The Great Renesis Porting Project!
11-16-2004, 09:06 PM
#6
port hacker
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i'm not an expert on renesis engines by any means, but i'll share what i did. feel free to critique, but try to be positive.
the intake is great to begin with, so not much there. just beveled the edges and brought up the inner edge to look a little more similar to the 4 port config. and for the rest, just the usual stuff, deburred the runners and on the secondary ports, there was a lot to be removed from the outside edge leading into the port runner. not very drastic though--i think the power is gonna come from the exhaust.
and for the exhaust...
i advanced the port opening a bit, but again, nothing drastic. the exiting gas has to make basically 2 90 degree turns to exit the engine. not really good for flow--which may be part of the contributing factor to exhaust systems not adding a whole lot of power (according to racing beat, anyway). i believe the restriction is in the port itself.
so i gave it a big radiused edge, and angled the boundry layer instead of having it come straight down, then make a 90 degree turn. it now starts at about 70 or so degrees, and makes a nice, gentle roll towards the sleeve. (this is all from the top view perspective)
and in everything, i was keeping the "line of sight" in mind. if you can see the combustion chamber from the outside port exit, it's good. the less turns, the better.
so that's what i did in a nutshell. i'd appreciate any constructive critisism if anyone has any so i can do an even better job next time. if anyone else has done it and is willing to share, i'd like to hear about it.
the intake is great to begin with, so not much there. just beveled the edges and brought up the inner edge to look a little more similar to the 4 port config. and for the rest, just the usual stuff, deburred the runners and on the secondary ports, there was a lot to be removed from the outside edge leading into the port runner. not very drastic though--i think the power is gonna come from the exhaust.
and for the exhaust...
i advanced the port opening a bit, but again, nothing drastic. the exiting gas has to make basically 2 90 degree turns to exit the engine. not really good for flow--which may be part of the contributing factor to exhaust systems not adding a whole lot of power (according to racing beat, anyway). i believe the restriction is in the port itself.
so i gave it a big radiused edge, and angled the boundry layer instead of having it come straight down, then make a 90 degree turn. it now starts at about 70 or so degrees, and makes a nice, gentle roll towards the sleeve. (this is all from the top view perspective)
and in everything, i was keeping the "line of sight" in mind. if you can see the combustion chamber from the outside port exit, it's good. the less turns, the better.
so that's what i did in a nutshell. i'd appreciate any constructive critisism if anyone has any so i can do an even better job next time. if anyone else has done it and is willing to share, i'd like to hear about it.
11-16-2004, 09:12 PM
#8
Registered
Originally Posted by guitarjunkie28
i'm not an expert on renesis engines by any means, but i'll share what i did. feel free to critique, but try to be positive.
the intake is great to begin with, so not much there. just beveled the edges and brought up the inner edge to look a little more similar to the 4 port config. and for the rest, just the usual stuff, deburred the runners and on the secondary ports, there was a lot to be removed from the outside edge leading into the port runner. not very drastic though--i think the power is gonna come from the exhaust.
and for the exhaust...
i advanced the port opening a bit, but again, nothing drastic. the exiting gas has to make basically 2 90 degree turns to exit the engine. not really good for flow--which may be part of the contributing factor to exhaust systems not adding a whole lot of power (according to racing beat, anyway). i believe the restriction is in the port itself.
so i gave it a big radiused edge, and angled the boundry layer instead of having it come straight down, then make a 90 degree turn. it now starts at about 70 or so degrees, and makes a nice, gentle roll towards the sleeve. (this is all from the top view perspective)
and in everything, i was keeping the "line of sight" in mind. if you can see the combustion chamber from the outside port exit, it's good. the less turns, the better.
so that's what i did in a nutshell. i'd appreciate any constructive critisism if anyone has any so i can do an even better job next time. if anyone else has done it and is willing to share, i'd like to hear about it.
