Mazda RX-8 Gas Mileage Reports

Replying to: paul_in_dc (May 12, 2006 12:33 pm)

If we talk literally then the renesis is only a few years old. The renesis is based on the earlier rotaries, however. In fact it is very close to the same except for the side exhaust ports (some performance builders are using renesis parts when rebuilding older motors as some of them are improved/lighter - and they fit, just so you see how close the engines are). The earliest rotary car from Mazda that we saw in North America was in 1968, as I recall (the R100). So that would make the engine design at least 38 years old. The basic design hasn't changed much, but the materials have changed a lot - for the better.
 
Early on Mazda tried using side exhaust ports, but in those days the apex seals were very experimental (read unreliable) and needed a lot of oil. This very quickly plugged the side exhaust ports so Mazda had to put the ports on the rotor housing for production vehicles. So the renesis is really not new, just vastly improved over the previous designs.
 
What was improved?
1. Moving the exhaust ports to the side housings allows much better control of the port opening timing, resulting in potentially better mileage and better power.
2. Many moving parts were lightened, raising the redline from 7500 RPM to 9000 RPM (the side exhaust ports also helped with this - when the apex seals traversed the old ports on the rotor housing they "bounced" a lot at high RPM and this eventually resulted in seal breakage). Of course when I say "many parts" I'm talking of only many compared to how many there are - there are very few moving parts in a rotary engine!
3. The PCM (engine computer) is greatly improved, allowing much better control of the engine and providing much better protection for it.
 
So you are both right in some way!

Replies to this message:
• w9cw (Sep 25, 2006 4:06 am)

Replies to this message:
• trispec (Jul 25, 2006 4:55 pm)

Replying to: murfbear (Jul 25, 2006 4:35 pm)

Replying to: paul_in_dc (May 12, 2006 12:33 pm)

Replies to this message:
• claires (Jul 28, 2006 1:54 pm)
• murfbear (Jul 28, 2006 4:44 pm)
• trispec (Jul 29, 2006 5:34 am)
  • div2 (Aug 02, 2006 9:09 pm)
    • trispec (Aug 03, 2006 2:10 am) and 2 more...

Replying to: geckozoid (Jul 28, 2006 11:23 am)

Hi, geckozoid,
 
You might want to post those numbers in our Ford Mustang MPG: Real World Numbers topic. Or, if you'd like compare and contrast the Mustang vs. the RX8, you're welcome to start a new topic.

Replying to: geckozoid (Jul 28, 2006 11:23 am)

Replying to: geckozoid (Jul 28, 2006 11:23 am)

Replies to this message:
• div2 (Aug 02, 2006 9:09 pm)
  • trispec (Aug 03, 2006 2:10 am)
    • flipper897 (Aug 10, 2006 8:15 pm) and 1 more...

Replying to: trispec (Jul 29, 2006 5:34 am)

I've been lurking in this forum because I'm considering picking up a used RX8. I've enjoyed reading your comments on the car. I usually hang out on a few of the BMW boards and over there we frequently get those "My [insert make here] is faster/cheaper/better then a BMW" postings. I'm glad to see we're not alone...
To paraphrase one of my fellow Bimwads, I doubt many RX8 owners lie awake at night wondering if they should have bought a Mustang

Replies to this message:
• trispec (Aug 03, 2006 2:10 am)
  • flipper897 (Aug 10, 2006 8:15 pm)
    • murfbear (Aug 14, 2006 9:45 pm)

Replying to: div2 (Aug 02, 2006 9:09 pm)

I do enjoy 'Stang roasting when giving an opportunity. The MPG thread was just such.
 
Agreed 'Stang envy is not a problem here. An RX-8 sighted on the road still strikes me as "Wow that looks good, and I'm driving one". Where as the new 'Stangs looks like that '70ties show sans the chrome.

Replies to this message:
• flipper897 (Aug 10, 2006 8:15 pm)
  • murfbear (Aug 14, 2006 9:45 pm)