CVsIS250

I found a Sunoco yesterday that is selling 94 Octane. What would this do if put in the GX besides increasing your bill?

CV

seanyepez

Nothing, unless you are on a race track.

The ECU might adjust and give you a couple more horsepower over 91, but I really doubt it. The engine is the same one in the Sequoia and 4Runner. It can run perfectly on 87. The reason Lexus recommends 91 is because it will make slightly more horsepower (which helps them in magazine testing).

That said, I run 91. I tow a pretty heavy trailer and race car lot, and the extra power can't hurt.

BobsGX

Around here, premium fuel is 93 octane. I doubt the GX would notice the 1 octane boost.

malhokc

I use 87 and am very satisfied with the performance, and more importantly cost.

Rx900

i'm definitely satisfied with 87. i really don't want a $100 fill-up. bad signs are: the odyssey my dad has eats up $45 easily, when back in the day, $45 fill-ups were only for suburbans and expeditions. no matter how empty that van was, it never reached $30. besides, i don't tow or haul anything big, so 87 is good enough. unless i want to have no dinner for a couple nights, then i'll put 91.

Lexmex

Well, speaking from experience on a race track, the higher octane gas won't do anything unless your timing is adjusted or you have something like an eManage for an FC Commander, which you can adjust for the higher octane.

sayadil

Yeh I'm using 89 (from esso n sunoco only) for last 2 yrs... on a full tank (usually $75CAD) i get 375 miles... i'm very happy with it.. considering its a V8 we r driving.. I tried higher octanes as well like 94 from sunoco but dint notice any difference.. except milage improoved 10 miles per tank... which dint justify the $10 price difference. Felt 87 is as good as 89... but since its only $3 difference on a full tank... i go with 89 for somewhat peice of mind..

CVsIS250

Thanks for the replies ladies and gents. You expressed my sentiments too.

CV

trebien

Just to clarify, some engines can actually make use of higher octane gas, some can't. It depends on the engine's ability to increase the timing to make more power. In order to increase timing, but hold off on detonation, it needs a higher octane gasoline. The 2003/2004 version of the GX470 engine doesn't seem to be able to make the most of increased octane gasolines. Most older engines can't change their timing, and if they weren't designed with high compression components from the factory for higher octane gas, then they can't make the most of that increased octane. But many newer engines can change their timing on the fly, to utilize the higher octane.

The 2005+ engines can advance the timing enough to make use of the extra octane. If using a lower octance gasoline, the engine will retard timing and make less power, therefore burning more gasoline to make the same power/cover the same distance. I drive a lot of highway miles, on long, flat Texas roads with easily re-producable results. On several vehicles (that can all adjust timing) I have tried mid-grade vs. premium fuels. On all accounts, the MPG went up with the higher octane, more than enough to offset the increased price. Especially now that the increase in price is fractionally smaller than it used to be... i.e. those 10 extra cents per gallon is about 3% costlier, when it used to be about 8% costlier. If you can recoupe 3% better mpg, then the increased cost of premium gasoline pays for itself. Not to mention that upper grade gasolines tend to have more additives and detergents in them to keep the engine healthy - an added bonus.

Either you understand how engine timing works, and how it affects power production, or you don't. That can be researched and learned on your own. I've built race engines and know my way around performance and engine electronics. All I can tell you is that I regularly see an additional ~1.2 mpg (hwy) when using premium (92-93) over mid-grade (89) octane gasoline in my GX. That more than justifies the additional cost of using premium for me.

IF you do choose to try experimenting, do it more han once. It is common practice for some stations to actually have 90-91 octane gas in the "mid-grade" tanks. The number assigned is a guaranteed minimum... sometimes they purchase overflow reserves of a higher octane gasoline, even though they only need mid-grade... because it's cheaper than an order of mid-grade gas at that time. This happens quite frequently. For instance, a gas station orders 10,000 gallons of premium... the tanker holds 20,000. The distribution center will call other nearby gas stations and offer a low price on the remaining premium gas, since they can still have half a trailer full of gas... and it's cheaper to sell it that same trip, then sending a different truck with mid-grade. Point is... you may purchase mid-grade, but actually get 91 octane in the tank for that fill-up.

The G Man

I been going back and forth between 87 and 93 now for about 6 tanks. I do notice a difference in accelaration, very little I might add. I also notice a difference in engine noise and smoothness, once again, just a tiny bit. On 93, according to the computer, I get 0.5 MPG more, this is almost all city. For now, I think I will stick with 93 octance.

sayadil

well mine is a 2004 build.. and in little over 2 yrs i have driven around 70 k. when i first got this car.. i use to drive on premium (94 sunoco) , i would say for the first 20k approx and was told by few local dealerships that this car engine is designed with minimum octane rating of 87 and as long as that rating is maintained the car should drive as intended. Higher octane are always a plus but putting in higher octane would only impact my wallet more then anything while addictves from the higher octane will surely help. the price difference between 94 and 89 is about 10 cents here in toronto while 91 is 5 cents... which is about $8-9 every gas tank meaning the car should give around 425 miles per tank instead of 375.. to justify buying higher octane which is clearly not the case with mine (with my regular driving habits)... it will cost me around 85 instead of $75 and with rising cost of fuel.. i see no point spendin the extra dough... plus every now n then i do tend to add STP fuel addictves for the car...

CVsIS250

There is no such thing as a production mid-grade gasoline. The petrol companies only make ultra and regular gasolines. The mid-grade is nothing more than a mix of the two. I don't know where you are getting your facts.

trebien

I never said that refineries produced "mid-grade" gas. It's all done in the mixing, but it's pre-delivery. That's the point. Your mid-grade pump may be labelled a guaranteed 89 octane, but it was filled with leftover premium grade, and actually has a much higher octane... such as 91. So for that fill-up, it may not be that different from the premium in terms of octane.

If the station has a "mid-grade" pump... there is a related "mid-grade" underground tank for that pump, filled from the tanker trucks. It's not like the mid-grade pump mixes gas from the underground "premium" and "low-grade" tanks in real-time.

poyzinus

really don't know much about gas.. but all i know is this.. usin' the higher octane such as 94 is very good. it's good for your car, acceleration wise and cleans your engine (fuel injectors) and all. so you can't go wrong. i try to put 94 in my gs everytime.. its smooth and good response when i jam on the paddle.... but to tell you.. i really can't tell the diff. between a 91 or a 93... but if the price is good and low.. grab the higher one.. otherwise get crap gas and put an octane booster in...
i guess you can say its like a good beer.. u'll like it and enjoy it.. compared to a crappy beer.. ewww.. just think about that one.. haaa

sayadil

Well logically an engine designed to run at lower octane level such as 87 should peform as intended at that Octane level or higher. while Putting in Higher octane is obviously a plus but putting in lower octane is not a bad (crappy) thing either... The car has been tested with minimum 87 octane fuel and it should perform at level. Putting in higher octane is good but not compelsary.. i doubt putting it makes the car more efficient or makes it accelerate more... An engine designed for lower octane fuel can't utilize the benefits of higher octane except the addictives do help out... Your GS most likely needs minimum octane level of 91 where as GX should be fine with 87 n above.