Valkyrie

Ok, so the RX-8's engine has side ports for both the exhaust and intake, and that helps a lot since you can have them on both sides, and have just as much flow as a stock peripheral exhaust (I guess)...

But why not have both a side port, and an peripheral port?

Not all the time... just have it closed off until about 6000 RPMs where it would open up on both the intake and exhaust...

Sure, it would make the manifolds a bit more complicated... and you'd have to have a system to open the P-ports up, but that's no more complicated than the 6-port induction, I think...

The way I see it, is with the side ports, you get the mileage and emissions, but with even a small P-port, you can make some sort of high-end gains, since you're giving it more flow without sacrificing low-end performance.

GUITARJUNKIE28

the thing with that is the unburned HC's get recycled with the current renesis setup. if you added a PP with a flapper or whatever kind of method of actuation, the HC's would get trapped in the "pocket", and jam it shut.

also, since you probably couldn't get it totally flush with the rotor housing, it would create overlap, and idle quality would suffer. you'd have to run it richer to compensate, and there go the emissions.

then, the apex seals are shorter, so they'd bow when traveling over the pocket and there goes the compression and longevity.

with the current port layout, good gains can be had from mild exhaust porting. the exhaust has 2 90* SHARP edged turns that it must get through to get out. taking care of the turns and sharp edges will help it breath quite a bit in the top end.

here are third and fourth gear pulls from a stock renesis, and a lightly ported one.

exhaust was only opened like 2mm, radiused and polished edges, and lots of attention paid to flow path.

the primary ports were closed a few mm later, and backfilled with epoxy for a better turn-in, polished and radiused closing edge.

secondary and aux. ports were stock timing, just the secondary runners cleaned up, and edges radiused.

also, i might add, that the engine was running about .3-.4 afr RICHER after the porting, (it ***** with the MAF sensor) so in reality, it would have picked up a few mor hp with identical afr's.

getting past the computer is the REAL trick with the rx8's.

GUITARJUNKIE28

just that little amount (although it was a LOT of work) made 14 hp in third gear, and 18 hp in fourth, with no additional tuning to take advantage of it.

so very little port timing change is needed (actually, none) to get a 20+ hp gain from that engine.

Valkyrie

Well, I hope that's the low-power version in those dynos :p

GUITARJUNKIE28

those computers are just fucked up! they don't like being dyno'd.

don't look at the numbers, look at the % gain

rotaryengineering

Valkyrie, I am in the process of building an engine similar to what you described but, I will be eliminating the Renesis center cast iron. That port is small and will be replaced with a standard 1985 GSL-SE Rotor Housing. So on the exhaust side of the motor it will be a 4-Port design using the front/rear Renesis cast irons and incorporating the standard "old school" P-Port exhaust housing. This is a experimental motor but, the results should be major horepower gains at mid-range and make massive top end horsepower. My RX8 rotors are already cut to a standard 2mm seal so Apex Seals should not be a problem. At low RPMS it might be a little rough but, what the hell it is a full Drag Race application so I am not too concerned with how it idles. The engine will more than likely be a D-Port or J-Bridge Renesis 13B with a custom Intake manifold with 2 62mm Terminator Carbs.

Guitarjunkie28, do you have a number I can reach you at I am very interested in talking to you about the Renesis porting you performed.

BLUE TII

iTrader: (9)

I was thinking of this as well. I had in mind a single rotor motor as a test engine with RX-8 4 port rear and front housings and rotor housing, but earlier rotor for the apex seal depth.

Or a 2 rotor with TII intermediate plate so it mounts easily in FC .

Port a smaller P-port exhaust that closes with the sideport exhausts and opens a bit earlier. Make a collector with P-port in middle and sideports merging at the sides. Time the pulse with runner length so that the smaller earlier opening high velocity P-port scavenges the larger sideports runners at the collector!

Then put a small P-port intake in the rotor housing as well to scavenge the side intakes in the engine (Ito style combi-port).

How high can a 2 rotor rev? It is not as dynamically balanced as a 2 rotor, but it does have 2 main bearings for its 1 rotor for much less e-shaft flex?

GUITARJUNKIE28

sounds cool.
lemme know how it turns out.

but i think if your pp is small, there will be no need to go to earlier apex seals.