2010 RX350 Mileage over 10,000 mi Road Trip; Premium & Regular fuel ....
10-03-11, 08:05 PM
#1
Lexus Champion
Thread Starter
2010 RX350 Mileage over 10,000 mi Road Trip; Premium & Regular fuel ....
My wife and I completed a two month road trip last month in our 2010 RX350, going from central TX to California, then north to Oregon, Washington, BC and AB Canada, then Montana, Wyoming, Idaho, Utah, back to California and then straight trip home to TX, a total of 10,100 indicated miles from July 15 thru September 15. Temperatures ranged from 110 in the desert of CA to 35 in Oregon around Crater Lake at 6:30 am. About 1200 miles in the range of 75-80 mph in those areas of TX and UT which have higher interstate speeds. I would say about 75% of the mileage was interstate or major highways, the rest in more congested areas (maybe 40 mph avg). Vehicle had 4,500 mi on the clock when we left and 14,600 when we pulled into the driveway. Vehicle has 19" wheels, and stock tires kept at suggested inflation pressures. No special attempt to maximize mileage was made, we just drove as we wanted and kept putting fuel in it when it got low.
Here is actual performance data from detailed fuel records:
1. Odometer consistently reads 3% LOW, checked a half dozen times in different states over a 20-30 mile stretch of marked milepost Interstate highway, it always shows the same error. But the speedometer is almost spot on. Go figure. All data corrected for the discrepancy.
2. Overall mileage over this distance was 24.8 mpg, increasing slightly over the trip but very consistent.
3. Once we got to Canada in mid-August and saw the silly prices premium fuel was we switched to 87 octane regular and kept using it for the remainder of the trip. We saw absolutely NO degradation in performance or mileage, in fact it kept increasing slightly. My opinion, don't waste your money on premium fuel, it just isn't needed.
4. Obviously no service station was used twice and many brands of fuel were used; it made no difference in performance or mileage. Gas is gas.
5. Conclusion is that mileage seemed to increase slightly as the RX had more miles on it but was remarkably consistent except for the dip at the end of September (lots of mileage around the wineries of Oregon and then city driving in Portland and Seattle areas).
Mileage for 10,100 miles over two month period (Jul 15 - Sep 15, 2011)
Here is actual performance data from detailed fuel records:
1. Odometer consistently reads 3% LOW, checked a half dozen times in different states over a 20-30 mile stretch of marked milepost Interstate highway, it always shows the same error. But the speedometer is almost spot on. Go figure. All data corrected for the discrepancy.
2. Overall mileage over this distance was 24.8 mpg, increasing slightly over the trip but very consistent.
3. Once we got to Canada in mid-August and saw the silly prices premium fuel was we switched to 87 octane regular and kept using it for the remainder of the trip. We saw absolutely NO degradation in performance or mileage, in fact it kept increasing slightly. My opinion, don't waste your money on premium fuel, it just isn't needed.
4. Obviously no service station was used twice and many brands of fuel were used; it made no difference in performance or mileage. Gas is gas.
5. Conclusion is that mileage seemed to increase slightly as the RX had more miles on it but was remarkably consistent except for the dip at the end of September (lots of mileage around the wineries of Oregon and then city driving in Portland and Seattle areas).
Mileage for 10,100 miles over two month period (Jul 15 - Sep 15, 2011)
Last edited by Evitzee; 10-03-11 at 08:10 PM.
10-04-11, 07:02 AM
#4
A long trip is not a good way to measure gas mileage, there are many factors that can affect the outcome such as different road surface, wind condition, elavation, temperature, dew point or gas quality from different station. I am sure the gas from Canada is formulated differently from the US.
10-04-11, 07:32 AM
#5
Lexus Champion
Thread Starter
It means your odometer is wrong. If it says you travelled 100 miles you have actually travelled 103 miles, you are travelling further than you think, by 3%..
