think the opposite of a renesis. The renesis and side intake and exhaust port where as a peripheral ported motor has both the intake and the exhaust ports in the same location as the exhaust ports on a typical 13B

 

I have many times thought how cool it would be to have a PP FC, not the most streetable but still wicked to have. I have done a little bit of research on this and found that the most simple ( cheapest ) way to do this would in a Fc is to run a 51 mm IDA carb, remove FC ignition and use a dizzy, premix, low psi fuel pump, it would sound awesone.

 

this thread sucks.

all this guy wanted to know is if anyone on here has a peripheral ported FC, and the only responses he got were "PP FC's arent streetable"

everybody says everything is unstreetable. he already said he doesnt care about how neighbor-friendly and quiet and smooth the ****** thing is, he just wants a badass peripheral-ported 13b, whats the big deal.

 

It won't be on the streets when the cops keep pulling him over for noise.

I've heard a race PP 13B and its loooooud. Although very sweet sounding.

 

You olny have to look at the Australian Rotary Scene for PP RXs there are a few that I am aware of being run as street cars (not exactly daily drivers though )

The reason I went 1/2 bridge rather than anything more extreme was to keep it streetable, idles high, makes wierd noises that scare the kids, but can be used in town withough too much problem - my wife hates driving it though!

regarding ECUs I'd say either Microtech or Haltech would be the best options, over here in the UK Microtech as no-one runs Haltechs so we don't having any mapping ability here!

Interesting reading this thread, but it is fair to say the guy wanted to know about PP FCs not whether or not anyone thought it would be streetable!

 

Having a PP FC driven on the street is still the plan. The car only has 78k miles on it now so it may be awhile until the project gets started as I am waiting for the engine to blow before i do anything. The FD isn't a finished project yet though (are they ever?), so this project is probably a couple years down the road. I may start it early depending on my FD and what i feel like doing.

 

scathcart: I have a couple of thoughts perhaps you could clarify.
1. Couldn't a semi-PP or a less agressive PP could theoretically make good power ~8.5k on a S5 n/a engine or S6 engine which is designed for a 8k redline?
2. I can't imagine anyone would bother, but why couldn't a stock ECU with a S-AFC work with a PP or semi-PP engine?
3. When you're talking about reliability, what components are an issue at the 250hp you stated? What about at the 300hp you said makes them unreliable?
4. What are your thoughts on a semi-PP that could be RPM actuated like the stock 6th ports to allow for essentially a stock engine under X RPM?

Thanks.

 

There is no reason that I can think of why a stock ECU with S-AFC couldn't control a PP'd 13b (my 1/2 bridge is currently running in on a stock ECU but I'm getting a Microtech LT10s in the new year) the point is you wouldn't see a large increase in power or performance as the stock ECU isn't mappable so won't allow you to utilise the engines performance especially in the higher 8-9.5k rev ranges! The guy who built my engine runs an FB drag car using a 12a ported turbo'd engine with Water Injection, no IC and he has seen 11250rpm on the strip and still drove the car home afterwards. With a PP you need to be able to use the high rpms to get the power.

 

If you want sub-PP performance, you stick with side ports. All the diadvantages of a PP (cost, noise, driveability, etc) with only bridgeport power seems pointless.

Would it really be worth the hassle and complexity? This is one of those things that would've been done long ago if it was worth it. I would confidently predict that no-one will ever bother trying.

Two words: injection timing. Because of the massive port overlap the injection timing is far more critical. Get it wrong and you fire half the fuel straight out the exhaust. The stock ECU's injection timing is set up for a completely different manifold, and would be far from ideal for a PP. Without the ability to adjust injection timing you'll never get close to a PP's full potential and are just wasting a lot of time and money.

 

1. Yes... but cutting off any PP, even small w/sideports, below 10,000 rpm is a waste of a great engine. A large streetported engine will continue making power until 8000 rpm... a peirphereal port is just kicking inat 7000.

