes use the pulse generated by the closing rotor to force air into the opposite rotor.

However the exact opposite is actually true. Overlap is great at spooling turbos because of the misfires created by exhaust dilution. At low speeds you don't have very good combustion so a lot of energy is thrown out the exhaust into the turbine. Of course the side effect is the lump idle and horrid gas mileage, plus a possible lack of low end torque (though the turbo makes up for that and then some!).

You can port a bit towards the rotor housing, and in fact that's what most of the templates do. But you only have about 2.5 - 3 MM before you start to get into an area where you risk the leading edge of the side seal.

This of course is why bridgeports exist. You bring the housing side of the port to the limit, leave a small bridge to support the seals, then port on the other side of that bridge towards (and often into) the rotor housing.

Because you've created a monster port with a HUGE port runner. With such a huge runner the air entering the port just kind of lazily flows along. With a proper sized port, the air volume is forced to gain speed which forces it into the chamber and pulls along more behind it...Not an entirely accurate description but an easy one.

 

Here's my take on porting 6 port engines. I'll start with proven info and finish with a rant on the topic. Don't do much to the ports. They don't need it. Their open timing is the same as a 4 port but the close much later at 80*. That's an awful lot of intake timing. There are so many people that make the mistake of porting these too large. Larger is not always better in regards to porting although many claim it is. I also wouldn't bridgeport the aux ports. It's a waste of time and no one has made any more power with this setup than without. At least not naturally aspirated. A turbo however can compensate for so many screw ups it isn't even funny and the rules change a bit. More on this in a minute.

Do not open those ports up into one large port. If this was a dedicated race engine in a close ratio transmission that sees no street use, go for it. Port velocity will just die. Although on a flowbench a 6 port engine flows less in terms of static flow, dynamic flow is different and they can still make good power right with the 4 ports. There's a good reason for this. Flow is not steady and air has inertia. When the intake ports open on the outer plates, they don't open together. they obviously don't close together either. The secondary ports (the lower ones) open a little bit before the aux ports above them. This gets the air moving through the bottom port runner first. Of course I am assuming that the rotating sleeve is open as well. Velocity of flow is very important not only at full open but also everywhere else. We want velocity of the incoming charge to be as high as possible without going too fast. That's when we get to the need for larger runners. As the ports open, air flows towards the engine. As the ports start to close, the secondary port starts to get closed first. the rotor passes from bottom to top. The secondary port is completely closed before the aux port even starts to close. All of the air moving towards the engine in the intake runners suddenly has only one port runner to flow though. This air has inertia and while there is a small pulse that goes back through the manifold, part of that pulse and much of the moving column of air in the intake runner all cram into the upper port and ram their way into the aux port. This combined with the late closing timing of 80* helps to overcome and keep filling the chamber even though the chamber is starting to get smaller. You only need to hit about 3500 rpm or so for this phenomenon to start taking over.

What if we make the runner one large open area? While it doesn't look like much, you greatly increase runner area. It actually gains by about 50%. Don't look at only the port area. Look at the runner area increase if you open it up. This slows down intake velocity which also means you lessen any inertial effects of the incoming charge. They are still there. It just takes a much higher rpm for their benefits to be realized. Meanwhile down low, you lose power compared to alternative setups. With one giant port, you lose the reversion pulse from the closing secondary port which helps push air into the engine's aux port above it before it closes. You also don't get the forced rush of air through an upper runner. It behave far more conventionally now. Air starts moving, accelerates to a peak and then slows down. On the 6 port engines, air accelerates, peaks, slows down and stops in the bottom port while still flowing in the upper port. The upper port then receives a surge of air and peaks in velocity a second time before closing. 6 ports are good things!

What then about the aux bridgeport? If you look at any successful bridgeported engine, it has 2 very important things. it has a free flowing intake and a free flowing exhaust. Scavenging is very important on a bridgeported engine. If your intake or exhuast are subpar, your bridgeport will be worthless. Sometimes you can make LESS power with a bridgeport as a result. Don't tell anyone though!

