6 port timing idea
11-17-11, 02:06 PM
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6 port timing idea
so most say that 6 port irons cant make the power na because they close to late, but what if you used some kind of epoxy to make them close earlier? well maybe not epoxy but you guys catch my drift right? I mean they close at 80* what if we brought that down to 70* or 65*? wouldnt that be early enough for it not to loose that so so important dynamic compression?
11-18-11, 11:56 AM
#2
Scott Howard
It's not that there is no benefit from closing the ports that late, it's just that the hp gains are relatively small. The street port templates for 6 port irons close the aux ports even later.
A good portion of hp to be gained on a 6 port would probably come from enlarging the primary ports on the center iron, the secondary ports are limited somewhat because of the aux ports sitting above them. I'm not an expert though!
Enlarging the primary and secondary ports with attention to the bowl can yield some good gains. The highest hp I've seen from a 6 port streetport was in an SCCA EP car, they made 267 flywheel hp on an engine dyno. This is approaching the limits of what's possible.
There is still more potential in the 4 port irons though.
A good portion of hp to be gained on a 6 port would probably come from enlarging the primary ports on the center iron, the secondary ports are limited somewhat because of the aux ports sitting above them. I'm not an expert though!
Enlarging the primary and secondary ports with attention to the bowl can yield some good gains. The highest hp I've seen from a 6 port streetport was in an SCCA EP car, they made 267 flywheel hp on an engine dyno. This is approaching the limits of what's possible.
There is still more potential in the 4 port irons though.
11-18-11, 03:18 PM
#3
Rotary Freak
It's not that there is no benefit from closing the ports that late, it's just that the hp gains are relatively small. The street port templates for 6 port irons close the aux ports even later.
A good portion of hp to be gained on a 6 port would probably come from enlarging the primary ports on the center iron, the secondary ports are limited somewhat because of the aux ports sitting above them. I'm not an expert though!
Enlarging the primary and secondary ports with attention to the bowl can yield some good gains. The highest hp I've seen from a 6 port streetport was in an SCCA EP car, they made 267 flywheel hp on an engine dyno. This is approaching the limits of what's possible.
There is still more potential in the 4 port irons though.
A good portion of hp to be gained on a 6 port would probably come from enlarging the primary ports on the center iron, the secondary ports are limited somewhat because of the aux ports sitting above them. I'm not an expert though!
Enlarging the primary and secondary ports with attention to the bowl can yield some good gains. The highest hp I've seen from a 6 port streetport was in an SCCA EP car, they made 267 flywheel hp on an engine dyno. This is approaching the limits of what's possible.
There is still more potential in the 4 port irons though.
Turbo pieces are pretty plentiful and reasonably cheap. I would start looking before I would even take another minute on the 6 Port.
Eric
11-18-11, 03:50 PM
#4
Anyone porting a 6 port motor should only do so if they want essentially stock drivability in a street car and want a nice power upgrade over stock but with the understanding that they are probably still going to be outrun by the average Camry. If someone wants some serious na power (serious power being relative to stock), then they need to make some sacrifices but only use a 4 port motor. No amount of epoxy trickery, bridge porting, guessing, wishing, or creativity will make the results from a 6 port motor worth the effort that went into it. The reality is that a stock turbo equipped and stock port TII will beat any ported na motor short of a purpose built peripheral port in almost every way with nothing more than raised boost and a nice exhaust.
11-19-11, 08:13 AM
#5
I had a friend with a streetported 6 port s5 n/a with rx8 internals and all the bolt on's. Made a wonderfully wide powerband, seemed to want to pull forever. Great improvement over stock, just no rush of power like a turbo.
On the other hand, a TII swap with an rtek and a BNR turbo would have yielded 100 more HP for only a little more money.
On the other hand, a TII swap with an rtek and a BNR turbo would have yielded 100 more HP for only a little more money.
11-19-11, 08:24 AM
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oh I understand that rotarygod. I was just trying to offer a solution to a problem. has anyone tried filling the 5th and 6th ports then making the sec ports bigger? and has anyone tried a few D shape pp but I mean like a honeycomb, and the pri ports (feed the pp through the coolant passage from the end irons, and stage it kinda like the 6port system,and if not do you think you could get more port area with less overlap) ? should be less likely to spit up apex seals then a full pp.
thats crazy that a E prod car could make that much out of them i was thinkin 230-240 was the limit.
thats crazy that a E prod car could make that much out of them i was thinkin 230-240 was the limit.
