are all gas stations alike?

[johnnyrauder]

i got a dyno tune the other day,the tuner said i should use only shell,mobile or BP. because my knock sensor was kicking in at high rpms. says it may be the gas. some off name stations dont have detergents that the brand name places do. your thoughts?

[kirk]

Gas stations are definitely not all alike. They do use different ingredients.

[crouse]

It depends on their level of Premium fuel. At my local BP, it's 93. Other stations's Premium might be 91 or 92.

[Marauderjack]

Use "Top Tier" fuels only and only one brand if you can....save receipts JUST IN CASE!!:beer:

I use Shell exclusively except the once when I blew my motor!!:mad2:

[Bluerauder]

The octane rating should be the key. The stock Marauder tune says 91 Octane minimum. My tune is for 93 Octane because that is commonly available in this area and up and down the mid-Atlantic. What Octane is specified in your tune ??

I have a personal preference for Sunoco, BP, Shell, and Exxon in that order. Basically, I trust the Octane ratings of major brands more than the off-brand, discount, and one off Mom & Pop stations. I have heard that some off-brand stations buy the bottom of the tank dregs from other stations (no first hand knowledge of this) that contain sediment and may have mixed Octanes. Seems plausible that they could buy the crap at the bottom of the tank and resell at a big discount.

Did you get fuel-air readings with your dyno tune ?? I would look at fuel flow especially at high RPMs if you are using the recommended Octane for your tune. JMHO.

[ByronRACE]

If you're tuned right at the edge of detonation, the additives/absence of additives in various fuel brands can be enough to prevent/cause detonation. I've seen it many, many times on customers that insisted on every last horsepower. Ideally, after tuning on a dyno (especially an intertia dyno), spark should be backed off slightly to give you some real world headroom on a street car. The extra few horsepower is not worth engine damage. Or, buy some Torco Unleaded Fuel Accelerator, and add a small amount to each fill up. Does wonders for preventing knock; and in small amounts...absolutely does not foul sensors. I ran the stuff for 80K hard supercharged miles in my Cobra without incident.

[Mr. Man]

The octane rating on the pump is the minimum allowable for that style fuel, it could be more though unlikely to be much more. The octane and volume are maintained by the states weights and measures dept.

[johnnyrauder]

What Octane is specified in your tune ??
its tuned for 92 but i put 93

[johnnyrauder]

Torco Unleaded Fuel Accelerator, and add a small amount
how much is a small amount?

[camelgrundle]

The tuner should have never put you in that predicament. Look for another tuner or tell him to back it off a bit. You can get bad gas anywhere, you should not have to worry about that.

[ByronRACE]

Torco Unleaded Fuel Accelerator, and add a small amount
how much is a small amount?

The ratio information is on the product, as well as on the website. I would recommend trying 1/4 the specified doseage if all you're doing is trying to get away from the edge of knock.

How much is that? Depends on how much fuel is in your tank, and what the octane of that fuel is. You'll have to figure that out for yourself. For my california summer fuel with 10% alcohol in it, I used about 4oz per tank to compensate for the changes in summer/winter fuel...which was enough to get away from occasional knock around peak torque and let me keep the power.

[1Marauder]

The ratio information is on the product, as well as on the website. I would recommend trying 1/4 the specified doseage if all you're doing is trying to get away from the edge of knock.

How much is that? Depends on how much fuel is in your tank, and what the octane of that fuel is. You'll have to figure that out for yourself. For my california summer fuel with 10% alcohol in it, I used about 4oz per tank to compensate for the changes in summer/winter fuel...which was enough to get away from occasional knock around peak torque and let me keep the power.

Nice! Can I do this for NA cars too?

[kirk]

Use "Top Tier" fuels only and only one brand if you can....save receipts JUST IN CASE!!:beer:

I use Shell exclusively except the once when I blew my motor!!:mad2:

^^^ What he said ^^^

[Mr. Man]

i got a dyno tune the other day,the tuner said i should use only shell,mobile or BP. because my knock sensor was kicking in at high rpms. says it may be the gas. some off name stations dont have detergents that the brand name places do. your thoughts?Call Marty at Mo's he may have an idea what's going on and have a remedy. :)