2008 RX-350 Fuel Octane Rating
#32
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Why does the same engine in a Toyota only need Regular?
Just got the latest Consumer Report magazine and they have an article on regular vs premium gas. The bottom line is if Premium gas is suggested by your owners manual you can use regular 87 octane but if your manual states Premium gas is required than you better use premium 91 or 93 octane. This is due to engines with higher compression. My Z3 has a compression of 10.5:1 and requires premium.The RX350 engine is 10.8:1 thus it requires premium. I alternate between 93 and 89 octane when my fuel gage is at the halfway mark, trying to keep a 91 octane blend. No problems and great gas milage 26 mpg highway @ 73 mph.
Yesterday I bought my bride a new RX350 for her 25th anniversary, as a well deserved reward for putting up with me all those years. Looking through the book I see Premium gas is required. I read somewhere the RX350 is based on the same platform as the Toyota Camry and Highlander, so I looked for the fuel spec on those. I could not find the spec on Toyota's web site, but I found several references on car review sites indicating the Toyota burns regular gas. From Motor Trend's data below it appears the same 3.5L V6 is used in both vehicles.
I understand the octane requirement is correlated with compression, but what I don't understand is why the Lexus needs premium but the same engine in a Toyota Highlander only requires Regular.
Lexus ( http://www.motortrend.com/cars/2009/...350/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 94.0 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Premium unleaded fuel 91
- Multi-point injection fuel system
- 19.2 gallon main premium unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 251 ft lb , 340 Nm @ 4,700 rpm
Toyota ( http://www.motortrend.com/cars/2009/...der/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 93.9 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Unleaded fuel 87
- Multi-point injection fuel system
- 19.2 gallon main unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 248 ft lb , 336 Nm @ 4,700 rpm
Any experts out there who can explain this?
Last edited by AV8R_BOB; 09-11-08 at 06:07 PM.
#33
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Hi folks,
Yesterday I bought my bride a new RX350 for her 25th anniversary, as a well deserved reward for putting up with me all those years. Looking through the book I see Premium gas is required. I read somewhere the RX350 is based on the same platform as the Toyota Camry and Highlander, so I looked for the fuel spec on those. I could not find the spec on Toyota's web site, but I found several references on car review sites indicating the Toyota burns regular gas. From Motor Trend's data below it appears the same 3.5L V6 is used in both vehicles.
I understand the octane requirement is correlated with compression, but what I don't understand is why the Lexus needs premium but the same engine in a Toyota Highlander only requires Regular.
Lexus ( http://www.motortrend.com/cars/2009/...350/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 94.0 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Premium unleaded fuel 91
- Multi-point injection fuel system
- 19.2 gallon main premium unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 251 ft lb , 340 Nm @ 4,700 rpm
Toyota ( http://www.motortrend.com/cars/2009/...der/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 93.9 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Unleaded fuel 87
- Multi-point injection fuel system
- 19.2 gallon main unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 248 ft lb , 336 Nm @ 4,700 rpm
Any experts out there who can explain this?
Yesterday I bought my bride a new RX350 for her 25th anniversary, as a well deserved reward for putting up with me all those years. Looking through the book I see Premium gas is required. I read somewhere the RX350 is based on the same platform as the Toyota Camry and Highlander, so I looked for the fuel spec on those. I could not find the spec on Toyota's web site, but I found several references on car review sites indicating the Toyota burns regular gas. From Motor Trend's data below it appears the same 3.5L V6 is used in both vehicles.
I understand the octane requirement is correlated with compression, but what I don't understand is why the Lexus needs premium but the same engine in a Toyota Highlander only requires Regular.
Lexus ( http://www.motortrend.com/cars/2009/...350/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 94.0 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Premium unleaded fuel 91
- Multi-point injection fuel system
- 19.2 gallon main premium unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 251 ft lb , 340 Nm @ 4,700 rpm
Toyota ( http://www.motortrend.com/cars/2009/...der/index.html )
- 3,456 cc 3.5 liters V 6 front engine with 93.9 mm bore, 83.0 mm stroke, 10.8 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 2GR-FE
- Unleaded fuel 87
- Multi-point injection fuel system
- 19.2 gallon main unleaded fuel tank 16.0
- Power: 201 kW , 270 HP SAE @ 6,200 rpm; 248 ft lb , 336 Nm @ 4,700 rpm
Any experts out there who can explain this?
The 3.5L in the Highlander and RX has 270HP.
The RAV4 3.5L has 269 HP.
Same engine with 4 different HP ratings.
I believe the 3.5L has the best performance and MPG on premium.
Toyota would lose sales if premium was required in the Camry,Highlander and RAV4.