11-19-11, 12:11 PM
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perhaps saying 80 is too late is misleading, the PP engines close at 80 too. one of the reasons the P port makes twice the power is because the OPENING time is different, and the port actually FLOWS too.
however in the compromise that is an engine package, the 6 port is designed to have more low rpm power than a 4 port while keeping the same high rpm performance. which is probably where you spend most of your driving time.
however when we try to get more out of it, the 5th and 6th ports don't flow well, and the other ports have conservative timings and there isn't much we can do to fix it. the 4 port housings don't have this problem.
the exhaust ports between the FC/FD and the MFR PP housings aren't that different, but the PP housings actually have slightly smaller exits.
however in the compromise that is an engine package, the 6 port is designed to have more low rpm power than a 4 port while keeping the same high rpm performance. which is probably where you spend most of your driving time.
however when we try to get more out of it, the 5th and 6th ports don't flow well, and the other ports have conservative timings and there isn't much we can do to fix it. the 4 port housings don't have this problem.
the exhaust ports between the FC/FD and the MFR PP housings aren't that different, but the PP housings actually have slightly smaller exits.
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11-20-11, 01:48 PM
#9
There are a few tried and true porting styles that are proven to work. Everything else is nothing more than a bad idea that failed. Here they are:
6 port motor:
Stock port
Street port
4 port motor:
Stock port
Street port
Bridge port
Peripheral port motor can be based on either the 4 or 6 port irons but are best based off of 4 port motors simply due to the fact that there is less port area to fill in on the outer housings.
Bridge and peripheral port motors require properly tuned and free flowing intake and exhaust systems. They are not going to work well or at all with stock ecu's or even stock ecu's with piggyback systems. They are never ever ever going to be street legal under any standards regardless of what anyone anyone has ever ever ever claimed. It's impossible. Street legality means it HAS to be emissions legal, even if the state doesn't technically require an emissions test.
Filling in ports in housings with epoxy to change timing doesn't work. Cheese ports don't work. Auxiliary bridgeports don't work.
Creative thinking is good and all but what is or is not proven to work is already known. This is the list. Forget anything else. It won't work. Keep in mind this list is naturally aspirated based. Forced induction has a neat way of hiding mistakes so the results may vary a bit.
In your case you have a 6 port motor and by your own admission have very little money to spend. This leaves you with 2 possibilities based on your motor. One is a stock port and the other is a street port. The budget may even make a street port or any engine work at all for that matter completely out of the question which leads me to the next issue.
If you aren't replacing every single seal in the engine, you are doing it wrong. If you are not resurfacing your end and center plates, you aren't going to have as much power as you could and you can't take the mileage back off of them. Your rebuilt engine at 100K miles (just an example) still has 100K on the housings even if the seals are new. If you are reusing rotor housings that have ANY flaking at all or have any marks that you can feel, you are doing it wrong. These need to be replaced.
If you do it properly and cheaply, with properly being the priority, it really isn't possible to rebuild and engine correctly for less than $2000. Many people rebuild engines for well less than $1000 all the time. I would argue that not a single one of them has done it properly which will ultimately cost them more money when they have to rebuild it again.
If you have already cut bridge ports into 6 port housings, throw them away. They are ruined. Don't try to save them, salvage them, use them anyways. You've wasted time and money and are going to waste more if you use them.
I know that it's hard to admit but cut your losses and do it properly. Keep in mind the forum is crawling with people who do things wrong. Copying them doesn't make it right.
6 port motor:
Stock port
Street port
4 port motor:
Stock port
Street port
Bridge port
Peripheral port motor can be based on either the 4 or 6 port irons but are best based off of 4 port motors simply due to the fact that there is less port area to fill in on the outer housings.
Bridge and peripheral port motors require properly tuned and free flowing intake and exhaust systems. They are not going to work well or at all with stock ecu's or even stock ecu's with piggyback systems. They are never ever ever going to be street legal under any standards regardless of what anyone anyone has ever ever ever claimed. It's impossible. Street legality means it HAS to be emissions legal, even if the state doesn't technically require an emissions test.
Filling in ports in housings with epoxy to change timing doesn't work. Cheese ports don't work. Auxiliary bridgeports don't work.
Creative thinking is good and all but what is or is not proven to work is already known. This is the list. Forget anything else. It won't work. Keep in mind this list is naturally aspirated based. Forced induction has a neat way of hiding mistakes so the results may vary a bit.
