subdued

^^^ No, no that is not a real math formula.

But I already did a calculation in my head while driving home to figure out
and I have a close enough guestimate

Question:
How many gallons of 100 octane* to mix with 91 octane* to get 95 octane?

These answers should be good.

*Yes 100 octane is available in Nor Cal at selected 76 stations
and 91 is the highest octane generally available here.

In case you are wondering, I can't do any mileage tests b/c my driving is too erratic (and because it varies too) -ed

subdued

OK please set me straight.

my armchair/driving seat calculation is this:

4.5%tank of 100oct 450
5.5%tank of 91oct 500.5

................................950.5 / 10 = 95.1oct

0.45 of 17gal = 7.65 gal. 100oct
0.55 of 17gal = 9.35 gal. 91oct

notice this is not a formula.

Essetially I'm looking for a formula to determine the ratio of two different ratings to get to a third rating. I could also use this to mix different weight fork oils.

subdued

OK please set me straight.

my armchair/driving seat calculation is this:

4.5% of tank of 100oct...450
5.5% of tank of 91oct....500.5

................................950.5 / 10 = 95.1oct

0.45 of 17gal = 7.65 gal. 100oct
0.55 of 17gal = 9.35 gal. 91oct

notice this is not a formula.

Essentially I'm looking for a formula to determine the ratio of two different ratings to get to a third rating. I could also use this to mix different weight fork oils.

BusyShifter

5 parts of 91 mixes with 4 parts of 100 will bring it to 95. This is by volume.

Your own calculation is very close as well (should be 44.4% of 100 and 55.6% of 91)

hunterk1

Let's try this one.

91*x + (T-x)*100 = 95 T

where

T is the total number of gallons you put in the car.
x is the numer of gallons of 91 octane you put in the car.

Solution for x is 5/9 T. So you should fill up with 5/9 of 91 octane, 4/9 of 100 octane. Simplify and make it 1:1 (i.e. half of each) and it will be easier to remember and you'll get a little better than 95 RON.

Reach

I'm curious why you're trying to obtain 95 oct. Is there something special about this formula of fuel for performance or economy reasons?

stogie1020

Wow, cool mod! Custom octane blending.....

It's like enriched air scuba diving, you are only cool if you have some exotic, almost normal ratio of breathing gases that you come up with all on your own (37.4% EAN...)....

subdued

let's say I was going to dyno....I might use a higher octane than is normally available here in NorCal but is available in udder parts o the USA/world.
Plus I was just mathmatically curious. Thanks for the formula hunterk1

but don't hold yer breath: subdued = 0 mods :tomater:

Reach

Cool idea none the less. How much for 10 gallons of 100 oct shipped to the east coast?

subdued

reach, actually I'll drop some off when I visit the parents. 10 gal shouldn't be any problem as a carry-on-

BTW 100 is $5.25/g at that 76 station (8/23/06) 91 is $3.30/g

Kikaida

Haven't you seen the news? No Liquids, Gels, or Pastes are allowed as carry-on. Not that they would EVER allow you to take gasoline on a plane...

Oh, wait, just realized you may be talking about Bus or Train?

subdued

^^^ funny.....I migrated to CA from NY via bus; never again!
besides gas is not a liquid, it's a food group!

subdued

^^^ funny.....I emigrated to CA from NY via bus; never again!
besides gas is not a liquid, it's a food group!

Reach

gas is a by-product of a food group, really...

Yes, too bad w/ the carry-on ban, otherwise you could have put it in your starbucks cup. Damn federales...