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#9088 of 9950 Re: Show Me the Alphabet Soup . . . [srs_49]
Jul 17, 2012 (2:20 pm)
Yeah, I'm not sure what makes it worse... the AWD or the automatic.
I had a 350z 6-speed and averaged 25.5mpg. My G35X auto? 21.
#9089 of 9950 saving $350 per year with 87 vs premium.
Jul 18, 2012 (3:22 am)
During the cold half of the year or especially on long highway cruise-control drives , it's 87 ctane in my pontiac that prefers premium, so that's about half of its 100k miles so far. Maybe it's saved $500 or $1k over 7 years? I'll take it. That should pay for lower-control-arm/bushings/balljoints.
Also sometimes I've seen a 75 cents or $1 cost difference between 87 & 91+, instead of the usual 20 or 25 cents. Unless it's super-hot I'll select 87 in that case too.
Naturally all this works much better thanks to the manual transmission... and the stock ECM "tune".
#9090 of 9950 better mpg with 87 than premium too. only with a manual transmission?!
Jul 18, 2012 (3:25 am)
for me, multiple "anecdotal" long-drive test results are all consistent with better mpg on highway cruises using 87 octane compared to 91+ octane. owners of other (lighter) cars with similar engine have reported the same result.
I understand there is more energy content per gallon of 87 than premium, so there is theoretical basis to explain the results toc.
who knows, maybe it applies for automatic transmissions too :|
#9091 of 9950 Re: better mpg with 87 than premium too. only with a manual transmission?! [elias]
Jul 18, 2012 (6:22 am)
having seen and held in my own hands the effects of detonation, there is no way I will ever use less than premium in a vehicle that either 'recommends' or requires PUL.
you can only do so much with a knock sensor and timing retard.
besides the possibility of severe engine damage, you get horrible mpg when the timing is being pulled back.
yeah, not in my cars. I'm ok with paying the premium for premium.
#9092 of 9950 Re: better mpg with 87 than premium too. only with a manual transmission?! [colin_l]
Jul 18, 2012 (2:05 pm)
have you got any facts or manufacturer specs to support your surmise? do you imagine that the risk is worse with a manual transmission than with automatic, since with manual one might be in too tall a gear for longer than an automatic, since automatic will kick-down more quickly and more reliably than manual shifter would!?
if one considers that knock and pinging are two different things, then there's no worry of damage in an engine that supports 87 octane as well as being optimized for 91+ .
Knock is bad.
Pinging is good (it is part of maximizing mpg).
I've put about 900k miles on 9 engines that "recommend" premium.
half with 87, half with premium. half manual-transmission, half automatics. 5 GM V8 cars, and three volvos/automatics with 5-cylinder engines, two with turbos, one without. No worries, the engines all ran fine with the 87 octane just as manufacturer wrote in the owners manual, but sometimes maybe with lower performance.
Can anyone identify a single engine problem in the history of humanity in any modern vehicle optimized for 91+ but which supports 87 octane too?
Colin, What happened when you saw "detonation" with a stock tune in a factory car that supports 87 octane as per manufacturer? Mushroom cloud? Threw a rod? something spectacular?
Until I see evidence of a single engine problem, I'll have to believe the car manufacturers specs and a million or so miles of driving, instead of your imagination & surmise. Show us facts & details, not just handwaving. Even your "anecdotal example" will be as interesting as my ~1M miles of driving. For my "anecdotal evidence", I'm showing you the manufacturers own specs/warranties, and 500k of driving with 87 octane in engines optimized for 91+ but which allow 87... (GM V8s and volvo I-5s). Cheers !
#9093 of 9950 Re: better mpg with 87 than premium too. only with a manual transmission?! [elias]
by Mr_Shiftright HOST
Jul 18, 2012 (3:49 pm)
too risky to not use premium in a premium-recommended car---your engine "map" may not handle the engine timing too well and combustion "detonation" can tear an engine to pieces--literally.
#9094 of 9950 Re: better mpg with 87 than premium too. only with a manual transmission?! [Mr_Shiftright]
Jul 18, 2012 (4:51 pm)
Premium-RECOMMENDED or premium-REQUIRED? There's a difference...some of the ones that recommend premium will work with regular gas, just with a power reduction. The ones that won't would be the ones where it's required.
#9095 of 9950 yes, there is a difference between RECOMMENDED and REQUIRED
Jul 19, 2012 (4:31 am)
they are both R-words but they do have different meanings, indeed. Thanks for reiterating my point, bpizzuti. It's probably best for those who don't care to understand the difference between the two R-words to just use premium ALL THE TIME in every vehicle - "just in case" - you can't be too careful, huh?
Maybe some day someone can show a single bad thing that ever happened to a "premium recommended" engine due to putting 87-octane in it! It could happen some day. Maybe if I put another million miles on my car(s) something bad will happen to the engine and we can blame it on 87 octane. I will let yall know!
#9096 of 9950 Re: yes, there is a difference between RECOMMENDED and REQUIRED [elias]
by steve_ HOST
Jul 19, 2012 (5:19 am)
Well, if you assume that regular outsells premium by a factor of 10 to 1 or more, that would mean your chances of getting stale, engine ruining gas by burning premium is much higher.
Maybe the cheaper econoboxes will breed some new MT drivers.
"Auto companies believe young drivers such as Pscheidl, 19, are a good target for manual transmissions, which are cheaper to manufacture, purchase, drive and insure. And they're being marketed to the millennial 20-somethings as a hipper, more interactive way to drive.
It could help explain why the stick shift seems to be making a minor comeback this year, accounting for 7% of new cars sold during the first five months, compared with 4% in the same period last year, according to Edmunds.com, which tracks car sales."
Automakers stick more teens with manual transmissions (USA Today)
#9097 of 9950 Re: yes, there is a difference between RECOMMENDED and REQUIRED [steve_]
Jul 19, 2012 (6:21 am)
That might just be because they're running out of auto-equipped Elantras and Accents, and DCT-equipped Focuses and Fiestas.