ghetto 4 rotor build
04-05-07, 11:57 AM
#51
There kinda is a way. If you only used Y intermediate plates and ported the center one to flow match the front and rear, they could be your secondaries. The other intermediate plates could be your primaries. This would be a lot easier if you stay with Y all the way including front and rear. The only problem is the oil pump may not be large enough to feed all the bearings. That's why we went with an FD front plate for the larger higher volume oil pump.
You can mix and match 1st and 2nd/3rd gen if you fill in the coolant seal area on the 2nd/3rd gen plates.
You can mix and match 1st and 2nd/3rd gen if you fill in the coolant seal area on the 2nd/3rd gen plates.
04-05-07, 01:40 PM
#54
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Wow, I usually just peruse the first gen forums...but damn! This is gonna be huge...by the time the whole thing is done this thread is gonna be like 50 pages long(if not longer). I love this idea. I know I'm still of noob status in the FB field and don't know a lot of the regulars too well yet...but this is noteworthy of keeping track of. Boggles the mind on the E-shaft thing. I ALWAYS hear ppl saying "you can't make a 4 rotor, they're too expensive...e-shaft...blah blah blah" MAD props to you Jeff!!! Pioneer in the working. I hope this all works out...I'll be watching from the shadows! lol
04-05-07, 01:58 PM
#55
MPG will be laughable. Large P ports, like what we're planning, will have sucky part throttle cruise. I originally wanted to go with small custom made ports for streetability but we couldn't seem to find a reliable builder (scalliwag et al) so we bit the bullet and committed to some MFR housings. That's expensive. The bright side is if any of them ever get damaged, replacement would be easy and no need for port matching or finding the original builder, as would be necessary if we had custom housings. Another silver lining as since they are 12A size, they are smaller than 13B MFR, so some driveability will be retained... I suppose.
phoenix_flame, hang out for a while. I like the 1st gen section because we aren't as limited as the 2nd and especially 3rd gen guys are. The 1st gen's potential is wide open. I'm taking advantage of that times 2; this joint 4 rotor project and my own personal 20B project. Both 1st gens, both very excellent mechanical challanges to overcome.
phoenix_flame, hang out for a while. I like the 1st gen section because we aren't as limited as the 2nd and especially 3rd gen guys are. The 1st gen's potential is wide open. I'm taking advantage of that times 2; this joint 4 rotor project and my own personal 20B project. Both 1st gens, both very excellent mechanical challanges to overcome.
04-05-07, 04:23 PM
#57
Extremely easily. Start with a stock '81-'85 distributor. Move one of the pickups 135° away from the other one. It doesn't really matter which is moved although it might be best to leave the original leading pickup alone and move trailing to 135° for ease of stabbing the dizzy. No need to mod the reluctor, which is actually the key to make this work.
Now mentally follow along while I guide you through a typical engine cycle. L1 and L2 of the first coil will fire together at TDC. Then 90° later or 135° up in the dizzy (since it spins at half speed), L3 and L4 will fire from the second coil. 90° later the eccentric shaft is now at 180° from TDC and L2 is ready to fire. So L1 and L2 fire together again (thus completing L1's late leading exhaust phase) and 90° later at 270° L4 fires (and L3 is now late leading). Still 90° later we arrive at 360° eccentric rotation and L1 is ready to fire again.
I'm not sure I explained it very well if you don't have a point of reference or a basic understanding of ignition. It's very simple if you think of L1 and L2 always firing together regardless of which one is in its combustion phase and which is in its exhaust (late leading) phase. Likewise L3 and L4 always fire together regardless of which phase they are in. These two events are seperated by 90° so L1+L2@0° or 180° and L3+L4@90° or 270°.
This is all made possible by the four tipped reluctor and simply moving one of the pickups to precisely 135°.
Now mentally follow along while I guide you through a typical engine cycle. L1 and L2 of the first coil will fire together at TDC. Then 90° later or 135° up in the dizzy (since it spins at half speed), L3 and L4 will fire from the second coil. 90° later the eccentric shaft is now at 180° from TDC and L2 is ready to fire. So L1 and L2 fire together again (thus completing L1's late leading exhaust phase) and 90° later at 270° L4 fires (and L3 is now late leading). Still 90° later we arrive at 360° eccentric rotation and L1 is ready to fire again.
