Mutaku

before you go through with this consider this, are you doing this for power? or are you doing this for show factor/being different? if its for power i'd suggest just going turbo swap or if you want to keep it N/A go for a P port.

sintri

20b n/a if you're going for power and still want to spend that much money, plus you'd probably still be putting out more power than stock t2s. Not quite sure why you'd want to put a renesis when there are better ways to fit pretty much whatever situtation you want. But if you want it, it's really up to you, though I seriously doubt it's anything you would call "unique" as to every single rx-8 was sold with that engine (and rx-8s are pretty much more common than mustangs around here) and in the end you'll probably still find yourself disappointed in the ammount of power. But gl whatever you choose.

Mutaku

but u don t see very many FC s with them lol. but yea if you want to drop 10k in the car then the 20b idea is a good idea. Leave the Renesis to the 8s

sirx7

or you can take t2 motor, take the rotors and cut them like they do in the renesis engine.. that is what i did.. and it helps in the power band casue the intake track is open slightly longer

playdeadva

+1

rotarygod

iTrader: (1)

Why is the 7 forum so full of dead wrong info in regards to the Renesis. Is it the closed minded peanuts for a budget based attitude? It must be. Sadly this attitude hasn't changed yet. The Renesis is superior to the 13B in every way and this is even true without it's fancy intake manifold. Admittedly it would be best to keep it working properly as this is far and away a better intake than any 13B ever had. It takes a streetported 13B to get this much power and even then the 13B has certain sacrifices to get to this point. Too few people here truly understand the Renesis and it's benefits to give any good advice on it. If it costs money, many here are against it. That's also why there are so few RX-7's on the road that are worth anything. In Chevy piston engine terms it's like arguing for a new LS2 vs an old L98 and trying to say the L98 is a better engine. It isn't even in the same league.

For a conversion you will need a complete standalone ecu and new motor mounts. That's it. the motor mounts would be the hardest part but by no means difficult. You could use the RX-8 driver's side mount. You just need to make something work on the passenger side. As far as ecu's go you could use almost anything including a Megasquirt. Soon it will be able to read the stock RX-8 trigger wheel. Any other ecu can be made to work though. Since it's the factory RX-8 ecu that needs to read the stock trigger wheel, it's easy to change this with no issues. I even have a 36-1 trigger wheel for an RX-8 that was off of a Speedsource car so making a standlone work isn't an issue. It bolts right up and I don't need it.

You can find a Renesis engine for about $2500. Maybe cheaper if you know where to look. Call Paul at Mazmart in Atlanta. It bolts right up to the factory transmission. You will need an aftermarket flywheel but can retain the stock 2nd gen clutch. If you have a TII tranny, you can keep the stock RX-8 flywheel. There are a few issues to work out but as a whole it's a pretty easy conversion. It definitely won't cost $10K to do. It's not to say that it's a quick few hundred dollar job either but no properly done 13B rebuild is that cheap anyways. Just remember, it doesn't matter who advertises what, there is no such thing as a budget rebuild that was done properly. It would be a cool swap. Go for it. You'll walk all over any stock TII with authority anyday. You'll spend a little bit of money but do what makes you happy. Screw everyone else.

As far as coils go you have a good selection but you should be able to keep your 2nd gen coils. I run them with a Megasquirt in a 1st gen with no issues. The 2nd gen coils are actually very strong units and I have yet to find any aftermarket coils that I'd rather have.

86TwinTurbo

if anyone does happen to have a spare renesis laying around I will take it...I just bought a rx8 from a police auction, it was stripped with no engine and other misc missing pieces for 2000 and I was thinking or doing an 13b re swap or a 20b but I would take a renesis just to make it all matching

Sideways7

iTrader: (7)

Actually a properly done NA 20b will be a lot more powerful than a stock t2. Even a streetported 13b can be more powerful than a stock t2.

RETed

Lesse...

Shorter apex seals - less mass? Certainly can't be for strength...

So explain to me how side ports are more advantageous when it comes down to ultimate power potential? How are PP motors less advantageous to a MSP-RE motor?

Take away the fancy intake manifold, and all you got is a full side port motor (which is not advantageous for maximum flow, especially at the top end), and slightly higher compression...


-Ted

rotarygod

iTrader: (1)

You don't have any Renesis experience do you? Yes it has shorter apex seals. So what? They are stronger. The stock 13B seals are 3 piece and no single piece is any taller than the Renesis (2 piece) seals. Logic would say they can't be any stronger than the Renesis seals as a result. They aren't. The Renesis apex seals also don't travel over an exhaust port so there is less stress on them at this point. It's a non issue. Yes people can change 13B seals to 2 piece for strength but you can also mill out Renesis rotors to do the same thing.

