Coolidge

Ok, when the RX-8 is on sale, how much do you think Mazda would charge for a recplacement RENESIS engine?

How much did they charge for a replacement 3rd gen engine core?

I'd ****** swap that ****** into an FC for sure! Shouldn't be too hard either.

WackyRotary

I'm sure you won't find a cheap one for a long time unless its in a crashed car in a junk yard. ...even then, it probably won't be cheap since it will be quite new still...It going to take years to get these engines past 50,000miles before things start going wrong on owners if Mazda fixed what they said they did. LOL

Node

iTrader: (1)

I don't think they're gonna sell crate engines, we all hope they would, but its seriously doubtful.
And please no racism
Thanks

Flobb

Go buy an RX-8. Wreck it intentionally, damaging only the rear end of the car enough to total it. Buy back the carcass from insurance after getting check for it. Pull engine out. Figure out what other drivetrain upgrades will be needed. Voila!

j9fd3s

iTrader: (3)

we need to actually get one to see how they mount up. if they changed the mounts or the bellhousing pattern that will dictate how hard the swap is.

mike

Coolidge

Yeah, that's true. Mounts are a piece of cake. The bellhousing parttern would be an obstacle, but nothing to bad that would stop me from doing the swap

I don't mean used engines from engine suppliers or importers... I mean a new replacement engine from mazda. They would have to sell them as soon as RX-8's are on sale, incase an owner ***** his up and needs a new one. Think about this... someone puts sugar in an RX-8 owners gas tank. He needs a new engine. I'm sure mazda isn't going to tell him to wait a few years and get one from a junkyard.

Coolidge

Mazda will probably intentionally make the mounts and bellhousing parttern and various other stuff different just to be jerks so RX-7 owners aren't swapping in the engine.

If they were smart they would make it all the same. If it would bolt up, just imagine how many rx-7 owners woudl buy the engine. They could make a decent profit off just that I would think.

WackyRotary

I don't know if 3rd gen engines even bolt to 1st gens, do they? All I know is that 2nd gen's are pretty interchangable with 2nd gens. Some one educate me on this....

Coolidge

The bellhousing bolt pattern of all 13B engines are the same, regardless of if it's a 1st, 2nd, or 3rd gen. I know the mount are a little different on some of the engines (ie: to put a 3rd gen engine in a 2nd gen you have to do a bit of work with the mounts)

But ya, all RX-7's with 13B's have the same bellhousing pattern I am 99% sure about this.

Jerk_Racer

Ummm Renesis=gutless
Oh, I'm sorry. That was harsh. The Renesis has 151ft/lb of torque and about 250hp. That 151ft/lb is SOOOOOOOOOOOOOO strong and worthwhile the effort and cost of putting into a FC at any cost.

jerk_racer@hotmail.com

Coolidge

Ok... gutless? And what does the stock FC engine have. 146 ft lbs? wow! that's so much more than 151!
Of course I'm not going to leave it stock if I put it in (hello mr.turbo)
Mr.turbo=Mr.torque... problem solved

Node

iTrader: (1)

mr turbo wasnt built for mr renesis and mr renesis might blow his top if mr turbo upsets him, you'd probly have to swap rotors at the least, and does it have any type of 6th ports like the N/A FC?

Coolidge

Haha. Yes, that is also a possibility.
No, it doesn't have a 6-port type of thing

von

What the hell is this torque crap talk... Dont u know top end hp wins races not stupid torque... I like torque but Dont need it in a 7. Well that my opinion... If anyone thinks just becasue it has the same torque means its not going to be faster. Uuuuuu your wrong.

peejay

Bellhousing wise, all production 2-rotors from '74 to the present are the same. The design has undergone very few changes over the years. I don't know about the 20B. But you could bolt a 12A from a '74 RX-3 right up to an FD transmission, and vice-versa if you took the FD flywheel off. (It won't fit in the bellhousing but without the flywheel it'll bolt right up)

There's also lots of parts interchangability - some things have been revised over the years so it's best to use the new stuff (corner seal springs for example) but it's interchangeable, if only one-way.

WackyRotary

I'm sure the thing to remember is this Renesis engine will probably be better then a stock N/A 13b, righT? As a stock replacement engine, not a all out performer, this engine will likely walk over a N/A 13b don't you think? If you plan on just giving the Renesis a lightweight flywheel and since the sideport exhuast on a renesis probably you should have a long lasting engine. Also, the 3stage intake runners probably makes it tuned best for their exhaust setup. But then again, Mazda is known for leaving restrictions were they shouldn't.

People who really want to modify a renesis portingwise, will likely bridgeport the exhuast since they are on the side. But I am thinking the hot exhuast may be too much for a bridge.

peejay

I have a really cool idea... do a small bridge port on the intake and leave the exhaust alone. This sounds like just a backwards version of the normal side intake/peripheral exhaust setup, and well, it IS.

But that can be a good thing. Today's stock setup has the overlap period shifted retarded of TDC. A bridge intake/side exhaust setup will have the overlap period shifted advanced of TDC - this should have the effect of enhancing low RPM and midrange torque compared to retarded.

