pmexpert
Full Access Member
98 here
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i just bought a 2010 tahoe ltz, and am running 87 so far.
If it isn't knocking, i don't believe there is an advantage to running higher octane.
98 here
Where? Where? Where? Where? Where? Where? Where? Where? Where? Where? Where? are you getting 98 octane fuel. The highest I have ever seen at a pump is 94 and that was near a Drag Track other wise the highest 92 and if your lucky you may run into 93?
You only need 92 or higher to prevent knocking which is known in high performance vehicles. My Yamaha R1 needs 94 or higher due to the performance needs, when I punch it I need the ignition to blow up and take off. If your a casual driver 87 (no Ethanol) will give you the same results from 87 (without Ethanol) to 93. My Denali needs 93 because of my pulse plugs and my Cold air intake and turbo generating 4 PSI so I need a little richer octane to handle the higher intake of air. If I would get it tuned I could maybe drop the octane for now but in my Bonneville's I use 87 except my Bonneville GXP with the North Star V8 engine I use 93 also because of the demand with K&N cold air intake. I guess it just what you feel that's best for your state of mind. Put 93 and calculate the MPG then put in 87 without ethanol and do the same I bet it would be close if not identical. The reason I go with no ethanol is because it introduces junk into your engine, keep it clean unless you have a Hybrid, no hybrid don't put ethanol in your tank.
I don't mean to sound like a dick...but you don't have a clue what you are talking about. Or, if you do, you've done a less than stellar job of articulating your point. Lets get a couple of things laid out on the table.
1. Not all areas have fuel without ethanol. Around here, all gas stations have ethanol and there isn't anything we can do about it.
2. Not all areas have access to 93+ octane fuels. 91 is the best that it gets from here to Cali, unless you're paying out the ass for race fuel (which isn't practical for daily driven vehicles).
3. If a vehicle is optimized for high octane fuel from the factory, 90 octane should be sufficient, motorcycles included, due to the varying octane levels of "premium" fuel around the country. The lowest grade of premium I have encountered is 90, sold at most stations in NW texas and some parts of NM (and possibly other areas of the country too, those are just the places I've found it). It would be counterintuitive of a car manufacturer to produce a vehicle that requires fuel of a higher grade than can be commonly found anywhere in the country.
Is your R1 modified from stock? If not, then it shouldn't require 94 octane...if that were the case, it'd be awfully hard for Yamaha dealers to sell them in parts of the country that only have 90 or 91 at the pump. And as far as your Yukon goes, you mentioned that it's turbocharged and requires a "richer octane" due to the turbo and pulse plugs (which are a gimmick btw) and K&N. I'm assuming you meant "higher" octane, and a "richer" A/FR, which would only be required because of the turbo, the other mods notwithstanding. Then, again you mentioned needing 93 on your Bonneville because of the K&N intake. Really? If you think you need to run 93 simply because you slapped an intake on your car, then I've got a bridge to sell you. An intake has nothing to do with requiring a higher octane.
I think you need to do a little more research on your own mods and what types of fuel are available in a given area before making suggestions as to what other people should put in their tank. GM might market these trucks as being capable of running on 87, but I trust the folks at Black Bear who have scanned and tuned thousands of these trucks. If they say 89 is where it's at to prevent pinging, I'm inclined to listen to them. YMMV.