JDamon

iTrader: (2)

So as we all know, gas prices are going up again. I always fill up my 7 with Chevron 87(lowest grade here). Chevron is supposibly good, clean gas for your car? But I was thinking about just using Costco brand gas because it's cheaper.

What's your take on quality gas? Would cheaper, low quality gas be bad for a rotary? Would it burn differently and leave more deposits than higher quality? Just wondering.

chatchie

iTrader: (22)

Assuming you have an N/A, run the cheap ****. I run 87 in everything but my TII. Even my SLK with its "Premium Fuel Only" supercharged 4 seems to run smoother on 87. Its stock tho.

JDamon

iTrader: (2)

Yes, I do have an N/A. & using low quality brand like Costco won't really make such a big difference as in using Chevron, eh? I use 87 all the time.

slowgxl

I work at costco and we use pretty good gas. Also we do everything we can to keep the gas super clean. It's the only gas I use and I never have a problem with it.

Derekcat

iTrader: (8)

I've never tried Costco gas, but back when I ran Arco all the time the car flooded a lot more... Since then I've always used Top Tier gas [I actually noticed it when it was consistently flooding and then I had to get Shell gas on a road trip... and the problem disappeared]

Normally I use 87 Chevron too. For the station I've found, Costco across the street is only a few cents cheaper - not worth the savings in my opinion..

Also the owner of the fuel injector cleaning shop I use told me to use Shell/Chevron/76 gas [They all happen to be Top Tier..]

Top Tier brands: Chevron, QuikTrip, Kwik Trip, Conoco-Phillips, Shell, Entec Stations, MFA Oil Company, ExxonMobil, Aloha Petroleum, KwikStar, Somerset Refinery Inc., Tri-Par Oil Company, Shell Canada, Chevron Canada, Sunoco Canada and Petro Canada.[From Wikipedia]
Official retailers list: http://www.toptiergas.com/retailers.html

CAPTN_SLAPPIN

iTrader: (1)

hmmmmm. how about sunoco?

brian_skotch

iTrader: (6)

I use the cheapest stuff i can find and no problems!

_Mac_

iTrader: (9)

I rock 87 octane Chevron and 76 all day, cheap gas like valero doesn't last me as long

MadScience_7

The Costco here only has 85 or 91. I might be able to get away with the 85, but I don't want to chance it. 91 in an N/A it is...

JDamon

iTrader: (2)

Hmmmmmm, well Mac, if you say the cheap gas doesn't last you as long, I guess I'll try an experiment. Haha, I'll see how Costco gas treats my 7. If it lasts me longer, I'll start using it!

Mad Scientist, I read on a thread here that someone used 85 gas all the time, and the lower the grade, the better? I don't have personal experience though. And I think in the FAQ it says that N/A's are supposed to run 87?

Brian, what brand do you use?

Captain, according to Derek's link, sunoco is a top tier brand!

Derek, was the flooding really caused by the low quality gas? You didn't find any other causes?

slowgxl, you run Costco gas in your 7 all the time?

Derekcat

iTrader: (8)

Yep, that was all that had changed.. Arco to Shell/Chevron and the problem went away.

Though thinking about it, it is possible that one of the ~3 Arcos I switched between had dirty tanks or something and I hadn't noticed if it was only on those tank fulls..

Evil Aviator

All pump gas in the USA must meet federal standards, so you will not get any bad gas unless a particular gas station screwed up and accidentally contaminated the gas or let it sit too long in storage. All pump gas sold in the USA must have a certain amount of detergents. However, if you want even cleaner burning, then stick with Top Tier gas:
http://www.toptiergas.com/retailers.html

Different brands and grades may burn slightly differently depending on the composition and regional standards. Most likely the only side effect will be reduced power, so if you notice this then just switch to a different brand next time. Generally, the more alcohol the less power, so look on the pump to see how much it is "ethanol enriched". The 1Gen and 2Gen RX-7s are rated for a minimum of 87 octane (R+M/2) with no more than 10% alcohol.


That's not a very good idea. I am not familiar with that particular engine, but in most cases if you use regular unleaded in an engine that requires super unleaded, then the ECU retards the timing. While it may feel smoother it is reducing the power and economy, as well as increasing emissions and engine deposits.

An NA engine rated for 87 can use 85 at high altitude. My recommendation would be to fill up with the 91 if you plan to drive to a low-altitude area in which you plan to drive your car under heavy load (racing, driving up steep hills, loaded-down, towing a trailer, etc.). Otherwise, the 85 should work just fine if you stay at high altitude. If you notice any knocking then move up to the higher octane, as old engines with lots of deposits sometimes need higher than the recommended octane.

HoustonMS3

The EPA regulates a minimum amount of detergents that the refiner must certify that their gas includes to keep injectors etc clean. Many manufacturers claim that this was set to low in the mid 90's.


Cheaper no name stations (I'm not talking about Costco because I have no experience with them) also seem to have less quality highest octane gas. My MS3 runs 20lbs boost with a knock meter set to light when a knock over reading over 1; it is has been very evident to me that they are not providing the advertised octane reading.

I'm not sure if this is because the small cheap stations sell less premium fuel and it degrades in containment faster because of the ethanol, or perhaps they have looser procedures/standards.

flipkc

I use Chevron 94, only. Until I get a 2nd tune on 91, then 94 is my weapon of choice.

2g3n7

i stay with the shell gas...neverh ad a problem and car runs great..only gas i run in my cars ill pay the extra 10 cents vs costco.. 10%nitrogen ftw!

Zenki FC3S

Q16

Primos003

iTrader: (1)

I usually just pick the one that does not have ethanol in it, around here thats the most expensive one (91 octane I think)

Derekcat

iTrader: (8)

I imagine that you're probably better off with 87 Octane E10 [10% Ethanol - it's the only thing virtually every station here sells.. ~_~], though someone with more knowledge of the characteristics of both would know better..

flipkc

I consider myself lucky to be living in Canada and get to put 94oct in my car, no ethanol!

I heard from my buddy who drives an Evo9 that when he got his car tuned in the states, the 91oct was of higher quality then the 94oct he had when he made it down there. Apparently he made more power on the 91? Weird.

airquin23

iTrader: (8)

Hydrogen...lol. I run whatevers cheapest. Lasts me the same time.

GuiltySoul

iTrader: (7)

i always fill up with 91 octane and I have a stock n/a, nothing bad ever happened, doesn't burn faster, or down grade on performance. I use 87 just to see the difference and it ran like crap didn't pick up as good so i'm sticking with 91 octane.

airquin23

iTrader: (8)

Hmm I thought N/A's ran better with lower octane...

jerd_hambone

My old 89 NA ran better on premium, my first FC ran better on 87. I'm not sure why though.

Evil Aviator

No, that's an urban legend based on a misinterpretation of a statement in a rotary performance book. The octane rating is only an anti-knock rating, and is not necessarily related to the energy content or burn rate. Pump fuel with a lower octane rating does tend to have a slightly higher energy content, but that is not always the case.

If the engine is worn or otherwise in poor tune then it will usually run better with a higher octane fuel.

Also, some brands of gasoline are better than others, some regions have different blends, and some gas stations may have contaminated fuel.

Derekcat

iTrader: (8)

Really? That's pretty bizarre.. on my 87' the guys at the station accidentally filled it up with premium once and I got noticeably worse fuel economy.. Didn't notice anything else different though.

Maybe you had one of the causes Evil Aviator mentioned?