the intake is great to begin with, so not much there. just beveled the edges and brought up the inner edge to look a little more similar to the 4 port config. and for the rest, just the usual stuff, deburred the runners and on the secondary ports, there was a lot to be removed from the outside edge leading into the port runner. not very drastic though--i think the power is gonna come from the exhaust.
and for the exhaust...
i advanced the port opening a bit, but again, nothing drastic. the exiting gas has to make basically 2 90 degree turns to exit the engine. not really good for flow--which may be part of the contributing factor to exhaust systems not adding a whole lot of power (according to racing beat, anyway). i believe the restriction is in the port itself.
so i gave it a big radiused edge, and angled the boundry layer instead of having it come straight down, then make a 90 degree turn. it now starts at about 70 or so degrees, and makes a nice, gentle roll towards the sleeve. (this is all from the top view perspective)
and in everything, i was keeping the "line of sight" in mind. if you can see the combustion chamber from the outside port exit, it's good. the less turns, the better.
so that's what i did in a nutshell. i'd appreciate any constructive critisism if anyone has any so i can do an even better job next time. if anyone else has done it and is willing to share, i'd like to hear about it.
I'd love to see a dyno too.
11-16-2004, 09:17 PM
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port hacker
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haven't taken pics because i gots no cam 
if anyone is close to hesperia, i'd love to get some taken--i'll buy lunch.
and as for how it runs... i don't know, and i won't ever find out. this engine is going to get turbo'd when it goes back together next week. i really want to find out though. i bet it would make quite a bit more power throughout the rpm range.
one thing i forgot to mention before is the water jacket! it is extremely close to the port wall. being the redneck i am, i hogged right through it and took it to a shop and had them weld it back up, then i cleaned the port up again. fairly simple, but worth mentioning that there is not very much you can do to the exhaust port without going through the wall.
if anyone is close to hesperia, i'd love to get some taken--i'll buy lunch.
and as for how it runs... i don't know, and i won't ever find out. this engine is going to get turbo'd when it goes back together next week. i really want to find out though. i bet it would make quite a bit more power throughout the rpm range.
one thing i forgot to mention before is the water jacket! it is extremely close to the port wall. being the redneck i am, i hogged right through it and took it to a shop and had them weld it back up, then i cleaned the port up again. fairly simple, but worth mentioning that there is not very much you can do to the exhaust port without going through the wall.
Last edited by guitarjunkie28; 11-16-2004 at 09:18 PM. Reason: please excuse my typos...my fingers are cold
11-16-2004, 10:04 PM
#13
Kaiten Kenbu Rokuren
I'd love to hear more about porting the renesis. I wish more people would do it so that I could get a feel for what it would do power wise, go port your engines!! :D
I'd really like to see comparitive dynos with and without porting and maybe some timeslips. I know Ito should hopefully have some of that soon, but a larger sample space is always better for measuring averages. Thanks to anyone with more info, and to guitar for his writeup.
I'd really like to see comparitive dynos with and without porting and maybe some timeslips. I know Ito should hopefully have some of that soon, but a larger sample space is always better for measuring averages. Thanks to anyone with more info, and to guitar for his writeup.
11-16-2004, 10:35 PM
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if the sleeve in the intermediate iron was removed, it'd free up heaploads of space in the port. anyone know if the motor would care if the exit wasn't divided? would it maybe be a good idea to remove all the sleeves? or would that be detrimental to anything?
this will have a custom turbo manifold made.
this will have a custom turbo manifold made.
11-16-2004, 10:48 PM
#16
Kaiten Kenbu Rokuren
Originally Posted by guitarjunkie28
if the sleeve in the intermediate iron was removed, it'd free up heaploads of space in the port. anyone know if the motor would care if the exit wasn't divided? would it maybe be a good idea to remove all the sleeves? or would that be detrimental to anything?
this will have a custom turbo manifold made.
this will have a custom turbo manifold made.
