Regular Unlead Gas On Rx400h

[vaboy]

Has anyone use regular unleaded gas on the rx400h? How was the performance?

[Better Luck]

Has anyone use regular unleaded gas on the rx400h? How was the performance?

I buy my gas fr either Costco or a local chain WaWa. I have had the car since November and have used premium only two or three times. I find no difference in either performance or mileage. I would doubt there will be any long term effects from using regular but I am not a mechanic. My avg fuel economy on my normal routine seems to be about 24-25 MPG. My typical tank involves two or three 35 mile hwy trips and local driving in suburban traffic and two-three reverse commutes with stop and go traffic. Does that seem typical?

[SOMEONE ELSE'S GOT MY NAME]

Has anyone use regular unleaded gas on the rx400h? How was the performance?

The search tool is a wonderful thing :P

The topic usually goes like this: Yes, the book sez regular is fine. The book sez primo is fine too. The book sez that high test usually yields sufficiently better mpg's to offset the higher cost. The posts then indicate, "your results may vary".

btw, welcome to the group!

what year is your 400h?

[Gryphon]

I am approaching 20,000 miles in my RX400h and plan to switch from premium to regular fuel for a 5000 miles comparison.

Tom

[hwilke01]

Tom- how did your comparison go? Did you find a difference in the higher/lower grades as far as fuel economy goes?

Hal

[katzjamr]

I find more power with premium fuel and a 2 to 3 mpg increase over regular that can justify the cost. This was an extensive topic when our cars were new some thought a 'green' vehicle should be able to run on regular. It does, however not as well as premium. It will take three tanks of one fuel or the other for the difference to be noted, you cannot just switch one tank and use that as a reference. I am a general fan of costco, (not the tire dept) however none of my vehicles run well on their regular fuel, even my older trucks (designed for regular) start to missfire after a few tanks, dont ask me why. I have used costco premium in my 400h with no problem. Also if you search there was a post by an automotive engineer who felt that our toyota engines were made to run on premium and performed optimally with that fuel. He called it a 'sweet spot'. Those are my real world experiences after 73,000 miles on a 2006 400h, of course each person will have to decide for themselves.

[RX400h]

Initially, I would switch from regular during the colder months and mid-grade during the warmer months, but lately, I have been running mid-grade almost exclusively. I find that it provides a very good balance of power and economy. (saves me enough to buy a couple of coffees, too)

Keep in mind, though that due to the higher density of intake air during cold Ambient conditions, running regular gas is similar to running premium gas during warmer ambient conditions. Those who live in cold winter climates may be wasting money by buying premium fuel during that time of year.

[riwyle]

Similar regarding what? Maximum power available? Could you expound on this? At first thought, it seems it would only apply at WOT, which I doubt I have ever had to apply to my vehicle.

Cheers,

R Wyle

Initially, I would switch from regular during the colder months and mid-grade during the warmer months, but lately, I have been running mid-grade almost exclusively. I find that it provides a very good balance of power and economy. (saves me enough to buy a couple of coffees, too)

Keep in mind, though that due to the higher density of intake air during cold Ambient conditions, running regular gas is similar to running premium gas during warmer ambient conditions. Those who live in cold winter climates may be wasting money by buying premium fuel during that time of year.

[RX400h]

....not simply more maximum power,but more power throughout the rev range. This is why more and more vehicle designers are incorporating CAIs (cold air intakes) into their engine/engine bay designs: Colder air = more horsepower. Of course the extra horsepower is likely to be "felt" at wide open throttle conditions.

[cduluk]

When i had my Rx300 there was a significant difference in acceleration ability when going one month at regular and the next at premium. I eventually stayed with premium and have used it exclusively in my Rx400h (minus one 1/4 tank full the day i was really low on gas and only had a $20 to get me home).

I also read that premium fuel can save some engine parts such as sensors and what not...

[Jim Nazium]

I have tested Regular Unleaded (not the 10% mix stuff) and the Mid as well as Super Unleaded, under the same conditions (temperature, driving conditions, traffic, route etc), and over the same span (when I purchased the vehicle, and again a year later) on two separate occasions... found on a consistent basis that Regular Unleaded gave me results of 2-3 mpg greater efficiency.

I drove at least ONE tank of gas, per fuel type. Made sure to operate the vehicle in an identical manner (with AC off, didn't require it, nor with the heater running), and after each fillup I went through the tedious ISC Reset procedure.

Time and time again after that, when I had the chance to purchase fuel on sale (LOL, it happens, but not often and only the Super Unleaded stuff) driving for long stretches (like a trip of 6 plus hours) I had a reference point when taking a trip in one direction and driving back home along the same route. The Regular just delivered better gas mileage.

The bonus, is you get to save a bit too at each fillup, so why pay for the Octane (that's really, why, Super Unleaded Costs more, not because it is refined or of better quality) when the 400h does not take advantage of it.

Cheers,

MadloR