2008 and Premium Gas

What else could it be? You'll never get 390 MPG in a red Miata or a blue Miata or a silver Miata or....

I would assume it listens for the characteristic sound frequencies like others?

I do not know about that. The point is that if you discover unacceptable knock, you already have red-hot carbon deposits on your solid surfaces. The device *must* retard the ignition much more than would be needed if it was advanced earlier to prevent knock and the resulting red-hot deposits in the first place. And the device must stick to retarding large amounts until they are cooled down enough.

I would agree completely there. But I would think designing optimized controls against knock is complicated by the fact that these devices have no clue about how big carbon build-ups are in the engine. And how bad their geometry is. And the equation is further complicated by the fact that a moderate amount of knock is perfectly acceptable.

I would guess Mazda would take the conservative view and assume that people may have squeezed a piece of coal in their cylinders.

I would hope it would at least make a note if the maximum retard did not manage to get knock within acceptable parameters, but I do not know.

Leon

Against these attacks on my scientific credibility, I must vigorously point out that I never claimed any 390 mpg for any white Miata. I was referring to photon drag, and never claimed that air resistance would be reduced by extremely large amounts. (OK, I did mention the effect on boundary layer turbulence, but that leaves laminar resistance.)

Leon

From the E-version of the 2008 MX-5 owner's manual.

--------------------------------------------------------------------------------- Your Mazda will perform best with fuel listed in the table.

Fuel Octane Rating*(Anti-knock index)

Premium unleaded fuel 91 [ (R+M)/2 method] or above (96 RON or above)

• U.S. federal law requires that octane ratings be posted on gasoline station pumps.

You may use a regular unleaded fuel with an Octane Rating from 87 to 90 (91 to 95 RON)

but this will slightly reduce performance, such as reduced engine output, and engine

knocking.

Fuel with a rating lower than 87 octane (91 RON) could cause the emission control system

to lose effectiveness. It could also cause engine knocking and serious engine damage.

----------------------------------------------------------------------------------------------------------------------------

Jim

I was never debating better milage because of a tank being near empty. It is just simple math, a nearly 13 gal tank (12.8) in my 2000. So on a highway trip, easily getting 30 MPG 30 X 13 = 390, case closed. And like I said, I plan to stop and get gas as I get near that figure.

It wasn't quite that simple the first time.

First you told us that the car takes 32 gallons to go a mile, and then you said that it gets 390 miles to the gallon.

It just seemed to be a fairly wide variation there. ;-)

Pat

The second time was after he painted it white.

WHOOOOSH!! (sound of joke zooming over your head)

This group tends to ravage typos with ruthless glee. 390 MPG was too juicy to resist.

Take your time, never trust a spell checker, and proofread twice before you click the Post button.

My tank fill is 38l or 9.8US gallons so I get 33.4mpg but despite being white still doesn't match 390:-)

When I got the car I put regular gas in it and was driving it over one of the bridges around Tampa Bay and I could feel it miss a bit. This was pretty extreme conditions, full throttle, up hill, temps in the mid-90's. But I've used premium ever since.

Elsewhere in the thread someone used my favorite rationalization: the 20 cents/gal differential over regular at $3/gal is only a third what it was at $1/gal. Premium gas is practically a bargain...

Hey what can I say, my typing fingers must be getting ahead of my brain. Last trip to the central Calif. coast, gave me a round trip of

LOL>Not sure about over there in MO, but here in Calif. MPG means Miles Per Gallon>>LOL. But that was 32 MPG, 390 total tank :-).

What year only had a 9.8 gal. tank???? Man that is a bummer :-).

The liter has become smaller? Is it so that we United Stateans can still afford a 750 ml bottle of wine with the current dollar?

Leon

Never driven it until it stops so unless a just below empty guage is a long way from empty then I'd say my tank is 40l. Its a 2000-2001 Jap import (I'm in NZ) so maybe the domestic models were different. Its also 1600 which I believe is not common for this year either.

Yeah, I use premium and I don't gas-shop. If it is around 10 cents more at one station, so what. We are talking about a dollar for a complete fill-up. I am just glad that I am not dumping $100.00 in at every fill up like a large percentage of my fellow truck-driving Texans are doing.

Pat

Mine is a 1991 and will take about 10.5 gallons. That has always been enough to get from one gas station to the next with many miles to spare.

Pat

socamb wrote in news:b78432bf-f681-4707-8e87- snipped-for-privacy@p25g2000hsf.googlegroups.com:

I have a 2006 MX-5. I buy premium because Mazda recommends it.

The price of gas is going so high that the percentage difference between regular and premium just gets smaller and smaller. Premium costs less than

Funny you complaining about fuel prices,ULP in Oz is around $1.48 / LITRE!!! 4.5 of them in a Gallon.

BTW I run my 2005 on SPULP at an average of something like $1.54/litre

OzOne of the three twins

I welcome you to Crackerbox Palace.