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ethanol in the RX8

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Old 03-19-2007, 05:07 PM
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ethanol in the RX8

would that be a good idea? I mean, correct me if I am wrong, but isn't the e85 rated at 102-101 octane?

would that be good for our engine?
Old 03-19-2007, 05:09 PM
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read the quote in my signature
Old 03-19-2007, 05:38 PM
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yeah, well the owners manual says a lot; sometimes even contradicting itself.

My favorite was the owners manual for my 93 FD...
Introduction - "Always use the highest octane available"
Maintenance Section - "Higher octane is always recomended, but your RX7 can run normally with 87 octane fuels"
Back of Manual - "Always use gasolines with an octane rating of 91 or higher!"
Old 03-19-2007, 05:41 PM
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Steven - to save you the trouble of looking for yourself, the RX8 manual says never to use fuels that contain more than 10% ethanol, so e85 would be your motor's ticket for a one-way trip to the great racetrack in the sky.
Old 03-19-2007, 05:45 PM
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Oh!! I see... It was just a question
but doesnt the Manual also say that we shouldnt put anything under 91? but alot of people use lower octane than that??
Old 03-19-2007, 05:59 PM
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hey, try it. if it works for you, i might try it.
Old 03-19-2007, 05:59 PM
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but doesnt the Manual also say that we shouldnt put anything under 91?
yeah, well the owners manual says a lot
No matter how hard you try, no two cars will ever be the same. Motor A comes off the assembly line, followed by Motor B 7 mintues later. Motor A is sold to a guy who runs synthetic oil & 87 octane, gets his oil changed once every 10,000 miles, and his engine turns a spirited 120,000 miles before keeling. Motor B is sold to a guy who runs mineral oil & 93 octange, gets his oil changed once very 3,500 miles, and his engine keels before it hits 25,000 miles despite being driven exactly how a rotary should.

Find what works for your motor. Who knows, you might see 200,000 long miles by running e85. You could also kill your motor at the gas station immediately after filling up with it. The owners manual is a guideline - it's up to you, the owner, to listen to your car and figure out what it wants.
Old 03-19-2007, 06:36 PM
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Cool Same but not equal......

Octane has nothing to do with it.
Motors may differ, but physics remains constant - E85 needs to be injected much faster than gasoline to make the same power, that is why E85 'gas' mileage is so much poorer.
Conversely, E85 injected at the SAME rate as gasoline will provide a very weak mixture, detonation, and send your motor to apex-seal heaven.

....but don't take my word for it.

S
Old 03-20-2007, 03:04 PM
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besides that the alcohol will eat the aluminum housings and destroy your fuel lines.
Old 03-20-2007, 03:14 PM
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Put it in, and let us know !

but whatever the result is, you'll always be the World's First person to use E85 in Rx8 !

I have a feeling that it will work for maybe 1 minute, then the engine gonna say bye bye.
Old 03-20-2007, 03:46 PM
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Originally Posted by steven000e
...but doesnt the Manual also say that we shouldnt put anything under 91? but alot of people use lower octane than that??
It actually says something more complicated, about how it will run on 87 or higher but best on 91. Something like that.

Questionable whether an RX-8 would run on E85 at all. That's 85% ethanol. In the old days you could convert a car from gas to alcohol by changing the carburetor jets. But there's no simple way of doing that for a modern computer controlled fuel injected engine.

Plus, as everyone else has said, alcohol is corrosive. Unless the fuel system is designed to handle it, the stuff will eat its way through everything.

Ken
Old 03-20-2007, 07:16 PM
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Add on the fact it isn't that much cheaper than conventional gasoline and the fuel mileage is less with E85, so why would you risk it.
Old 03-20-2007, 08:53 PM
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He wants to post the worst gas milage on an RX 8.
Old 03-20-2007, 09:41 PM
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When piston cars are 'born' I heard they use some sort of natural gas to start them - what do they use to do the first fire up on a rotary?
Old 04-09-2007, 10:46 PM
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Yuengling Lager I think.
Old 04-09-2007, 11:02 PM
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Where are you guys getting this info about using Ethanol (E85)??

First, of all I don't know where you guys are getting this info about distroying Fuel system. I would agree if we were back in 60s and 70s.. but most modern fuel system will handle Ethanol fine. Also, someone did an experiment soaked Rotary engine o-rings submerged in 100% EtOH and 0 effect on them (I believe for several months). I do agree that some Orings might deteriate in EtOH but usually not the ones used in OIL or Fuel system.

Two, its true that your gas mileage will get worse.

here is the reason:
E85 - 83k btu/gal
Gasoline - 114k btu/gal
You will get about 25% Less MPG as Gasoline.

But the biggest issue might be the ECU and how your map is set up to run.. I'm not an expert in RX8s but in FDs, as long as you tune the car properly, you could run E85 without an issue. There are several Rx7 Force induced cars out there running E85... and several all out Drag rotaries that run 100% EtOH and Methanol.
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