Erv187

Does the renesis motor have the same exhaust ports as the 13B-REW becuase I was just wondering if it is possible to bolt on the twin turbos from the FD to the renesis motor. that would be kinda cool to have a twin turbo RX8

Rx-A-Ho

The Renesis engine (13b-MSP) does not have the same exhaust ports as the RX-7 (13b-REW). The Renesis has all side ports for both intake and exhaust and the RX-7 has perpheral(sp) exhaust ports. So the exhaust/turbo systems are not interchangable.

Hope that helps.

Mikelikes2drive

i dont know of anyone or heard of anyone that has tried... but if it were that easy to just bolt one of the many rx7 turbo kits on the rx8 i wouldve bet all those tuners wouldve done so instead of swapping it out with a fd engine.

rotarygod

The 13B has 2 exhaust ports. The Renesis has 3. They aren't in the same spots either.

DreRX8

Besides that--you really don't want to complicate things with a twin turbo setup--a good single will be much more efficient and less complicated to trouble shoot--you'll have a virtual woss ness of hoses under there to 'play with'. Twin turbo setups were typical for big horsepower or for reducing lag--modern turbochargers are efficient enough that they don't have much lag.

Dragonfc3s

I'd love to see somebody cut the O-Ring seal area in to FD rotor housing and use them in a 6 port Renesis. 4 side and 2 peri ex ports would make for one pain in the *** manifold, but with lots of boost I think it would be quite interesting...

guy321

What's a woss ness?? I thought the term was "wasp's nest". Are there a bunch of rappers in the engine bay??

DreRX8

BWHAHAHAHHAHAHAHAH----I see you must be up on the gulf coast rap game,
you are on my list of respected users

Glyphon

chassis code is se3p. body code (in the vin) is fe. the rx-7s were refered to from their body codes. so why is calling the 8 an fe wrong?

Gerael

Amen brother!

rotarygod

That would be a terrible setup. No exhaust tuning abilities. Every port having different timings. Poor exhaust gas velocity. That engine wouldn't make crap for power. More is not better.

ZoomZoomH

iTrader: (1)

because FC3S and FD3S were CHASSIS codes for those cars, not just letters in the VIN

VINs differ in different regions around the world, chassis code is universal, and that's what you should use to call your 8, SE3P

Glyphon

good answer
so, its not wrong to refer to it as FE, its just not the best way. personally, i just call it "the 8".

sorry for the sidetrack

ZoomZoomH

iTrader: (1)

yea until the 2nd gen comes along, there's only 'one 8'

93RedX7

Close, but not exact. The Renesis has a 4-3 exhaust port setup. It has 4 exhaust ports, inside the block, and 3 exiting the 2 end and center housings. Hope this helps.

rotarygod

Believe me, I know what the engine has. I was only giving the relevant information to the original inquiry. Look at the engine fully assembled from the outside. How many pipes need to be built into a turbo manifold? 3. How many need to be built for a 13B? 2. Does the fact there are 4 exhaust ports internally change this? No

Dragonfc3s

You would of course port the Peri etc. to better match the side's(remember you can change port timing) and would take some playing around with to get the max power out of it. It would definitely be turbo and on a turbo rotary the power is more in the exhaust ports than the intake and how much you can get out of the engine as fast as possible to elevate contamination of the intake air/fuel mixture. To make things even funer punch a small peri in the intake side as well like the scoot FD and run a large side/peri intake. Plumbing and cost is the only thing that would make it not work. As for gas velocity I'm not a whinny it's got turbo lag wuss since I like to Drag race and would run a large ex housing or possibly a twin setup and would be happy to get and keep full boost higher in the rpm range. I think your just thinking about a different aspect or type of racing than what I am for that type of build.

As an addition to the 2 posts above, Knight Sports (I think they are the only ones) have a 4 runner header with 42.7mm front and rear plate runners and separate 38mm runners off each port in the intermediate housing. Pretty much every one else went with a 3 runner header...

