I've been studying some of the Renesis pictures really closely and have come up with some observations. Take a look at the first link. Look closely at the picture in the far back right of the room showing the Renesis intake manifold. They still have those damn no flow 6 port sleeves!

http://media.mazda.ch/dossiers/RX-8/...h/img_2777.jpg

The second link is of the intake manifold design. We know they are going to have 2 different power levels of the car. I have the link showing the dyno plots comparatively. The lower power car only revs up to about 7500 or 8000 or so vs the 9500-10000 of the high power one. What is this drawing suggesting? A 4 port and a 6 port??? All the photos show a 6 port but is the low power one a 4 port? This is also an interesting shot because there are only 2 intake runners at low rpms, then 4, then 6 total.This is in addition to VDI. Interesting stuff!

http://media.mazda.ch/dossiers/RX-8/...dynamics09.jpg

 

they didn't want to design an auto staright off that could handle the rpm so the "detuned". nothing to do with ports. probably just timing, fuel cut, etc. and i'm sure there is some reason mazda engineers left the sleeves in. however since i'm not one of them, i don't have the answer.

 

However, you must remember, the engineers are restricted by accountants.

 

rotarynews asked mazda if they made "nice" flowing sleeves, and they said they did.. it was in the interview when they where test driving the RX-8...



-Zach

 

I need a RENESIS...I don't care if it DOESN'T WORK, I just need one to study! It's driving me crazy!!!!

*starts to violently pull at hair*

 

My suspicions about the 4 port vs 6 port Renesis are correct. Mazda has stated that the standard transmission of the Renesis will have the 6 port engine while the auto will have a 4 port Renesis!!! Look at the diagram in the second link above. I knew it! Yes it is lower horsepower but this is due to the redline of 7500 vs the standards 9000 rpm. The 4 port engine has about 5 ft pounds of torque more than the 6 port and lower in the rpm range. The new 6 ports now open at a much higher 5700 rpm vs the old 2nd gens at about 3800 or so. Good stuff! Lets get a turbo or equivalent on it now.

 

Actually, you are half correct. The 210 HP version of the Renesis has 6-port induction with redline set at 7500 RPM and the 250 HP version of the Renesis has 8-port induction and redlines at 9000 RPM. The reason the 210 HP version redlines at 7500 is because the last set of ports on the 8-port are set to open at 7500, so the curve would actually level out at 7500. The best articals I have seen to date are in the last Sport Compact Car and in a recent Car & Driver.

 

Check out the special 65 page edition of Road and Track's Guide to the RX-8. Kickass magazine with tons of good info and pictures.

 

Ya, I got that in the mail, but forgot about it. Man, that was good reading

Actually, I am trying to remember...are the ports 4 and 6 or 6 and 8. I think I am confusing Dave Coleman's article in SCC saying there would be a 16B displacing, well, 1.6 L (or 3.2L according to him ), adding a 4th port to the side housings.

basically, everything I said above is correct except the possible number of ports. Anybody remember? If not, I'll check when I go home for lunch.

 

According to eveything I've been seeing the engines are a 4 and 6 port. This fits in perfectly with the link above showing the intake manifold diagram. The one I drove had the 6 port but felt pretty weak. Engineering mule I guess.

 

I agree...The Renesis comes in a 4 or 6 port version, and everything I said above applies.

-At 3750 RPM, the secondary intakes open.
-At 6250 RPM, the "power ports" open.
-At 7250 RPM, the variable fresh air duct opens, basically allows a shorter intake path.

According to Dave Coleman with Sport Compact Car, the exhaust ports are moved to the center housing. Each port collects in the housing before it gets to the exhaust manifold. And apparently, the exhaust manifold wraps around an engine mount, which might make for some pretty weird headers.

Other facts from SCC:

-A/C now bolts to block instead of a bracket.
-Flywheel lightened to 14.75 lbs.
-Each rotor weighs 8.6 lbs.
-Engine weighs 273 vs. 359 for the FD tt's
-6 fuel injectors
-Now uses a low-restriction hot wire mass airflow sensor
-Uses a wideband O2 sensor.

I might just scan some of this stuff in if anyone wants to read it that doesn't subscribe.

 

the side exhaust ports are there for emissions purposes and loses the fd's impact of ultra hot exhaust gases spooling the turbos faster then a piston. tree hugging technology at work. and yes, they are monster truck wheels.