I have a 2007 Lexus 350 which the dealer and car manual recommends premium gasoline. Has anyone tried regular or plus or a mixture of either? I live in the Northern Virginia area and "supposedly" be blends of gasoline are somewhat different for this metropolitan area. Appreciate any feedback.
The part about "your mileage may vary" also applies to the use of regular or mid grade fuel instead of premium. When you use lower octane fuel, the engine knock sensors may detect knocking and retard ignition timing, which will reduce the power the engine produces, which may reduce fuel economy.
Calculate the fuel economy you are getting with premium on a cost per mile basis and compare with what you get with regular or mid-grade fuel. I've found that fuel economy goes down a little with regular, so that on a cost per mile basis, there is no difference between regular and premium except for the slight loss of performance.
Regular grade won't hurt it, but your mileage won't be as good (the timing gets retartded to avoid repeated pinging/knocking/detonation.
I find that the higher price of mid-grade gas is more than offset by the better mileage, so almost always avoid regular for that reason. I haver not found the additional cost of "super" to worth any further slight improvement in mileage, so avoid that as well.
I have an 05 rx 330, about the same vehicle, and have always run regular gas with no ill effects, the possible issues from using regular in this car could be a slight loss of engine power and very slight hit on fuel economy, neither of which has been an issue in my case __________________________________________ Never argue with an idiot. They'll drag you down to their level and beat you with experience.
I remember reading this when gas was $2.00 a gallon (premium was say $2.20/gallon or a 10% premium - so presumably you got 10% better mileage w/ premium).
Now gas is $4.00/gal (say premium $4.25/gal or 6.25% premium so you need only 6.25% better mileage).
My question is, is the extra mileage really 6% or 10% better??
Frankly, I have tried to measure this on my car. I take the same 450 mile (each way) trip every year, at about the same time of year, for the last 6-8 years and stop at the same stations. Frankly I haven't been able to prove any consistent difference between premium and mid-grade in my SC400 as other factors (temperature, wind, tire pressures/air filter restrictions/state of tune, etc.) seem to offset the effects of difference in fuel. So now I just stick with the mid-grade.
I heard that too, Ray, but at my 20K service stop, the Lexus rep recommended I switch my 2006 GS300 engine from premium to regular. My beef was actually sooty tailpipes, even though the car does not use oil. Three things: (1) yes, some loss of power when not downshifting, (2) no more hesitation when I stop quickly and try to step on the gas immediately, like at a stop sign when there is no oncoming traffic, and (3) about 10% better mileage on the highway... I could not believe it, I thought maybe because the knock sensor had not reset itself for less timing advance, when I switched to regular, but after almost 14000 miles on regular, I cannot say I regret going to regular. Now I may reduce engine valve life, because I think regular burns hotter, but I do not plan to keep the car beyond 75K. Would appreciate your feedback on my comments Ray! BTW, my tailpipes are as sooty as ever, but I notice all GS300 have sooty tailpipes..
Good question! I haven't calculated cost per mile since gas was $3.00 per gallon so I don't know the answer. My guess is that as the price of gas increases, you start to come out ahead with premium. I've been using mid-grade for the past couple of months and have been getting between 18.5 and 18.9 MPG, while I used to get about 1 MPG better with premium.
Switching from regular to premium or vice versa should not have any effect on the amount of soot visible in the tail pipes. Using regular will not reduce engine valve life. The notion that regular burns hotter than premium is an urban legend. Regular and premium fuel have the same BTU content and burn at pretty much the same temperature. The difference between regular and premium is in the additives and octane, which reduces the fuel's tendency to detonate under compression.
If you switch from premium to regular, the ECU will reduce timing advance as soon as it detects a signal from the knock sensors. If you accelerate slowly and don't put a load on the engine, the ECU may never reduce timing advance.
If you switch from regular to premium, it will take roughly 2 tanks of fuel for the ECU to start to advance timing again.
since purchasing my 2007 RX350 new, I haven't used anything but premium.
if you believe the display, the car gets anywhere from 21-23 mpg, mostly city driving. since I don't put a lot of miles on the car, I have never used regular. I don't know about the accuracy of the MPG display.
By the way, my friend's Toyota Avalon trip computer displays the mpg with 0.1 mpg accuracy. My Lexus GS300 trip computer displays the mpg with a CONSISTENT 1.5 mpg overage, meaning my actual mpg is exactly
1.5 mpg less than indicated. Just thought this might be interesting.
WOW, my BMW 328i with a 6cyliner (in line) gets 18-19mpg around town, and up to 30mpg on the highway, and the engine is smaller than the RX. That's extremely GOOD gas mileage. Have you checked that on a trip? It's easy to do, I get 200+ miles around town on 11 gallons of gas. Consistent.
Subtracting 1.5 mpg from my trip computer, I get around 18-21 mpg when making short trips around town, but as soon as the car has really warmed up (about 12-15 miles) then the mileage gets fabulous, with the trip computer registering 32-34 mpg (30.5 - 31.5 actual). The mileage is a bit less during cold weather, perhaps 1 mpg. And that's for a 3 Liter engine! I never used to get that much out of my prior 4 cyl Chrysler product! Plus I use regular nowadays.
wait a minute. You're telling us that you're *averaging* over 30mpg? The RX400h *averages* 21mpg and it's a hybrid!
Incidentally, I test drove the RX400h and didn't like it *at all*. For a vehicle that cost over $40k, it barely got better mpg than an RX350 and it was noisy and cramped and the navigation system was grainy and discolored and looked like it hadn't been upgraded since
1995.
We had hoped that Lexus would of made a hybrid version of their ES350 (to coincide with Toyota's hybrid Camry) but they never have so last weekend we traded in my wifes 2000 ES300 for an 07 Hybrid Camry.
Wow..it's an incredible car. We *average* 38mpg in the city and 37 on the highway (better mpg in the city where it's running predominately on electrics). The navigation system and fit and finish rivals a Lexus and it was only $28k.
And it's *creepy* quiet. Something you have to be careful about since pedistrians often won't hear you coming up on them.
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