Best Gas for ZHP'S?

[pilotnick1203]

Hi all,
I was wondering, what type of gas is best fro the ZHP engine? Is it above a 10 compression ratio?

[Hermes]

At least 91 octane, preferably something without ethanol

[Avetiso]

It is above a 10:1 ratio. Use 91, Shell or Chevron are both great choices.

[ELCID86]

91 if you can find it. Mostly 89 or 93 here in NOVA (Northern VA). Check out http://www.toptiergas.com/retailers.html

Costco claims to have good gas and the price is certainly better.

[3ZHPGUY]

http://www.toptiergas.com/retailers.html


http://www.youtube.com/watch?v=x366kxmgqEw#t=91

[pilotnick1203]

Thanks guys!

[stephenkirsh]

It is above a 10:1 ratio. Use 91, Shell or Chevron are both great choices.

+1

These are the only two places I use.

[BRGcoopahS]

I try to get shell when I can. 93 octane of course.

[STREETFIGHTER50]

91 over here in Cali. Shell or Chevron for me

[stephenkirsh]

yea no 93 in my area either :/

[derbo]

Found this on the internet about California 91.

Unfortunately there isn't much beyond 91 here in California. I use Chevron/Shell 91 in my ZHP



This is the best explanation I've found from Technobabble in 2001.

Quote:
By the time you read this, residents of Nevada and Arizona will have been screwed too. What, you don't live there? Just wait, you're next.
It's not like West Coasters haven't been screwed before. From roadside smog dynos to tickets for shiny mufflers, we're used to the man getting us down, but this time they're hitting us where we eat. This time they're taking our gas. We already have pretty crappy premium fuel in California. Just like most of the West Coast, we're stuck with 92 octane, while much of the Midwest and the East Coast got to play with 93 or better. Now, as of August 1, 2001, the best we can get is 91. Time to turn down the boost.

On the off chance you're only now trading in your Schwinn 10-speed on a twin-turbo Supra, I guess I should stop here and explain what octane is and how it affects your engine.

When fuel is injected into the cylinder, compressed and ignited, one of two things can happen. It either burns quickly and smoothly, shoving the piston down with a strong, even push, or it explodes all at once, releasing its energy in a sudden burst of heat and pressure. This explosion is called knocking or pinging, and it's something engineers like to call "really bad."

Knock is usually ill timed, occurring early in the combustion cycle when the crank and rod are still straight up or even worse, still trying to complete the compression stroke. As a result, all the energy released slams into the top of the piston without actually turning the crank. When this happens under stressful enough conditions--like, 20-psi of boost in a Miata--you start breaking things. Usually the ring lands; however, if your pistons are strong enough, you might get lucky and blow a head gasket.

Octane, for those of you still on the bike, is the rating of a fuel's ability to not do this. The higher the number, the less likely the fuel is to detonate. What this means to us, of course, is the higher the number, the more boost we can throw at that Miata. High-octane gas isn't just for tuners though. Plenty of stock cars depend on the stuff, including a Celica GT-S with its 11.5:1 compression, or a turbocharged WRX or Volkswagen 1.8T.

These cars rely on high-octane gas to keep from detonating. Feed them 91 octane and they won't start breaking things, because their knock sensors will see it coming and retard the timing, turn down the boost or otherwise reduce your chances of having any fun.

Whose fault is it this time, CARB? The EPA? The CHP? None of the above. This time we're being victimized partly by the oil companies, and partly--this is the one that hurts--by ourselves.

You see, when crude oil is refined into gasoline, the refinery doesn't have all that much control over what comes out. Crude oil is full of all kinds of stuff, and a refinery simply separates it, sorting all the iso-this and hepta-that in order of density. The really heavy stuff, like tar, is near the bottom, while the really light stuff, like butane, is near the top.

Somewhere in the upper ranges of the stack are the components of gasoline. There are between 10 and 15 different blend stocks, each with a different octane rating, which are mixed together to make gasoline.

