The Great Renesis Porting Project!
Kaiten Kenbu Rokuren
Joined: Jul 2004
Posts: 934
Likes: 2
From: Central Valley, NY
Originally Posted by rotarygod
I met Rob at Sevenstock. I will say that he is a very well spoken person and he is very easy to believe because he talks so well. I will also not hide the fact that I disagree strongly with several things he believes in. Flowtesting is one of them. It happens and I hope he doesn't take it personal because I do believe him to be a good and honorable person. I know he's done this for a long time and he does know alot about rotaries. What he doesn't know though (and this is my opinion) is about the science and dynamics of airflow and pressure. The only person to truly belive on this subject is Paul Yaw. I remind everyone that they should read his article on flow testing. I'll dissect Pineapple's comments from the above quote to show you how this statement is actually true but it is missing something very important.
First of all, if you aren't testing, you're guessing. Period. To say that flowtesting on a rotary is worthless is to justify ones own lack of testing. It's plain and simple, an excuse. Excuses aren't results though. Just because something works better than stock, doesn't mean it can't be improved upon. Anyone can take a die grinder and make a port larger and get more power. Someone who flow tests can get the same flow result with a smaller port. This is a wider powerband with more average power. If I'm going to take an engine apart and modify it, I'd like to know that I am getting the most for my money and effort rather than just simply "more". Anyways enough with the rambling. I'll requote the post and then answer it.
"Flowbenches are great tools, particularly for piston engine work."
Yes they are.
"However, their usefulness in porting rotary engines is virtually nonexistant."
Really? Explain...
"First, there is no easy way to simulate the operational characteristics of rotary engine ports."
And there is on a piston engine? This comment is too vague so let's go on...
"Simply strapping a side housing to a flow bench and measuring static flow rates is a futile excercise."
True! It doesn't work this way on a piston engine either! You don't just strap a cylinder head to a bench with no valves in it and test away. This too is a futile exercise. There's more to it than that.
"One would have to build a very special apperatus to replicate the dynamics of port flow and the related turbulance of the intake charge."
No you don't. When you test a cylinder head on a flow bench, you do so without the rest of the engine. Why would a piston engine not need a special apparatus to replicate turbulence and flow dynamics but a rotary would? This is irrelevant. When a cylinder head is tested, it's valves are opened at different amounts and flow through them is measured. When you see a flow number for a cylinder head, you see it at a certain amount of valve lift. Having a fully opened valve and going solely by it's numbers is no more indicitive of performance on a piston engine than just simply strapping a rotor housing on a bench to obtain a total flow number. As with a piston engine, flow is done at several points on a rotary with a rotor housing and a rotor also bolted on. This way the port is tested with the rotor in varying states of opening and closing. You get a pretty damn good idea of how much flow there is at different points in the intake cycle this way. This is the exact same way it is done on a piston engine and their results speak volumes. If you take a piston engine that has great flow at max lift but poor flow at lower lifts and compare it to an engine that has great low lift numbers but a lower total lift flow (that got confusing!), the one with more average flow but less peak flow will make the better power. This is no different than on a rotary. The difference is that instead of opening or closing the valves a certain amount, we move the rotor across the port at varying stages to simulate the same thing. To say that, "Simply strapping a side housing to a flow bench and measuring static flow rates is a futile excercise" is inconclusive. While technically true, it also tells me that there is absolutely no experience with a flowbench nor is there any knowledge of how to properly test anything on one. That's not how you do it. If this is the case, then everything is in fact just a guess!
"And, the extremely limited performance benefits make it hard to justify the expense. 2-3 hp for $200-300 in additional labor is not very cost effective. We recommend that you invest that money more wisely."
How can anyone with zero experience in flowtesting claim that there is only a 2-3 hp benefit? Maybe it will, maybe it won't. You won't know unless you test it. I agree with the very last sentence. Spend your money more wisely. Do you want your engine builder guessing or testing?
First of all, if you aren't testing, you're guessing. Period. To say that flowtesting on a rotary is worthless is to justify ones own lack of testing. It's plain and simple, an excuse. Excuses aren't results though. Just because something works better than stock, doesn't mean it can't be improved upon. Anyone can take a die grinder and make a port larger and get more power. Someone who flow tests can get the same flow result with a smaller port. This is a wider powerband with more average power. If I'm going to take an engine apart and modify it, I'd like to know that I am getting the most for my money and effort rather than just simply "more". Anyways enough with the rambling. I'll requote the post and then answer it.
