Renesis?

[fortyoz2eric]

so the rx-8 engine is a "280hp NA 13B" rotary engine with Renesis technology right? if its the same engine as the rx-7 but NA wheres it getting this extra 25 hp? and what the hell is this Renesis technology?

[fortyoz2eric]

thanks guys..."connecting the auto enthusiasts" my ass. anyways if anybody cares i found out at the detroit national trade show. the 13b re is the same but the intake and exhaust ports have been ported and the rotors have a notch cut in each side to raise the c.r. aw yea, and mazda finally officialy says its 250hp. i have full faith it will kick the 350z's ass after comparing the crowds around the displays

[Weeves]

I don't know man...

The Nissan 350Z and Mazda RX8 are very close in comparison. In the end, even though the I like the RX8 to death, I think the Nissan 350Z would out-perform the RX8 in many aspects.

Its already a given that the Infiniti G35 and Honda S2000 would also out-perform the upcoming Mazda RX8.

[fortyoz2eric]

i don't mean to sound closeminded to the RX-8s competition but i don't think those are good cars to put up against it. the s2000 is a roadster and i highly doubt the g35 can out perform it - it ways 3,300 lbs. the only thing i'm wondering is if there is a demand for $28k fast family sedan

[dw1784]

getting back to the RENESIS engine, if anyone has more details please join in.

Here's my observation:
the RENISIS engine has light weight rotor, seems smaller than the 12/13's. Based on its symetrical design of the webbing and voids(cooling?) and the larg dished combustion surfaces, it might be a forging rather than casting as all these features are made by forging instead of secondary machining operations required in previous design.

Rotor housing is a complete reversal than the 12/13, where it was designed for cooling, the RENESIS seemed to be design for heat retention(smaller cooling holes/water passages). Possibly the thermal efficiency mentioned by mazda pr. Notice the lip around the housing? closer tolerance, tighter fitting, stronger integrity. These are aluminum? wonder what kind of surface treatment/coating/secondary process was used.

Notice how large the bearing surfaces are! The crank/eccentric shaft is a hefty unit, very rigid for its length=less deflection, reduced power loss, more power.

please join in, add your observations.

[fortyoz2eric]

well that is quite interesting - i had never heard before that they focused on heat retention. i couldn't tell you much other than maybe heat isn't quite as much an issue now that they got rid of the turbos. didn't they also switch to twin exhaust ports? i'm sorry its been a long time since i've looked at any RX-8 info

[dw1784]

right, I'm comparing the photo with turbo housings(pic from the cd comparing to my racing beat catalog). Just seems there aren't a whole lot of disscussion about this engine. Everybody's more interested in additional power, adding turbo, adding wings, etc. Guess we're are the only one's that see the engine as the highlight of the car.

Heat retention, as in the housing, has to do with combustion efficiency. After all, energy loss is in the form of heat. Yes, you're correct regarding the exhaust.

[FC3S]

In Car magazine April 2002 issue, Mazda claimed that the RENESIS engine without turbo is 40% more fuel economical and 25%-30% more cooling efficiency than RX-7 13B-REW.

[Buger]

Hi everyone,

I posted the below at the rx8forum (http://www.rx8forum.com/showthread.p...3269#post13269)

The renesis works much like other internal combustion engines by igniting an air-fuel mixture and using the expansion to do mechanical work. How can engines make more power?

1. More displacement - Is there no replacement?

2. Better volumetric efficiency - How much air can we get in the engine?
a. Stuff more air into the engine (ie. turbocharging, supercharging, Nitrous, Miller cycle?) More air is good. Compressing air also heats it though.
b. Cool the incoming air (ie. intercoolers, nitrous) Cool air is good because it is more dense.
c. Let more air into the engine. (ie. dual intake valves, tuned intake manifolds) More air is good.
d. Let exhaust leave the engine easier - (ie. dual exhaust valves, headers, high flow exhaust) More bad air going out means more good air can come in. More air is good.

3. Better use of the air/fuel mixture for power (Thermal efficiency)
a. Higher compression ratios. The air-fuel mix will be more prone to detonation & will need higher octane gas though.
b. Better thermal efficiency
c. Improved fuel atomization
d. More powerful spark
e. Better combustion stability

4. Less friction / resistance to movement (Mechanical efficiency)
a. Use lighter weight moving parts - waste less energy
b. Improve pumping losses (ie. Miller cycle with shorter compression stroke than expansion *huh?*)

How and why does a renesis make more power than previous rotaries?

1. Larger displacement - No.

2. Better volumetric efficiency
a. The side exhaust allows an intake port approx 100% bigger than previous production rotaries.
b. The side exhaust allows an exhaust port approx 30% bigger than previous production rotaries. Unfortuately, the port is not open as long as previous production rotaries and the exit path for exhaust is not as straight.
c. The intake manifold has been greatly improved to provide laminar airflow and uses 3 different length paths to tune the dynamic effect of the intake air pulses. This improves the supply of air to the engine for the entire powerband.

3. Better thermal efficiency
a. Better atomization of fuel due to ultra fine fuel injectors
b. More powerful spark due to higher power coils
c. Higher compression (unknown how high?) - [limited by sealing improvements and reliability]
d. Improved combustion stability/efficiency at low speed & light load due to no overlap.
e. Better thermal efficiency due to longer power stroke (exhaust port opens later)
f. Better thermal efficiency due to possible use of cermet (ceramic/metal hybrid alloy)?

4. Better mechanical efficiency
a. 14% Lighter rotors. Rotors will be approx 8.2 lb (9.54 * .86) leading safely to higher revs.
b. Shorter and lighter driveshaft. Carbon-fiber driveshafts are cool.

What else am I missing? I believe the side exhaust design was never used in the past because the peripheral exhaust offered a straighter path and led to greater power. While I'm sure that peripheral port rotaries with port jobs are capable of at least as much power as the renesis, we should congratulate Mazda on their R&D of the side exhaust port renesis since we can now have a rotary with larger ports AND greater fuel economy and emissions.

Brian

[archlight]

Ive been interested in the Rotary engine for a long time, while not for a car you see.

It all started when a buddy of mine asked me to help him fix his homebuilt airoplane. That plane was powered by the mazda rotary (13b i think) pushing 180 hp. The main problem was space and how to find a good enaugh oil cooler.

Now im sure. The new engine is going into my homebuilt plane, which should be finished in 3 - 5 years. Im looking forward to put that beast in.

The advantage
Small size
low vibration
low weight per horsepower
turbo option(they will have that in a couple of years or so )

the dissadvantage
high fuel consumption
high temperatures

but those engines are a dream come true for airoplane builders, just so you know guys

[2of9]

has any Performance made a Twin-Turbo package for the RENESIS engine, cuz if they did, DAMN the RX-8 would be fast, close to the 350Z TT.