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Discussion Starter #1
I just came from hanging out at the lexus dealer behind the scenes so to speak. I just got a look at a brand new crusty black carbon covered SC430 motor that got swapped out for a new one. Mechanic told me that the guy put 89 octane in it and ran it. THIS THING had thick filthy black carbon build up all over the pistons. He says that when carbon builds up the heat doesn't transfer away quick enough and it burns the rings and stuff..

Is anyone running low octane gas and has anyone heard of or had any issues like this with their IS300 or other lexus?. I run lo-octane occasionally and can't tell a difference except it kind of pings when you hit the gas but immediately goes away..

I had no idea that it builds crap up on your motor like that!!.. I could take a pic tommorow if you all want to see it?
 

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You answered your own question w/ your Subject title: Low Octane Blown engine.. that says it all right there.

If you look on your gas door, it says, PREMIUME(sp) GAS ONLY
 

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Freelance said:
You answered your own question w/ your Subject title: Low Octane Blown engine.. that says it all right there.

If you look on your gas door, it says, PREMIUME(sp) GAS ONLY
PREMIUM! :wink:

I never put anything less then Sunoco ULTRA 94 octane....

our motor deserves the best fuel...and I want it running its best....always!

8)
 

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tsopranoMB said:
Freelance said:
You answered your own question w/ your Subject title: Low Octane Blown engine.. that says it all right there.

If you look on your gas door, it says, PREMIUME(sp) GAS ONLY
PREMIUM! :wink:

I never put anything less then Sunoco ULTRA 94 octane....

our motor deserves the best fuel...and I want it running its best....always!

8)
Thanks man, now I know why I didn't do too well in Spelling class... :D
 

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That pinging you hear is pre-igniton knock. It goes away because the ECU retards the ignition timing to compensate. By doing that you're losing performance.

Once an engine is all carboned up, the carbon can get hot enough to glow and cause detonation. That's how one gets blown. Carbon can also cause the motor to try and keep running after you turn off the key.
 

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brads said:
I just came from hanging out at the lexus dealer behind the scenes so to speak. I just got a look at a brand new crusty black carbon covered SC430 motor that got swapped out for a new one. Mechanic told me that the guy put 89 octane in it and ran it. THIS THING had thick filthy black carbon build up all over the pistons. He says that when carbon builds up the heat doesn't transfer away quick enough and it burns the rings and stuff..

Is anyone running low octane gas and has anyone heard of or had any issues like this with their IS300 or other lexus?. I run lo-octane occasionally and can't tell a difference except it kind of pings when you hit the gas but immediately goes away..

I had no idea that it builds crap up on your motor like that!!.. I could take a pic tommorow if you all want to see it?
amazing...how a person would spend all that money on a car like that, and then put in the cheapest gas..... :shame:
 

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Discussion Starter #7
Unbelieveable..

Does anyone know WHY low octane gas leaves this residual?.

I will take some pics tommorow of that poor little V8
 

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brads said:
Unbelieveable..

Does anyone know WHY low octane gas leaves this residual?.

I will take some pics tommorow of that poor little V8
lower octane gas doesn't burn as clean...thats why in Japan they have like 114 octane gas at the pumps...also because their motors are all high compression but...u get the point.
 

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Because it’s more volatile and burns at a lower temperature which can leave residue that's un burnt that’s why its regular unleaded and high octane is premium. --amongst other reasons of course.

brads said:
Unbelieveable..

Does anyone know WHY low octane gas leaves this residual?.

I will take some pics tommorow of that poor little V8
 

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bartkat said:
Carbon can also cause the motor to try and keep running after you turn off the key.
"oh all new cars do that. you think you hate it now, but wait til you drive it." - clark griswold dicussing the wagon queen family truckster
 

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i had to fill up one time on 89 octane, because the chevrons i went to were out of premium gas....damn i regreted that, car felt sluggish...i should just put 2 gallons instead of a whole tank
 

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so there is really that much of a difference between 89 and 91?
 

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tsopranoMB said:
amazing...how a person would spend all that money on a car like that, and then put in the cheapest gas..... :shame:
See what leasing does?

People who ordinarily couldn't afford these vehicles now can, but barely.... :rolleyes:
 

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i have been riding on 87 octane for the last 1500 miles...i havent noticed anything different..i dont feal slower or what not like others say...?...ill go back to 93 as soon as i can ...but right im on a tight tight budget do to school and books...every penny counts until im back on my feet again...and at my gas station ...the diff. between 87 and 93 octane is almots 50 cents...so im saving like what 8$ almost...hopefully ill be using premium soon
 

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i've been runnin 87 for hte past 2 fill ups. reason why is cause gas is expensive and i have bills to pay and seein how gas is down here in the 310 i aint putin some 91 octane since its $3.15 a gallon
 

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$3.19 for 93 Mobil here in CT. Cheapest I could find. For the first time in a LONG time I put in the regular 87 for 2.99...and still cost me over $40.00. I really can't feel the difference. I've done mostly highways since I filled up and I've been babying the throttle so much. Last tank I averaged 22mpg, which i'd like to increase. There might be a slightly rough idle but it may be my imagination.
 

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LexatheLexus said:
$3.19 for 93 Mobil here in CT. Cheapest I could find. For the first time in a LONG time I put in the regular 87 for 2.99...and still cost me over $40.00. I really can't feel the difference. I've done mostly highways since I filled up and I've been babying the throttle so much. Last tank I averaged 22mpg, which i'd like to increase. There might be a slightly rough idle but it may be my imagination.
that is exactly what is happening. Detonation is occuring and it is bad for the engine :jawDrop:
 

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CYBERTECK said:
i've been runnin 87 for hte past 2 fill ups. reason why is cause gas is expensive and i have bills to pay and seein how gas is down here in the 310 i aint putin some 91 octane since its $3.15 a gallon
hahaha i went to the gas station and put 89 today. hey Daniel, when are we gonna play texas hold'em again?
 
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