"Flowbenches are great tools, particularly for piston engine work."
Yes they are.
"However, their usefulness in porting rotary engines is virtually nonexistant."
Really? Explain...
"First, there is no easy way to simulate the operational characteristics of rotary engine ports."
And there is on a piston engine? This comment is too vague so let's go on...
"Simply strapping a side housing to a flow bench and measuring static flow rates is a futile excercise."
True! It doesn't work this way on a piston engine either! You don't just strap a cylinder head to a bench with no valves in it and test away. This too is a futile exercise. There's more to it than that.
"One would have to build a very special apperatus to replicate the dynamics of port flow and the related turbulance of the intake charge."
No you don't. When you test a cylinder head on a flow bench, you do so without the rest of the engine. Why would a piston engine not need a special apparatus to replicate turbulence and flow dynamics but a rotary would? This is irrelevant. When a cylinder head is tested, it's valves are opened at different amounts and flow through them is measured. When you see a flow number for a cylinder head, you see it at a certain amount of valve lift. Having a fully opened valve and going solely by it's numbers is no more indicitive of performance on a piston engine than just simply strapping a rotor housing on a bench to obtain a total flow number. As with a piston engine, flow is done at several points on a rotary with a rotor housing and a rotor also bolted on. This way the port is tested with the rotor in varying states of opening and closing. You get a pretty damn good idea of how much flow there is at different points in the intake cycle this way. This is the exact same way it is done on a piston engine and their results speak volumes. If you take a piston engine that has great flow at max lift but poor flow at lower lifts and compare it to an engine that has great low lift numbers but a lower total lift flow (that got confusing!), the one with more average flow but less peak flow will make the better power. This is no different than on a rotary. The difference is that instead of opening or closing the valves a certain amount, we move the rotor across the port at varying stages to simulate the same thing. To say that, "Simply strapping a side housing to a flow bench and measuring static flow rates is a futile excercise" is inconclusive. While technically true, it also tells me that there is absolutely no experience with a flowbench nor is there any knowledge of how to properly test anything on one. That's not how you do it. If this is the case, then everything is in fact just a guess!
"And, the extremely limited performance benefits make it hard to justify the expense. 2-3 hp for $200-300 in additional labor is not very cost effective. We recommend that you invest that money more wisely."
How can anyone with zero experience in flowtesting claim that there is only a 2-3 hp benefit? Maybe it will, maybe it won't. You won't know unless you test it. I agree with the very last sentence. Spend your money more wisely. Do you want your engine builder guessing or testing?
Good write up Rotarygod, thanks for giving us some clarity. Does Pineapple read this site? Maybe if they see this write up they can pay you some money to explain some things to them and maybe build them some flowbenches :p
Registered
Joined: Apr 2003
Posts: 9,134
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From: Houston
I'm not trying to start a fight with Rob. This isn't intended to be a shot at Pinapple. I'm sure he knows that there are various points of view out there and that some will disagree. I do believe him to do good work. He is a person who has done things the same way for years because he knows it works based on his experience. Nothing wrong and I won't debate that. He is a respected person in the rotary community and I don't want anyone to not appreciate his efforts just because I disagree with him on a few things. That is the nature with doing business with anyone. It's your job to draw your own conclusions. He is actually a very thorough and careful person when it comes to engine assembly and he can be trusted to put together a good solid engine.
I just disagree with him when it comes to exhaust design and flow testing. That's all. You guys would probably be very surprised at the flow of their radiused 6 port engine auxillary sleeves! Good or bad I won't say. I like the guy. I got along with him pretty good. You don't hae to agree with everything someone says in order to get along with them.
I just disagree with him when it comes to exhaust design and flow testing. That's all. You guys would probably be very surprised at the flow of their radiused 6 port engine auxillary sleeves! Good or bad I won't say. I like the guy. I got along with him pretty good. You don't hae to agree with everything someone says in order to get along with them.
Last edited by rotarygod; Jan 21, 2005 at 06:04 PM.
Go Texas Longhorns!