The crude oil being used and little else determine the amount of each blend stock available for mixing. Generally, if you just dump all the blend stocks into a bucket, you end up with something around 88 or 89 octane. If you're selective and only mix the good stuff, you can make 92, 93 or even 95 octane. But once you take out the good stuff, you're left with crap--something like 85 octane. Then you have to leave enough good stuff in the bucket to bring this pee-water up to at least 87 octane. This limits the amount of 95-octane gas you can make. If you make 93-octane premium instead, you use up less of the high-octane stocks, allowing you to make a higher proportion of premium fuel.

In the Midwest, where an extensive customer base of good old boys in pickup trucks consume vast quantities of 87 octane, demand for premium fuel is low enough to make genuine high-octane premium.

In California, however, Lexus-driving executives suck down premium fuel like it's Evian, so 92 was the rule.

CARB isn't entirely innocent. Many of its standards for evaporative emissions and misdirected attempts at oxygenation have raised the manufacturing cost of high-octane gas, but it doesn't seem to be behind the sudden change to 91. Instead, according my super-secret oil industry mole, it all comes back to money. Unocal, you see, has a patent on the 173 easiest ways to make California-friendly 92-octane gas. As a result, every other oil company has to pay Unocal 5.75 cents for every gallon they make using one of these techniques. They haven't actually been paying it, but that's an issue for the lawyers to sort out.

Suddenly it's pretty obvious why our gas sucks, but why doesn't Unocal still sell us 92? Because it can't. In 1997, Unocal sold off all its 76 gas stations, and with them, its ability to decide what kind of gas to make. All Unocal can do now islook for oil, suck it out of the ground, and wish it had some way to make everybody else keep using its patents. You see, not only did Unocal screw us, they screwed themselves.

Ironically, the only gas stations in California with anything better than 91 octane are the ones Unocal used to own--the few 76 stations offering 100-octane race fuel. You can locate these elusive stations at www.76.com, but bring your wallet. The current going rate is $6.00 a gallon.

[Rovert]

I wonder how accurate the octane standard measurement is across the board and even Canada vs USA.

[derbo]

It's probably even different comparing different companies as well. Time to google about octane ratings and accuracy.


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[Avetiso]

CARB can suck it.

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[Damian]

91 only. I like 76

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[gmurphy]

I exclusively try to fill up with Shell V-Power but if I can't I always fill with premium. But rarely a full tank. I get bored after about $30 bucks :)


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[Stu]

It's entirely subjective of course, but as long as you use a top-tier gasoline you'll be great.

http://www.toptiergas.com/retailers.html

I decided to do an experiment and fill up solely with Shell 91/93 while doing the same commute every day. I did notice an increase of about 40-50 miles on my tank, so maybe there is really some legitimacy to the marketing hype. I've just about gotten to the fabled 500 miles mark. So now I solely use Shell :) I'll go out of my way to find a Shell station.

After doing this experiment, I was able to go from Chapel Hill, NC to Columbus, OH on one tank of gas after doing a few random stops and exploring with a friend and a full trunk of luggage and stuff. It was about 470 miles in total. Impressive stuff for a 235HP car, BMW engineers :)

[ELCID86]

^ interesting. The Shell here is very expensive. Exxon is reasonable. Have you tried going back to other gas and check mileage to verify?

[Stu]

^ interesting. The Shell here is very expensive. Exxon is reasonable. Have you tried going back to other gas and check mileage to verify?

I haven't, but I should do that and see how it changes. The Shell stations here accept Kroger gas rewards cards, and the closest grocery store to me is a Kroger so usually I can get a good 10-30 cents off per gallon depending on how many groceries I've been buying :)

[ELCID86]

I haven't, but I should do that and see how it changes. The Shell stations here accept Kroger gas rewards cards, and the closest grocery store to me is a Kroger so usually I can get a good 10-30 cents off per gallon depending on how many groceries I've been buying :)

Very nice arrangement. Wish we had that here. I think Giant does that but the nearest station is ~22min away. Let us know if you decide to try the "cheap" gas again.

