I usually run 87 in my 2003 5.3 Silverado and the last 2 tanks I tried 91 just to see if I could tell a difference. So far I don't think so. My buddy says I could hurt the engine by running 91 as it's too high for this engine. Is there any truth to this? I also use FP in every tank.
Can running high octaine(premium) hurt an engine?
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GM Dealers have been warning folks with 90's vintage V8s like by Dad Buick Roadmaster (has Corvette Motor, dual exhausts..) to only run regular. Claim is tht slower burning higher octane will leave more deposits behind. fyi
i have actual first hand expierence with this in lawnmower engines atleast. i sort of repair lawnmowers as a side job. i can awalys, and i mean awalys tell when a customer brings in a mower for repair or maintence and uses premium. the deposits in the combustion chamber are usually quite high, espically if the are realeasy on the engine and never work it. im talking literally 4-5mm thick with deposits in some cases. i could go outside and snap some pictures of high deposit engines which would scare some of you.
while this isnt directly automotive, it is related and i would guess that using too high of an octane for a given automotive engine could lead to deposits just like it can on a mower engine.
while this isnt directly automotive, it is related and i would guess that using too high of an octane for a given automotive engine could lead to deposits just like it can on a mower engine.
The Premium fuels here also contain fuel system cleaners. Are these likely to reduce the carbon buildup ?
I run Premium fuels (98RON, Shell Optimax or BP Ultimate) in all my cars (4) with only one actually mandated, as it is a turbo. The extra fuel economy tends to negate the extra cost, about 10%.
[ June 10, 2004, 10:43 PM: Message edited by: theguru ]
I run Premium fuels (98RON, Shell Optimax or BP Ultimate) in all my cars (4) with only one actually mandated, as it is a turbo. The extra fuel economy tends to negate the extra cost, about 10%.
[ June 10, 2004, 10:43 PM: Message edited by: theguru ]
Higher octane fuels will leave more CC deposits is what I have heard. I only run the regular unleaded fuels. The only time I ever had to run higher octane fuels is when I had a Z-28. The regular would cause it to ping.
Daily Drives:
-2003 Toyota Tacoma PreRunner XtraCab, 2.7 Liter , Mobil1 Synthetic SS 5w30.
ODO 8800 Miles.
-1995 Toyota 4-Runner 3.0 V6, Mobil1 Synthetic SS 10W-30.
ODO 90500 Miles.
http://community.webshots.com/user/amkeer
Daily Drives:
-2003 Toyota Tacoma PreRunner XtraCab, 2.7 Liter , Mobil1 Synthetic SS 5w30.
ODO 8800 Miles.
-1995 Toyota 4-Runner 3.0 V6, Mobil1 Synthetic SS 10W-30.
ODO 90500 Miles.
http://community.webshots.com/user/amkeer
Pretty good article from USA Today...they talk with Chevron and GM engineers.
http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm
http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm
Maybe of interest to read what Shell say about Optimax. Shell Optimax
I've heard that higher octanes leave more deposits, and here in the US, all grades of gas are mandated by law to have the same additives. If gas companies are following the law, the only difference between gas grades should be the octane rating.
Is there any way to determine weather an engine needs premium simply by a compresson test? I've been using premium since I built my engine which produces 190 psi on a compression test. But I'm not sure what that means... I dont want to take the chance of having my engine knock (which I wouldnt know what it sounds like) Yet at $2.50 a gallon it gets expensive.
Not the same here. The higher octane fuels are different - well the claim to be! I understand all companies however have the same standard fuel, except of course those that add ethanol. Maximun of 10% allowed and has to be signposted. Few here in Victoria legally add it anymore due to a backlash after rogue traders added up to 20-40% ethanol.
All gasolines are NOT goverment mandated to have the same additives Palut. Gasolines are governed as to what octane range they must meet.
In the U.S., I understand that refiners are required by law to provide a certain level of detergents and/or detergent performance (standardized testing) for all grades. But a refiner can choose to INCREASE detergents over that amount for a given grade, primarily for marketing reasons, I suspect. At least a few firms claim their premium fuels have higher detergents.
"Is there any way to determine weather an engine needs premium simply by a compresson test?" Other factors also come into play, such as prior deposit build-up, sharp edges in the cylinders (which preheat and ignite the mix), presence of knock detection, etc.
"Is there any way to determine weather an engine needs premium simply by a compresson test?" Other factors also come into play, such as prior deposit build-up, sharp edges in the cylinders (which preheat and ignite the mix), presence of knock detection, etc.
No benefits running higher octane gasoline than the engine is built for, especially in high altitude regions like Colorado.
If combustion chamber deposits cause knocking which results in the knock sensor retarding the spark, combustion chamber cleaning is a better approach than buying more expensive fuel.
If a modern engine pings slightly, it might be designed to do so harmlessly for best performance. If there is any real spark knock, the knock sensor or other computer gizmo needs repair.
Ken
If combustion chamber deposits cause knocking which results in the knock sensor retarding the spark, combustion chamber cleaning is a better approach than buying more expensive fuel.
If a modern engine pings slightly, it might be designed to do so harmlessly for best performance. If there is any real spark knock, the knock sensor or other computer gizmo needs repair.
Ken
Ok I'm still trying to decide if My 2002 LS1 V8 Camaro needs 91(highest octaine/premeium in Colorado). Last 2 tanks on 87 I do not think I have heard a knock, the engine sounds as if it was on 91. How can I tell if it is damageing the engine. I asked the dealer to hook up a scanner to see how the the engine was doing on the 87 and thay did not want to do it and blew it off. They did say if I ran 87 I would get more deposits then with 91. What should I do? I'd like to save $$ but I don't want to hurt the engine.
If the dealer won't do it take it to a dyno tuner witha tank full of 87 grade. Also it can take some time for the computer to adjust up the timing advance when you fill up again with 91. Depends how you drive as well. Reset the computer makes it relearn. Pulling the battery lead will do this. Make sure you have the codes for your radio!
Your dealer is probably like most other dealers and knows nothing about cars. Check your owner's manual, but I'm pretty sure you can use 87 if you want. My buddy has a 2002 T/A Firehawk with the LS1 and it says he can run 87, so he sometimes does since he's on a farm and there's no premium stations close to home. He notices a decrease in power but no knock.
[ June 11, 2004, 09:26 PM: Message edited by: rpn453 ]
We have a 93 Taurus with over 175k miles and a 99 Taurus with over 70k miles, and notice a big difference between Chevron premium and other brands of regular. I guess the difference is that we live on a hill, which is when it's obvious that we aren't using premium. There is a fair amount knocking, it gets worse when it gets hot out, and although the knock sensors are supposed to retard the timing in order to minimize the knocking, I guess they'll still allow some level of knocking in order to avoid retarding the timing too much.
I'm surprised they would knock on 87. Maybe you have some carbon buildup?
Are you sure those cars have knock sensors? It just seems odd that it wouldn't compensate for that if it did.
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