11-16-2004, 11:20 PM
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we're still looking into what to use for fi.
i used to be a big haltech fan..until the "x" series came out. that pretty much ruined it for them.
the aux ports may or may not go back in. we might test it both ways and see what's up. in any case, they're going to be a bitch-as they're electronically controlled, instead of pressure actuated like on the 2nd gen rx7's. my prediction is they'll probably end up being omitted and we'll just deal with the low end, but don't quote me on that yet.
in the end, we may leave the stock computer in there, and use either a piggy back, or a combination of that, aic, and ignition timing control. it's still up in the air right now.
i used to be a big haltech fan..until the "x" series came out. that pretty much ruined it for them.
the aux ports may or may not go back in. we might test it both ways and see what's up. in any case, they're going to be a bitch-as they're electronically controlled, instead of pressure actuated like on the 2nd gen rx7's. my prediction is they'll probably end up being omitted and we'll just deal with the low end, but don't quote me on that yet.
in the end, we may leave the stock computer in there, and use either a piggy back, or a combination of that, aic, and ignition timing control. it's still up in the air right now.
11-16-2004, 11:26 PM
#18
Kaiten Kenbu Rokuren
Originally Posted by guitarjunkie28
we're still looking into what to use for fi.
i used to be a big haltech fan..until the "x" series came out. that pretty much ruined it for them.
the aux ports may or may not go back in. we might test it both ways and see what's up. in any case, they're going to be a bitch-as they're electronically controlled, instead of pressure actuated like on the 2nd gen rx7's. my prediction is they'll probably end up being omitted and we'll just deal with the low end, but don't quote me on that yet.
in the end, we may leave the stock computer in there, and use either a piggy back, or a combination of that, aic, and ignition timing control. it's still up in the air right now.
i used to be a big haltech fan..until the "x" series came out. that pretty much ruined it for them.
the aux ports may or may not go back in. we might test it both ways and see what's up. in any case, they're going to be a bitch-as they're electronically controlled, instead of pressure actuated like on the 2nd gen rx7's. my prediction is they'll probably end up being omitted and we'll just deal with the low end, but don't quote me on that yet.
in the end, we may leave the stock computer in there, and use either a piggy back, or a combination of that, aic, and ignition timing control. it's still up in the air right now.
Last edited by Aoshi Shinomori; 11-16-2004 at 11:41 PM.
11-17-2004, 12:44 AM
#20
Registered
I don't see alot of potential for the intake ports. I'm not going into bridgeports since we really don't know how the engine responds with less drastic forms of porting yet. No need to jump the gun.
On the intake ports, I would mainly focus on the short turn radius where the port runners turn into the ports entering the engine. It sounds like you have done this. I'd also add a minor bevel or radius to the closing side of the ports. Nothing serious that would necessarily enlarge them. Just take the sharp edge off of things for seal longevity. I would probably enlarge the primary ports a little. They really can't open any earlier but they can close a little later. I wouldn't even enlarge the auxillary ports to make them close later either. You can get too late. Try to convince the RX-7 guys that. Basically it's extend the closing time of the primary ports a little and work on the short turn radius of the runners.
The exhaust side needs more help than anything. If you hit the water jacket, you went much more crazy than I would. The ports can be opened quite a bit earlier but I wouldn't go down any farther than the bottom of the exhaust runner. Those who have never seen a Renesis taken apart may be a little confused by this. There should be no issues at all in regards to hitting the water jacket. The short turn radius of the exhaust ports is absolutely horrid. It is very sharp 90 degree bends. The sleeves need alot of grinding down to take care of this issue. It sounds like you got that taken care of if you can see inside the engine through the exhaust runners. I would not just remove the exhaust sleeves. You probably won't get as much from this as you think you will but you will succeed in getting more exhaust runner area. This isn't necessarily a good thing since the ports shouldn't be able to outflow them anyways. What you will do is to slow the exhaust gasses down and hurt low end performance more than just leaving them alone. Machining a new center sleeve may prove worthwhile. I'd personally like to see each exhaust port have it's own runner and then use more of a conventional header. The exhaust ports in the engine are so restrictive stock and kill the velocity through the short turn radius to the point that any benefit you get after this point is irrelevant. Combine this with siamesed center ports and no port overlap, and you have an exhaust that can't help you at all. I believe with porting and seperation of the center runners that this can be changed.