[danewilson77]

My gas mileage changes significantly (2-3mpg) with anything less than 93.

Verified.

[Rovert]

My fuel mileage changes significantly in random. Even if I fill premium at top tier or other tiers. It's all over the board. I filled up last night across the street from Shell at a no name place. My OBC said miles to a tank is 520 miles right now. Sometimes I get 420 miles using Shell premium. Maybe the concentration of ethanol isn't regulated. Less = more range.

[az3579]

I exclusively try to fill up with Shell V-Power but if I can't I always fill with premium. But rarely a full tank. I get bored after about $30 bucks :)


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This is by far the most interesting reason I've ever seen to not filling all the way up. Usually it's "too expensive", but nope... it's just "I got bored". :rofl

[gmurphy]

This is by far the most interesting reason I've ever seen to not filling all the way up. Usually it's "too expensive", but nope... it's just "I got bored". :rofl

Haha sometimes I go to $35 if it's not too boring :)


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[pfr]

I can relate to that. There are some stations/pumps where the flow rate is sooo slow I feel I spend half my youth there (the other half, that is) so I give up sooner. (especially if it clicks off a few times too)

[gmurphy]

I can relate to that. There are some stations/pumps where the flow rate is sooo slow I feel I spend half my youth there (the other half, that is) so I give up sooner. (especially if it clicks off a few times too)

Hehe yes


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[derbo]

LOL wow boredem. haha. Usually its either I don't feel safe here or I can't afford more than that.


Curious if I would get better mpg with the 93 out east...

[az3579]

Haha sometimes I go to $35 if it's not too boring :)


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Ya know, this is what smartphones are for... so you could fill up. :biggrin

[danewilson77]

LOL wow boredem. haha. Usually its either I don't feel safe here or I can't afford more than that.


Curious if I would get better mpg with the 93 out east...

You would. I do. Why wouldn't you?

[3ZHPGUY]

Just throwing this out there.

I have filled up "3 ZHP" 322 times and 227 of them have been V-power. That leaves 93 tanks "other 93 octane" and about 50 of them were before V-power was recommended by the dealer service dept. nuff said

[webster]

we have 93 octane in TX, i almost always go to Shell or Exxon.

[az3579]

Just throwing this out there.

I have filled up "3 ZHP" 322 times and 227 of them have been V-power. That leaves 93 tanks "other 93 octane" and about 50 of them were before V-power was recommended by the dealer service dept. nuff said

I always love hearing your stats. Nobody else I've seen does this, so seeing your data is always a treat. :)

[RITmusic2k]

Great links and references here, guys!

A fun little tidbit: U.S. gas stations list their pump octane ratings using the (R+M)/2 standard, which is an average of the two major methods of measuring octane ratings. Over in Top Gear land, i.e., Great Britain, they only use one of those standards (RON or MON, I forget which), and it's a more optimistic number. So next time you hear Jeremy Clarkson explain that some particular Aston Martin requires 98 octane, that's about the equivalent of our 93 Premium here.

[NorCal-Dimitri]

I always use 91. Never fueled up anywhere but chevron.

[Daddyoh]

I most always use either BP or Shell 93.
I keep thinking that I read, or heard one or more of our people comment, that a car should be "tuned" to 93 octane. (I did not search our forum on this.)
Thoughts???

[3ZHPGUY]

I most always use either BP or Shell 93.
I keep thinking that I read, or heard one or more of our people comment, that a car should be "tuned" to 93 octane. (I did not search our forum on this.)
Thoughts???

I've ran nothing but 93 for over 100K and never did anything special to my car. Also, I've never used BP, heard more bad than good about it and that included the dealer service rep.

[az3579]

Also, I've never used BP, heard more bad than good about it and that included the dealer service rep.

You should try me some time. ;)