Who can do peripheral ports for a 12A?
01-20-2007, 11:47 PM
#1
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Thread Starter
Join Date: Nov 2001
Posts: 2,284
I'm looking for someone who can do streetable peripheral ports. They must provide a useable idle below 2k RPM and as wide a power band as possible (like the peripheral NSU and old-old Mazda engines). Stock apex seals will be used, limiting redline to 8000 RPM (8400 max).
Sammy at Marvelspeed recommended 1.5" diameter ports to reach my driveability and HP goals, and offered his services. Unfortunately Marvelspeed no longer seems to be with it. Their phone number was disconnected or in no longer in service last time I checked, and there appeared to be a few other problems with some customers' cars as well.
So now I'm back to looking for shops and individuals who can do a run of four 12A rotor housings for me with well placed, nicely shaped, modestly sized ports, capable of producing 425-450HP without exceeding 8000.
Think of a 2 rotor 12A with 200-225HP max at oh, lets say 6000 or 7000 RPM. Sounds reasonable, right? If an MFR (large ported) engine can hit 300 reving over 10k, why not 200 at 6k? 225 at 7k?
Sammy at Marvelspeed recommended 1.5" diameter ports to reach my driveability and HP goals, and offered his services. Unfortunately Marvelspeed no longer seems to be with it. Their phone number was disconnected or in no longer in service last time I checked, and there appeared to be a few other problems with some customers' cars as well.
So now I'm back to looking for shops and individuals who can do a run of four 12A rotor housings for me with well placed, nicely shaped, modestly sized ports, capable of producing 425-450HP without exceeding 8000.
Think of a 2 rotor 12A with 200-225HP max at oh, lets say 6000 or 7000 RPM. Sounds reasonable, right? If an MFR (large ported) engine can hit 300 reving over 10k, why not 200 at 6k? 225 at 7k?
01-21-2007, 07:28 AM
#2
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Join Date: Jan 2004
Location: Central Ohio (Hebron) Zephyrhills Fla.
Posts: 1,322
Originally Posted by Jeff20B' post='854249' date='Jan 20 2007, 10:47 PM
I'm looking for someone who can do streetable peripheral ports. They must provide a useable idle below 2k RPM and as wide a power band as possible (like the peripheral NSU and old-old Mazda engines). Stock apex seals will be used, limiting redline to 8000 RPM (8400 max).
Sammy at Marvelspeed recommended 1.5" diameter ports to reach my driveability and HP goals, and offered his services. Unfortunately Marvelspeed no longer seems to be with it. Their phone number was disconnected or in no longer in service last time I checked, and there appeared to be a few other problems with some customers' cars as well.
So now I'm back to looking for shops and individuals who can do a run of four 12A rotor housings for me with well placed, nicely shaped, modestly sized ports, capable of producing 425-450HP without exceeding 8000.
Think of a 2 rotor 12A with 200-225HP max at oh, lets say 6000 or 7000 RPM. Sounds reasonable, right? If an MFR (large ported) engine can hit 300 reving over 10k, why not 200 at 6k? 225 at 7k?
Well,
225 HP at 7000 RPM requires 169 foot pounds of torque. and 200 HP at 6000 RPM requires 175.5 foot pounds of torque. A bridge ported 12A is just about right on these numbers.
RPM X torque
___________ = HP
5252
The Pport will idle down well below the bridgeport, and will be much more fun on the street. We only use bridgeports because the rules do not allow the Pport. Port timing on a Pport is much milder than a bridge port to begin with. More like 50-70 instead of 110-85 so it will have just a hint of torque just off idle.
Go to paul yaws web site and buy a set of his housings or copy his step by step instructions. A lathe and a vertical mill are required.
www.yawpower.com
Use a thick wall tube and pot it solid into the housing with an aluminum filled mechanical epoxy. The thinner the tube wall the more of the housing at the sides must remain intact to prevent chrome flaking when you clamp up the stack. Leave ample support at the side for the apex seal ends.
Lynn e. Hanover
Turbo 13B as an airplane engine.
01-21-2007, 10:10 AM
#3
Senior Member
Join Date: Feb 2003
Location: Calgary
Posts: 564
I got my 13b pp running awhile ago and have been driving it regularly on the street. I did the housings, intake and header myself, its injected running on a haltech e6k in a 87 na gx(se). I am running the turbo transmission along with twin plate clutch.