I wouldn't worry so much about Haltech. If you like their older stuff then by all means use an older ecu. You will need to use a conventional style throttlebody though. Only the Motec systems that I am aware of have the ability to control drive by wire. I think you should leave the S-DAIS system active. With the exception of the auxillary ports, the rest are all vacuum or rather pressure actuated. This would be very easy to set up using positive pressure air from the turbo and rpm activated vacuum switches. It is simple. The electric auxillary ports could work based off an rpm switch as well. Keep all of the off boost drivability. Leave it all working. It isn't hard to do. You are going through so much trouble. Don't skimp here. Also I wouldn't use the stock ecu with a piggyback unless you absolutely have to. Always use a standalone if you can. The stock ecu still makes tuning a bitch. change over to a more conventional fuel system as well.
If you are going to all of the effort of porting it and fabbing up forced induction, finish the job with a better fuel system and ecu as well. If you don't, you'll probably end up doing it all again later.
On the intake ports, I would mainly focus on the short turn radius where the port runners turn into the ports entering the engine. It sounds like you have done this. I'd also add a minor bevel or radius to the closing side of the ports. Nothing serious that would necessarily enlarge them. Just take the sharp edge off of things for seal longevity. I would probably enlarge the primary ports a little. They really can't open any earlier but they can close a little later. I wouldn't even enlarge the auxillary ports to make them close later either. You can get too late. Try to convince the RX-7 guys that. Basically it's extend the closing time of the primary ports a little and work on the short turn radius of the runners.
The exhaust side needs more help than anything. If you hit the water jacket, you went much more crazy than I would. The ports can be opened quite a bit earlier but I wouldn't go down any farther than the bottom of the exhaust runner. Those who have never seen a Renesis taken apart may be a little confused by this. There should be no issues at all in regards to hitting the water jacket. The short turn radius of the exhaust ports is absolutely horrid. It is very sharp 90 degree bends. The sleeves need alot of grinding down to take care of this issue. It sounds like you got that taken care of if you can see inside the engine through the exhaust runners. I would not just remove the exhaust sleeves. You probably won't get as much from this as you think you will but you will succeed in getting more exhaust runner area. This isn't necessarily a good thing since the ports shouldn't be able to outflow them anyways. What you will do is to slow the exhaust gasses down and hurt low end performance more than just leaving them alone. Machining a new center sleeve may prove worthwhile. I'd personally like to see each exhaust port have it's own runner and then use more of a conventional header. The exhaust ports in the engine are so restrictive stock and kill the velocity through the short turn radius to the point that any benefit you get after this point is irrelevant. Combine this with siamesed center ports and no port overlap, and you have an exhaust that can't help you at all. I believe with porting and seperation of the center runners that this can be changed.
I wouldn't worry so much about Haltech. If you like their older stuff then by all means use an older ecu. You will need to use a conventional style throttlebody though. Only the Motec systems that I am aware of have the ability to control drive by wire. I think you should leave the S-DAIS system active. With the exception of the auxillary ports, the rest are all vacuum or rather pressure actuated. This would be very easy to set up using positive pressure air from the turbo and rpm activated vacuum switches. It is simple. The electric auxillary ports could work based off an rpm switch as well. Keep all of the off boost drivability. Leave it all working. It isn't hard to do. You are going through so much trouble. Don't skimp here. Also I wouldn't use the stock ecu with a piggyback unless you absolutely have to. Always use a standalone if you can. The stock ecu still makes tuning a bitch. change over to a more conventional fuel system as well.
If you are going to all of the effort of porting it and fabbing up forced induction, finish the job with a better fuel system and ecu as well. If you don't, you'll probably end up doing it all again later.
