going peripheral 12a!
03-25-03, 11:11 AM
#27
Old [Sch|F]ool
That's funny, '84-85 12A's have the same rotors as '83, and all 12A's (in RX-7s at least) have 9.4:1 compression. The difference is '83-85 12As have LIGHTER rotors. They're within a few grams of the '89-02 13B rotors. (S5 T2/S5 NA/FD rotors all weigh the same)
I don't see any reason to use carbon seals if you're not going to wind the engine past 8500.
I don't see any reason to use carbon seals if you're not going to wind the engine past 8500.
03-25-03, 11:29 AM
#28
'Last Minute' Rallying
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Originally posted by Hyper4mance2k
i'd do a half bridgy w/ street port on intake side , RB race exhaust port, with a 51 IDA. that way the car will still idle at 1000 rpm. and i've never heard of a PP idleing at anything below 1800 rpm normally around 2000 redlining at 10,ooo rpm
i'd do a half bridgy w/ street port on intake side , RB race exhaust port, with a 51 IDA. that way the car will still idle at 1000 rpm. and i've never heard of a PP idleing at anything below 1800 rpm normally around 2000 redlining at 10,ooo rpm
Its not the p-port that makes for the unstreetable driving its the port timing, overlap etc. that are selected when building the P-port that make it so
Mike
03-25-03, 11:49 AM
#29
Old [Sch|F]ool
Where's RICE RACING when you need him... 
I recall him mentioning that he got his old PP motor idling at 1100, even with a big fat Weber.
For a street motor a PP or bridge wouldn't be such a good idea since the more overlap there is the more sensitive the engine is to exhaust restriction. (Not saying it can't be done, lots of people do it... but you have to know what you are doing exhaust-wise)
But on a race motor.... PP all the way, if rules allow it.
I recall him mentioning that he got his old PP motor idling at 1100, even with a big fat Weber.For a street motor a PP or bridge wouldn't be such a good idea since the more overlap there is the more sensitive the engine is to exhaust restriction. (Not saying it can't be done, lots of people do it... but you have to know what you are doing exhaust-wise)
But on a race motor.... PP all the way, if rules allow it.
03-25-03, 11:57 AM
#30
Originally posted by mperformance
just anything as long as I keep it 12a n/a
hey what kind of seals you guys recommend, I was thinking on building it for now with normal 2 piece atkins for this race. I plan on not reving it too high maybe 8tish so I might not even do the hardened stationary gears. Basically I just want the PPport to help up in the 6 to 8k range and try to keep it reliable by shifting at the end of the stock redline.
The idea is to have lots more power than the stockport but I don't really need that much if you consider that I need to be around 220hp - 230hp with the 12a. I'll crack open the engine after the race and as $ permits build a much better peripheral.
just anything as long as I keep it 12a n/a
hey what kind of seals you guys recommend, I was thinking on building it for now with normal 2 piece atkins for this race. I plan on not reving it too high maybe 8tish so I might not even do the hardened stationary gears. Basically I just want the PPport to help up in the 6 to 8k range and try to keep it reliable by shifting at the end of the stock redline.
The idea is to have lots more power than the stockport but I don't really need that much if you consider that I need to be around 220hp - 230hp with the 12a. I'll crack open the engine after the race and as $ permits build a much better peripheral.
I'm racing with http://www.touringcarclub.com/detail...ls_classes.htm 2.2L challenge MA. My class sounds similar to yours. Keep it n/a and 12a. I put a 12a Jbridge in there and when it's all tuned and done I'll have 30-40 more hp than the Integra Type R's that dominate that class.
-bp-
03-25-03, 03:27 PM
#33
standard combustion
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I don't know if a streetports "that wide", a bridgeport I made has a reasonable powerband. Mildport is fairly linear and not as half fun as a bridgeport, thats forsure!
Easier to drive in traffic though, or a dead stop on a incline and not bogging.
For my bridge, I'd say 5000rpm-8500rpm were its in its "fast" range. Yes, it bogs if you floor it below 3500rpm. I would take it past 8500rpm in 1st and 2nd just because it rev's so quick and you want to be in the powerband of the next gear or you will lose your top rate of acceration. Each shift usually brings it down barely to 6500rpm or higher in the next gear in a full throttle sprint.
Easier to drive in traffic though, or a dead stop on a incline and not bogging.
For my bridge, I'd say 5000rpm-8500rpm were its in its "fast" range. Yes, it bogs if you floor it below 3500rpm. I would take it past 8500rpm in 1st and 2nd just because it rev's so quick and you want to be in the powerband of the next gear or you will lose your top rate of acceration. Each shift usually brings it down barely to 6500rpm or higher in the next gear in a full throttle sprint.
