Don’t know if this has been posted or even if these guys are legit. Have at it.
FAQs | D.A.P. Tuning
FAQs | D.A.P. Tuning
LX570 Premium required (1 Viewer)
- Thread starter SWUtah
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
This is exactly what I allude to in all these octane threads.
The main difference I see here is the LX says “for optimum engine performance”, whereas the LC does not.
It also says "use of unleaded fuel with an Octane Rating lower than 91 may result in engine knocking or drastically reduce output to protect itself while driving with a heavy load. Persistent knocking can lead to engine damage..."
I don't think many would reveal they've shot themselves in the foot and destroyed their engines because they tried to save a penny. This could very well be a case.
I'm not aware of any OBD codes for fuel octane...not that it matters. Since I've been here for a while with both 200 and 100 Series trucks, I'd note that I've NEVER seen a thread or post here about regular gas in a premium "required" vehicle causing an issue. I'll qualify that by noting I'm writing about naturally aspirated engines...i.e., no turbos, no supercharges, no nitrous injection.
Do you know of an instance where octane used has caused an engine issue? Or is this just another maybe, could be, or might be maybe exercise.
Off topic, imo finding no-ethanol v. ethanol is more important than finding 91 v. lower octane.
Last edited:
They lost me with two "weathers"
I bought the LC instead of an LX in part over the premium fuel requirement.
I think running regular in an engine with an ECU set up for premium (different timing) would have more impact at higher altitude. If you are closer to sea level, not such a big deal. If you live at a mile high (or half a mile...) you might actually get that knocking. If you try regular and don't get knocking you are probably okay.
Edit: someone pointed out that I've got it backwards, and they're right. You can use lower octane fuel at higher altitude with less knocking because the air is less dense so you get less compression in the cylinders. Sorry to have caused confusion.
I think running regular in an engine with an ECU set up for premium (different timing) would have more impact at higher altitude. If you are closer to sea level, not such a big deal. If you live at a mile high (or half a mile...) you might actually get that knocking. If you try regular and don't get knocking you are probably okay.
Edit: someone pointed out that I've got it backwards, and they're right. You can use lower octane fuel at higher altitude with less knocking because the air is less dense so you get less compression in the cylinders. Sorry to have caused confusion.
Last edited:
- Thread starter
- #28
Damn first helpful post I’ve gotten yeah I’m in Jacksonville at sea level I basically cruise around on these smooth level streets no hills at 40 to 45 miles an hour I like what you’re saying thanks!!
Interesting but in most places at altitude in the west i run 85 octane gas because that’s what they sell. Again, zero issues over literally hundreds of thousands of miles.
Old engines with advance timing, lower octane and no knock sensors goes kaboom!!! New engines with knock sensors retard timing, you get less power and engines don’t go kaboom. It’s just science, octane ratings are there for a reason... I challenge anyone who runs 87 to remove their knock sensor and see what happens to their engine running 87.
We should have 2 stock lx570’s with the same tires and the same year drag race. one on 87 and one on 91.
then we should go dyno those 2 exact same lx570’s. it would be a cool science experiment and we can settle this once and for all scientifically.
We should have 2 stock lx570’s with the same tires and the same year drag race. one on 87 and one on 91.
then we should go dyno those 2 exact same lx570’s. it would be a cool science experiment and we can settle this once and for all scientifically.
Last edited:
Makes sense to me!
IIRC, the HP difference between the Lx and Lc is three (3) (380 v 383)
So, with regular in an LX you might knock long enough for the ECU to compensate by adjusting the timing to what the LC comes with and then you'll have 3/383 less HP which is roughly a loss of >1.0%.
I suppose the only caveat is "as long as your knock sensor is good."
To answer OPs question: regular wont harm your LX engine because of the miracle of technology and shouldn't void your warranty. If you get some knocking and/or a check engine light with a knock sensor code, switch to premium and get it fixed.
Glad we could work through this together!
Last edited:
Except it's actually backwards. You can get away with running lower octane at higher altitudes than at sea level.
I'm not aware of any OBD codes for fuel octane...not that it matters. Since I've been here for a while with both 200 and 100 Series trucks, I'd note that I've NEVER seen a thread or post here about regular gas in a premium "required" vehicle has caused an issue. I'll qualify that by noting I'm writing about naturally aspirated engines...i.e., no turbos, no supercharges, no nitrous injection.