Joined: Apr 2003
Posts: 1,818
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From: Houston, Texas
Porting an engine to me is only of the performance mods I would spend the most time analyzing and testing to get the most possible bang for my time and money. To me its like my transmission…..taking that apart is a royal bitch…. And I'm doing it right and only going in there once.
You could experiment and change things much easier with exhausts, intakes, ECU’s hell even turbo’s, but I’m leery of taking the engine apart multiple times, once ok, but more than that would bother me…..therefore I think testing with P&P is incredibly important.
You could experiment and change things much easier with exhausts, intakes, ECU’s hell even turbo’s, but I’m leery of taking the engine apart multiple times, once ok, but more than that would bother me…..therefore I think testing with P&P is incredibly important.
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Hi folks, thought I would stop by and see what is going on. I am amazed how this thread has grown. Good job.
A couple pages back there was some talk of flow characteristics of surfaces.
I find that a surface with a roughness similar to 320 grit sand paper flows very well, dry.
Although I have never seen an actual rotary port, I can perceive the space (combustion chamber) that needs to be filled and the dynamics that may accompany it. I would like to comment on these.
The intake port is a bounded path that appears to be terminated with a flat surface. I see two objectives that may enhance flow. The first being the clean separation of the flow from the port. Just as a lip or spout on a jug help a fluid to cleanly separate from the surface without dribbling down the side when trying to pour the fluid, so too should the port exit. A well designed port exit could achieve optimum separation and exit speeds by maintaining a straight exit path of the intake charge. If the intake charge tends to follow the surface from port to plate surface, the dissipation of the charge will slow the velocity.
Second point I would address is aiming the intake charge into the largest area of the chamber, making sure the charge is not aimed at the opposing wall of the chamber, or a surface that will cause any slowing of the intake charge. Perhaps aiming at the trailing tip surface of the rotor would be a good place since this surface would be moving away from the charge as the charge approaches.
A flow bench and threaded wand would be very beneficial in attempting to achieving these goals.
Later, John
A couple pages back there was some talk of flow characteristics of surfaces.
I find that a surface with a roughness similar to 320 grit sand paper flows very well, dry.
Although I have never seen an actual rotary port, I can perceive the space (combustion chamber) that needs to be filled and the dynamics that may accompany it. I would like to comment on these.
The intake port is a bounded path that appears to be terminated with a flat surface. I see two objectives that may enhance flow. The first being the clean separation of the flow from the port. Just as a lip or spout on a jug help a fluid to cleanly separate from the surface without dribbling down the side when trying to pour the fluid, so too should the port exit. A well designed port exit could achieve optimum separation and exit speeds by maintaining a straight exit path of the intake charge. If the intake charge tends to follow the surface from port to plate surface, the dissipation of the charge will slow the velocity.
Second point I would address is aiming the intake charge into the largest area of the chamber, making sure the charge is not aimed at the opposing wall of the chamber, or a surface that will cause any slowing of the intake charge. Perhaps aiming at the trailing tip surface of the rotor would be a good place since this surface would be moving away from the charge as the charge approaches.
A flow bench and threaded wand would be very beneficial in attempting to achieving these goals.
Later, John
Last edited by diyPorting.com; Jan 23, 2005 at 12:02 AM.
Thread Starter
port hacker
Joined: Nov 2004
Posts: 1,275
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From: socal
thanks for bringing that up.
i already posted theis, but i'm not gonna look throught 50+ pages to find it...
here's what i did with the primary port.
the secondary and auxilliary ports we have little control over the exit angle.
i already posted theis, but i'm not gonna look throught 50+ pages to find it...
here's what i did with the primary port.
the secondary and auxilliary ports we have little control over the exit angle.
Thread Starter
port hacker
Joined: Nov 2004
Posts: 1,275
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From: socal
^ blue is the closing line (i think the real port turned out a little bigger)
green is what i was trying to do as far as aiming the flow is concerned
red is where i backfilled with epoxy so it didn't have to make a dead 90* turn
green is what i was trying to do as far as aiming the flow is concerned
red is where i backfilled with epoxy so it didn't have to make a dead 90* turn
thats right...the KING!
Joined: Jan 2005
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From: tallahassee
Originally Posted by guitarjunkie28
i get the feeling that the omp is injecting too much oil...
thank god for wire wheels!!!
thank god for wire wheels!!!
Go Texas Longhorns!