It can idle incredibly low, as low as any sideport engine, normally I let it tick over at 1100-1200 rpm. I have been averaging slightly better mileage than the stock n/a 6 port engine on the highway, on off throttle loading really does eat fuel as the peripheral port volume likes a lot of accelarator pump shot.
Through a full length exhaust system with 2 mufflers, it made a peak of 206 at the wheels at around 8400 rpm on a mustang dyno at 3800 feet altitude , I have the sheets to 200, always seems the peak sheet never wants to print...
...
This was just an experimental motor I built out of parts off the shop floor and junk bucket. The housings were not in great shape, and I think fresh parts would add another 25 to it easily, and also I kept the ports really conservative as the wife and I still drive this thing shopping and touring around on the weekends..
Mazda did a lot of PP research in the 80's on all the engines, and I took direction from their engineering papers when I did mine.
When you talk of hp is that flywheel at wheel, I dont think those hp numbers at the wheel are attainable at those revs or with that displacment.
It can idle incredibly low, as low as any sideport engine, normally I let it tick over at 1100-1200 rpm. I have been averaging slightly better mileage than the stock n/a 6 port engine on the highway, on off throttle loading really does eat fuel as the peripheral port volume likes a lot of accelarator pump shot.
Through a full length exhaust system with 2 mufflers, it made a peak of 206 at the wheels at around 8400 rpm on a mustang dyno at 3800 feet altitude , I have the sheets to 200, always seems the peak sheet never wants to print...
This was just an experimental motor I built out of parts off the shop floor and junk bucket. The housings were not in great shape, and I think fresh parts would add another 25 to it easily, and also I kept the ports really conservative as the wife and I still drive this thing shopping and touring around on the weekends..
Mazda did a lot of PP research in the 80's on all the engines, and I took direction from their engineering papers when I did mine.
When you talk of hp is that flywheel at wheel, I dont think those hp numbers at the wheel are attainable at those revs or with that displacment.
01-21-2007, 02:48 PM
#4
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Thread Starter
Join Date: Nov 2001
Posts: 2,284
Excellent information!
It's encouraging to know a peripheral port will idle better than a bridgeport, and that it will be closer to 1000 than I thought.
When I worked out the HP of a 4 rotor 12A (23A), my goal was to get at least 400 flywheel HP at 8k or below. I figured it was a realistic goal seeing as a 2 rotor 12A can hit at least 200 HP by 8k (300 at 10k etc). The stock apex seals would improve low RPM sealing over carbon, and cost much less than ceramic. Adding more rotors to the equation builds torque at a geometric rate instead of a linear rate (I could be wrong) thus allowing for lower RPM use for the same power per rotor (could be wrong). Of course there is increased friction, but it's still less than a comparible piston engine.
Modest ports will limit power and RPM, of course, but we don't want to have to rev this thing to the moon to make any power as it will be a street car. Two ideas which seem to fly in the face of typical (racing) peripheral port designs. Hopefully these two caveats should coexist harmoniously on this project.
What diameter and port timing are required to peak/max it at 7k? Sammy recommended 1.5" which sounded good to me. He said nothing about port timing or shape though. The exhaust sytem will also necessarily need to be quiet enough for the street (at least as loud as a typical "free flow" Racing Beat system or what have you). I designed a functional one which may not flow enough volume for 10k, but should be adequate for 8k and below.
I sent an email off to Paul Yaw. I hope he takes the time to reply.
I'd honestly prefer to let someone else crunch the numbers and design and build a set of p-ports for me because a lot of it sails over my head. Plus I don't know anyone locally who could do them.
Maxt, if Paul is unable or unwilling to do some modest ports for me, would you consider it? By the way, I asked j9fd3s about the availability of some J-spec 12A rotor housings with an oil injector hole, undrilled intake manifold coolant passage, and an exhaust port which closes 10° later than US spec. We've used them before on a stock 12A. He said the number doesn't work in MazdaUSA anymore, but to contact you about them. We want to use that type of housing for the oil injector capability. He thinks the part number is N210-10-100
It's encouraging to know a peripheral port will idle better than a bridgeport, and that it will be closer to 1000 than I thought.
