Easy_E1

iTrader: (2)

I have some time tomorrow after I take MM to the airport. I'll come up with some for ya.

Hoss

Also, next to all of their porting options the prices are listed as "N/A", perhaps its a service they dont offer currently.

Ajax

There is a picture of a bridge ported reni on there. It was owned by someone on this forum, i don't remember who.
It was ported at the aux port only so not to impact the idle.
Dave cut through the water jacket and back filled it with something while porting this car. He said he also cleaned up the exhaust and intake ports in the process.

The biggest issue they had with this car was tuning. They tried a LOT of products back then but they could not get it to run right. Back then, the interceptor and e-manage were pretty much all you could get to work with the 8. Cobb's tuner would do the job a lot better.

The motor I'm talking about is here:



EDIT: and yes, renesis in front and that's an FC plate in the back. I had more pics of this as he sent them to me directly way back then. He did this in 05, if I remember right.

Hoss

Is that the BP'ed ren in front and the stock ren in the back? I dont know too much about these motors yet, but have been following this thread for a few days and doing my own research on them as I get questions

So I am assuming that is the stock ren plate in the back, and the bridge ported ren up front? Reason I am assuming such is because I have not seen that third port on any ren images yet. But I also havent seen the third and final port on any renderings or pics of the six port yet...

The 3rd intake port isnt peripheal is it?

chickenwafer

iTrader: (9)

No, that's an FC plate in the background, notice there is no side exhaust port

Hoss

Gotcha, did not pick up on that. Is teh FC plate what was used in teh REW motors?

avanti_racing08

Does this help anybody at all to fig this out???

http://www.turborx7.com/rx8renesis.html

https://www.rx8club.com/showthread.p...hp+non-turbo..

TeamRX8

iTrader: (25)

You're thinking too 1-dimensional. If you don't modify the primary port, but only modify the auxillary and/or secondary port to have overlap, then the primary port will never directly experience the overlap cycle. At the point that the auxillary/secondary overlap occurs the primary port will be covered by the rotor. Neither the auxillary/secondary port will not be operating at low rpm, so it's possible there may be some small EGR effect because you've created a void for some exhaust gas to flow into the auxillary/secondary port cavities even though they aren't operating. However, this happens to some extent anyways once the rotor uncovers them heading toward the intake cycle when they're not operational.

Mazmart

iTrader: (12)

You're description is not bad. Back in the day, people started doing bridge ports on the secondary ports only, with the hope of having the best of both worlds (I first drove one of these street and bridge ports back in 1990). Unfortunately, the breathing dynamics caused them to sound and behave like a full bridge at light throttle low rpm anyhow; even though the secondry throttles were closed. This was later confirmed to me by Mr Engman when I met him. It's probably better to run all bridge or a nice street port. By the way, the renesis can make more power unported than any street port ever done back in the day. Typical street port numbers were around 225 hp give or take with proper tuning with some making as much as 240ish numbers (Flywheel hp of course).

MUCH care should be taken with the ports on the renesis since they are already SO large. Those who have the time and the parts should rig up a device like we use to view the rotor in it's travel in relationship to the ports. It requires you to cut an eccentric shaft. We use it with a degree wheel and try different templates to figure things out. The side seals, as many have heard by now, aren't always happy in consistent 9000+ rpm running. This is due to how they work with the ports (Clipping, scissoring as they travel over and by the port). Any further modification would need to consider these dynamics and the ramifications of creating more power even higher up the rev range including temperature increases.

Bridge ports do sound good though.

Paul.

TeamRX8

iTrader: (25)

I don't claim to be an expert, just posing the idea. Don't you think that in this regard the Renesis is more unique than the earlier application given that the primary port would still operate in a zero overlap configuration?

Mazmart

iTrader: (12)

Nope! The trans-migration of waves (I just made that up by the way) will cause the 0 overlap to be nullified. Rick was saying it would be advantageous to have bridged exhausts but that the bridge would not be able to survive that level of temperature.

Paul.

rotarygod

You can't have zero overlap on one port yet no overlap on another. Well I guess technically you can but overlap doesn't work that way. It works from the standpoint of the intake and exhaust connected somehow through some passage. It doesn't matter where it is. You either have it or you don't. Even a half bridge still has full overlap. The total area that it occurs through is just smaller.

Mazmart

iTrader: (12)

Fred. You must be tired. Re-read your post.

Paul.