03-25-03, 03:54 PM
#34
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Originally posted by DriveFast7
Streetport's powerband is lots wider than peripheral or bridge.
Streetport's powerband is lots wider than peripheral or bridge.
03-25-03, 03:56 PM
#35
Old [Sch|F]ool
Look at a dyno chart of a streetport... the torque curve is none too flat.
Personal experience, mine was like a lightswitch. It was fine at lower revs (a little better than stock) and at 5500-6000 WHAM, the torque curve hit. Hard enough to break the tires loose. (And then the crappy combination of parts meant i had to shift at only 8000 )
Personal experience, mine was like a lightswitch. It was fine at lower revs (a little better than stock) and at 5500-6000 WHAM, the torque curve hit. Hard enough to break the tires loose. (And then the crappy combination of parts meant i had to shift at only 8000
)
03-25-03, 05:51 PM
#36
I had a 12a streetport from 97-2000. nice motor, it did start making good power around 5500. It wasn't like a switch, nice gradual increase in power all the way up.
At what rpm does a peripheral make peak torque? 7500? That's my point here.
At what rpm does a peripheral make peak torque? 7500? That's my point here.
03-25-03, 06:24 PM
#37
Rotary Enthusiast
Thread Starter
ok nice arguements here, both with lot's of info and I see that you guys understood my idea. I still haven't decided yet on the peripheral due to the costs and time involved. Is there a page where I can see some dyno numbers (although to tell you the truth since I'm doing a half *** job it's not all that important) just for reference. Like showing a peripheral ported and a large streetport for comparison, I want to see that torque curve.
anyhow Brad thanks for the ideas and like always Peejay appreciate your help and sharing your past experiences.
Hey wacky I have a radical bridge port template, but I'm getting two piece seals and can't go for the carbons, maybe you can recommend another idea...you think a halfbridge (RADICAL extending thru the water seal) could yield some good results?
anyhow Brad thanks for the ideas and like always Peejay appreciate your help and sharing your past experiences.
Hey wacky I have a radical bridge port template, but I'm getting two piece seals and can't go for the carbons, maybe you can recommend another idea...you think a halfbridge (RADICAL extending thru the water seal) could yield some good results?
03-25-03, 07:10 PM
#38
standard combustion
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First of all, no one get mad at me, don't take anything I say personally, just read and do the right thing first.
mperformance,
If I were you, I'd send the 2-piece seals back(are they stock seals?), and get carbon seals if you intend to do ANY rpm above 7500rpm for any amount of time in a race situation. Don't take this personally, but apex seals are the LAST part of a rotary engine that should be skimpy on. Get the right seal for the right job and you will save money. I guess, I would wouldn't build any high rpm n/a rotary engine without the right parts, but that is just me going from experience.
2piece Steel seals intended purpose: low rpm/street use-boost. Stock, and mildport are the only time I'd use them. (by low rpm, I mean less then 7500rpm 99% of the time). Its not a joke, steel seals slowly damage rotor housings if you rev it like crazy all the time, and REALLY damage them fast if you exceed 8000rpm every shift-chatter marks and flaking make rotor housings useless...to me anyway. Rotor housings are not cheap to replace, and used ones in good shape is very rare mainly because too much high rpm on them.
Carbon 1piece seals purpose: All race rotary engines that don't see boost or NOS. Cheaper then stock seals, non-abrasive to the housings, NO chatter marks.
Good for stockport all the way to perpheral ported race engines(with aftermarket intake/exhaust ofcourse)that get A LOT of high rpm sustained. I can believe all the topics with
"half-bridges", "half mildports", "half perherals?" engines!! ARGG!!! HERES MY ADVICE: do a full bridgeport, mildport, full j-bridge, Full perpheral, get the right seals for the job and you'll be much more happy then the "GRAY ZONE" of half-bridge crap....
carbon Downside: Sure they don't seal well below 3000rpm, but just drive it in a gear that keeps it above 3000rpm, and drive it hard all the time and it will last a long time with pre-mixing, believe me I know!!!!
Why do a half-engine job when you can do it right the first time and be more satified with its output and not need to take it apart and spend more money on fabercations and gasket sets? I have to say the "gray zone" of half bridges don't seem all that practical to me, lumpy idle, and unless you have a 4barrel with actuators to control them to open the bridgeports after 3500rpm, its seems like a waste to me.
