HollywoodHall

i couldnt break 15 mpg if i drove highway the entire time. with the windows up, the a/c off, granny shifting, cruising @ 60 on a downhill.... i mean seriously, this sucks! I sit here in absolute awe and disbelief when i see some people posting 20+ mpg. and getting over 300 miles out of a tank of gas, Im lucky to break 200 miles on a tank. I have 3600 miles on the car. and have owned it since birth. gas has had absolutely no improvement from day one to now. Mazda says 18/24 mpg. we get 13/15 mpg. I pay friggin $28-$30 ever 3 days. thats $250-$300 a month. screw that. I WANT A SOLUTION. I WANT A FIX. I WANT AN EXPLANATION. FROM MAZDA. IF EVERYONE CALLS / E MAILS MAZDA... THE PEOPLE WHO ARE EXPERIENCING THE SAME ISSUE AS I AM. OUR VOICE WILL BE HEARD. AND MAZDA WILL BE FULLY AWARE THAT THE PROBLEM IS WIDESPREAD. AND A FIX COULD BE AROUND THE CORNER.. OR ATLEAST SOME FORM OF REISBURSEMENT.. WHO KNOWS..www.mazda.com... e mail them. I DID!

rx8cited

Do you have the "M" flash? If not, get it!

shawnio

Hate to revive a dead thread, but ...

On other DOD engines they keep the valves closed so the piston is no longer getting any air. We already have a system to shut down intake runners, couldn't a similar system be mocked up on one of the primary intake runners so that air cannot go to that rotor? Then of course, you would probably pump air back in from the exhaust into the engine again ... this is probably not a big deal ... I don't know what to think really ...

You wouldn't be able atlernate firing cycles or something, but how long do you expect to be running on one rotor? I suppose if you were cruising on the highway at 60 for four hours it wouldn't be a good thing ...

I suppose you could cycle opening/closing the runners and switch rotors every few rotations. Might as well use some sort of piezoelectric device, and switch the other ones with piezoelectrics too. That would make them open faster, but i'm getting off topic now.
whatever became of this anyway?

robertdot

i think just cutting air to one rotor would either freak the ECU out, or be a problem otherwise. As said before, the air in the cylinder gets trapped (as both valves stop working) and acts as a "cushion." Rotaries have no valves to trap air on the exiting side, so if you stop all air into the engine, it will still get pushed out the exhaust ports, and try to pull air in on the next rotation... something will have to give in this sort of vacuum, and it will probably be whatever is blocking the passage or a weaker point after it.

That said, you still have to cut fuel to the rotary or you haven't solved anything.

I think an ECU hack would be the best method, still. I think thats what RG was suggesting for the '8. Of course, on his older '7, he had a couple of switches.

Anyway, don't apologize for reviving this thread. I rather liked it.

rotarygod

Unfortunately due to the archaic and primitive ecu technology of 1984, I can't make it work very effectively on my old RX-7. The car has far less than half of its normal power. I have to keep it floored to hold 60 mph and at this point the a/f ratio is so out of whack that it is only a bad thing. I would like to find a way to completely close off the intake and exhaust pipes of one rotor. This may do something but until I get a programable ecu, I can't do this. Since I have an air flow meter, the ecu bases fuel by how much total air is entering the engine. If I were to close off one side, this rotor would not pump any air and only half of the airflow would be sensed by the air flow meter. This would only give me half of the fuel necessary to run. I really have the wrong setup to do experimentation on. Maybe later on when I update some things will I try it again.

shawnio

After the intake runner is first closed, and assuming the valve blocking the runner does not break, there would be some vacuum in this chamber minus whatever amount of exhaust gasses that are left in the chamber. Perhaps it would be better to have a valve that is slightly open, it would act as a throttle plate at idle or such? After one time past the spark plugs, when the exhaust port opens, it would suck gasses in from the exhaust port, and then would continue recycling these spent gasses until the intake runners are opened again. This is what I was referring to, sorry, my mind tends to get ahead of my fingers. And I didn't think fuel and spark shouldn't be cut, but merely suggested this because it more closely mimicks what they do with piston engines, shut down the intake and exhaust. Then again, it would probably be very difficult to plug up the hot exhaust pipes. So we're back at square one ...

Trying to sort all this out in my head is a mess -- Maybe it would just be easier to get a hold of someone who did this on an airplane.

wakeech

well i know you know that this was explored a while back, and you-know-who didn't think it was a good idea for a few reasons.

do you think that an extra throttle, actuated between full-on and full-off in association with the fuel and spark cut, could be incorporated into the system, like i dunno, between the UIM and LIM, to help reduce the amount of drag your front/rear rotor is putting on the system with all the drawing and compressing and whatnot?? i know, a TON of extra work, but i wonder if it'd be worth it...

ok, so i spotted your post saying you're thinking the same thing. do you think you could rig something up with just a cable and some rough cut (home made) throttle plates on a spindle??

as for the exhaust, ha, good luck. i have no idea how the hell you could close that off. 'cuase of the design of the stock exhaust header, and maybe even a tubular would have the same issue, i'd be more worried about losing power on the running rotor from the exhaust running up backwards (if the intake was closed on the off rotor) than the drag of having the exhaust still open...

...and again someone has posted the same thoughts. i should read these things all the way through more often.

Nubo

It occurs to me that differential heating of the center plate might result in some distortion.