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I only use 93 because the gas station I use doesn't have 91/92, and I have a thing about always using the same station (and usually the same pump). Hooray for OCD! lol I use it for my Exige anyway, as the tune is for 93.
Well for us here in Canada (if all things well) then it would be nice if could use non premium fuel on the winter months at least since we don't need the extra hp and then put the premium when it gets warmer . Here I would think its about 10 - 15 bucks canadian per fill up so it makes a difference. If it does not damage engine AND you get same mpg I mean.
As with anything, manufacturers generalize everything because it takes alot of effort to put conditions on things since the majority of people do not care/follow.
something like: "You can run 87 but only on the Lexus IS350 awd with luxury package, but you must do this only in temperatures bellow 0 degrees celcious and you must be at least 500 meters max from sea level and not go more than 140 km/hr " yikes.
Well for us here in Canada (if all things well) then it would be nice if could use non premium fuel on the winter months at least since we don't need the extra hp and then put the premium when it gets warmer . Here I would think its about 10 - 15 bucks canadian per fill up so it makes a difference. If it does not damage engine AND you get same mpg I mean.
As with anything, manufacturers generalize everything because it takes alot of effort to put conditions on things since the majority of people do not care/follow.
something like: "You can run 87 but only on the Lexus IS350 awd with luxury package, but you must do this only in temperatures bellow 0 degrees celcious and you must be at least 500 meters max from sea level and not go more than 140 km/hr " yikes.
I honestly can't see a scenario where it would cause you damage, and my Lexus tech friend agrees. So why not try it and calculate your gas mileage? You might get the same or a little worse, but the difference in money will more than make up for it.
Rather than continuing to discuss what theoretically could happen if you use 87 Octane, my recommendation is to collect some actual data using Techstream or datalogging apps like OBD Fusion with a Bluetooth OBD adapter to determine how the ECU is reacting to the lower octane fuel. The critical value to observe would be the Knock Correction Learning Value (KCLV) which is the ECU's long term ignition correction factor. A healthy car's KCLV should read over 20+ when you are coasting and when you're at Wide Open Throttle (WOT).
Here's an example of a KCLV reading at WOT using one of my older datalogs:
I'd recommend getting a baseline KCLV by using premium-grade octane fuel (91-93) and recording the KCLV when at idle, coasting at a steady speed, and at WOT. KCLV should be at 20+ which means ignition timing advance is at its peak and no detention/pinging is occurring.
When switching to a lower-grade 87 octane, the probability of the knock sensors picking up knock will greatly increase and should that occur, the KCLV will reduce to values below 20 and in turn will retard the ignition timing to prevent further pre-detonation. If a driver were to go WOT in their 3IS with 87 octane, I would anticipate that the KCLV will drop accordingly in order to protect the engine. What I'm not certain is if using 87 octane and only driving in the lower RPMs would also reduce the KCLV (which is why datalogging this info would be greatly beneficial).
Rather than continuing to discuss what theoretically could happen if you use 87 Octane, my recommendation is to collect some actual data using Techstream or datalogging apps like OBD Fusion with a Bluetooth OBD adapter to determine how the ECU is reacting to the lower octane fuel. The critical value to observe would be the Knock Correction Learning Value (KCLV) which is the ECU's long term ignition correction factor. A healthy car's KCLV should read over 20+ when you are coasting and when you're at Wide Open Throttle (WOT).
Here's an example of a KCLV reading at WOT using one of my older datalogs:
I'd recommend getting a baseline KCLV by using premium-grade octane fuel (91-93) and recording the KCLV when at idle, coasting at a steady speed, and at WOT. KCLV should be at 20+ which means ignition timing advance is at its peak and no detention/pinging is occurring.
When switching to a lower-grade 87 octane, the probability of the knock sensors picking up knock will greatly increase and should that occur, the KCLV will reduce to values below 20 and in turn will retard the ignition timing to prevent further pre-detonation. If a driver were to go WOT in their 3IS with 87 octane, I would anticipate that the KCLV will drop accordingly in order to protect the engine. What I'm not certain is if using 87 octane and only driving in the lower RPMs would also reduce the KCLV (which is why datalogging this info would be greatly beneficial).
I might actually do that. Although I am not interested in running 87, it would be interesting to see the difference. One tankful should not hurt anything.
Shout out to the 6.42 % of "regular gas" users. Don't say we didn't warn yall when that engine start knocking (Not the knocking that makes the room rocking) lol
Seriously though, quit putting regular is these luxury cars.
I'be had my IS300 for a little more than a year now and have only put Premium in it. I plan on driving it till the wheels fall off so not taking any chances cutting corners.
ok, my 2 canadian cents. I filled up with regular gas on Sunday Dec 2 from empty (gas light was lit up). Cost of regular at the time was like 98 center per liter (records low now a days). I did a quick calculation and if I was to buy premium at that time I would have spent 9 dollars more.
Let me say that I drive mostly highway for work and I typically fill up every 4-5 days. My style of driving is not aggressive at all but on occasions I step on the gas (rare).
I think i feel that there is a very slight power loss but not a lot. Could be on my mind but the car feels slight heavy. It does not feel sluggish tho or unrefined.
Fuel economy from computer I see that it is the same or even slightly less? but not much. I still have some gas left (I worked from home Monday and Today) so its looking pretty good.
Thats my experiment. It would be good to see/ask the 2nd gen people. Maybe some of them have a longer test on this or maybe even the ones that are running 87 for years can tell us if they run into any problems relating to putting regular vs premium.
11-28-18, 08:57 AM
. Here I would think its about 10 - 15 bucks canadian per fill up so it makes a difference. If it does not damage engine AND you get same mpg I mean.
