Do you use premium gas?

[Donger]

Originally Posted by Detoxing

But the article doesn't answer any questions about using alternate octanes over a long period of time and what kind of effects if may have on the longevity of the car, which is the main issue imo.

Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends, as any performance gain realized will surely be far less than the percentage hike in price. Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump. If the car is sufficiently new and sophisticated, it may not suffer any ill effects, but all such skinflints should be ready to switch back to premium at the first sign of knock or other drivability woes. And finally, if a car calibrated for regular fuel begins to knock on anything less than premium or midgrade, owners should invest in a tuneup, emissions-control-system repair, or detergent additives to solve, rather than bandage, the root problem. Class dismissed.

[ToxSocks]

Originally Posted by Donger

[I]Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends,

Right, but it's a 2-day study. You can't possibly reach any conclusions regarding the longevity of the components in the car to see what kind of affect the fuels may have. As Radar noted, running 91 in a 87 octane car prematurely ****ed out his Cat.

And my concern really isn't about 87 Octane cars running on 91, but rather 91 octane tuned cars running on 87.

So really, the article didn't do much to answer the question other than to let us know that 91 Octane doesn't really boost performance in an 87 octane car.....but that should be a bit of common sense. I found that out with my Firebird back when i was 19.

[Donger]

Originally Posted by Detoxing

Right, but it's a 2-day study. You can't possibly reach any conclusions regarding the longevity of the components in the car to see what kind of affect the fuels may have. As Radar noted, running 91 in a 87 octane car prematurely ****ed out his Cat.

And my concern really isn't about 87 Octane cars running on 91, but rather 91 octane tuned cars running on 87.

So really, the article didn't do much to answer the question other than to let us know that 91 Octane doesn't really boost performance in an 87 octane car.....but that should be a bit of common sense. I found that out with my Firebird back when i was 19.

I'm not familiar with any potential damage that running 87 in a motor that "requires" 91 will cause. For me, it's a question of am I willing to spend another $0.30/gallon to not lose 20% performance reduction? My answer is yes.

[ToxSocks]

Originally Posted by Donger

I'm not familiar with any potential damage that running 87 in a motor that "requires" 91 will cause. For me, it's a question of am I willing to spend another $0.30/gallon to not lose 20% performance reduction? My answer is yes.

But as the article noted, the car may start experiencing "knock" and if it does then you'd want to switch back to the appropriate fuel.

When i bought my Turbo Mazda i asked my business partner (A master fabricator/technician) if he thought the 91 Octane was required. His advice was to try it. If the car starts pinging louder than normal, then you need to switch back. Mine did, so i switched back.

My car is also known to have timing chain issues, which results in catastrophic engine failure. I have to wonder if those timing chain failures that people are reporting have anything to do with using improper fuel.

[Donger]

Originally Posted by Detoxing

But as the article noted, the car may start experiencing "knock" and if it does then you'd want to switch back to the appropriate fuel.

When i bought my Turbo Mazda i asked my business partner (A master fabricator/technician) if he thought the 91 Octane was required. His advice was to try it. If the car starts pinging louder than normal, then you need to switch back. Mine did, so i switched back.

My car is also known to have timing chain issues, which results in catastrophic engine failure. I have to wonder if those timing chain failures that people are reporting have anything to do with using improper fuel.

Sorry, I thought that was understood. Yes, if running 87 in a 91 motor leads to pre-ignition, you absolutely want to switch back to 91.

I don't see why running lower octane would cause a timing chain/belt failure. But yes, interference engines are not much fun. I just replaced my belt because it's 14 years old but only 50,000 miles. The tech handed me the belt and just grimaced. No wear at all... But, I knew that if it goes, goodbye engine.

[loochy]

Originally Posted by Detoxing

But as the article noted, the car may start experiencing "knock" and if it does then you'd want to switch back to the appropriate fuel.

When i bought my Turbo Mazda i asked my business partner (A master fabricator/technician) if he thought the 91 Octane was required. His advice was to try it. If the car starts pinging louder than normal, then you need to switch back. Mine did, so i switched back.

My car is also known to have timing chain issues, which results in catastrophic engine failure. I have to wonder if those timing chain failures that people are reporting have anything to do with using improper fuel.

I think most modern cars have knock detectors that dial things back if excessive knock is detected.

[GloryDayz]

Originally Posted by loochy

I think most modern cars have knock detectors that dial things back if excessive knock is detected.

Yeah, my 2002 Silverado has one that's pissing me off! Right after I cleaned the engine (t'was dirty as a power steering line had been leaking for a few months!!!), but ever since I get the knock sensor warning. I've read that it might be from the moisture I introduced while cleaning the engine, but it's been more than a month and I'm getting tired of resetting it.

And the fix seems like it has the potential to break as many things as replacing the sensor would alleviate.

But hey, it's a 2002, 250,000+ miles and I could not be more happy.

[SAUTO]

Originally Posted by GloryDayz

Yeah, my 2002 Silverado has one that's pissing me off! Right after I cleaned the engine (t'was dirty as a power steering line had been leaking for a few months!!!), but ever since I get the knock sensor warning. I've read that it might be from the moisture I introduced while cleaning the engine, but it's been more than a month and I'm getting tired of resetting it.

And the fix seems like it has the potential to break as many things as replacing the sensor would alleviate.

But hey, it's a 2002, 250,000+ miles and I could not be more happy.

Yep you ****ed those sensors, probably should get a harness also. They are cheap. You could do that job yourself easily. Add in the problem solver intake gaskets and that thing will last forever.

[Radar Chief]

Originally Posted by loochy

I think most modern cars have knock detectors that dial things back if excessive knock is detected.

Yes, to an extent but that adjustment has to be within the parameters of what the engine can adjust for.
For most fuels available in the US I don't think it's a problem just stay far away from that E15 crap they're starting to push.

[Warpaint69]

Originally Posted by Detoxing

But as the article noted, the car may start experiencing "knock" and if it does then you'd want to switch back to the appropriate fuel.

When i bought my Turbo Mazda i asked my business partner (A master fabricator/technician) if he thought the 91 Octane was required. His advice was to try it. If the car starts pinging louder than normal, then you need to switch back. Mine did, so i switched back.

My car is also known to have timing chain issues, which results in catastrophic engine failure. I have to wonder if those timing chain failures that people are reporting have anything to do with using improper fuel.

Knock and pinging is also known as pre ignition. Thats when the fuel is being ignited before the actual engine ignition process. The greater the octane fuel rating the greater its resistance to pre ignition.