When I worked out the HP of a 4 rotor 12A (23A), my goal was to get at least 400 flywheel HP at 8k or below. I figured it was a realistic goal seeing as a 2 rotor 12A can hit at least 200 HP by 8k (300 at 10k etc). The stock apex seals would improve low RPM sealing over carbon, and cost much less than ceramic. Adding more rotors to the equation builds torque at a geometric rate instead of a linear rate (I could be wrong) thus allowing for lower RPM use for the same power per rotor (could be wrong). Of course there is increased friction, but it's still less than a comparible piston engine.
Modest ports will limit power and RPM, of course, but we don't want to have to rev this thing to the moon to make any power as it will be a street car. Two ideas which seem to fly in the face of typical (racing) peripheral port designs. Hopefully these two caveats should coexist harmoniously on this project.
What diameter and port timing are required to peak/max it at 7k? Sammy recommended 1.5" which sounded good to me. He said nothing about port timing or shape though. The exhaust sytem will also necessarily need to be quiet enough for the street (at least as loud as a typical "free flow" Racing Beat system or what have you). I designed a functional one which may not flow enough volume for 10k, but should be adequate for 8k and below.
I sent an email off to Paul Yaw. I hope he takes the time to reply.
I'd honestly prefer to let someone else crunch the numbers and design and build a set of p-ports for me because a lot of it sails over my head. Plus I don't know anyone locally who could do them.
Maxt, if Paul is unable or unwilling to do some modest ports for me, would you consider it? By the way, I asked j9fd3s about the availability of some J-spec 12A rotor housings with an oil injector hole, undrilled intake manifold coolant passage, and an exhaust port which closes 10° later than US spec. We've used them before on a stock 12A. He said the number doesn't work in MazdaUSA anymore, but to contact you about them. We want to use that type of housing for the oil injector capability. He thinks the part number is N210-10-100
01-21-2007, 02:58 PM
#5
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Join Date: Jan 2003
Location: London, Ontario
Posts: 2,871
Jeff, here is my idle with the housings I made, 2" holes in a 13b.
http://cranked.nopistons.com/index_files/Page419.htm
Idling below 2000 is easy. I went to a local machine shop, who cut the holes in the housings, turned the sleeves with a slight outside taper and press fit them for me.
http://cranked.nopistons.com/index_files/Page419.htm
Idling below 2000 is easy. I went to a local machine shop, who cut the holes in the housings, turned the sleeves with a slight outside taper and press fit them for me.
01-21-2007, 04:01 PM
#6
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Join Date: May 2002
Location: California
Posts: 22,465
couple thoughts.
1. the 4 rotor should be able to idle better with pretty radical ports, vs a 2 rotor. twice as many power strokes AND more rotatery mass, so the ports are gonna be a little more forgiving.
2. be interesting to know what an intake port thats shaped like an exhaust port worked like, oval = less timing but more area than a round port. area = good, more timing, ehh maybe you dont need it
3. the n210 number i think is the euro 12a, so its got the big port, but i dont think its got the metering holes, and i have no idea about the water jacketry. i'm not sure but the one with blocked off water and metering holes would be the 12at housings, but i dont know about the ports.
1. the 4 rotor should be able to idle better with pretty radical ports, vs a 2 rotor. twice as many power strokes AND more rotatery mass, so the ports are gonna be a little more forgiving.
2. be interesting to know what an intake port thats shaped like an exhaust port worked like, oval = less timing but more area than a round port. area = good, more timing, ehh maybe you dont need it
3. the n210 number i think is the euro 12a, so its got the big port, but i dont think its got the metering holes, and i have no idea about the water jacketry. i'm not sure but the one with blocked off water and metering holes would be the 12at housings, but i dont know about the ports.
01-22-2007, 12:41 PM
#9
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Join Date: May 2002
Location: California
Posts: 22,465
Originally Posted by Jeff20B' post='854452' date='Jan 22 2007, 10:00 AM
Mike, can you still get 12AT rotor housings?
Maxt, are you interested in doing some peripheral ports?
i dunno, i dont even have a part number for those, n236-10-100? n225 i think is the 6 port 12a.... none of those numbers work in mazdausa though
01-22-2007, 06:35 PM
#10
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Join Date: Jun 2004
Posts: 524
Originally Posted by Jeff20B' post='854337' date='Jan 21 2007, 12:48 PM
Modest ports will limit power and RPM, of course, but we don't want to have to rev this thing to the moon to make any power as it will be a street car. Two ideas which seem to fly in the face of typical (racing) peripheral port designs. Hopefully these two caveats should coexist harmoniously on this project.
I've "heard" that they work really well...