I can foresee some flies in the ointment already, though. I've been thinking on this... The Renesis has 8 degrees of null time between ports open, right? With stock side ports as we know them, the intake port begins to open at 32degrees ATDC. By opening up the port window as far as possible without risking the corner seal, the side port can open as early as about 25deg ATDC. The exhaust port would have similar constraints given the same seal setup.

So with seal geometry as we know it today, the MINIMUM null time would be about 50 degrees, and NOMINAL for stock porting would be 64 degrees!

There are three ways Mazda could have only 8 degrees of "null time"... first, and most likely, they're counting 8 degrees in a different way than measuring eccentric shaft rotation. If they're going by actual rotor rotation, then we have to divide E-shaft degrees by 3 to get the true figure. In this case, we get roughly 21 with nominal ports and roughly 16 degrees with "maxed street port" ports. This is still not very likely, given that the early-opening ports are letting over half of the corner seal unsupported - I doubt Mazda would do something this risky on an engine it would have to warrant.

Another way would be significantly altering the seal geometry. They might make the corner seals much smaller and further up, and by altering the trochoidal geometry they could minimize apex seal travel so the corner seals need not be so deep. Such geometry alterations could have other benefits as well that I don't feel like going in to.

Some people have also theorized that the engine might have bridge ported intakes right from the factory. If so then they'd have to be VERY small, and only on the 5th and 6th intake ports, otherwise there would be port overlap.

I find it very interesting that there are no clear pictures of the intake ports of the side-port engine, as well as the fact that all cutaways of the engine have half of the rotor cut away, so that the seals cannot be seen.
I just found this at archive.mazda.co.jp:

So we're probably dealing with new seal geometry and closer-opening intake ports. If they're not bridged, then the corner seals would be so close to the rotor housing that bridge porting may not be possible.

Have to wait till I get my grubby mitts on it. But looking at what I've laid out there, the Renesis engine is probably a dud, unless you bore peripheral ports in through the rotor housings or make low-compression rotors so that it can be more readily turbocharged.

hawk 7

iTrader: (2)

I'd ****** swap that ****** into an FC for sure! Shouldn't be too hard either. [/B][/QUOTE]

WHAT IS UP WITH THE RACIAL SLUR!!!

Coolidge

WHAT IS UP WITH THE RACIAL SLUR!!! [/B][/QUOTE]

Oh **** give it up and don't be a baby.
You think I actually mean it like a slur? lol take it easy man, i'm not talking about swapping a black person into an FC!!! I mean ****** as in "good engine"

here's i'll change it to make it better for you...

"I'd ****** swap that bitch into an FC for sure!"
good?

Coolidge

That is right on correct!!! And a renesis sure has good top end (so I read)

rxrotary2_7

does anyone think it possible to take the housings and put fd rotors in there? hence a turbo motor....do we know anything about the rotors? are they the same size? i know they were changing them, but what were the differences? you know the first week this thing is out someone will offer a turbo manifold for it. at least we hope......no?

Coolidge

I am 99% sure the rotors are the same size. I know they are a "hollow" desisgn with a "frame" in them for rigidity and the RX-7 rotors are solid. This is one of the features that allows the 10,000 rpm redline and such quick reving. I bet the new rotors will be able to take boost, it's just a question of how much.

Yeah, I'm sure as soon as it's out there will be a turbo manifold made for it. It probably wouldn't even be that hard for one to fabricate one themselves.

peejay

All production rotors are hollow. Oil is sprayed in there to cool them internally.

As for low end torque, to get to the high end you must first work through the low end. A 200hp 1300cc motorcycle engine would suck in a car because it doesn't have any torque. The S2000 proves this, despite having lots of HP it is slow on the racetrack (drag and road) because it doesn't have the torque to come off the line/pull out of corners.

I really think the rotors will wind up being "not interchangeable"... the Mazda website clearly said that seal geometry was altered in order to change when the ports open. if they did what I think they did (moved the corner seals upward, which would require less apex seal travel, which would require different rotor housing shape) the rotors would not be interchangeable forwards or backwards. If they only moved the corner seals somehow without affecting the apex seal travel/rotor housing shape, then it's possible that the Renesis rotors could be used in an older engine but if you put older rotors in the Renesis the corner seals wouldn't be very well supported. Assuming that the rotor width and eccentricity and the other major dimensions are the same as the 13B. Remember the 13A? It was a 1.3l rotary using 12A-width rotors but a larger eccentric radius and larger rotor housings. The 13B used the 12A-sized everything except rotor width. Mazda might do the same thing again to eke out more efficiency, probably in reverse - making the rotors wider and the eccentric radius smaller.

Felix Wankel

RX-7 rotors are hollow as well:

Coolidge

Wow, I always thought RX-7 rotors were solid. WTF happend to that one? That must have been one mean detonation and an extremely high boost level or no?

Once again, swapping in the renesis and leaving it fairly stock wouldn't be worth the money, since you could make the 13BT that powerful with a couple hundred bucks.
If I were to swap it in, it would DEFINITELY go turbo. I just wonder how much PSI it can take. I guess I will have to wait and see in a few years after guys have turbocharged and messed up their RX-8 engines.

I read in an interview with a head engineer at mazda that they have no plans at all to offer a turbo (or sc) option and they didn't experiment with one and have no plans to.