10-04-11, 07:37 AM
#6
Lexus Champion
Thread Starter
A long trip is not a good way to measure gas mileage, there are many factors that can affect the outcome such as different road surface, wind condition, elavation, temperature, dew point or gas quality from different station. I am sure the gas from Canada is formulated differently from the US.
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10-04-11, 11:59 AM
#8
What a great trip report and the news about overall MPG and no noticeable difference between premium and regular grade. You obviously saw some fantastic scenery by travelling in the States you mentioned in addition to Canada. I live 90 miles from Crater Lake and marvel at seeing it every time I visit.
10-04-11, 02:45 PM
#9
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I came to the same conclusion doing my 80mile trip daily. 89 octane actually increased mileage a bit and no degredation in performance. Been using 89 for the last 30K miles so far and all is great. 91 or 93 is overkill IMO. waste of money for me.
Nice review.
Nice review.
10-04-11, 06:02 PM
#10
Over the last year plus, I've constantly received mileage of 30mpg plus. I use COSTCO 93 octane, the price is cheaper plus there is a 3% reduction using their AMEX card.
Driving is a mix of city/rural route, and highway near the posted speed limits (I put up my radar detector when I got the (h). Acceleration unless passing (which is really fun with this power) is light to moderate.
Driving is a mix of city/rural route, and highway near the posted speed limits (I put up my radar detector when I got the (h). Acceleration unless passing (which is really fun with this power) is light to moderate.
10-05-11, 06:53 AM
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I like to take a quick survey. How many of you out there, after reading this forum thread, will still insist on using 91 or higher octane gas just because the owner's manual said so?? (This question does not apply to 2012 model owners).
10-05-11, 07:32 AM
#12
Out of Warranty
I made that same trip (in the opposite direction) in May of 2000 with a new RX 300 that I'd had for two weeks. Conditions varied from snow in Colorado-Wyoming, to blazing heat in North Texas. Mileage was consistent at 24, plus or minus a little depending on traffic. I covered the territory in three weeks, putting some 6800 miles on an untested car. Although mileage never changed significantly, running 87 octane wasn't bad, but seemed to induce a delay in response as the engine's knock sensors dialed back the ignition to cope with the 87. I used regular out on the road, and premium in town - the idea being a stumble in traffic might be more expensive than the savings in gas.
In 2000, Lexus was not even sold in most of the states I visited, so I got a lot of strange looks from people on the street. About that time I realized there probably wasn't any service for my RX either, or it would be extremely limited. The only Lexus service in Seattle at the time was a one-bay shop behind the Lexus dealership in Redmond. I'd have to wait for a week for an appointment for an oil change. No thanks.
What did I learn? First that the RX was a superb car for a road trip, comfortable and able to gobble up miles without incident. Second, that even with AWD, the car came with a really sorry set of OEM tires (Goodyear Infinity) that never failed, but had me going sideways down the western slope of Snoqualmie Pass. Upon my return to Houston, I put a set of Michelin Cross Terrains on that greatly outperformed the GY's and never experienced another problem in the next 40,000 miles. When I traded it was for an RX 330.
In 2000, Lexus was not even sold in most of the states I visited, so I got a lot of strange looks from people on the street. About that time I realized there probably wasn't any service for my RX either, or it would be extremely limited. The only Lexus service in Seattle at the time was a one-bay shop behind the Lexus dealership in Redmond. I'd have to wait for a week for an appointment for an oil change. No thanks.
What did I learn? First that the RX was a superb car for a road trip, comfortable and able to gobble up miles without incident. Second, that even with AWD, the car came with a really sorry set of OEM tires (Goodyear Infinity) that never failed, but had me going sideways down the western slope of Snoqualmie Pass. Upon my return to Houston, I put a set of Michelin Cross Terrains on that greatly outperformed the GY's and never experienced another problem in the next 40,000 miles. When I traded it was for an RX 330.
Last edited by Lil4X; 10-05-11 at 07:36 AM.