Joined: Apr 2003
Posts: 1,818
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From: Houston, Texas
Ater taking my exhaust manifold off with Rotarygod, I can see why the attempts to fix our exhaust flow problems with a better header yield little results, the internal airflow must be so bad that by the time it gets to the header, it really doesn't matter much how well it flows.
I'd say this is pretty well evidenced by the fact that the stock manifold is a real piece of Sh*t, that said, Racing Beat wasn't able to get much out of a good set of equal length headers with a center pipe that was siamesed just like the port. To me that speaks volumes…..We have some pictures and rubbings of the stock manifold that we will post soon that will make this clearer.
If I was you guys, I would see if maybe you could get your hands on a better set of headers and dyno the car now that you’ve ported it. Hell, maybe RB would lend you theirs for experimentation. Combine that with the ECU tuning, and you’ll likely have much better low/midrange power.
I'd say this is pretty well evidenced by the fact that the stock manifold is a real piece of Sh*t, that said, Racing Beat wasn't able to get much out of a good set of equal length headers with a center pipe that was siamesed just like the port. To me that speaks volumes…..We have some pictures and rubbings of the stock manifold that we will post soon that will make this clearer.
If I was you guys, I would see if maybe you could get your hands on a better set of headers and dyno the car now that you’ve ported it. Hell, maybe RB would lend you theirs for experimentation. Combine that with the ECU tuning, and you’ll likely have much better low/midrange power.
RB said they "We have tried quite a few header designs (including “adjustable length” models for dynamometer testing) and have found very little improvement. The maximum increase in power comes at high rpm and is not more than 4hp. We will continue testing but do not expect a large change in power."
So, with a mild street port, do you think the peak HP will increase by how much with a properly designed header? I agree, this needs to be tested.
So, with a mild street port, do you think the peak HP will increase by how much with a properly designed header? I agree, this needs to be tested.
Go Texas Longhorns!
Joined: Apr 2003
Posts: 1,818
Likes: 1
From: Houston, Texas
Well, if you consider the first attempt about porting got about 11-14whp (per this thread), and that was with the stock manifold and the computer fighting back against the leaning caused by the porting, I would think you could get 25-30 with the porting, headers and ECU (being conservative) across the power band, with more probably in the top end.
For those wanting neck snapping power, porting and headers aren't going to give you that. It will feel much like the regular engine in that its a smooth build up of power, so for some, a FI solution will be the only way to get the acceleration feel they want. Hell, its hard to argue with a $3000 turbo kit that gives you an assumed 60whp reliability and doesn't require yanking your engine. I think a good NA Renesis could get you close to the Greddy turbo results, but the feel would be different. In addition, what you will get from the porting is an increase in mileage, something you won't from the turbo.
RG and I are hoping to do some decent testing of the ports and the sleeves that sit inside the ports. It could be that you don't need bigger ports, just ones with more consistent diameter, since the stock exhaust ports get bigger then smaller then bigger once they hit the manifold.
I commend Snoochie and Guitarjunkie for their work, Yanking out an and tearing down an engine is not easy, they have proved the potential is there, we just need someone to do some good testing and create some flow proven templates for porting. Maybe we should set up a fund to buy some housings for RG I’ll make sure he doesn’t spend it on beer
For those wanting neck snapping power, porting and headers aren't going to give you that. It will feel much like the regular engine in that its a smooth build up of power, so for some, a FI solution will be the only way to get the acceleration feel they want. Hell, its hard to argue with a $3000 turbo kit that gives you an assumed 60whp reliability and doesn't require yanking your engine. I think a good NA Renesis could get you close to the Greddy turbo results, but the feel would be different. In addition, what you will get from the porting is an increase in mileage, something you won't from the turbo.
RG and I are hoping to do some decent testing of the ports and the sleeves that sit inside the ports. It could be that you don't need bigger ports, just ones with more consistent diameter, since the stock exhaust ports get bigger then smaller then bigger once they hit the manifold.
I commend Snoochie and Guitarjunkie for their work, Yanking out an and tearing down an engine is not easy, they have proved the potential is there, we just need someone to do some good testing and create some flow proven templates for porting. Maybe we should set up a fund to buy some housings for RG I’ll make sure he doesn’t spend it on beer
If I go porting, headers, and an enhanced ECU by someone like Racing Beat, I could always add a SC to the mix later on. 
