M3the01

Any issues? I'm not looking for a tune but just to help with potentially timing being pulled due to knock. It's pretty crazy hot lately and have dealt with this on previous cars via better, higher octane fuel.

We have 94 and 100 available.

I was thinking of mixing 94 periodically, not harmful, right?

Finally, shell, chevron, Costco... All top tier, from my research there is little difference. Thoughts?

ipse dixit

No, not harmful at all.

Only difference in Top Tier gas is (wait for it) ... the price.

SCCAForums

Running 93+ is always best for the FI cars... even the N/A cars like to be at least 93... so you'll definitely only 'help' the car running a mix/blend.

There is absolutely a difference in top tier fuels... I'm a huge costco fan... for my daily drivers... however I would experience more timing being pulled (light knock) when running in sports cars, vs. Shell and Chevron.

Best Regards,
Dave

M3the01

Do u have data logging to prove this? Additives / detergents don't prevent knock.

LexVan

If you can easily buy 94 from a busy (fresh) national brand station, do it! Always. You don't need 100. Ditch the 91.

Mattyrae

The difference is the fuel additives. Costco does not have fuel injector cleaners added to their gas, Arco the same. Over time, using cheap non additized gas will form deposits on your fuel injectors. Arco is crap gas as well.

Mattyrae

No they don’t but I always get better mileage with Chevron gas. Do you put Walmart oil in your Porsche? 😉

M3the01

Im just looking for some clear details besides opinions... real test data. As per the oil, there are clear cut tests that prove certain additives, properties are advantageous in oils for engines, tranny, etc and these have been test thoroughly, i want something for the fuel. As a note, i will likely just put shell or chevron in cause there are high-volume stations near me.

fskof

Walmart does not produce oil but they do sell Mobil 1 so to answer your question.... yes many here use oil purchased at Walmart

fskof

There has been many independent test on gasoline quality in the last 10 years.
Shell and Chevron usually end on top and companies like citco were on the bottom.

FourT6and2

I prefer Sunoco gas where I can find it here in CA. At the track they have 94 and 96 that are ethanol-free. 100% pure gasoline. When I can't find that, sometimes I'll put 5 gallons of SS100 in with 91 to bring the mix up to 93. But as far as run of the mill stations, I go with Chevron or Shell. I get discounts at Chevron (10 cents/gallon). So go there first. I just wish California had 93 octane...

richk

My RS seems to run best on Shell.

ipse dixit

Do you have evidence that fuel additives (not detergent additives) actually help with deposits in fuel injectors?

SCCAForums

The data I have proving this is driving cars back to back... and getting detonation earlier on Costco gas than Shell. It took my dad 3 years to believe me...he now runs Costco in his daily's but not his sports cars.

I'm a huge Costco fan... but at least in AZ... where you're getting only 91 octane... I'd say Costco is closer to 90.5 and Shell is 91.4. Just saying that I'm sure the 'rating' of 91 has a range... and Costco is on the lower end, and Shell/Chevron run on the higher end.

Best Regards,
Dave

As you can see others weighing in.. if you want the best performance, Shell/Chevron (West Coast) are your best bets. I would love for us to get Sunoco on the west coast!

M3the01

Checked out the 76 on Almaden and it had 100 octane racing fuel at $8/ gallon. I worry though there isn't much volume, station seems pretty much rundown.

Ultimately I left and filled up at @ high volume shell with 91 Octane... So what's the recommendation to get this back to the recommended 93 octane? Octane booster?