Bridging the aux ports is usually justified by people for one simple reason and it's pure human logic. Too bad human logic isn't always logical! People want to be able to keep the aux port sleeves working so their low end and emissions stay good and they want the sleeves to open into a bridgeport so top end can be good. Sounds nice on paper. Too bad it doesn't work for crap. Why? It goes back to flow. The rods that rotate the aux port sleeves run right through the intake runners. They take up a good amount of area too. The sleeves have turbulence through them at the opening as there is a little lip there. The sleeves also have a dead flat angle at the back although this doesn't really hurt anything. The rods restrict airflow. Worse than that, the airflow that does flow through them is very turbulent. What does a bridgeport need? A nice smooth intake system that flows good. Not happening here. Then consider that you've got a tiny intake runner with little area and room for air to turn sharply quickly. A bridgeports advantage is in it's early port opening. There is no intake velocity here to help push air into the engine. An aux bridgeport quickly turns into a noisemaker for use at idle and that's about it. Flow through the upper runner is so bad from the rotating rods that even the radiused 6 port inserts only add a measely 1 cfm or so of airflow at 28" measured H2O on the bench. That isn't crap. A bridgeport can't breathe this way. Remember the benefits of the aux ports and their separate runners despite the poor flow characteristics happens due to a flow and pressure phenomenon that is caused by the inertia of air in the intake runner as the ports are closing. This benefit is not there as the port opens and why a bridgeport can't gain from it.

I know someone will just say to leave the sleeves out altogether. Now you've got all of the disadvantages of a bridgeport on a street car but without the nice power gains that a bridgeport should give you. Bridge it all or don't bridge any of it but pick one. If you aren't using a true standalone ecu and aftermarket intake manifolds, a bridgeport is a waste of time anyways.

A turbo setup on the other hand is slightly different. It needs to be mentioned because if I don't someone is going to assume this applies to all setups. A turbo is an amazing device. It gives us pressure. Pressure hides many flaws. Look at Supra setups! What ultimately is making the 6 port upper ports dynamically flow so well despite the turbulence? Pressure! It's the pressure from the inertia of the column of air in the runners. A turbo forces air into the engine. If you have even a small bridgeport, the turbo will force air through it. It does the work of moving the air through the runners and the ports. On an n/a engine, the engine does the work. Air does different things when it's being pulled on vs pushed on.

Basically on a 6 port, just buy the 6 port template from Mazdatrix. I know some people say that it is mild. That's fine. That's all it needs to be. Larger isn't going to get you anything more. The secondary runners need to get smoothed out and can be opened ever so slightly earlier. The aux ports can be opened earlier but should not be close later. The primary ports can gain in size a decent amount but don't try to get too greedy. You can hit the water jacket pretty easily. The intake runners on the primaries aren't very large anyways so trying to go too large on these is futile at best.

This combo would be very nice. It makes good streetable power and is very drivable. The ports themselve physically flow enough at this point to top 200 rwhp. Does that mean you'll get that much power? Not necessarily. You need to have everything else matched up perfectly. It'll also have to be tuned. The engine may have the potential to hit that much power but the rest of the system may not. When you view it like that, there's not much point in trying to port larger when you can't use it anyways. If more people would stay mild in regards to porting, we'd see more faster cars than we do now. Sounds like a paradox but it's true.

Here's the rant part: Now I don't want some nonbeliever to get on my case and give the standard response of "theory is all fine... yada yada yada...". This is FACT. This is the default excuse used by people that know NOTHING about the topic. This isn't the cartoons and you aren't Wile E. Coyote. Just because you don't know the law of gravity doesn't mean it still doesn't apply to you. In the same fashion, ignorance to a topic doesn't change fact and it doesn't matter if you want to believe those facts or not! I don't like people that don't know how things work to question it somehow believing they can change the laws of physics. You don't have to agree with it or even believe it but at the end of the day this is the way it is. I also don't want to hear from people that still try these things with an excuse along the lines of "just because everyone else that has ever tried it has had bad luck doesn't mean that I will". Yeah. Right!

