19psi

you'll never really notice any preignition problems, the knock sensor and ecu are much faster to respond than your ears. the only other thing to consider is that as cars age that havne't been driven hard, carbon will build up on the piston tops and actaully raise compression. plenty of old cars actually have pre ignition problems that never even had high compression because of hte additional compression due to the carbon build up.

i think we're allaffected by this BS fuel prices, but i figure it's only 0.20 difference between 87 and 93 so over a 20 gallon fill up that's only $4. i've been driving cars that all needed 93 for the past 10 years anyway, so i'm accustomed to it by now.

lexus114

I definatly agree with Celsior400!

mebush

I would argue that a vehicle with such sophisticated electronics as to detect and prevent preignition and electronic fuel injection should not have a carbon build up problem unless it has an oil consumption problem. My LS uses about a pint in 4000 miles--not bad at all.

As I said previously a new or low mileage vehicle probably warrants the premium fuel. In my case it simply isn't necessary. I just find it humorous that many of the same people that will cry from the mountaintops to use premium because the sticker on the fuel door says so would refuse to run their engine oil 7500 miles even though many new car owner's manuals say just that.

19psi

one would think that is true, but carbon builds up no matter what unless the car is revved out regularly. but that's also a car to car variable, with many factors affecting how much. take your intake manifold off, you'll find tons of carbon and other gunk in the plenum; it has nothing to do with the fuel but just age and mileage.
again, your fuel choice is up to you and how you drive, so i'm sure you're doing the right thing for your car.

wilkie1020

I drove my 05/LS430 the first 3K miles that I owned it on 87 octane & the next 3K on 91 octane & couldn't tell any difference in preformance or MPG. I never have heard any pinging. I bought it with 30K miles on it. I have driven it the last 4K on 87. That runs around 30 cents a gallon difference. I picked up the following web site from some one on this site.

http://www.consumerenergycenter.org/...s_premium.html

I don't think hardly anyone changes their minds over these discussions, but there are interesting points made on both sides from some very smart people on this site. I have gotten a lot of great info here!

19psi

wow, that article didnt' explain it fully at all; they left many important facts unsaid; my explanation is much better.

Neofate

iTrader: (1)

Rofl psi. That struck me as funny.

19psi

what is truly funny is that, i, an underpaid mechanic, can explain and write about things like that better than the over educated, over paid person who wrote that article!

Neofate

iTrader: (1)

Well that is fantastic. Well educated and well spoken. Just save your pennies and open your own shop in the next 5-15yrs and charge your own rates. Get your ASE and so forth if you haven't already. You know the drill. I have no idea how old you are.. You could be 40 with an ASE cert.. and tell me to **** -- But I am assuming you do plan to do something along these lines.

Being a mechanic is great no? A labor of love I hope.. (of course not all the time.. but taking things apart and then fixing them is joy) -- Good mechanics are often underpaid,.. I think more distinguishing needs to be done through schooling/certification so mechanics can be determined 'good' or not much more easily through consumers eyes.

IE: equivalent to Masters/PHD/MD.. Or even MSCE/MCSD/Cisco Cert for IT prof's.. and so on.

Though I guess I shouldn't be flipping the subject matter so much.. I can see how this can easily turn into a 'what is a proper mechanic?' topic now

Though, how do you know the person who wrote the article was paid well?

SweetS160

Manual said to use 91 and better so that is what I use.

Neofate

iTrader: (1)

Yup, 91 is considered 'premium' by most manufacturers, esp. in First gen with the year it was developed.

I've considered this many times,.. should I go 'mid grade' with 91 and save a few bucks or just go ahead with 93. I always end up with 93,.. but how much difference does it really make? Beuller?

19psi

91 is actually fine if that's what you have as a midgrade. here in KY, we have 87, 89 (absolutely pointless) and 93. the resistance to knock of 91 is good enough for our engines and even some turbocharged very well tuned performance engines.

19psi

i completely agree, and yes, all that is underway and mostly accomplished.
although, you're right, i have no idea how much they were paid, i just assumed....
anyway, back on topic, don't want to litter my own thread with off topic stuff...

Neofate

iTrader: (1)

You know what they say about assumption right?

Man, I wish I could find a Lexus enthusiast,.. even more so an LS owner/enthusiast that had access to a lift local to me. Become reasonable friends and be able to utilize the lift and help each other out when need be.

I think I'm going to go to the regional forums and see if I can dig any poor sucker out

19psi

oh i know! you'd be welcome to use mine, but you're a bit far!