Bridge Porting the Renesis
#77
What about These guys?????
http://www.rotaryheads.com/porting/rx8-porting.html
I know it was brought up on the other topic of the one from over seas but nothing really said about them???
http://www.rotaryheads.com/porting/rx8-porting.html
I know it was brought up on the other topic of the one from over seas but nothing really said about them???
#78
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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:
![](http://www.rotaryheads.com/porting/images/renesis-vs-fc.jpg)
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.
#79
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 ![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
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?
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
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?
#82
Qucik Sliver
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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..
http://www.turborx7.com/rx8renesis.html
https://www.rx8club.com/showthread.p...hp+non-turbo..
#83
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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.
The primary port is always open to intake when the engine is running. The secondary port opening on the cast iron face is open to the intake chamber cycle at the same time as the primary port. The auxiliary port (regulated by the SSV) is open to the intake chamber a few degrees behind the secondary port (regulated by the APV). So theoretically if absolutely no intake air is coming through the secondary and auxiliary ports you would have no over lap. If a standard bridge port was implemented in that area. Is this what your saying?
But, if the port design described previously with the Rotor housing being cut back is done there would be an opening to the intake section of the chamber at the same time as the exhaust section of the chamber.
So cutting back the rotor housing is opening the intake cycle to the exhaust cycle. Correct?
So which ever port is open would not matter at this point. The cycles are not separated due to the cut back rotor housing.
There is no seal closing that open area of the rotor housing. It will allow the chambers to meet regardless of which intake port, primary, secondary or auxiliary is open. The apex seal will not close that opening and separate the two chambers at the point.
Overlap will occur.
This is some interesting **** huh?
But, if the port design described previously with the Rotor housing being cut back is done there would be an opening to the intake section of the chamber at the same time as the exhaust section of the chamber.
So cutting back the rotor housing is opening the intake cycle to the exhaust cycle. Correct?
So which ever port is open would not matter at this point. The cycles are not separated due to the cut back rotor housing.
There is no seal closing that open area of the rotor housing. It will allow the chambers to meet regardless of which intake port, primary, secondary or auxiliary is open. The apex seal will not close that opening and separate the two chambers at the point.
Overlap will occur.
This is some interesting **** huh?
#84
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.
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.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Paul.
#86
Paul.
#87
Registered
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.
#89
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.
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.
Last edited by Easy_E1; 06-01-2009 at 06:14 PM.
#92
Life begins @ 30 psi
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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
#93
#94
So here we go. My latest findings.
Let's use the numbers we came up with already on port size and location. (In yellow.)
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis01604-1.jpg)
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.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis009-1.jpg)
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.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis003-3.jpg)
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis004-3.jpg)
And the exhaust port shuts. No more overlap.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis015-1.jpg)
So if we could do a port like we described we would have a Bridgeported Renesis.
Let's use the numbers we came up with already on port size and location. (In yellow.)
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis01604-1.jpg)
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.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis009-1.jpg)
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.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis003-3.jpg)
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis004-3.jpg)
And the exhaust port shuts. No more overlap.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis015-1.jpg)
So if we could do a port like we described we would have a Bridgeported Renesis.
#95
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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.
#96
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.
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.
![](http://i59.photobucket.com/albums/g307/Easy_E1/Bridgeport/bridgeportrenisis00102-1.jpg)
Last edited by Easy_E1; 06-04-2009 at 01:50 PM.
#97
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?
I mean, could we find some gains there at this point or would they all work like actual headers work on stock engines?
#99
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.
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.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Paul.