You are right, I edited my post. Lower octane at higher altitude may not even cause knocking since you get less compression.
I run regular with no issues in Denver CO.
Let me help with another key detail.
In order for a knock sensor to work, it means it has detected knock.
An ECU will continue to probe back to its baseline timing, only to experience knock again. This is why baseline calibration for octane matters and one doesn't want to ride the knock sensors to maintain retarded timing.
No amount of knock is ever good. Rinse repeat. It's only a few hp lost. Until it's not because of carbon buildup and microscopic wear, which furthers the likelihood of knock events and degradation. These don't generally result in catastrophic failure with modern ECU tuning. Rather gradual losses of compression, performance, headgasket failure, even catalytic converter wear.
Ever lookup the prices of catalytic converters? To save bucks at the pump?
Threshold and tolerances stack. One might be unlucky enough to be towing a heavy load, bad batch of 87 (which is less than 87 octane), on a super hot day, with a compromised engine run on a lifetime of junk food. The engine may very well have a catastrophic heart attack. Your doctors recommendations, like Toyota's, are guidance to help you last a lifetime.
Toyota has already taken care of that for you...the difference it makes is 3 horsepower...no "you-know-what's" given.
See below...If your knock sensor(s) are not "good", you get a CEL and I'd assume you'd fix the issue.
Assuming all of that, I still have yet to see a blown engine due to octane in an LX or Cruiser here or anywhere else. You're saying a 3 hp difference in a truck is in the same category as a Doctor's recommendation. Seriously?
This argument is funny to me nobody argues 5w 30 oil vs 0w 20 oil... why don’t we just put different weight oil in then what the engineers recommends. Or why don’t we put in hydraulic brake fluid in the ahc resovoir instead of actual ahc fluid.
why don’t we just pick a random tire pressures instead of the one that is recommended. Will your tire blow up? If it’s under inflated or over inflated maybe? Maybe not, But it will wear all funky..
engineers recommend things for a reason we can question them all day long. I just find it comical that us common folks who didn’t design these things are smarter than toyota engineers who make the most reliable cars in the world
engineers may recommend max payload on a truck is 2000lbs why don’t we ignore it and put in 4000lbs it’s fine it’s not going to ruin the suspension
if your tow rating is 8200 why not tow 12,000 lbs the 5.7 liter can tow a space shuttle after all.
how many land cruisers out there have the driveline thunk? It’s recommended to grease the driveline but I guarantee you there are thousands upon thousands of land cruisers that never get their drive line greased... are they all breaking? No, but they sure aren’t as smooth as when they were new.
bottom line put in 87 if you like. The 5.7 is a tank. It’s not going to blow up.
Toyota recommends 91 in the Lx570 if you are inclined to follow toyota engineer specifications. then put in 91...
honestly has anyone, anyone at all had an engine failure on this forum??? The 5.7 is a tank
why don’t we just pick a random tire pressures instead of the one that is recommended. Will your tire blow up? If it’s under inflated or over inflated maybe? Maybe not, But it will wear all funky..
engineers recommend things for a reason we can question them all day long. I just find it comical that us common folks who didn’t design these things are smarter than toyota engineers who make the most reliable cars in the world
engineers may recommend max payload on a truck is 2000lbs why don’t we ignore it and put in 4000lbs it’s fine it’s not going to ruin the suspension
if your tow rating is 8200 why not tow 12,000 lbs the 5.7 liter can tow a space shuttle after all.
how many land cruisers out there have the driveline thunk? It’s recommended to grease the driveline but I guarantee you there are thousands upon thousands of land cruisers that never get their drive line greased... are they all breaking? No, but they sure aren’t as smooth as when they were new.
bottom line put in 87 if you like. The 5.7 is a tank. It’s not going to blow up.
Toyota recommends 91 in the Lx570 if you are inclined to follow toyota engineer specifications. then put in 91...
honestly has anyone, anyone at all had an engine failure on this forum??? The 5.7 is a tank
I doubt engineering had anything to do with it. Knowing this industry (having spent years at Toyota, Nissan, GM, and Ford) I would expect this is all due to Marketing. A premium car like a Lexus requires a premium fuel. Happens all the time.
