SVX Gas
 

if you don't run at least 91 you risk pre-ignition in the combustion chamber, which can destroy the engine.

even if the pre-ignition doesn't reach that level, the on-board computer will retard timing in an attempt to avoid knocking - which will reduce gas mileage enough that I suspect you will actually use enough more gas to pay the difference.

as an alternative the ECU tuning mod will allow the running of "regular" through use of an alternate fuel mapping (I suspect it runs quite rich).

Running 92 instead of 87 is only a couple dollars more per tank. I don't think it is that big of a deal to spend two or three dollars more a tank. I paid 2.69 a gallon yesterday to fill up.

I've done it and have only noticed a slight difference in power response. My experience is that the ECU adapts very well to whatever I put in it. I calculated the difference in cost between the premium grade and the cheap stuff and found that it only costs me about $100 per year. I figure the extra horsepower is worth the money. If I didn't want power, I wouldn't be driving an SVX.

The SVX has a high compression engine. High compression can easily lead to engine knock if too low of an octane is used. When the computer senses knocking it will retard timing to help lessen the knocking. Retarded timing causes lower engine performance and lower gas mileage. Using a lower octane on the SVX to save a two or three bucks at fill up is false economy and if done on a repeated basis, potentially dangerous. Consider the extra expense of premium to be insurance against engine performance problems:)


Dave

Yep. This ain't no 91 Legacy L:)




Dave

Personally I think it'll be a wash. From my experience with my former 300ZX TT (yeah I was a poor college student at the time), when I could afford premium gas my mileage would be around 21-22mpg in mixed city & highway. When I ran 87 octane, it would drop to around 19-20mpg in similar driving. I wouldn't be surprised if the extra 2 mpg I got in fuel economy when I ran premium would effectively make the cost-per-mile similar to when I ran regular.

-Chike

Chike - here I go, getting ready to embarass myself by doing math in public, but....

using 20mpg on regular, 22mpg on premium (your figures), you would use 5 and roughly 4.55 gallons to go 100 miles. At $0.20 difference per gallon (what it is around me anyway) and using $2.25 and $2.45 (what I saw yesterday), the costs to travel the 100 miles would be:

$11.25 regular
$11.14 premium

so, over the course of the average driver's year (12K miles), the difference would be $13.64 cheaper to use premium - not to mention what savings would come about through less stress on engine internals.

Lee - I like your math whether is is true or not! :) :) That is why it is interesting to do the math on the cost. You may not be saving anything and be doing harm to the engine. :o

or just buy huge quanities of oct tain booster and do some math and figure out how much to use to bring u to around the 90s. :eek: :D

I think that would cost more than premium gas. Anybody ever able to go down to the air port and fill up with the 100+ octane gas? I hear it is amazing.

Your math looks sound to me Lee. When I finally sat down and figured this out for myself back in college, I only put premium in my 300ZX TT and utilized the campus buses more often! :p

-Chike

I would. :) :) :)

As Dave mentioned earlier, AIRCRAFT GAS CONTAINS LEAD.

(Do not run leaded fuel in an SVX.)

Besides, the higher octane won't make a bit of difference, performance-wise. Aircraft and racing engines require higher octane to prevent knock; it's not like running nitro or something. So it's not amazing.

dcb