93RedX7

First off, calm down a bit. I wasn't challenging your knowledge. I was just trying to be as specific as possible. And in a way it does kind of matter in terms of flow characteristics. Because of the 13B's peripheral ports, it can spin a turbo slightly faster than one with side exhaust ports. Truce?

tuj

For FI, less overlap will make more power.

rotarygod

No it's cool. I wasn't mad. It was more sarcasm than anything.

rotarygod

The problem is that you still won't have any velocity to spin the turbo. The gasses will back up into the engine easier. You need velocity. No amount of port matching will allow you to get a peripheral port and a side port to have the same timing. It can't be done. Physically opening and closing the same? Yes but the rate at which they open and close can never be matched. The peripheral port is fully open and fully closed much faster than the side port due to the fact that the rotor slides sideways over the side ports in addition to moving upwards. Tuning will be all messed up. While it is important to get all the air out of the engine, you still need enough velocity n the exhaust that it tries to pull the chamber cleaner and into the negative pressure zone. This is difficult with a turbo. Having too much port area will only hurt this aspect and make less power where you need it. You'd probably find the engine to be very peaky and not have enough charge velocity to get a turbo spinning really well until a very high rpm. To compensate for this you'll need a smaller exhaust housing which will add back more pressure and further complicate matters. The key is to flow just as much as you need to and no more. It's also important to keep all of your ports flowing about the same amount with the same timing. Alot of people use boost as a bandaid to overcome their mistakes elsewhere. Boost is a great mask for mistakes. Look at the Supra community. They may make some impressive numbers but their power curves look like crap because they are doing many things wrong and relying on boost to overcome those issues. Bigger and more is not always better. The combination port exhaust would make less usable power.

crimson-rain

Sorry if I sound like a bone head (really trying to learn this stuff), so as long as you have x amount of air coming in AND going out at y velocity, that would be considered an optimum flow rate; never mind the ports themselves?

Man trying to keep up with some of the things you say dude ....

tuj

RG is talking about reversion (among other things). Once the chamber fills with air, the flow will reverse and spill back into the intake. If you close the chamber at the ideal time, you will trap the max air at that engine speed. The 'cam' timings and intake sizes to get this ideal charge vary per rpm.

rotarygod

The key is that velocity is just as important as volume. This is completely ignoring the importance of port timing which has it's own effects. If you have too much volume, you have too little velocity. Your powerband shifts upwards and your low end suffers. If you have too much velocity, you have too little volume which means too much backpressure. This is too little flow up top. This will shift your powerband down low and hurt your topend. This all applies to forced induction as well. The key to thinking about forced induction is not to think of it as more air getting rammed into the engine. The key is to think of it as behaving the same as a naturally aspirated engine but with more air molecules packed into the same space. Everything still behaves the same and all the rules still apply. There is a point where you have too much velocity in the runners. Whatever rpm that happens at makes that the peak spot. Obviously the area required to hit this number increases as rpm's increase. Look at the intake and what Mazda engineers are doing. They are leaving runners closed at lower rpm's until they get the max effect in those runners. Once they need more flow, they open up another set of runners and do it again. Only add area when you need it. Otherwise you'll hurt power. If you were to open up all of your intake runners full time, you would gain nothing anywhere and only lose low end power even though you have more runner. More is not always better.

Dragonfc3s

I understand where you are coming from, but I'm not talking about an engine that would be run in the normal power band areas. This would have to be a high rpm engine. 10,000-11,000 rpm with a narrow power band for drag. You wouldn't want to drive this engine on the street or circuit . You can adjust the velocity of the exhaust by using smaller diameter header pipes and adjusting the shape of the port. Since you will have more of them you would need less diameter and still have a good volume. The intermediate ports would act as a balancer pipe between the rotors. I would also not want exact port timing with the ports. I would want the Peri to open first and port it with a flat edge across the bottom so it would open with a strong hard pulse, I would also want it to close last with a slightly rounded top to scavenge the combustion chamber area of the rotor. I wouldn't open the peri port up any wider than stock though so that you can keep the maximum apex seal support over the port during those high rpm runs. I totally understand where you are comming from as I have ported and built more than just a few engines. Something like this would take time to perfect, but I personally think it would have some good potential..