If side ports are so bad, why does the Renesis make WAY more power than a side intake, peripheral exhaust port rotary? You aren't comparing apples to apples by comparing a full non strteetable (under any circumstances regardless of who falsely claims otherwise) peripheral port engine to a non overlap side port street engine. Answer this one, why does it take a bridge port 13B (or turbocharged) to even catch the side port Renesis engine's power level stock? A streetported 13B won't even do it and if it does, it's at it's limits. It isn't because of the intake manifold and it's not the compression ratio.

Compression ratio differences between about 9.0:1 and 11.0:1 are negligable when it comes to power. Mazda did tons of research on this and I even have a copy of the SAE paper showing power vs compression. They raised the compression to help with emissions. Sounds weird but I'm not going to get into it here. Compression ratio isn't what did it. Just think about this, we don't only compress air in the engine, we also move it. There are flow issues with too small of a dish in the rotor. I'll leave it at that.

There is far more to an engine's powerband than purely how much it can flow. Flow is important to know but it must be used with a frame of reference. That's called timing and rpm. Too many people don't understand how this all fits together. The peripheral exhaust port is actually open far too long in relation to the side intake timing. More flow with the same timing will increase power across the entire powerband but port timing will affect where the powerband actually is. That's actually mostly correct as they are both related but again I'm not going to get into it here. Technical info is typically lost here. If you want to just crudely simulate this phenomenon, get a hold of a computer program such as desktop dyno. While not terribly accurate as far as what an egine will actually do with their choices, it will show the effects of timing changes. This part they got right. Yes it's for piston engines but the effects of timing are easily simulated. Just pick any standard engine choice. It doesn't matter. Take a look at it's power curve. Then change the exhaust timing only and make it longer and longer and watch what happens to the powerband. By the time it gets to the equivalent duration of a peripheral rotary exhaust port (since the Renesis exhaust ports are equivalent in timing to an average piston engine relatively speaking of course) power has fallen off pretty hard. This is what happens in the rotary and is why the Renesis is a far more powerful engine. You can go back and modify the intake side to increase duration to that which would be a piston engine equivalent of a rotary peripheral intake port and power goes back up. Timing does some neat stuff when it comes to power. More is not always better.

On a peripheral port race engine, port timing is fairly close between intake and exhaust. There is far more to it than simply that though but needless to say exhaust timing on the side intake port engines is everything. The big advancement in that engine comes from the side exhaust ports. That's where the big secret is. It's not the intake or the compression ratio. They are contribute to widen the powerband but it's the exhaust ports that really changed things. Without the side exhaust ports we'd still be stuck at sub 200 hp levels without forced induction except we'd never meet emissions standards.

The Renesis easily trumps any streetable 13B anyday and it can do this stock. There's just no room for debate. It may not appear that way because the RX-8 ecu is tuned like crap but that's not the engine's fault. Even the low power 4 port Renesis is the last n/a 13B's equal.

rotarygod

iTrader: (1)

Mazmart is now selling Renesis engines for $2000. That may sound like a lot until you consider that they are all rebuilt by master engine builder Rick Engman (race engine builder for Jim Downing) to his specs with all new seals. That's a pretty damn good price. You couldn't get a Renesis core and rebuild it yourself with new seals for that price. If Rick built it, you know it's going to be nice. He also has changed some of the seal clearance specs to his standards as he feels Mazda was sloppy with some of them.

arghx

iTrader: (3)

You make a strong case for the superiority of the Renesis as a naturally aspirated motor and for the Renesis as a worthy swap if one wished to stay n/a. My 172rwhp n/a is close to stock renesis numbers but has almost zero emissions equipment and is pretty loud.

BUT, as it stands, there's no serious writeup or guidance for swapping a renesis in though. What would one use for manifolds then? How about engine mounts? In the wiring department, what about sensors?

I think from the perspective of people here, they would rather do the proven easy T2 swap then have to gather up a ton of parts and devise all sorts of custom stuff when the final power output is near the Renesis.

rotarygod

iTrader: (1)

A TII is still a fairly competitively priced (to a Renesis swap) option with the advantage of having more overall power potential by the sheer fact that it has a turbo. These get more and more rare everyday as the car keeps getting older and the Renesis keeps getting mroe and more plentiful and affordable.

