This is just a question for my own curiosity, i wasnt nessesarly considering doing this any time soon if not at all, i just wanted to know. Has anyone ever tried doing a conversion where they put an rx8 motor, or one similar (age wise), into their fc3s. It should be the same size i would think so why wouldnt it work?

 

simmilar age wise as in what? the rx8 motor is diffrent from all the rx7 motors

myself, i havent seen./ read / hurd of anybody putting an rx8 motor in an fc

it probably would fit, however you need the proper electronics to support it, welding up some steel to get it mounted is 4% of the battle

 

Seen one in a FB but that about it.

 

The renesis is the failure of the rotaries anyways, it already underpowers the Rx-8, although its a good car its suspension and handiling make it what it is, this is why you see most people swaping a different motor into the Rx-8 I dont think anyone is really planing to swap a renesis into their FC.

 

You post fails. 238HP is no joke NA. If you think that is undrpowered then please tell us what a good number from an NA would be.

 

If the Renesis is such a failure please explain this dyno graph below comparing it's output to a S5 NA. This image was taken from rx7.com.



Noteworthy achievements with the Renesis:

Won engine of the year in 2003 scoring 44 out 50, a record for the Engine of the Year Awards.

9K redline: lighter rotors that are cast more efficiently, plus a different arrangement of the location of the gears, and hardened gears allow this.

Survived a 24HR top end endurance test with an average speed over 125 including pit stops to top off fuel/oil and change the driver/oil @ the 6 hr mark(figures may be inaccurate as they are from memory). Less than 1% drop in compression at the conclusion of the test which was completed by a PRODUCTION RX-8/Renesis with no mods.

Even with 2 MORE injectors than our cars, it consumes less fuel, makes more power, and produces less emissions. Uses 30% less fuel @ idle.

Vince

 

I've heard that the output of the renesis is way over rated... here's a post from the dyno section, he said he saw an rx8 put down 155 to the wheels... https://www.rx7club.com/time-slips-dyno-128/dynod-my-turbo-ii-yesterday-525579/ still not bad considering he also said the dyno reads low and thats WHP, so... i dont know what that would make the actual flywheel HP, but definitely lower than 238 i'd say. BTW that wasnt the first time i'd heard that.

I think it would be cool to use the rx8 rotating assembly in a regular 13b because of how well balanced they are for that high redline. I shouldnt get started on dreaming though because i'll probably never have money for that kind of thing...

 

That thread also says they were using heavier drums

 

FCDrifter13 is pwnng this thread.

And to the poster, no, I haven't seen this done .

 

Did you even read that thread?

 

The Renesis engine is not balanced from the factory..people need to stop spreading false rumors. It is laser-cut or some ****, but it is NOT a balanced rotating mass, so to speak..

182rwhp on a stock motor / 1mm seals is not bad at all for an NA..9k rpm redline..lighter..burns less fuel..I don't see a downside to this motor, do you?

 

I've never heard of it before, but i seems like it would be worth while if you had the time/money etc. It probably be as much work as dropping a v-8 in. New mounts, computers, etc.

One other thing renesis haters seem to love to post is dyno runs in an automatic rx-8. which has less hp than the 6-speed. Two different engines.

 

how is that S5 NA that high, I thought it was 160BHP factory, how is it hiegher wheel hp than what it came from the factory? but I dont doubt that rx8 dyno, that looks right from all the disapointment its brought.

 

Red = Rx-8. Blue = Rx-7.

 

Maybe you are confused, S5 NA is in BLUE, RX-8 is in RED. So, 126 (34hp drivetrain loss) for the S5, 182 for the RX-8. Still a disappointment because it is apparently a 56hp loss through the drivetrain, lol.

Too look at it another way though ->
S5 NA rated 160hp, puts down 126hp, 78% drivetrain effieciency.
RX-8 rated 238hp, puts down 182hp, 76% drivetrain effieciency.

Although, if you've driven and RX-8, it's not that big of a deal. It still seems fast, pulls hard, sounds amazing, and handles great. That and it's just a rush to take it up to 9K repeatedly.

Vince

 

Any idea why the dip in the Renesis just before 6.5K?

 

Not to mention the Renesis is much more environment friendly. It's like what, LEV II rated I think I read somewhere?

 

Funny thing also is the fact that the rx8 dynos poorly. There have been a few, not many, cases where stock rx8's were able to dyno at ~200rwhp after SAE correction. My guess is that these were the base models without the traction control devices. Many other rx8's have traction control problems on the dyno and they must turn them off to run it. Then the abs light goes nuts, sometimes a CEL too, and so on. RX8 really doesn't like being dyno'd heh, some tuners I've talked to have said that they cant tune on the dyno either, it's always street tuning because the rx8 doesn't repond properly.

 

I learned to try and not to post wrong info. And I also read up alot. Most people come in here and think they can box, but end up falling on there face because the info they got he heard from a guy that talked to a guy that knows a guy who knows a salesman that told him it was true. Or some BS like that.

But then again there are times I look above my avatar and just say ****.

 

The RX-8 matches track times with the 350z and m3, both cars sell for more cash than the RX-8 - and fit more than two people more comfortably with more fun ~ per Top Gear.

I would suggest that the gap at 6.5k rpm is where the 3rd stage of injection phases in, a lot like vdi, just 1k higher and it takes a lil bit of the torque away as it builds to that next level of intake.

I would love to get the efficiencies of having side ports, the slightly higher compression ratio, and a flash upgradable ecu - but I don't think it's going to happen - just go buy an RX-8 and enjoy it.

The RX-8 is also a bit more fun because it has a 4.44:1 final diver versus the FC 4.10:1 final drive.

 

I can tell you right now that there may not be a single N/A rx-7 passing emissions and putting down 180+ whp

On the other hand, the power potential for the renesis is pretty much zilch. Maybe an extra 10-15 horsepower N/A if you run with no emissions.

 

The dips are the intake stages changing.

Vince