LuckoftheGTP Posted November 25, 2008 Report Share Posted November 25, 2008 Since gas prices are low, is there any advantage to going to high grade gas besides a little better gas milage? with the exception of the SC and turbo guys anybody put high grade in their W's Quote Link to comment Share on other sites More sharing options...
MonteCarloChick Posted November 25, 2008 Report Share Posted November 25, 2008 Higher octane does not give you better gas mileage. It does NOTHING for a car that doesn't require it. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted November 25, 2008 Report Share Posted November 25, 2008 ^^^^^^ x2 Quote Link to comment Share on other sites More sharing options...
Crazy K Posted November 25, 2008 Report Share Posted November 25, 2008 ACTUALLY... it "could", but probably doesn't pay for the difference in cost if it does. And if it is giving you better gas mileage it is because the timing would be able to to advance a bit more, but only if you are getting detonation/pre-ignition with regular pump gas. Here is my ONLY consideration with higher quality gas... is it ETHANOL free? Some places may sell gas containing 10% ethanol, but also offer ethanol free gas at a higher price. ethanol free = better. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted November 25, 2008 Report Share Posted November 25, 2008 You only get better mileage using higher grade gas in a car that is designed to use it, usually high compression engines, or forced induction. This is because an engine like that generally requires the higher octane to avoid detonation. If you give that same engine lower grade fuel, it will usually retard spark timing to avoid detonation caused by the lower octane fuel. The retardation of the timing is what causes a fuel mileage decrease. Thus, an engine like what I've described will get better fuel mileage when run on premium. The LQ1 is not one of these engines. Quote Link to comment Share on other sites More sharing options...
jeremy Posted November 26, 2008 Report Share Posted November 26, 2008 don't waste your $, stick with the 87 Quote Link to comment Share on other sites More sharing options...
LuckoftheGTP Posted November 26, 2008 Author Report Share Posted November 26, 2008 THanks. Just wanted to make sure. Quote Link to comment Share on other sites More sharing options...
pwmin Posted November 26, 2008 Report Share Posted November 26, 2008 never helped me in either of mine Quote Link to comment Share on other sites More sharing options...
BXX Posted November 26, 2008 Report Share Posted November 26, 2008 The OBD2 PCMS (OBD1 should have it as well) have 2 spark advance base maps. 1 high octane and 1 low. Even the 3100s and such. It tries to use the high octane map, but if it notices more than acceptable KR, it will revert to the low octane map. There are also a few other spark modifier maps. Running premium all the time will allow for more advance and the potential for a couple more HP... Now, those of us with tuning done, running premium is well worth the little extra power than untuned and running 87 Quote Link to comment Share on other sites More sharing options...
lb79theone Posted November 26, 2008 Report Share Posted November 26, 2008 I always have becuase I had bad experiences with gas stations "watering down" there gas to make more money and my car lagged, and I always thought it is cleaner. Quote Link to comment Share on other sites More sharing options...
BXX Posted November 26, 2008 Report Share Posted November 26, 2008 My stock 96 CS (L82) always showed no KR with premium and on 87 it would ofter hit 5 counts.. That will pull a lot of timing.. And so what, it only costs like $2-$5 per tank depending on gas prices.. Quote Link to comment Share on other sites More sharing options...
pwmin Posted November 27, 2008 Report Share Posted November 27, 2008 My stock 96 CS (L82) always showed no KR with premium and on 87 it would ofter hit 5 counts.. That will pull a lot of timing.. And so what, it only costs like $2-$5 per tank depending on gas prices.. of course, if it's getting KR, you need to increase the octane (or change settings) my cobalt gets 0 KR w/ 85 octane Quote Link to comment Share on other sites More sharing options...
BXX Posted November 27, 2008 Report Share Posted November 27, 2008 My stock 96 CS (L82) always showed no KR with premium and on 87 it would ofter hit 5 counts.. That will pull a lot of timing.. And so what' date=' it only costs like $2-$5 per tank depending on gas prices.. [/quote']of course, if it's getting KR, you need to increase the octane (or change settings) my cobalt gets 0 KR w/ 85 octane You also have a more agressive PCM as far as KR goes with more convervative spark maps... Pushrods engines are more prone to knock anyway Quote Link to comment Share on other sites More sharing options...
pwmin Posted November 27, 2008 Report Share Posted November 27, 2008 My stock 96 CS (L82) always showed no KR with premium and on 87 it would ofter hit 5 counts.. That will pull a lot of timing.. And so what' date=' it only costs like $2-$5 per tank depending on gas prices.. [/quote']of course, if it's getting KR, you need to increase the octane (or change settings) my cobalt gets 0 KR w/ 85 octane You also have a more agressive PCM as far as KR goes with more convervative spark maps... Pushrods engines are more prone to knock anyway everyone always tells me you cant do that w/ the LSJ, but it even says in the manual you can run it if you aren't getting knock. I run a tank of 93 through it before I race, but that's not very often. I've scanned it under heavy load in hot weather. Quote Link to comment Share on other sites More sharing options...
jake91 Posted November 27, 2008 Report Share Posted November 27, 2008 im lost what is KR Quote Link to comment Share on other sites More sharing options...
Andrew Posted November 27, 2008 Report Share Posted November 27, 2008 knock retard. if the engine's knock sensor hears knock, it will retard the timing to protect the engine. Quote Link to comment Share on other sites More sharing options...
jake91 Posted November 27, 2008 Report Share Posted November 27, 2008 now that makes sense Quote Link to comment Share on other sites More sharing options...
jeremy Posted November 27, 2008 Report Share Posted November 27, 2008 Knock Retard ^^ oops....didn't realize there was an answer already posted Quote Link to comment Share on other sites More sharing options...
rockfangd Posted November 27, 2008 Report Share Posted November 27, 2008 honestly my cutlass runs fine with 87 but hogs gas but 89 seems to be perfect Quote Link to comment Share on other sites More sharing options...
BXX Posted November 27, 2008 Report Share Posted November 27, 2008 Yeah, but remember, the engine can only pull so much timing with its default tuning. Quote Link to comment Share on other sites More sharing options...
92GPSpeeder Posted November 28, 2008 Report Share Posted November 28, 2008 My '92 gets much better mileage with 93, I get 11.24 miles per the dollar as a opposed to 10.14 miles per the dollar on 87. 93 also got me a higher avg fuel economy, this was tested over 3 tanks of each 87 and 93 octane it was 20mpg avg for 87 and 25mpg avg for 93 Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted December 1, 2008 Report Share Posted December 1, 2008 My '92 gets much better mileage with 93, I get 11.24 miles per the dollar as a opposed to 10.14 miles per the dollar on 87. 93 also got me a higher avg fuel economy, this was tested over 3 tanks of each 87 and 93 octane it was 20mpg avg for 87 and 25mpg avg for 93 And this is on an LQ1? Quote Link to comment Share on other sites More sharing options...
92GPSpeeder Posted December 1, 2008 Report Share Posted December 1, 2008 whoops no its s 3.1L but I thought I would share Quote Link to comment Share on other sites More sharing options...
old442man Posted December 2, 2008 Report Share Posted December 2, 2008 I checked with my 97 3.1 and after the third tank I figured out it was 17% better mileage with 91 octane. But like King Ken said you can't have ethanol, I tried some that was advertised as 92 and I lost about 50 miles to a tank. It takes about three tanks to clear it out before you see results too. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted December 2, 2008 Report Share Posted December 2, 2008 Corn kernels in my gas tank FTL Quote Link to comment Share on other sites More sharing options...
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