2. Its just too far outside the design of the ECU and its sensors. With the extremely limited vacuum range of a periphereal port (they don't draw 12-18 inches of vacuum like a side-port engine will) and the engine airflow exceeding the maximum measurable range of an N/A AFM, the ecu mapping simply isn't set designed to deal with an engine that performs so far out of range of stock.

3. for 250 hp, mostly your standard 10,000 rpm items... all your oiling mods, balancing, etc. For 300+ hp... you generally just need to make sure the actual periphereal ports are large enough (and their matching exhaust ports), and then increase your revs... up to and including 14,000-15,000 rpms. With said rpms (and the coinciding launches... ever heard a car launch at 12,000 rpm?), other parts start to break. The associated wear and load on the engine as such an rpm is just a huge strain on the entire drivetrain: this is a race engine, so you can kiss street reliability good bye. No one expects a 15,000 rpm engine to be reliable.
Its not just an engine we're talking about here, though. to be able to utilize an engine that makes power in such an rpm range, you would be stupid to utilize the stock gearing (not to mention the danger of it).

4. "Essentially" is the key word here... you still have the periphereal ports fully open (port timing, not port flow) when the exhaust is open, and you will still get some of the intake dilution with exhaust gases, causing a need for a higher idle: periphereal port intakes, eve small ones, have TONS port overlap...
To limit this, and keep the idle as low as possible, you would want to have your actuators as close to the engine as possible... ideally, you would use a pair of slide throttles, though I suppose a pair of butterfly plates would work as long as they were kept as close to the engine as possible.
The other trick would be actuating them... but with enougn money, anything is possible, right?

To be honest, I actually looked into building an intake manifold that worked like such when I built my periphereal port engine, but decided to scrap it: if you build a race engine, use it as a race engine.

 

So.. ANY BOOKS OR WHAT?????

No one can answer this it seems... Im gonna mail this question to turbo mag.

 

problem with forums! you can't emphasise words correctly!
I meant that theoretically the PP would just about run on the stock ECU but it would be hunting costantly at lower revs due to the overlap and you would get NO PP benefits as the power band is to high in the rev range for the stock ECU to be able to use.

 

Did someone say Peripheral Port?

 

Just a little reminder...

If you do a PP and are living in the high RPMS, do yourself a favor and be sure to get a Kevlar flywheel sheild. Many people have been paralyzed and/or killed by a fragmenting flywheel.

-Joe

 

If all it took was reading a book on EFI tuning, then guys like Steve Kan and RETed would be out of business. Once you have mastered EFI theory, all EMS tuning entails is learning the interface.

Also, most aftermarket EMS have 3 critical sensors: MAP, Intake Temp, and Coolant Temp. Not too difficult to place them.

With that being said, I think there is a rotary specific modding and tuning book out there...somewhere...

 

Only book I know of is an introduction to the different brands of EMS systems, and how they differ, as well as a description of how EFI works and what you're trying to achieve through tuning. Basically, an introduction only. I'd have to look up the title, if you're really interested.

There are no books that will in depth describe how to tune a stand-alone on a rotary.

 

Thanks for the responses to my questions, that's good info. I've got a couple in response to your responses.

I don't see why it would be that horrible of a hassle if a custom manifold like Scathcart mentioned was already being fabricated to have a valve operate further up the intake than the stock 6 ports (picture a simple valve in a peripheral intake tube say ~1 foot away from the block). Can you see any further faults in such a system?

If you had a PP engine open/close at timing that wasn't disimilar to what's done with a side intake engine, what changes in both injection and ignition timing would be optimal? (obviously I'm looking for a fairly general answer) Essentially I'm curious as to the ECU differences with a peripheral intake engine.

Many of Mazda's racing PP engines did not rev that high. eg. '77 Racing 12A "Sports Kit", '77 13B Racing, and a number of more modern ones, etc. made peak power @ 9k. Those kind of engines appear to be able to produce 250hp and above. Even more exotic multi-rotor engines as well such as the 13G, 13J and R26B in the 787B made peak power @ 9k and in the RX-792P @ 8.5k. There must be a power advantage over a bridge and I can imagine a bridge is more likely to break. Thoughts?