A Renesis swap isn't all that complicated. Once you get a standlaone ecu you're half way there. I's use the stock intake manifold and just adapt a cable style throttlebody. The VDI and aux port valves can be operated with an air pump or exhaust pressure depending on how creative you get. That's actually not that hard to do. As far as engine mounts, the driver's side 2nd gen mount will bolt right up. Take another one of these mounts but bolt it up to the passenger side of the engine as well. It will need to be spaced out. Instant Renesis engine mounts. It's easy. The flywheel size is diferent so it'll need an aftermarket one. The oil metering pump is obviously different. You can either premix or adapt an S4 mechanical pump to it with a little creativity. I've done it to S5 front covers before. This is best done before the engine goes in. I would also personally make a different oil pan as the RX-8 pan is smaller. That pretty much covers most of it. There are always little things to do but it's not nearly as hard as people think it is. You'd also need new fuel rails and a regulator.

My5ABaby

iTrader: (7)

Post a full write up.

RETed

Mazda hasn't made a 3-piece apex seal in years.
Your argument is not applicable in this case.
Care to argue taller 2-piece versus shorter 2-piece?


Get rid of the overlap.
Keep combustion in longer = more torque especially on the low end.
Can't forget the revised intake paths.


[QUOTE]You aren't comparing apples to apples by comparing a full non strteetable (under any circumstances regardless of who falsely claims otherwise) peripheral port engine to a non overlap side port street engine.[/QUOTE}
I thought we were talking about maximum power?
Now you're going to narrow it down to what is "streetable"?
I've know people to have argued that BP's and PP's are streetable - take it up with them.


It's called a higher redline.


Last time I checked, the numbers were 9.7 versus 10.0?
Where did you get 11.0 from?


I agree, but you claimed that the MSP-RE was superior in all aspects.
I countered that argument.


-Ted

rotarygod

iTrader: (1)

Show me a 2nd gen or 3rd gen that was sold in this country that came with 2 piece seals. They didn't have any. Since 2nd and 3rd gens in this country all had 3 piece seals, that means that any one long piece is not very tall. Remember there are 2 pieces stacked on top of each other. Not counting the triangular corner piece of course. The 3 piece seals can withstand a very high amount of power. There just aren't many people that can tune well enough to get real high. Yes the Renesis apex seals are shorter but they are no shorter than any one piece of the 2nd or 3rd gen seals. They can't be any weaker as a result. Stare at some sometime. You'll understand then. The 13B apex seals used electron beam chill hardening on the tips alone. On the Renesis they harden the whole thing. The Renesis seals are stronger. Now is that clear enough or do I need to post a picture to get the point across?

Your argument is irrelevant. Again, get some experience with one. The Renesis with no overlap makes FAR more power than the streetable 13B and it isn't because of higher overlap, intake manifold, or compression ratio. If it were all low end based, why is the Renesis more powerful everywhere?

Last time I checked the Renesis is a street engine and this guy asked about installing a Renesis in his street driven RX-7. PP's and BP's are not streetable. Go pass emissions with one, get decent gas mileage, not buck wildly a part throttle, and have the ability to muffle it well. A streetable engine can do all of these. A BP or PP engine can not and still make enough power to have been worth the effort. I don't care who drives one on the street. An F1 car could physically drive down the street. Does that mean it's streetable? Nope. There are people that drive cars with full roll cages on the street too. Those are not streetable either. Just because you "can" physically drive it down the street and just because someone is crazy enough to do it doesn't mean it's streetable by any means. All of the questions from people who ask about doing street or bridgeport engines for street use are typically people who are still learning and haven't yet realized that there are serious tradeoffs. These also seem to be the people who actually try it. If you have a dedicated play car that's one thing but if its a daily driver, it's a terrible idea. When people learn mor they usualy get away from these for the street. Keep things in context. Of course you can't win an argument against the Renesis if you do.

Irrelevant. The Renesis makes far more power than the 13B at any rpm and load level. Leave race engines out of it. Street engines and those can not include BP's or PP's as they are NOT streetable. Again, I don't care who does what. They are NOT streetable. Period. Some people actually understand the design differences between race engines and street engines.

Well if you knew more about rotary history and design you'd realize that there is no appreciable power differnece between a 9.0:1 compression ratio all the way up to an 11:1 compression ratio. Mazda determined this through research. Above 11:1 and below 9:1 power falls off. Now since they discovered this to be true, it would also seem logical that if we applied this to the actual compression ratios of each engine we'd see that power betwen 9.7:1 and 10:1 would be nearly identical. Therefore the slightly higher compression ratio does nothing for more power. Put the pieces together. How much do I really need to teach here?