And when you include ECU in your discussion, what do you mean? A tuneable CZ or E-Manage?
How much beer money does RG need?
And when you include ECU in your discussion, what do you mean? A tuneable CZ or E-Manage?How much beer money does RG need?
Originally Posted by brillo
Well, if you consider the first attempt about porting got about 11-14whp (per this thread), and that was with the stock manifold and the computer fighting back against the leaning caused by the porting, I would think you could get 25-30 with the porting, headers and ECU (being conservative) across the power band, with more probably in the top end.
Kaiten Kenbu Rokuren
Joined: Jul 2004
Posts: 934
Likes: 2
From: Central Valley, NY
Originally Posted by Nemesis8
If I go porting, headers, and an enhanced ECU by someone like Racing Beat, I could always add a SC to the mix later on. And when you include ECU in your discussion, what do you mean? A tuneable CZ or E-Manage?
How much beer money does RG need?
And when you include ECU in your discussion, what do you mean? A tuneable CZ or E-Manage?How much beer money does RG need?
http://www.mazdatrix.com/8engine2.htm
Kaiten Kenbu Rokuren
Joined: Jul 2004
Posts: 934
Likes: 2
From: Central Valley, NY
Originally Posted by PoLaK
I know for a fact that the Renesis can make 260 crank horsepower with different headers, removal of the cat, a slighty different port job and a tune to account for all of it. (as per Atkins)
Originally Posted by Aoshi Shinomori
How did you test crank horsepower? Do you have an engine dyno? Don't mind my dumb questions, but what is this Atkins you speak of? Thanks.
Kaiten Kenbu Rokuren
Joined: Jul 2004
Posts: 934
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From: Central Valley, NY
Originally Posted by PoLaK
Atkins Rotary and I were speaking when I met the owner at E-town. The guy that originally tuned the renesis "for mazda", is running a proRWD Rx-8 for the NHRA next season, he originally tuned 260 out of the motor with no regaurd for emissions, on an engine dyno of course.
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From: Rancho, So cal
Well if the car is 238 at the crank and we got 11whp i think. That's probably like 14 at the crank which is 252 and the rest only makes 8 that's pretty crappy imho. I don't know if this makes sense to anyone else. I would just expect a whole lot more from that list.
Cones need lovin' too!
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From: Beavercreek, Ohio
Assume 207-212 or so at the crank stock... per RacingBeat. (and their engine dyno)
When are you going to get your car tuned snooch? You haven't done that yet have you?
When are you going to get your car tuned snooch? You haven't done that yet have you?
Last edited by ranger4277; Jan 31, 2005 at 03:48 PM.
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From: Rancho, So cal
I pulled money out of the bank and am most likely picking it up from fanman later today. Latest I'm getting it 2marow so this is happening soon. I was kinda surprised at people lack of interest right when it was over. Anyways does anybody have an idea about that CEL code?? It's being dumb and I don't have FI...
Kaiten Kenbu Rokuren
Joined: Jul 2004
Posts: 934
Likes: 2
From: Central Valley, NY
Originally Posted by Snoochie
I pulled money out of the bank and am most likely picking it up from fanman later today. Latest I'm getting it 2marow so this is happening soon. I was kinda surprised at people lack of interest right when it was over. Anyways does anybody have an idea about that CEL code?? It's being dumb and I don't have FI...
Snooch, Anything you got at the wheels is very much what you got at the crank. The drivetrain loss tax has been paid already. Additional losses for the added HP will be minimal. If you got 14 HP extra at the wheels odds are you got the same at the crank.
As to all that power someone else is planing on getting, don't count on it. First they make less then 220 BHP to start with.
When I was a kid there was a big joke going around about if you read the JC Whitney catolog and added up all the power each item was going to give you it would be about twice the power you started with. So don't go around adding up advertised gains
As to all that power someone else is planing on getting, don't count on it. First they make less then 220 BHP to start with.
When I was a kid there was a big joke going around about if you read the JC Whitney catolog and added up all the power each item was going to give you it would be about twice the power you started with. So don't go around adding up advertised gains
Last edited by Richard Paul; Jan 31, 2005 at 05:47 PM.
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From: Houston
Originally Posted by Aoshi Shinomori
If Rotarygod gets the housings and flowtests them and all that the porting will be more fine-tuned and people will be more apt to get it done.