 

As I mentioned above, to keep a decent idle, you'd want the valve as close to the engine as possible to prevent the overlap-induced exhaust dilution of the intake charge to a minimum. If you don't care about idle, then one foot would be fine.

You could not build a PP engine that had opening timing remotely close to the stock ports while using Mazda aluminum rotor housings. Mock up a housing, use some machinist's blue or a felt marker, and even just mark a 1" PP hole on the rotor housing face, just below the tension bolt hole (for the latest opening possible), and then spin the rotor. You'll see that even this relatively small port will open FAR before any stock (or some bridge) ports.


Yeah, you keep the ports small, and peak power will occur at a lower rpm. For a race engine, where port size is limited, its your only choice... or for where durability is concerned (many of the modern examples you mentioned), you want to keep the revs down. For a street car, why bother with small periphereal ports? You can get 250 out of a turbo engine VERY easily and not have to deal with all the downsides of a PP engine.

So... why not just turbocharge the small periphereal port? Best of both worlds, right? Not exactly... turbocharging a PP is a whole 'nother discussion.

.. and why ever build a N/A bridge? Class rules limit the use of Periphereal ports... only reason I would ever do it... the periphereal port would definitely be more reliable.

 

I had looked at where a PP would go and I was thinking it would be similar, but I'll take your word for it because obviously PPs have lots of overlap. As for the idle, you think that with a distant valved semi-PP the idle would be poor because exhaust gases would accumulate in the intake manifold? How bad would it be and would there be an effect when the valve opened?

Any further comments (general) as to how the ECU would be tuned differently for such an engine? What impact would there be on reliabilty with a lower reving small peripheral intake?

As to motivation for a semi-PP valved n/a, I'm not saying I want to do this (in fact I couldn't if I wanted to right now), but I think it's an interesting concept. The concept I've been thinking around is to have a completely normal n/a engine with all the good stuff one associates with a straight from the factory street engine with serious power. Essentially it's what the Renesis could have been, but with more power and decent low end for a PP engine.

 

Thats bs. Just look at 'maximum boost' by corky bell. This book is out for turbocharged systems and people still pay big money to have pros install kits for them, tune them, etc. Just becuase theres a book out on a complicated system, does not mean that the secrets have been revealed and all the pros can get pink slips. It takes a lot of patience and understanding to grasp a book like that and actually learn from it, its that small % of people who turn into techs like reted and steve kan..
Theres gotta be a book specifically on ECU systems, installation and tuning out there somewhere.

 

I'll get you the name of the one I described by the end of the week. PM me as a reminder, its only $15 or so to buy and is an alright start.

 

I know the idle would be poor from exhaust dilution, not think
I would expect idle to be bouncing around 1600 rpm for a well-tuned 55mm PP with butterflies closing the periphereal ports at 12 inches from the engine.

ECU tuning compared to... stock, or a street-ported engine?

I know what you're seeking with this engine idea... insane power in a nice, neat, livable little container.... problem is, to make an engine livable, you have to put an exhaust on it... and the last thing you want to do on a high-overlap engine is to restrcit the exhaust flow to try to quiet it down. The renesis had to meet noise and emissions requirements, like all stock cars. If you didn't care about noise, or pollutants, sure, the engine would work.

 

Its getting closer..................................

I fit and welded the new engine mount last night.

 

I have cleaned up this thread. Now, I should delete all streetable vs. non-streetable posts, but some of them actually have a little bit of info.

Keep this thread clean. Any more crap and I will go through the entire thread, deleting all posts except the ones which I believe contain information.

 

I don't quiet understand why there would be such substantial exhaust dilution problems if the peripheral intake was closed, could you explain?

Have your pick, I'm just looking for a general idea because I haven't a clue.