In your case you have a 6 port motor and by your own admission have very little money to spend. This leaves you with 2 possibilities based on your motor. One is a stock port and the other is a street port. The budget may even make a street port or any engine work at all for that matter completely out of the question which leads me to the next issue.
If you aren't replacing every single seal in the engine, you are doing it wrong. If you are not resurfacing your end and center plates, you aren't going to have as much power as you could and you can't take the mileage back off of them. Your rebuilt engine at 100K miles (just an example) still has 100K on the housings even if the seals are new. If you are reusing rotor housings that have ANY flaking at all or have any marks that you can feel, you are doing it wrong. These need to be replaced.
If you do it properly and cheaply, with properly being the priority, it really isn't possible to rebuild and engine correctly for less than $2000. Many people rebuild engines for well less than $1000 all the time. I would argue that not a single one of them has done it properly which will ultimately cost them more money when they have to rebuild it again.
If you have already cut bridge ports into 6 port housings, throw them away. They are ruined. Don't try to save them, salvage them, use them anyways. You've wasted time and money and are going to waste more if you use them.
I know that it's hard to admit but cut your losses and do it properly. Keep in mind the forum is crawling with people who do things wrong. Copying them doesn't make it right.
11-20-11, 09:14 PM
#10
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oh understand that i have 6 port irons and little money, but i want to see if I cant make it better. maybe not the 6p or 4p just as long as its a rotary. hell I think a very smart man once said for every 1 idea that makes it 10 must fail. so im gonna keep on trying them and keep on asking you guys for opinions. and this isnt for my dd this is for a project car that doesnt need to work. more of a test mule something naked thats easy to swap engines in and out of.thanks
11-20-11, 09:27 PM
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I used all new seals and my new irons had about 10000 miles on them same for the bearings so I think I did it right and my lucky self was able to do it for $200 
11-20-11, 09:42 PM
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yea I see your point. but im not finding much as far as ports outside of what mazda did. but i had a thought that seems good.. what if you put reed valves on the 6 ports. late closing timing means you could almost have a actuator that works with every pulse.
11-20-11, 10:11 PM
#14
For a stock 6 port, I would just streetport the endplates, add a TII centerplate and streetport it if i could get one cheap enough, add atkins inserts, get a k&n drop in filter and get the rb true dual exhaust. It would make for a great daily driver, last a long time and just leave it at that. Want more, sell it and buy a TII or FD.
I have a supercharged gslse and a stock 6 port gslse with exhaust. Sure the supercharged one is faster, but at times I really enjoy the stock one too.
I have a supercharged gslse and a stock 6 port gslse with exhaust. Sure the supercharged one is faster, but at times I really enjoy the stock one too.
11-20-11, 10:45 PM
#16
I don't know how you bought all new seals and spent only $200. Again maybe you got lucky and someone was desperate to sell some that they bought and didn't use. All new seals means apex, springs, side seals, corner seals, oil rings, water seals, etc. Apex seals alone are more than $200. Bearings can often be reused. Bearings never break in since they should never touch.
11-20-11, 11:20 PM
#17
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+1 on the new parts
i've built a few new housing/rotors/irons engines, and they make a difference. two of the reasons the rotary lacks the low RPM torque of an equivalent piston engine are because the seal lengths are longer, and the rotarys strokes are 270 degrees instead of 180. so not only are there more places to leak, but there is more time to leak too.
the better you can seal the inside of the engine the more power you will have, always.
this means flat irons, NEW rotor housings, rotors that aren't bent (the faces move).
Mazda has also lowered the friction of the engine over the years, going to single side seals, 2mm apex seals, the coating on the rotor housings, the nitriding on the side irons. its all small things but they add up
granted there is usually a budget....
number 2 on the list is the exhaust. we over think it, and then run an RB header. the RB headers have a poor port match on FC/FD housings, and the length isn't right for your car. both of these are fixable.
number 3 is just making sure everything is working like its supposed to. timing, TPS, plug wire routing, VDI, 6 port etc etc. there is a tolerance for most everything, and there is usually a range that's better, you'd be surprised at how much power there is on an average FC, by just doing a tune up.
then you can start working on the suspension....
i've built a few new housing/rotors/irons engines, and they make a difference. two of the reasons the rotary lacks the low RPM torque of an equivalent piston engine are because the seal lengths are longer, and the rotarys strokes are 270 degrees instead of 180. so not only are there more places to leak, but there is more time to leak too.
the better you can seal the inside of the engine the more power you will have, always.
this means flat irons, NEW rotor housings, rotors that aren't bent (the faces move).
