Zero to sixty with *regular* gas ?
Thread Starter
Intermediate
Joined: Mar 2008
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Zero to sixty with *regular* gas ?
According to the manual, premium is (of course) recommended fuel for LS1 but using regular is acceptable, with expected loss of performance. I presume the computer alters the timing automatically to prevent knocking issues. But the big question to me is, how much loss exactly ?
Wondering if any magazine, like Road & Track, Consumer Reports, etc has ever done tests to put actual figures on this ? Would be fascinating to me to take same vehicle and do three seperate runs of 0-60 times with 87, 89 and 91 octane gas.
Wondering if any magazine, like Road & Track, Consumer Reports, etc has ever done tests to put actual figures on this ? Would be fascinating to me to take same vehicle and do three seperate runs of 0-60 times with 87, 89 and 91 octane gas.
Safety Car
Joined: Jan 2001
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From: Boise ID
If you’re thinking of cheaping out, don’t bother. Potential problem versus a few cents of savings is not worth it. As far as comparisons, I seem to recall someone doing it (either C4 or C5) but it don’t remember the numbers.
Thread Starter
Intermediate
Joined: Mar 2008
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Which I admit, still isn't enough savings to justify, if there is confirmed chance of serious potential problems. But when you say "potential problems" without spelling them out exactly, I get the impression you are just guessing really.
If anyone here knows of confirmed problems with using regular long term (or 89 for that matter), fire away...
Having said that, I'm really more curious to hear if the acceleration tests I mentioned has been done or not rather than get into arguments about the practicality of actually using regular gas in a C5 Vette.
Last edited by Milacron; Mar 20, 2008 at 04:39 PM.
Melting Slicks
Joined: Jan 2004
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From: West Coast
As a matter of fact, the FACTORY TUNE on these cars is VERY CONSERVATIVE. You can gain 10-20HP at the crank from just tuning the car for more aggressive timing.
Cars back in the 70s, 80's can and did have issues as they had no computer knock sensors and the technology wasn't there. Then yes, you would have issues with running low octane in a high compression engine.
Thread Starter
Intermediate
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OK, but as I said that's not my primary interest. My primary interest is simply actual performance figures with each octane in identical circumstances, be it zero to sixty runs, quarter mile runs or whatever.
Team Owner
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St. Jude Donor '03-'04
This is not a legitimate test.. Because the Ls1/2 is a high compression engine, 10.5 :1 it requires high octane gas. The lowest being 91 octane, but even that in the summer might require octane booster,, while it does say you can use 87 octane and the car wont break, but it is not recommended for this motor. It just to get you to the next gas station. Using this fuel will cause detonation under load. The knock sensors detect knock, this knock detection is caused by engine knock... the detection causes a timing change, but the engine is knocking before this change occurs.. this knocking causes connecting rod bearing failure, and wrist pin damage over time. Severe cases we have seen holes burnt right through pistons.. predominantly Piston # 7, when using regular gas over a long period of time.
Melting Slicks
Joined: Jan 2004
Posts: 2,246
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From: West Coast
Higher octane prevents detonation. If knock is detected, the computer will pull timing, preventing knock but at the cost of losing HP.
If the owners manual states to run 91 octane, then run that. If it states that you can run 87 but will lose performance. Then it is OK to run it but know that you will be losing performance.
I always ran 91 or 93 octane in my C5. Some areas only carry 91 due to the elevation. With higher altitudes, you have less oxygen, therefore less need to have higher octane.
For each 1,000 feet in elevation gain, you lose 3%-4% HP. For instance, if you are at 7,000 feet elevation, you got about 21%-28% HP loss.
You C6 will be making only 290-310 HP at that level. At 10,000 feet, you are at 240HP.
As they say, your engine is a AIR PUMP. That is why turbo's and superchargers work. They are trying to stuff more air in to get more HP. Vararam and the other "ram air" systems use the same principle of getting cold air and more air into the engine.
If the owners manual states to run 91 octane, then run that. If it states that you can run 87 but will lose performance. Then it is OK to run it but know that you will be losing performance.
I always ran 91 or 93 octane in my C5. Some areas only carry 91 due to the elevation. With higher altitudes, you have less oxygen, therefore less need to have higher octane.
For each 1,000 feet in elevation gain, you lose 3%-4% HP. For instance, if you are at 7,000 feet elevation, you got about 21%-28% HP loss.
You C6 will be making only 290-310 HP at that level. At 10,000 feet, you are at 240HP.As they say, your engine is a AIR PUMP. That is why turbo's and superchargers work. They are trying to stuff more air in to get more HP. Vararam and the other "ram air" systems use the same principle of getting cold air and more air into the engine.
Last edited by LBear; Mar 20, 2008 at 08:42 PM.
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Team Owner
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St. Jude Donor '05 thru '19
I don't often get involved in these types of debates, but how can someone who has a grand total of 21 posts make that type of comment about someone who helped develop and test the car we are all driving. This forum is, in my opinion, an opportunity to discuss and gather technical information "tech forum", why would you even post something like that?
Le Mans Master
Joined: Aug 2005
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From: Winter Park FL
I don't often get involved in these types of debates, but how can someone who has a grand total of 21 posts make that type of comment about someone who helped develop and test the car we are all driving. This forum is, in my opinion, an opportunity to discuss and gather technical information "tech forum", why would you even post something like that?
I don't think you need a lot of posts on one forum before you can aquire knowledge on a subject............
That being said, I have heard time and again that octane booster does next to nothing even if you dump in a few cans. I can't see running lower octane hurting performance that much. I also can't see why you would want to run it.
The cost vs risk doesn't seem to add up.
Melting Slicks
Joined: Dec 2004
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From: I have to return some videotapes
If you mean a joke in the sense of adding performance, you're right. Octane in a high compression motor isn't about power, it's about safety.
And ET has forgotten more about the C5 than you'll ever know.
And ET has forgotten more about the C5 than you'll ever know.
Last edited by Jesse; Mar 20, 2008 at 09:52 PM. Reason: Deleted comment by Milacron as unnecessary...
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