Easy_E1

iTrader: (2)

I think what Fred is trying to say and I believe also is,, Overlap occurs between the intake chamber and the exhaust chamber mixing. This is where I stand on overlap.
Ports play a role in this but once an intake port is open to an exhaust port this is where overlap occurs.
Now if there is a cut out in the rotor housing as we were talking about in prior posts, And the rotor apex seals would not have any sealing effect at that cut out. The combustion chamber and exhaust chamber would be open to each other regardless of the intake and exhaust ports. (total time I have yet to determine.) The thing would be the duration of the intake port cut out being open to the exhaust port. As soon as the rotor passes the exhaust port and begins the intake cycle.
Then it goes back to whether the intake and exhaust ports are open to each other at that time to allow this, overlap.
This overlap would occur for only the time as the rotor face passes over the intake port and before the side seals shut the exhaust port before the next exhaust cycle. I think Fred had mentioned 6 degrees.
Did that make any sense?

Another thing that has me curious is how is the beveling of the rotor side going to open a port any sooner? What dictates port opening/closing on a side port are the side seals. All this would do is allow a smoother flow past the edge of the rotor. The rotor does not seal anything. The Apex/side/corner seals do. The reason Mazda did this on the exhaust side was to make sure every bit of exhaust gas had a little extra time to squeeze out. We're not squeezing anything out of the intake side.
So call me crazy. I'll be in the garage taking pictures and stuff.

Mazmart

iTrader: (12)

I was just trying to figure out the difference between zero overlap and no overlap in Fred's post.

Paul.

rotarygod

Erick interpreted me correctly in his first sentence.

blackenedwings

Have I ever mentioned how cool it is that there are people that know this much about the engine chilling on this forum? You guys rock, its always an illuminating experience reading some of your posts. /back to lurking

Mazmart

iTrader: (12)

I understand what you're saying and it's correct. Maybe my phrase was more confusing. What I was trying to say is that you WILL have overlap once you bridge primary or secondary. It doesn't matter.

Paul.

Easy_E1

iTrader: (2)

So here we go. My latest findings.

Let's use the numbers we came up with already on port size and location. (In yellow.)



So here is the port in an approximate size and placement.
The BLACK marking (thin stripe) is where the rotor housing water jacket seal sits.
So the port is cut 1.0/1.5 mm away form that seal.



Here is a video of overlap in a stock Renesis.

STOCK RENESIS

Here is a video of a Bridgeported Renesis. (in theory)

BRIDGEPORTED RENESIS

So you can see that overlap is possible. Just remeber that the rotor housing is cut in like we talked about in prior posts.

Here is your overlap. The RED area is the proposed Bridgeport (cutout). As you can see the exhaust port and the intake port (red) are open to each other.





And the exhaust port shuts. No more overlap.



So if we could do a port like we described we would have a Bridgeported Renesis.

TeamRX8

iTrader: (25)

I don't take challenging the master lightly, but unlike a true overlap scenario the primary port will never actually experience the overlap pulse. It will instead pass over from the exhaust cycle to the intake cycle as an EGR effect at best, The reason is because at the point that the primary intake port is opening the exhaust port has closed and the intake cycle chamber volume is on the increase. Again, this is only occurring under low rpm conditions.

Either way, I doubt we'll really know the effect if any without actually employing the technique, assuming it's possible given the seal complications etc.

Easy_E1

iTrader: (2)

That is the other concern. The Bridge port depicted is on the secondary port side. But the other factor is that the rotor housing is cut and no sealing will occur at that point. So that means the primary port will be open to the exhaust cycle for a short period of time.
This is only going to occur if the rotor housing is cut to match the Bridgeport opening.
Also when you look down the side of the rotor housing there is little room for any type of gas mixing (exhaust/intake). The pocket in the rotor has to be open to both ports to achieve any type of substantial overlap.

Note how close the rotor is to the housing in the pic. RED lines. The GREEN line is where the Rotor Pocket opens up. Another thing to consider in overlap.
The BLUE area is where the rotor housing would be cut out next to the end cast iron plate. Again leaving an open area between the exhaust chamber and the intake chamber.

bse50

Good infos Erick and out of curiosity, what would you do to the exhaust headers considering that the design of ours is meant to work with a 0 overlap engine?
I mean, could we find some gains there at this point or would they all work like actual headers work on stock engines?

jfxp

iTrader: (2)

Thanks Easy E1 for all the pictures and video! This is great stuff. IMO one of the best threads on this forum.

Mazmart

iTrader: (12)

That's the thing: We HAVE employed the technique. Once the secondary intake port is exposed to the exhaust you have overlap. The one side of the rotor isn't isolated from the other side.

Paul.

TeamRX8

iTrader: (25)

On a Renesis

Again, it depends on when and how the overlap occurs, but I'm only looking at it theoretically in my head. Whether my mental idea on how it could be done is possible isn't clear to me without actually attempting it.