11-17-2004, 12:56 AM
#21
Kaiten Kenbu Rokuren
Originally Posted by rotarygod
I don't see alot of potential for the intake ports. I'm not going into bridgeports since we really don't know how the engine responds with less drastic forms of porting yet. No need to jump the gun.
On the intake ports, I would mainly focus on the short turn radius where the port runners turn into the ports entering the engine. It sounds like you have done this. I'd also add a minor bevel or radius to the closing side of the ports. Nothing serious that would necessarily enlarge them. Just take the sharp edge off of things for seal longevity. I would probably enlarge the primary ports a little. They really can't open any earlier but they can close a little later. I wouldn't even enlarge the auxillary ports to make them close later either. You can get too late. Try to convince the RX-7 guys that. Basically it's extend the closing time of the primary ports a little and work on the short turn radius of the runners.
The exhaust side needs more help than anything. If you hit the water jacket, you went much more crazy than I would. The ports can be opened quite a bit earlier but I wouldn't go down any farther than the bottom of the exhaust runner. Those who have never seen a Renesis taken apart may be a little confused by this. There should be no issues at all in regards to hitting the water jacket. The short turn radius of the exhaust ports is absolutely horrid. It is very sharp 90 degree bends. The sleeves need alot of grinding down to take care of this issue. It sounds like you got that taken care of if you can see inside the engine through the exhaust runners. I would not just remove the exhaust sleeves. You probably won't get as much from this as you think you will but you will succeed in getting more exhaust runner area. This isn't necessarily a good thing since the ports shouldn't be able to outflow them anyways. What you will do is to slow the exhaust gasses down and hurt low end performance more than just leaving them alone. Machining a new center sleeve may prove worthwhile. I'd personally like to see each exhaust port have it's own runner and then use more of a conventional header. The exhaust ports in the engine are so restrictive stock and kill the velocity through the short turn radius to the point that any benefit you get after this point is irrelevant. Combine this with siamesed center ports and no port overlap, and you have an exhaust that can't help you at all. I believe with porting and seperation of the center runners that this can be changed.
I wouldn't worry so much about Haltech. If you like their older stuff then by all means use an older ecu. You will need to use a conventional style throttlebody though. Only the Motec systems that I am aware of have the ability to control drive by wire. I think you should leave the S-DAIS system active. With the exception of the auxillary ports, the rest are all vacuum or rather pressure actuated. This would be very easy to set up using positive pressure air from the turbo and rpm activated vacuum switches. It is simple. The electric auxillary ports could work based off an rpm switch as well. Keep all of the off boost drivability. Leave it all working. It isn't hard to do. You are going through so much trouble. Don't skimp here. Also I wouldn't use the stock ecu with a piggyback unless you absolutely have to. Always use a standalone if you can. The stock ecu still makes tuning a bitch. change over to a more conventional fuel system as well.
If you are going to all of the effort of porting it and fabbing up forced induction, finish the job with a better fuel system and ecu as well. If you don't, you'll probably end up doing it all again later.
On the intake ports, I would mainly focus on the short turn radius where the port runners turn into the ports entering the engine. It sounds like you have done this. I'd also add a minor bevel or radius to the closing side of the ports. Nothing serious that would necessarily enlarge them. Just take the sharp edge off of things for seal longevity. I would probably enlarge the primary ports a little. They really can't open any earlier but they can close a little later. I wouldn't even enlarge the auxillary ports to make them close later either. You can get too late. Try to convince the RX-7 guys that. Basically it's extend the closing time of the primary ports a little and work on the short turn radius of the runners.
