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Racing Beat PCM Flash: Would engine knock if using 87 octane?

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Old 12-07-2006, 10:46 PM
  #26  
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Originally Posted by TeamRX8
if your motor likes 87 octane better it probably lost some compression ....

My 8 loves 87 @15,000 miles I dont think I lost any compression. Unless my engines not broken in?
Old 12-08-2006, 03:26 AM
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tales of two motors.... both made great power, both ran on 87 oct...

one ran a ltft of 3.4, the new one runs a 1.6, both +.

mpg a little better with the second motor.. but that could be due to syn fluid in tran and diff...

beers
Old 12-08-2006, 03:54 PM
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Originally Posted by turbine
(...snip...) The RX8 is certified to run on E85. (...snip...).
The Rx8 is not certified to run on E85. The 2004 owners manual states the following on page 4-2:
"Your vehicle can only use oxygenated fuels containing no more than 10% ethanol by volumne. Damage to your fehicle may occur whn ethanol exceeds this reccomendation, or tif hte gasoline contains any methanol."

and

"Vehicle damage and drivability problems resulting from the use of the following may not be covered by the Mazda warranty.
- Gasahol containing mroe than 10% ehtanol.
- Gasoline or gasohol containing methanol.
- Leaded fuel or leaded gasohol."

What's more, running on E85 isn't an indication of compatability with low octane as ethanol has a higher octane rating than gasoline.
--R.
Old 12-08-2006, 09:08 PM
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The RX-8 definitely can not run on E85 as it comes. Any gasoline engine can be made to work with it with some retuning though.
Old 12-09-2006, 11:47 AM
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A higher mileage Renesis could probably benefit from higher octane especially if it's been driven by your average Joe (Or Joanne for that matter) since they develop a fair amount of carbon buildup in typical granny driving style that some can't always avoid. Unfortunately, if you have majority short commutes in mostly traffic this may be the wrong car for you. You will potentially see reduced engine life and find abnormalities along the way.

Whatever octane works for you, within the guidelines, drive the snot out of it!

Paul.
Old 12-10-2006, 01:27 PM
  #31  
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ethanol eats aluminum. your housings are aluminum. do not use e85
Old 12-10-2006, 01:48 PM
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noob questions... whats engine knock and ping?
Old 12-11-2006, 06:23 AM
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Originally Posted by zoom44
ethanol eats aluminum. your housings are aluminum. do not use e85
He's exactly right.
Old 12-11-2006, 10:14 AM
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Your housings may be aluminum but none of the internal surfaces of the engine are. The rotor housing surfaces are different.
Old 12-11-2006, 10:27 AM
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Really? Hmm...
Old 12-11-2006, 10:50 AM
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Originally Posted by LiL BenNy
noob questions... whats engine knock and ping?
This is a condition when the fuel explodes, rather than burns. The explosion of the fuel mixture sounds like a knock or a ping, hence the name. You actually want the fuel to do a slower burn to get power out of an engine. A ping or knock condition can break the seals that are used around the rotor. These seals are the equivalent of a ring in a piston engine.
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