What Octane Gasoline For sc430? Premium fuel required? (Merged threads)
02-03-12, 09:07 AM
#106
03-27-14, 07:35 AM
#108
Pit Crew
Gasoline Octain
I purchased my SC430 late last summer. It was a replacement for my beloved 87 Cadillac Allente that I drove for the last 16 years. Before realizing that the SC required high test gasoline, I used regular grade gas in it, and it performed just fine. I do remember reading somewhere that if a car runs fine on regular grade there is no reason to use the higher grade gasoline in the car. I do not wish to screw up my car once I get it out of storage for the summer so please let me know what grade you all use in your SC's. Thanks in advance, Paul
03-27-14, 12:53 PM
#112
Let's say you drive 3K miles a year, at 30 cents more per gallon for premium, it would cost about $45 more for the entire year to use what your Lexus calls for.
Last edited by Slingshot1; 03-27-14 at 02:50 PM.
03-27-14, 01:21 PM
#113
Pit Crew
Thanks for the comment. Premium it is, I'll start as soon as I get it out of storage. I think that I may just have used not tank of regular before I filled it up with premium to store it for the winter. I'm sure that no harm to this beautiful car from1tank. Paul
03-28-14, 07:47 PM
#114
Doubt you harmed the car. When you use a lower grade of gasoline, the engine performs less efficiently than it was designed for and so in theory, your MPG's should go down. I have found that to be the case with other cars that call for premium and I used midgrade. I have always used 91 Octane or higher for the Sc430 though.
03-29-14, 11:52 AM
#115
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Premium gas
The car respond fast with premium gas and it has better mileage. I have not tried the regular gas in my SC430. But, I used regular and premium gas from my other cars. The car with premium gas definitely has faster acceleration comparing to the same car with regular gas.
03-31-14, 02:20 AM
#116
03-31-14, 07:31 AM
#117
In the old days if you used too low of an octane for the compression and spark timing you would get pre-detonation (before the spark) of the fuel (pinging), so you would know to go up in octane (or tune-up the engine, remove carbon deposits from the piston head, valves etc). Now with sensors for pre-detonation and adaptive timing to avoid pinging (and damage due to heat build-up in the cylinder) you don't get that feedback, but you will notice MPG and performance changes as the timing etc is adapted. So, unless you are hearing pre-detonation (most likely during acceleration) you probably aren't hurting the engine, but you also probably aren't getting the best MPG or performance unless you are running 89 octane or higher. Just my .02.
03-31-14, 11:01 AM
#119
In the old days if you used too low of an octane for the compression and spark timing you would get pre-detonation (before the spark) of the fuel (pinging), so you would know to go up in octane (or tune-up the engine, remove carbon deposits from the piston head, valves etc). Now with sensors for pre-detonation and adaptive timing to avoid pinging (and damage due to heat build-up in the cylinder) you don't get that feedback, but you will notice MPG and performance changes as the timing etc is adapted. So, unless you are hearing pre-detonation (most likely during acceleration) you probably aren't hurting the engine, but you also probably aren't getting the best MPG or performance unless you are running 89 octane or higher. Just my .02.