 

always enlightening

 

rotarygod Thank You. That is the information I needed.

Thanks you again.

Ok, well I am going to do the recommended mild port to the secondary and aux port, and just use the t2 primary ports. I will be using a wolf3d to tuning and fun.

You pretty much answered all my questions. Except one. Does the "phenomenon" work better or worse while in boost? My human logic (that is wrong most the time) says that it would work better, like a shock wave that is created from closing the throttle while in boost. (and the blow off valve releases the pressure wave) Although it really doesn't matter I just wondered if "phenomenon" had an even greater effect...

But maybe the turbo's pressure kinda masks it anyways... hmm

anyways THANK YOU for taking the time to explain that.

 

I guess I'll write a little on turbo systems too! As long as you have a port that closes, you'll have a pressure wave that can either help or hurt you. Now saying that, it is more critical on a nonboosted engine. On a turbo car you really want to let the boost do the work. Much of the accepted way of doing things on a turbo car comes from n/a experience but that doesn't mean it's the optimal way of doing things. People think that since a shorter intake runner makes more top end power on an n/a that is must on a turbo too. It does seem like it does too but there's something even more powerful in this regards on those engines and that is exhaust a/r. On a turbo engine you want a LONGER intake runner! Why? First let's look at something different.

What effect does a smaller exhaust wheel and/or a/r ratio have on boost? It allows boost to come online faster. However it does this at the expense of a flow restriction at higher flow levels which ultimately holds total power down. We always see people try to balance this out. A larger wheel/housing typically gives slower spool but greater top end due to increased exhaust flow. As with anything there is always the exception to that somewhere.

Since that's out of the way, I can go back to the intake length. For a turbo you want longer. Here's the reason. What makes a turbo spin? Flow. How do we increase flow? Increase power or rpms. Increasing rpms is obvious. How about power at lower rpms? Isn't that the point of a smaller a/r or exhaust wheel? How about we run longer in take runners. You aren't always in boost. The key to getting the best performance is to get into boost as fast as possible. If we use longer intake runners, we will make more low end power when not in boost. More power means more energy out the exhaust ports. More energy out the exhaust ports means we now spin a turbo faster at the same rpm. See how this works? Now we can adjust to a larger exhaust wheel or housing and keep the same spool characteristics as the smaller more restrictive wheel. A larger wheel flows better and typically makes more top end power. It's better everywhere. It doesn't matter that the intake runners are "tuned" for too low of an rpm. Remember boost is wonderful stuff. Let it do it's job. We aren't relying on a tuned length to help pull air into the engine. We are pushing it in. Let the manifold do it's job off boost and let the turbo do it's job on boost.

There is really so much more to it than this but you get the point.

 

Soooooo would you consider a 6 port turbo a waste?

 

Nope. Go for it! It's a better motor than most give it credit for.

 

I'd like to say how much I enjoy reading your posts. Yours are some of the few posts on this forum that make me stop what I'm doing and pay complete attention. Always a lot of info with attention to detail.

Isn't that what I've been saying in this thread?

No reason to do something like that. You can easily port the NA center iron to "TII specs". But likely you will port it larger then stock so you can use the NA iron if you want because the casting is the same.

I'd recommend a standalone that isn't a royal pain in the *** and actually supports rotary ignition. Something like the Haltech or Microtech.

The higher the pressure differential between the chamber and the intake manifold means greater flow and more velocity, which ends up creating stronger intake pulses. Most of the tuning in an NA application is perfectly valid for turbo applications. It's just generally easier to up the boost instead of make a tonne of intake manifold prototypes...