Actually you can keep your A/C on and still come out ahead in gas mileage than having your windows open :)

Just a heads-up for that one...

QUESTION 1:
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Is using high gear at very low speeds harmful for the engine in any manner? (e.g. 45mph in 6th gear).

QUESTION 2:
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How would you compare the effect of this driving technique on a piston vs. rotory engine?

1: No, I don't think so... the car rides at a lower RPM (45mph in 6th will put you ~2000RPMs).

2: It should also be the same for rotary vs piston because it's a transmission issue, not an engine one.

When I'm city driving I almost always skip second gear, and very often 5th as well. My shifting pattern is something like 1->3->6 traffic depending.

I know, I'm odd. It's what feel sgood to me when I'm not having fun and just driving. I also rarely runt he AC, but thats just because I love open window driving. I'll remember to pop open the rear windows, but not for more mileage. For less noise! :D

1. The RX-8 Manual actually gives tips on trying to conserve fuel. It states that if you are just 'cruising' (whatever that means) then changing gears as follows will result in best economy:
0 - 14mph 1st gear
14-21mph 2nd gear
21-28mph 3rd gear
28-35mph 4th gear
35-42mph 5th gear
42mph + 6th gear

Typically all the above shift points are around 2000-2300rpm. I tried it a few times - yuk. I usually go 1st, 2nd, 3rd then 6th at around 50mph if I want to drive slowly.

So to answer your question 42mph in 6th gear is actively recommended by Mazda, so should not hurt the engine.

2. Probably no different, but I am a rotary newbie so I don't have a valid opinion.

Ultimately it IS unsafe because if there is a need to quickly accelerate to avoid a collision, the extra time needed to:

think which gear you have to engage for your current roadspeed
put in clutch, engage gear, release clutch, etc...

That extra second or two might make a difference between avoiding the situation or a collision.

this is why I try to stay in gear as often as possible and rarely coast in neutral.

Waacheck your advice re ( doing 7mph over speed limit in residential area and cruising below speed limit on rural highway does not seem to make any sense as coping a speeding fine or possibly running some one over in a residential area because your 7mph over the speed limit , just to save a few dollars ???

SAVE A FEW CENTS BUT WASTE MUCHO DOLLARS???

Speeding fines buys lots of petrol .

Out of curiosity could you of any situation in where you're coming to a stop when you would need to accelerate?

YEAH when some one is coming towards my car with a crowbar and tries to belt the crapp out of my car or me , or worse car jack my ride .

Sure, you're coasting to a stop, look in the rearview mirror and see an SUV/Car flying at you because the driver fell asleep/lost his brakes/isn't paying attention, etc. Quick dip on the throttle with a possible lane change and it flies right by you instead of parking itself in the rear of your car.

Thanks for all the shifting advice. I was going through all the gears with slow acceleration and getting 15-16 mpg on mixed driving. I'll try the 1:3:6 pattern and see how I do.

BTW I've gotten the same mpg on premium and regular unleaded.

Aw come on Quickie, you need to do better than that. By the time someone gets 100 yards from you with an eccessive speed differential between the two of you, it's time to put it in gear & start doing or at least think about doing some evasive maneuvering. No need to wait until the last split second, unless you fell asleep too. I think you're devoting a tad to much time to put it back in gear anyway (assuming it's out of gear while you're coasting .vs. clutch merely depressed). Not much different timewise than having to lift your foot off the throttle & moving it all the way over to the brake pedal and pushing it in a more or less downward direction in order to apply the brakes.

I did at one time try to use the throttle to avoid an accident. I was going through a "T" intesection (my right of way) that was heavily overgrown with trees & brush to the sides of the roads. When I finally saw the GMC utility pickup truck attempting to run the stop sign (actually, there was a very small dirt access road straight ahead for him), it was too late to brake, so I floored it. Precisely 850 milliseconds later, BOOM!! I got t-boned right in the passenger-side door. Tore the rubber right off my driver-side wheels and sent my little Fiat 124 sport spider sideways, wheels dug into the asphalt & flipped it 2-1/2 times. I was OK, crawled out of it spitting glass. Uh, the throttle didn't help...

Also (I love these lightweight discords, don't you?) I almost always have it in gear well short of the upcoming stop in order to do some downshifting to the stop. If not enough speed to mess with downshifting, I put it in 1st after (if) I come to a complete stop.

No fun and not a great idea. During break-in you should change gears and vary rpm as much as possible (within reason), but if you had to do it, you had to do it, and to be honest it will probably not result in any problems.

For those concerned about the gas milage don't forget that if you are going to compare the gas milage of a rotary to a piston engine you have to double the displacement. In terms of gas consumption think of the Renesis as a 250 bhp, 2.6L V6.

BTW, so far I am getting 22.6 mpg in the S4 (2.7L bi-turbo V6) but that is only because I have not been running it with the chip turned on (in chipped mode the needle drops like a rock).

I'm a rather large fan of the 1-3-5 shift putzing around town...

Here is an example of not figuring the mileage correctly. or just using guess-timations. How could you possibly know that you have used 13.4 gallons if you haven't filled up again yet? You need to drive the 245 then fill up not go by how much gas you put in last fill up.

I only added 4 gallons Monday and have driven over 160 miles so far, looks like I'll get 40mpg. Cool.

With the heat generated by the rotary, as most of us have noticed, it doesn't seem possible to drive without A/C. When I turned mine off hot air pumped out.

You had it on the wrong setting. That was all that hot air being recirculated back from the driver. ;) :D

Mileage
 

i have just over 600 miles on the 8 and I am getting about 18 MPG. I run with the a/c on everyday (it has been about 105 degrees the last few days in Kansas City).

I have been trying to keep it under 4000 RPM's.

13 mpg






I'm upset by this

New update on MPG's
 

1st Fill-up = not documented

2nd Fill up = 20.0 MPG - This is all city driving (Tampa). Car never taken over 4500 RPM's.

3rd Fill-up = 22.2 MPG - 25/75 city/hwy (still during break-in, and my wife didn't use the cruise control on her trip, so I believe the hwy MPG's would have been higher if a constant speed was maintained.)

(went past break-in mileage)

4th Fill-up = 20.1 MPG - 40/60 city/hwy (more aspirated driving to see what the car can do in the upper RPM range)

It's looking like if we do mostly "boring" conservative driving (if we wanted to), we can come close or meet the EPA. If we do more fun driving, which my wife did betwen the 3rd and 4th fill-up, it looks like we will average 2-3 miles under the EPA. Expected, but not disappointing to me. As my wife pointed out, she never recalls us ever reaching the "optimum" EPA rating on any vehicle we have owned.

perspective
 

Putting MPG in perspective, I had a PT Cruiser GT Turbo and rarely got over 15 MPG. My former spouse had an Avalon and got 17-18 MPG just puttering around town.

Considering the performance we have on tap with the RX8, I'm satisfied with getting 17-18 MPG in town. I get 20 MPG and above in mixed driving (and not driving it conservatively, either).