Mazda has also lowered the friction of the engine over the years, going to single side seals, 2mm apex seals, the coating on the rotor housings, the nitriding on the side irons. its all small things but they add up
granted there is usually a budget....
number 2 on the list is the exhaust. we over think it, and then run an RB header. the RB headers have a poor port match on FC/FD housings, and the length isn't right for your car. both of these are fixable.
number 3 is just making sure everything is working like its supposed to. timing, TPS, plug wire routing, VDI, 6 port etc etc. there is a tolerance for most everything, and there is usually a range that's better, you'd be surprised at how much power there is on an average FC, by just doing a tune up.
then you can start working on the suspension....
11-21-11, 10:43 AM
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yes. Mr Ko used to offer 3mm machining back in the day, and since he was one of the few that did it in the 90's he used to get rotors from some bigger name places than you'd think.
since machining the groove requires precision, he built a jig to hold the rotors, and lo and behold some rotors aren't squarely triangular. for example if you had a jig to machine 3, 3mm slots in the correct spots and then went to put rotors in them, you'd find the rotors don't always line up.
its probably a turbo engine problem, but still, the rotors are soft.
since machining the groove requires precision, he built a jig to hold the rotors, and lo and behold some rotors aren't squarely triangular. for example if you had a jig to machine 3, 3mm slots in the correct spots and then went to put rotors in them, you'd find the rotors don't always line up.
its probably a turbo engine problem, but still, the rotors are soft.
11-21-11, 11:01 AM
#20
its hard to get a good exhaust without going custom beside RB. I always hear of 3 or so places that have done great exhausts for NA or exhaust tuning but I just don't see them available or find places to get them.
I'm beginning to wonder on my exhaust with the RB street header and muffler with a straight pipe for pre-silencer.
11-21-11, 11:59 AM
#21
the rotor faces can also bloat or collapse, caused by detonation from previous engines or overheating the oil in conjunction with hot internal combustion temps. i have seen some rotors that had what looked like a huge wart on the face of the rotor.
but i would consider this to be rather mild. the cast rotors still performed ok and the compression pockets in those rotors varied all over the place, probably by several tenths of a point of compression. the series 5 and 6 milled pockets were more consistent.
but i would consider this to be rather mild. the cast rotors still performed ok and the compression pockets in those rotors varied all over the place, probably by several tenths of a point of compression. the series 5 and 6 milled pockets were more consistent.
Last edited by RotaryEvolution; 11-21-11 at 12:01 PM.
11-21-11, 12:15 PM
#22
Old [Sch|F]ool
Cast iron is pretty flexible. You can take an iron cylinder head, support the middle and hold one end down, and you can flex the other end down by hand by a suprising amount... and it'll just boing right back.
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What you need is brought to you by the letters DCOE and the number 48.
11-21-11, 01:23 PM
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its hard to get a good exhaust without going custom beside RB. I always hear of 3 or so places that have done great exhausts for NA or exhaust tuning but I just don't see them available or find places to get them.
I'm beginning to wonder on my exhaust with the RB street header and muffler with a straight pipe for pre-silencer.
I'm beginning to wonder on my exhaust with the RB street header and muffler with a straight pipe for pre-silencer.
the second thing is the length, and that i think really requires a dyno and it needs to be tuned you YOUR car.
there are some giant threads on "best exhaust" but we're really overthinking it, just get the header to match the port, get the right length, pick a muffler that flows enough and drive the fing thing.
11-21-11, 02:18 PM
#25
the good news is that since RB uses the thickwalled pipe, there is enough meat to fix the header. if you put the RB header up to an extra rotor housing and then compare with a stock manifold, its pretty obvious what needs to be done.
the second thing is the length, and that i think really requires a dyno and it needs to be tuned you YOUR car.
there are some giant threads on "best exhaust" but we're really overthinking it, just get the header to match the port, get the right length, pick a muffler that flows enough and drive the fing thing.
the second thing is the length, and that i think really requires a dyno and it needs to be tuned you YOUR car.
there are some giant threads on "best exhaust" but we're really overthinking it, just get the header to match the port, get the right length, pick a muffler that flows enough and drive the fing thing.
That really is the only GREAT option, (and costly) but a good option is just getting the RB header and calling it a day.