The exhaust side needs more help than anything. If you hit the water jacket, you went much more crazy than I would. The ports can be opened quite a bit earlier but I wouldn't go down any farther than the bottom of the exhaust runner. Those who have never seen a Renesis taken apart may be a little confused by this. There should be no issues at all in regards to hitting the water jacket. The short turn radius of the exhaust ports is absolutely horrid. It is very sharp 90 degree bends. The sleeves need alot of grinding down to take care of this issue. It sounds like you got that taken care of if you can see inside the engine through the exhaust runners. I would not just remove the exhaust sleeves. You probably won't get as much from this as you think you will but you will succeed in getting more exhaust runner area. This isn't necessarily a good thing since the ports shouldn't be able to outflow them anyways. What you will do is to slow the exhaust gasses down and hurt low end performance more than just leaving them alone. Machining a new center sleeve may prove worthwhile. I'd personally like to see each exhaust port have it's own runner and then use more of a conventional header. The exhaust ports in the engine are so restrictive stock and kill the velocity through the short turn radius to the point that any benefit you get after this point is irrelevant. Combine this with siamesed center ports and no port overlap, and you have an exhaust that can't help you at all. I believe with porting and seperation of the center runners that this can be changed.
I wouldn't worry so much about Haltech. If you like their older stuff then by all means use an older ecu. You will need to use a conventional style throttlebody though. Only the Motec systems that I am aware of have the ability to control drive by wire. I think you should leave the S-DAIS system active. With the exception of the auxillary ports, the rest are all vacuum or rather pressure actuated. This would be very easy to set up using positive pressure air from the turbo and rpm activated vacuum switches. It is simple. The electric auxillary ports could work based off an rpm switch as well. Keep all of the off boost drivability. Leave it all working. It isn't hard to do. You are going through so much trouble. Don't skimp here. Also I wouldn't use the stock ecu with a piggyback unless you absolutely have to. Always use a standalone if you can. The stock ecu still makes tuning a bitch. change over to a more conventional fuel system as well.
If you are going to all of the effort of porting it and fabbing up forced induction, finish the job with a better fuel system and ecu as well. If you don't, you'll probably end up doing it all again later.
11-17-2004, 01:33 AM
#22
Registered
I'm a real estate agent! I just work on my own and freind's rotaries alot. I also played around and studied the Renesis housings at Racing Beat during Sevenstock weekend. You learn alot just looking at them.
I'd love to open my own rotary shop up. This wouldn't be hard since I would just tack it on to a friend's auto performance shop. He's offered me the opportunity. The hard part is knowing that I'll have steady traffic and therefore income. Time is already at a premium. I'd really have to drastically reduce my job as a real estate agent and I don't think a rotary shop would pay as well. There is alot to think about. It would be better if I just trained my friend to work on them. He is almost exclusively just a track car person so regular performance minded ricer types just don't go there. He does have a 4 wheel dyno on the way though! It will be installed in the very near future. He's got 4 lifts, a tire changing and balancing machine and an alignment machine. It would be a nice setup. It would just require too much money up front and too much of my time. I'd rather get ahold of a car and develop bolt on pieces and just sell and install them through him. This is more realistic but even then I'd need a car to begin prototyping with. That still leaves me with the time to do it dilemna. Oh well. It would be fun but I don't think I'd want a career out of it. I would like to be an Axial flow supercharger retailer though.
I'd love to open my own rotary shop up. This wouldn't be hard since I would just tack it on to a friend's auto performance shop. He's offered me the opportunity. The hard part is knowing that I'll have steady traffic and therefore income. Time is already at a premium. I'd really have to drastically reduce my job as a real estate agent and I don't think a rotary shop would pay as well. There is alot to think about. It would be better if I just trained my friend to work on them. He is almost exclusively just a track car person so regular performance minded ricer types just don't go there. He does have a 4 wheel dyno on the way though! It will be installed in the very near future. He's got 4 lifts, a tire changing and balancing machine and an alignment machine. It would be a nice setup. It would just require too much money up front and too much of my time. I'd rather get ahold of a car and develop bolt on pieces and just sell and install them through him. This is more realistic but even then I'd need a car to begin prototyping with. That still leaves me with the time to do it dilemna. Oh well. It would be fun but I don't think I'd want a career out of it. I would like to be an Axial flow supercharger retailer though.
