Miata Mailing List: April 1997, Message #59
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From: 	Steve Smith <ssmith@extremenetworks.com>

Subject: RE: Fuel Economy

Date: 	Tue, 1 Apr 1997 12:37:14 -0500



Another mileage data point. I had been running 14 degree timing with

87 octane and getting about 24 in mixed stop and go and freeway

driving. I'd guess in 200 miles I'd only have 40-50 freeway miles.

I bumped the timing to 18 and started using 92 and todays fill

yielded 28.4 mpg.  





Steve Smith

ssmith@extremenetworks.com

91 Red

95 Millenia S



>----------

>From: 	Lanny Chambers[SMTP:creative@inlink.com]

>Sent: 	Monday, March 31, 1997 8:06 PM

>To: 	Multiple recipients of list

>Subject: 	Re: Fuel Economy

>

>On 3/31/97 20:09, Broussard@smtp.outer.net (Broussard@smtp.outer.net) 

>wrote:

>

>>My '97 seems to be getting a pretty uniform 21.5MPG for mostly in-town 

>>driving.  This seems pretty low.  I fuel up with 93 octane too! 

>

>That could be part of your problem, Bill. In a car designed for 87 

>octane, 93 will not burn completely before the end of the power stroke, 

>unless you advance the timing a bunch or install a knock sensor (which 

>will do it automatically). High-octane fuel has no more energy locked 

>within it, it merely burns slower at a given compression ratio. Unless it 

>knocks more than occasionally, use 87 for the best power and mileage.

>

>---

>Lanny Chambers, St. Louis

>'94C. Red, of course.

>

>

>

>