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Premium gas vs. regular (CBC Marketplace)
- Thread starter iFly55
- Start date
Whatever octane your manual recommends is what should be used. Pretty simple. Problem is people don't understand what the octane rating means. It's the resistance to ignition. The higher the number the harder to ignite. This can allow higher performance if the engine is designed for it. Engines with high cylinder pressures will recommend higher octane. Because the low octane fuel may ignite prior to when it's supposed to. Modern engines will sense this and pull timing out. When this happens you lose power and efficiency.
If you put higher octane than you're suppose to use the ignition system may not have be optimized to ignite the fuel properly. So you may end up with less performance again.
If you put higher octane than you're suppose to use the ignition system may not have be optimized to ignite the fuel properly. So you may end up with less performance again.
Motorcycle Mike
Well-known member
I occasionally buy premium although I don't have a single vehicle (or motor) that requires it -- I do it to avoid ethanol (Shell or Ultramar).
I'd never put premium in my shitbox toyota though... just the bikes, the lawnmower, and the generator.
I'd never put premium in my shitbox toyota though... just the bikes, the lawnmower, and the generator.
daught
Well-known member
You are mixing up pre-ignition with knocking
. Octane if for knocking, which is a secondary explosion after the spark plug fired.
conundrum
Well-known member
Higher octane does resist combustion more than lower octane, like mentioned about. If your car can't use it, then yes it either won't make as much power, or it will make the same (note it will never make more). If your engine can adjust, then yes it will make more power.
For my bike, I just use 87 since that is what the manual recommends, although I do try to use Shell or other Top Tier brands. Only time the bike switches to Shell 91 is in October/November, when I'll likely be putting it to bed soon, and want 0% ethanol gas in the tank.
Also, ethanol actually increases octane numbers and most companies know this. AFAIK, Shell and Ultramar are the only ones who advertise 0% ethanol in their 91, when none of the others do. Remember this next time you fill up...especially with Sunoco 94....
I82l8
Well-known member
Same here, I just put premium in any carburated engine, because of the ethanol in the regular gas.
I've put in regular gas into cars that needed premium (Turbo, Supercharger, and my Si) and the Turbo and Supercharged cars could definitely feel a big change in the way that the engine ran.
The Si on the other hand you could feel that it was more lag in the response, as well as it didn't want to rev up as freely as on the premium. Could've been my imagination, but I noticed a difference right away. I'd have to do a check again though. But from what I read the premium for my car is highly recommended.
The Si on the other hand you could feel that it was more lag in the response, as well as it didn't want to rev up as freely as on the premium. Could've been my imagination, but I noticed a difference right away. I'd have to do a check again though. But from what I read the premium for my car is highly recommended.
Costco 91 is ethanol-free as well. The problem with ethanol is that it has half the energy per volume than gasoline, so if you can't take advantage of the octane increase by advancing ignition timing or boost, you'll see a slight decrease in available power/fuel economy.
As per my owner's manual I run 91 octane (Shell or Costco) in my bike, and I have to use 94 in my sedan that has an aftermarket ECU map to take advantage of it.
As per my owner's manual I run 91 octane (Shell or Costco) in my bike, and I have to use 94 in my sedan that has an aftermarket ECU map to take advantage of it.
You are mixing up pre-ignition with knocking
You're right. The engines doesn't sense pre-ignition. Just knock. Then pulls timing. But the higher octane is a requirement to primarily resist pre-ignition in high cylinder pressures engines, high compression and forced induction.
And just because the engine has a knock sensor that will let the ecu pull timing...what happens when that sensor fails? I still wouldn't use regular in a vehicle that recommends otherwise.
The test CBC did is stupid. What I'd like to know is if premium improves performance under WOT, not while cruising at 50km/h. I know the performance increase, if any, would be negligible, but it would still have been more interesting than that non-test.
The host has probably never owned a car that didn't require premium. Screw that demagogue prick.
The host has probably never owned a car that didn't require premium. Screw that demagogue prick.
kickstartt
Well-known member
That's true I hve experienced the same by putting 87grade gas in turbo 2.0L engines and noticed significant change in engine response and turbo lag. Plus 87grade gas gave me less mileage than 91grade.
The dyno test was interpreted wrong by them. You should get the same reading as they did. Not because the engine compensated due to the fuel like they said. But because it took the same amount of energy to spin the rollers and drive train to that speed. You may see a difference max hp if they went WOT.
The test that they performed was fine for THAT car, which was an econobox that doesn't NEED premium fuel. What they should have also done was performed a test on a car that requires premium fuel and do a test on regular (not recommended) and the premium (recommended) fuels to see if there is a DECREASE in power, not if an engine that is not designed for it.
As for the guy with the Vette, I don't think Vette's need premium fuel because they're not high compression engines (correct me if I'm wrong) and will run fine with regular fuel. They're just a big V8 that goes like stink.
When I had the Genesis 3.8 V6 there was ZERO difference in mileage/power/response in my opinion when I put in regular or premium (regular was recommended).
Correct... Both the Cruze and Vette have 10:1 compression ratios.
Ducati recommends a 98RON (Research Octane Number) fuel for the Testastretta DVT (12.5:1 compression ratio) in the Multistrada... I've been using Esso 93RON since new. Sunoco has a 94RON, however there are no Sunoco's to be found. I've heard of a place that sells 98RON, but it is something like 4$ a litre... I'll continue with Esso's 93RON.
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I82l8
Well-known member
98 RON = 94 AKI which you can get at any old Sunoco now Petro Canada Station.