10-05-11, 08:35 AM
#13
Things to consider
If you don't have a problem with 87 octane while you own it, then no foul to you.
BUT If you do have a problem with emissions or carbon or plug fowling during the warranty period and they say it was caused by not using the required fuel then was it worth to you ??? Because you'll probably have to pay for the repair.
When you sell it, are you going to tell the potential buyer you only burned high test when you didn't?
The Lexus engineers determined for each model what is required for proper ignition, timing, performance mpg/power and long term durability. I don't believe they suggested premium only because you'd feel better putting premium into a premium car. Inside my gas cap it reads "Premium Fuel Only". On page 624 in my manual it say's 91 Octane or higher. No where can I find the term 'suggested'.
I'm sure a tank of 89 octane now and then probably won't hurt it, but 87 on a constant basis ??? Hmm
Yep, it's cheaper, but we're driving cars around $50k. At today's gas prices to save a buck or two on $30 plus fill up IMHO doesn't make sense unless you're positively beyond a doubt sure it won't hurt. Read a few posts above and see the graph of my mileage burning high test which here in GA is 93 octane. To me, if I can't afford the required gas (according to the engineers), then I should have bought something else like a Highlander maybe.
I'm sure this won't stop the speculation, but until an official announcement from Lexus that nothing has changed in the engine set up on the 2012 models, they've just determined regular (87 octane) won't hurt it, I'll stay with "91 or higher" octane.
BUT If you do have a problem with emissions or carbon or plug fowling during the warranty period and they say it was caused by not using the required fuel then was it worth to you ??? Because you'll probably have to pay for the repair.
When you sell it, are you going to tell the potential buyer you only burned high test when you didn't?
The Lexus engineers determined for each model what is required for proper ignition, timing, performance mpg/power and long term durability. I don't believe they suggested premium only because you'd feel better putting premium into a premium car. Inside my gas cap it reads "Premium Fuel Only". On page 624 in my manual it say's 91 Octane or higher. No where can I find the term 'suggested'.
I'm sure a tank of 89 octane now and then probably won't hurt it, but 87 on a constant basis ??? Hmm
Yep, it's cheaper, but we're driving cars around $50k. At today's gas prices to save a buck or two on $30 plus fill up IMHO doesn't make sense unless you're positively beyond a doubt sure it won't hurt. Read a few posts above and see the graph of my mileage burning high test which here in GA is 93 octane. To me, if I can't afford the required gas (according to the engineers), then I should have bought something else like a Highlander maybe.
I'm sure this won't stop the speculation, but until an official announcement from Lexus that nothing has changed in the engine set up on the 2012 models, they've just determined regular (87 octane) won't hurt it, I'll stay with "91 or higher" octane.
Last edited by Cruiter; 10-05-11 at 08:37 AM. Reason: error
10-05-11, 01:38 PM
#14
95% of the people that buys a $50K+ car will trade it in at best 5 years or less. I knew I wasn't going to keep the RX so regular was fine and did the job.
01-22-12, 05:15 PM
#15
Thought I'd update this thread for what it's worth:
So I went for my 20,000 mile maintenance and I said to the service guy that I've been using the premium but is it really necessary on the 2010 model, because I know they changed the requirement for the 2012 and he said the reason they changed it for the 2012 is that the last two years with gas close to $4 a gallon, most drivers switched to the low octane and they didn't see any performance problems so they stopped telling people to get premium. So it has nothing to do with the 2012 being able to handle the lower grade better than the older cars.
So I went for my 20,000 mile maintenance and I said to the service guy that I've been using the premium but is it really necessary on the 2010 model, because I know they changed the requirement for the 2012 and he said the reason they changed it for the 2012 is that the last two years with gas close to $4 a gallon, most drivers switched to the low octane and they didn't see any performance problems so they stopped telling people to get premium. So it has nothing to do with the 2012 being able to handle the lower grade better than the older cars.