11-17-2004, 02:58 AM
#23
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thanks a lot for the input!!
a few things i'd like more clarification on though:
1) intake closing time. i can understand the adverse effect on a naturally aspirated engine, but i think it would help a turbocharged engine (once the turbo gets spoolin' anyway). in any reguard, i only extended them about 1mm of actual removal. the rest was just the bevel.
2) i'm unclear as to whether you're in favor of removing the sleeve from the intermediate housing. did you mean to remove it, and machine a new one that is fully divided? the runners are just tiny tiny...i'm wondering if it might help to just get rid of the center all together. (keep in mind it's only on this one turbocharged engine).
thanks again for the good advice. exactly the kind of constructive critisism i was hoping for. major props!!
a few things i'd like more clarification on though:
1) intake closing time. i can understand the adverse effect on a naturally aspirated engine, but i think it would help a turbocharged engine (once the turbo gets spoolin' anyway). in any reguard, i only extended them about 1mm of actual removal. the rest was just the bevel.
2) i'm unclear as to whether you're in favor of removing the sleeve from the intermediate housing. did you mean to remove it, and machine a new one that is fully divided? the runners are just tiny tiny...i'm wondering if it might help to just get rid of the center all together. (keep in mind it's only on this one turbocharged engine).
thanks again for the good advice. exactly the kind of constructive critisism i was hoping for. major props!!
11-17-2004, 03:08 AM
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Might want to contact Racing Beat. i know they have done a bit on porting the Renesis, maybe you could offer some valuable insight to each other. I know somebody asked Jim M. during the session if they had ported the Renesis, and he said they had, but only came up with about 4-8 hp, not much.
11-17-2004, 03:17 AM
#25
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You have to consider that you can only get so much air into the engine with forced induction regardless of timing duration. Let's just say that you are running 10 psi of boost. Once the pressure in the engine reaches 10 psi while the port is still open, you aren't getting any more air into it. There's no point in holding the port open any longer. You want it to start compressing as early as possible for best power. With low port timing you may or may not ever get to this point since the engine may never reach 10 psi while the ports are open but the 6 port engine has an awful lot of time to fill up, especially when the inlets are smoother and flow better and faster. The auxillary ports already stay open until 80 degrees. How much later do you need them open? A mm probably won't matter much but you still can get too much timing, even on a turbo motor.
I favor a new divided exhaust sleeve. Unfortunately you can't get around fairly poor flow characteristics here but you can improve on them. The problem with removing the sleeve is that the hot exhaust gasses from one rotor will directly blast the other rotor. This will also send a strong pulse directly into the other chamber. You don't want this. The runner area for the exhaust may be tiny but take some measurements and determine the total area for each rotor. Now compare this to the total area for the older engines. Here's a hint, the old engine exhaust sleeves expanded greatly over a very short distance. The 2" pipes that everyone uses are much larger than the exhaust port area. They are actually only equivalent to a 1 5/8" pipe! I'll bet the Renesis has more area than that.
If you try a divided sleeve, also try a completely seperate true dual exhaust setup. One pipe and muffler per rotor. No collector. I'll bet the car has tons more low end. This setup works great on low overlap engines.
I favor a new divided exhaust sleeve. Unfortunately you can't get around fairly poor flow characteristics here but you can improve on them. The problem with removing the sleeve is that the hot exhaust gasses from one rotor will directly blast the other rotor. This will also send a strong pulse directly into the other chamber. You don't want this. The runner area for the exhaust may be tiny but take some measurements and determine the total area for each rotor. Now compare this to the total area for the older engines. Here's a hint, the old engine exhaust sleeves expanded greatly over a very short distance. The 2" pipes that everyone uses are much larger than the exhaust port area. They are actually only equivalent to a 1 5/8" pipe! I'll bet the Renesis has more area than that.
If you try a divided sleeve, also try a completely seperate true dual exhaust setup. One pipe and muffler per rotor. No collector. I'll bet the car has tons more low end. This setup works great on low overlap engines.