I'd go at least 89 in a 3.5L 270 HP.
Here's an article on using regular vs premium when premium is required.
http://www.myride.com/lifestyle/feat...120-page1.html
#34
Use 89 at least, but 93 works better. More HP, need 93.
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I believe the 3.5L has the best performance and MPG on premium.
Toyota would lose sales if premium was required in the Camry,Highlander and RAV4.
Here's an article on using regular vs premium when premium is required.
http://www.myride.com/lifestyle/feat...120-page1.html
Toyota would lose sales if premium was required in the Camry,Highlander and RAV4.
Here's an article on using regular vs premium when premium is required.
http://www.myride.com/lifestyle/feat...120-page1.html
I suspect some marketing monkey business. Selling the Toyotas they know a premium gas requirement will cost them sales. So they design it to run on regular and specify that. Selling the luxury brand they figure specifying premium will make the buyers think they are getting a higher performance vehicle, and will INCREASE sales.
I already understand the points in the article you referenced...
"For those who drive cars designed for regular gas, you most likely will be throwing away your money by using premium -- stick with regular. For those with cars that require or recommend premium gas, you will be doing yourself a disservice by using regular. You need to use premium to achieve the rated power and the maximum miles per gallon."
But my point is I'm questioning whether the Lexus actually does require premium. It appears it's the same engine used in two different cars, achieving identical power in both cars, but one requires regular and the other premium. Therefore if the Toyota achieves rated power on regular, why not the Lexus? I was hoping someone could provide a logical explanation why the Lexus requires premium to achieve rated power but the Toyota does not.
#39
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"The 3.5 has the best performance on premium"? The point is the Highlander and Lexus engines appear to be identical and both get the SAME performance (HP and torque, at identical rpm's) even though one burns regular and one premium. That defies logic.
I suspect some marketing monkey business. Selling the Toyotas they know a premium gas requirement will cost them sales. So they design it to run on regular and specify that. Selling the luxury brand they figure specifying premium will make the buyers think they are getting a higher performance vehicle, and will INCREASE sales.
I already understand the points in the article you referenced...
I suspect some marketing monkey business. Selling the Toyotas they know a premium gas requirement will cost them sales. So they design it to run on regular and specify that. Selling the luxury brand they figure specifying premium will make the buyers think they are getting a higher performance vehicle, and will INCREASE sales.
I already understand the points in the article you referenced...
"For those who drive cars designed for regular gas, you most likely will be throwing away your money by using premium -- stick with regular. For those with cars that require or recommend premium gas, you will be doing yourself a disservice by using regular. You need to use premium to achieve the rated power and the maximum miles per gallon."
But my point is I'm questioning whether the Lexus actually does require premium. It appears it's the same engine used in two different cars, achieving identical power in both cars, but one requires regular and the other premium. Therefore if the Toyota achieves rated power on regular, why not the Lexus? I was hoping someone could provide a logical explanation why the Lexus requires premium to achieve rated power but the Toyota does not.The best thing to do in my opinion is go by what the vehicle manual recommends.
As far as the soccer mom RX or the ES350,I believe having those models require regular would not hurt sales.In fact,I believe sales would go up a bit.
Cadillac's 263 hp 3.6L requires regular fuel as well as the $42K 368 HP Hyundai Genesis.
Last edited by Joeb427; 09-13-08 at 06:58 AM.
#40
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Could be 3 different dyno tests... and 3 results. If you take the same model engine and take 10 of them off the assembly line and run dyno tests, you are not likely to get the same exact results for all 10. There will be some variability.
#42
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The very small differences in HP and torque you listed for the different Toyota 3.5's could be due to the above.
#44
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"If you check consumer reports, they will tell you to run other gas. We do question Lexus about this and they say you will get better mileage and performance with the premium gas."
Sorry, but that sounds like BS to me.
Facts:
- The Toyota Highlander and Lexus RX-350 have the same engine.
- The Highlander 4WD weighs 4321 lbs and gets 17/23 mpg with REGULAR
- The RX-350 AWD weighs 4090 lbs and gets 17/22 mpg with PREMIUM
But according to Lexus if I run the same gas in the RX-350 the mpg and performance will suffer?
That makes no sense.
Hence my suspicion this is all about marketing.
As an engineer I need a better explanation than what I've been seeing as to why the RX-350 needs to run premium. None of what I've seen so far makes logical sense.
#45
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Just use 87 and be happy.
My RX is leased.
I use 89 and an occasional 93 fill.
My GS is a purchase and I use Shell 93.
Don't tell me you would use 87 in a GS.
Even you wouldn't.
There isn't a Toyota model with the exact same engine.