I'm not sure I explained it very well if you don't have a point of reference or a basic understanding of ignition. It's very simple if you think of L1 and L2 always firing together regardless of which one is in its combustion phase and which is in its exhaust (late leading) phase. Likewise L3 and L4 always fire together regardless of which phase they are in. These two events are seperated by 90° so L1+L2@0° or 180° and L3+L4@90° or 270°.
This is all made possible by the four tipped reluctor and simply moving one of the pickups to precisely 135°.
04-05-07, 07:23 PM
#58
I'll be very interested to see how those e-shafts hold up. Mazda played with the same idea on their first experimental four rotors, using something called a curvic coupling to join the two shafts. Aparatly they had some problem with it and gave up on the idea and came up with the sleeved shaft instead. Still, I can't see any reason why it wouldn't work.
04-06-07, 11:44 AM
#61
openshot, think of it as 100HP per rotor, give or take a little depending on RPM, port size etc.
Here are the motor mounts. The bottom is beefed enough but I'd like to add a triangulation point at the top from the middle mount point down to the lower mount point. Then they should withstand the power and weight.
Oh, and that tension bolt looks bent but it's really straight.
The beginnings of a header.
Here are the motor mounts. The bottom is beefed enough but I'd like to add a triangulation point at the top from the middle mount point down to the lower mount point. Then they should withstand the power and weight.
Oh, and that tension bolt looks bent but it's really straight.
The beginnings of a header.
Last edited by Jeff20B; 04-06-07 at 11:53 AM.
04-06-07, 12:03 PM
#62
I bet the guys at Racing Beat would crap if they knew what you were planning on doing with those unwelded header parts. 
Keep up the good work Jeff! I think all of us should take out a life insurance policy in case something happens to you. Hahaha... 
Keep up the good work Jeff! I think all of us should take out a life insurance policy in case something happens to you. Hahaha...
04-06-07, 12:06 PM
#63
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That box of header parts looks like it will be alot of fun to build. Very nice stuff.
Are you looking at building a system that joins to one pipe, or leave it going out on 2 seperate pipes like the street port system?
Very nice stuff.Are you looking at building a system that joins to one pipe, or leave it going out on 2 seperate pipes like the street port system?
04-06-07, 02:37 PM
#64
Ok, imagine the RB single pipe system. It has a header, one presilencer, then a single (stock) pipe into a primaflow muffler. Easy to imagine. It would probably barely be adequate for a 2 rotor peripheral port with the biggest, corkiest part being the muffler itself. Also the collected header is kinda longer than RB's recommended 11-18" primary length before the collector for a PP. Also 1/8" smaller at 1 7/8" ID than their 1.9-2.0" recommended ID size. Just replace the muffler with one that will flow better for the PP and you got yourself a streetable PP setup. Fair enough?
Now imagine two of these single pipe systems side by side.
It will consist of two dissassembled "road race" header kits, as seen above, which just so happen to be compatible with the dual pipe "streetport" center section, but I'll get into that later.
Two unflanged collector assemblies, as seen above, to make fabrication easier. RB recommends a 30-40° angle at the Y for proper flow, which these Y adaptors have.
The dissassembled header kits are actually shorter than the collected ones, since the dual pipe center section is longer and when you get RB's full "streetport" exhaust system, the "road race" header comes already welded making it a bolt-in affair. I can use the dissassembled header kits to my advantage on the 4 rotor to make it all fit in the bay. Recall that RB recommends 11-18" primary length on PP for a short primary system, so it shouldn't be too hard. Each one will be at least 11" long before the collector. Equal length before the collector is more important than after.
We must also realize that a short primary system is quieter than a long primary system because the exhaust pulses mix closer to the engine. Stock manifolds are quietest, short primary headers are louder and long primaries are loudest.
I'm going to take advantage of 'acoustic canceling' by collecting each rotor pair phased 180° apart thereby allowing the pulses to cancel each other's noise like a woofer box where one driver is hooked up out of phase. Ever messed with speakers? You'll know what I'm talking about. Rotors 1 and 2 are phased 180° apart like any 2 rotor engine. Likewise with rotors 3 and 4, but the two pairs are 90°.