Compared to any streetable 13B, it is. Come on Ted, for once will you please do some semblance of research before you spout out misinformation again?

arghx

iTrader: (3)

Now I'm REALLY curious now about what a factory turbo Renesis could do and how the ports would be designed.

GGrip

There's nothing wrong with being a dreamer...at some point, your RX was somebody's dream. If Mazda engineers had come to you knuckle-heads for advice, the car would never have been built.

pengarufoo

+1


except I doubt the dreamers that made the rx-7 asked complete strangers if it was possible.

generally, those that ask lack the motivation or talent to get much past that point, if you're actually motivated you don't come on the web and ask people, you start working.

asking people is like trying to get discouraged, there will ALWAYS be naysayers, anyone whos done anything knows this. If you want to succeed go do it. If you want to entertain yourself go talk about your dreams on the internet.

$.02

arghx

iTrader: (3)

but once again, people naysay for a reason. There are so many people who will bullshit about doing a lot less ambitious things than a Renesis swap

pengarufoo

swapping an engine into a car is not very ambitious in the grand scheme of things...

edit:

and even if we keep it within the scope of modding a car, we're talking about swapping an engine that is such a close relative it's practically bolt-in. Why isnt this thread full of photos of a renesis in a FC instead of people bickering about wether it's worth it or not? Because talk is cheap.

RETed

And that was over 10 years ago...
Go to the Mazda dealer parts counter and ask for 3-piece apex seals, and they will all look at you funny.
So how do you get brand new 3-piece apex seals?
You're trying to compared used parts or something?


In a perfect utopia with no detonation, yes.
Sadly enough, people do detonate motors, and the 3-piece apex seal will most likely fail easier than the 2-piece design.


This point is moot.
See above.


Reference?
SAE paper?


Reference?
The OP did mention he's looking at using just the short block.
The only reference I know of is the Star Mazda engines, which the MSP-RE only makes like 10hp more than the older PP exhaust 13B's.


I brought that comparison up just to make a point about the porting.
It was to make a comparison of the SP exhaust port versus the PP exhaust port.


The OP wanted to throw ITB's on the engine.
I don't think emissions is going to be a problem.


I didn't want an argument on "streetable", and I refuse to further this part of the discussion, cause it will not get anywhere.
Agreed?


You got graphs on you?
I heard 10hp to be the number being thrown around.


Wow, this is interesting.
You tell me to keep on topic, and then you post this irrelevant tangent on non-existant compression ratios?

You're right.
I don't **** around too much with non-turbo rotary engines.
To me it's a waste of time.
I don't have customers that are willing to pay to build a big bucks non-turbo engine.
I do know lots who are willing to spend money on turbo 13B's though.
Like I said before, I don't want to get into a discussion on what is "streetable".
I think that discussion has been beaten enough.
My idea of street is actually pretty conservative.

Bottom line: if the OP wants to do this, go for it.
We're just the peanut gallery offering out opinion.
As long as we're not breaking anything in the TOC, we're allowed to offer out opinion, period.
You can chose to ignore out opinions.
Personally, I'd go turbo 13B putting out 350 to 400hp or 20B "just to be different".
I think normally aspirated is a royal waste of time and money.


-Ted

pengarufoo

10HP?

6 port pre-renesis/carbon chassis star mazda motors were 180
reference: http://www.texasautosports.com/carsfm.aspx

MSPRE new generation start mazda is 240
reference: http://starmazda.com/cars.htm and http://www.texasautosports.com/carspfm.aspx

Must be new math?

Juiceh

iTrader: (4)

Seriously, in the late 50s and early 60s when Wankel was developing the engine, do you have any idea what the random hippy would say if the concept was brought up to them?

The hippy would ask where the **** Wankel gets his weed so they can go get some and have similar dreams!!

RETed

Sorry, the numbers I heard was 220 versus 230.

And rotarygod is right: I don't have direct experience with those things.
But here's some guys who do...
http://p211.ezboard.com/fformulamazd...icID=532.topic

Just as I thought, that "240" hp number was taken straight from the RX-8 advertisement.
These guys confirm the motor is from the sub-200hp auto trans RX-8.
Star Mazda is using restrictors to be able to keep the old 13B versus the RX-8 13B on the same race series.
This is really not a very good comparison on the capabilities of each motor - yuck, restrictor plate racing.
There is even one comment about the new RX-8 motor putting out less power - probably due to the restrictions than anything.


-Ted