Sorry for seeming negative and direct, this topic is frustrating to deal with. And no, I'm not a carbon seal salesman, I am a advacate for getting the "right" parts for the "right" job though.
mperformance,
If I were you, I'd send the 2-piece seals back(are they stock seals?), and get carbon seals if you intend to do ANY rpm above 7500rpm for any amount of time in a race situation. Don't take this personally, but apex seals are the LAST part of a rotary engine that should be skimpy on. Get the right seal for the right job and you will save money. I guess, I would wouldn't build any high rpm n/a rotary engine without the right parts, but that is just me going from experience.
2piece Steel seals intended purpose: low rpm/street use-boost. Stock, and mildport are the only time I'd use them. (by low rpm, I mean less then 7500rpm 99% of the time). Its not a joke, steel seals slowly damage rotor housings if you rev it like crazy all the time, and REALLY damage them fast if you exceed 8000rpm every shift-chatter marks and flaking make rotor housings useless...to me anyway. Rotor housings are not cheap to replace, and used ones in good shape is very rare mainly because too much high rpm on them.
Carbon 1piece seals purpose: All race rotary engines that don't see boost or NOS. Cheaper then stock seals, non-abrasive to the housings, NO chatter marks.
Good for stockport all the way to perpheral ported race engines(with aftermarket intake/exhaust ofcourse)that get A LOT of high rpm sustained. I can believe all the topics with
"half-bridges", "half mildports", "half perherals?" engines!! ARGG!!! HERES MY ADVICE: do a full bridgeport, mildport, full j-bridge, Full perpheral, get the right seals for the job and you'll be much more happy then the "GRAY ZONE" of half-bridge crap....
carbon Downside: Sure they don't seal well below 3000rpm, but just drive it in a gear that keeps it above 3000rpm, and drive it hard all the time and it will last a long time with pre-mixing, believe me I know!!!!
Why do a half-engine job when you can do it right the first time and be more satified with its output and not need to take it apart and spend more money on fabercations and gasket sets? I have to say the "gray zone" of half bridges don't seem all that practical to me, lumpy idle, and unless you have a 4barrel with actuators to control them to open the bridgeports after 3500rpm, its seems like a waste to me.
Sorry for seeming negative and direct, this topic is frustrating to deal with. And no, I'm not a carbon seal salesman
, I am a advacate for getting the "right" parts for the "right" job though.
03-25-03, 07:17 PM
#40
standard combustion
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Also, I forgot to mention, I think there are several companies making single piece seals that are not carbon seals, but forgot which companies do and whether they are intended for high rpm. But as for trying to get the 2piece stock seals to work on a half- bridgeport is not the issue, its the rpm you will run a lot as a result of having a bridgeport. I don't care that you can orient the seals to make a half-bridgeport, j-port, etc, its about the damage you inflict to the rotor housings with steel combined with high rpm race conditions bridgeports require.
To answer your question, Racing Beat is the carbon seal seller.
Anyway I don't care, make whatever you want.
To answer your question, Racing Beat is the carbon seal seller.
Anyway I don't care, make whatever you want.
Last edited by WackyRotary; 03-25-03 at 07:23 PM.
03-27-03, 12:06 PM
#44
Old [Sch|F]ool
Originally posted by REVHED
Someone please post the chart showing a pp with far better VE from as low as 2000rpm.
Someone please post the chart showing a pp with far better VE from as low as 2000rpm.
(I'm betting this is of a "reasonable" peripheral port... not the huge *** ones like the Mazda Factory Race housings... it's not too fair to compare a mild street port with a full on race motor is it?)
edit: A word about VE.... VE is *dorectly* related to the torque output. In a nutshell and ignoring a few constants, VE x engine displacement = torque. You increase torque two ways, increase displacement or increase VE.
Last edited by peejay; 03-27-03 at 12:11 PM.
03-27-03, 03:31 PM
#45
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so.... could you use Carbon apex seals when rebuilding a stock 12a or 12b? i am just wondering how long they would last ? longer or shorter than the stock steel ones...
03-27-03, 04:00 PM
#46
Old [Sch|F]ool
Shorter. Generally much shorter.
If iron seals can be expected to live 200,000mi, then carbons can be expected to live about 50,000.
It depends on how you run it, too.... the faster you wind the motor, the more over you wind it there, the shorter the lifespan. One of the most powerful naturally aspirated engines ever built (360hp J-Bridge) had an engine life of 6 hours before it was worn out and needed rebuilt. This is six racing hours, and corresponded to the time spent on-track during one racing season.
If iron seals can be expected to live 200,000mi, then carbons can be expected to live about 50,000.
It depends on how you run it, too.... the faster you wind the motor, the more over you wind it there, the shorter the lifespan. One of the most powerful naturally aspirated engines ever built (360hp J-Bridge) had an engine life of 6 hours before it was worn out and needed rebuilt. This is six racing hours, and corresponded to the time spent on-track during one racing season.
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