So rotors 1 and 2 will flow into one Y adaptor and into one pipe of the RB dual pipe center section. Rotors 3 and 4 will flow through the other Y adaptor and into the other pipe of the center section. Each 180° pair will have its own presilencer making it no louder than a standard RB single pipe exhaust before it enters the muffler. That should make the task of succesfully muffling this beast an easier one. We'll add an H pipe somewhere in the system to keep it from sounding like two 12As reving together. It's gotta sound like a true 4 rotor. That's half the reason we're doing this project.
Now I must point out that I've heard the difference in noise level between the RB single pipe and dual pipe systems and I can tell you the single pipe system could almost get away without a muffler (tested it one my bro's RX-4 while fabricating a single pipe exhaust with RB components). Then more recently I got to hear my friend's 1st gen with a dual pipe system. We removed the muffler to test fit it on the GSL-SE to locate the dual pipe center section, and he fired up his car and I was deeply distrubed at how incredibly loud it was. Even several car lengths away, when he barely gunned it, it caused me to jump. It was scary-loud. Those presilencers don't muffle.
Anyway that should illustrate how effective accoustic noise canceling can be on a rotary, and I intend to take full advantage of it.
Here is a link to the RB center section for those curious about it. http://www.racingbeat.com/resultset....rtNumber=16398
Now imagine two of these single pipe systems side by side.
It will consist of two dissassembled "road race" header kits, as seen above, which just so happen to be compatible with the dual pipe "streetport" center section, but I'll get into that later.
Two unflanged collector assemblies, as seen above, to make fabrication easier. RB recommends a 30-40° angle at the Y for proper flow, which these Y adaptors have.
The dissassembled header kits are actually shorter than the collected ones, since the dual pipe center section is longer and when you get RB's full "streetport" exhaust system, the "road race" header comes already welded making it a bolt-in affair. I can use the dissassembled header kits to my advantage on the 4 rotor to make it all fit in the bay. Recall that RB recommends 11-18" primary length on PP for a short primary system, so it shouldn't be too hard. Each one will be at least 11" long before the collector. Equal length before the collector is more important than after.
We must also realize that a short primary system is quieter than a long primary system because the exhaust pulses mix closer to the engine. Stock manifolds are quietest, short primary headers are louder and long primaries are loudest.
I'm going to take advantage of 'acoustic canceling' by collecting each rotor pair phased 180° apart thereby allowing the pulses to cancel each other's noise like a woofer box where one driver is hooked up out of phase. Ever messed with speakers? You'll know what I'm talking about. Rotors 1 and 2 are phased 180° apart like any 2 rotor engine. Likewise with rotors 3 and 4, but the two pairs are 90°.
So rotors 1 and 2 will flow into one Y adaptor and into one pipe of the RB dual pipe center section. Rotors 3 and 4 will flow through the other Y adaptor and into the other pipe of the center section. Each 180° pair will have its own presilencer making it no louder than a standard RB single pipe exhaust before it enters the muffler. That should make the task of succesfully muffling this beast an easier one. We'll add an H pipe somewhere in the system to keep it from sounding like two 12As reving together. It's gotta sound like a true 4 rotor. That's half the reason we're doing this project.
Now I must point out that I've heard the difference in noise level between the RB single pipe and dual pipe systems and I can tell you the single pipe system could almost get away without a muffler (tested it one my bro's RX-4 while fabricating a single pipe exhaust with RB components). Then more recently I got to hear my friend's 1st gen with a dual pipe system. We removed the muffler to test fit it on the GSL-SE to locate the dual pipe center section, and he fired up his car and I was deeply distrubed at how incredibly loud it was. Even several car lengths away, when he barely gunned it, it caused me to jump. It was scary-loud. Those presilencers don't muffle.
Anyway that should illustrate how effective accoustic noise canceling can be on a rotary, and I intend to take full advantage of it.
Here is a link to the RB center section for those curious about it. http://www.racingbeat.com/resultset....rtNumber=16398
04-07-07, 05:21 AM
#65
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so i have thought about this as well, but my sticking point was how are the housing all bolted together?
it looks good and not ghetto at all just on the cheap which is good!
it looks good and not ghetto at all just on the cheap which is good!
