type of gas??
Driver
Joined: Aug 2005
Posts: 155
Likes: 0
From: WA
the premium does give you two to three mpg more so it is a wash cost wise, you will feel more power in the ICE, with premium some of us have felt more abruptness when the ICE kicks in, its not as smooth as with regular gas. dont know why.
Rookie
Joined: Aug 2004
Posts: 97
Likes: 0
From: AZ
I've been putting regular in my car for the last 10,000 miles and it runs great. The dealer never mentioned putting premium gas and i never noticed until a couple weeks ago that it recommends premium. I'll probably either start using 89 or just jump back and forth between regular and premium. So far no issues.
Ken
Ken
Out of Warranty
Joined: Aug 2001
Posts: 14,925
Likes: 13
From: Houston, Republic of Texas
ICE = geekspeak for "Internal Combustion Engine" 
Good point here - I've been running premium (93 octane) in my 330 since I discovered it solved occasional shifting roughness and improved engine response slightly. The problem, I was told, was the Engine Control Computer's spark advance curve was mapped for premium fuel, and that is the "default" setting the engine adopts on heavy acceleration. When the knock sensors detect the first signs of "spark knock", the ECC dials back the spark advance to accommodate what is taking place in the engine. This is very brief, only a revolution of so, but occasionally just enough to confuse the transmission as to what is being asked of it . . . hard acceleration . . . lift throttle . . . hard acceleration - sometimes causing a rough upshift.
Now, with the CVT in the 400h, you'd think this situation would never occur - unless the CVT is capable of changing ratios rapidly enough to interrupt the flow of power. Because the Continuously Variable Transmission has no “gears”, this perception of a lift-throttle condition – particularly near a shift point – could never happen since no “gear change” is taking place. If so, you'd think that hybrids (or any vehicle with a CVT) wouldn't benefit significantly from premium fuel at all.
Does this represent another savings of hybrid technology – cheaper gas?
Good point here - I've been running premium (93 octane) in my 330 since I discovered it solved occasional shifting roughness and improved engine response slightly. The problem, I was told, was the Engine Control Computer's spark advance curve was mapped for premium fuel, and that is the "default" setting the engine adopts on heavy acceleration. When the knock sensors detect the first signs of "spark knock", the ECC dials back the spark advance to accommodate what is taking place in the engine. This is very brief, only a revolution of so, but occasionally just enough to confuse the transmission as to what is being asked of it . . . hard acceleration . . . lift throttle . . . hard acceleration - sometimes causing a rough upshift.
Now, with the CVT in the 400h, you'd think this situation would never occur - unless the CVT is capable of changing ratios rapidly enough to interrupt the flow of power. Because the Continuously Variable Transmission has no “gears”, this perception of a lift-throttle condition – particularly near a shift point – could never happen since no “gear change” is taking place. If so, you'd think that hybrids (or any vehicle with a CVT) wouldn't benefit significantly from premium fuel at all.
Does this represent another savings of hybrid technology – cheaper gas?
Pole Position
Joined: Oct 2005
Posts: 373
Likes: 5
From: WA
A word of caution about fuel ....
Our nearly new RX400 supposedly got a batch of bad gas that gummed up the fuel injectors .....
https://www.clublexus.com/forums/sho...d.php?t=200500
The dealer took care of us, but cautioned us that RX400h fuel injectors are sensitive to poor quality gas, and suggested regular (every 3 months) use of a quality fuel cleaner additive (Redline or Techron).
Our nearly new RX400 supposedly got a batch of bad gas that gummed up the fuel injectors .....
https://www.clublexus.com/forums/sho...d.php?t=200500
The dealer took care of us, but cautioned us that RX400h fuel injectors are sensitive to poor quality gas, and suggested regular (every 3 months) use of a quality fuel cleaner additive (Redline or Techron).
Lexus Champion
Joined: Jan 2003
Posts: 2,754
Likes: 6
From: Colorado
Just about any brand of gas will do. Do visit a clean and high volume gas station whenever possible. Don't go to the rusty country stores with old fashioned pumps for gas. If the pump does not take credit card, it's too old. Move onto the next station.
My RX started out on mostly ExxonMobil, then BP, now 7Eleven/Citgo. Regular only. I go with whoever gives me the best rebate on my credit card.. now at 5%.
My RX started out on mostly ExxonMobil, then BP, now 7Eleven/Citgo. Regular only. I go with whoever gives me the best rebate on my credit card.. now at 5%.
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i just use regular...no need to put anything higher...i believe premium is mostly for older cars so the engines run more smoothly...but luxury cars require it so it allows the engine to last longer...i think...heh
Driver School Candidate
Joined: Apr 2006
Posts: 7
Likes: 0
From: Texas
As far as I know using premium will give all the advertised HP if you use regular performance will sufer but not to the point you will probably notice, most people dont and continue using regular.
Its my understanting that it takes several fill up's of premium to reset the computer to max performance..
Its my understanting that it takes several fill up's of premium to reset the computer to max performance..
Driver School Candidate
Joined: May 2006
Posts: 7
Likes: 0
From: IL
I noticed that going from 87 to 93 octane reduced the "rough" transition from battery to gas and back to battery. I'm not sure if it's something related to knock sensors or just my imagination, but it has me convinced to stick with higher octane.
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