crazymikie

It certainly won't hurt anything. You could try it for a couple of tanks and see if there are any differences in power or fuel economy. Maybe try a mix of 94 and 91 and find the ideal ratio where you get diminishing returns on power.

Since most of the US doesn't have 93 at the pump, and only get 91, I think the car will be fine.

Sullen0313

ford has had a fairly large issue with the e85 fuels in quite a few of their vehicles, though most notably the explorer. the explorer has an aluminum block on the drivers side frame rail that the fuel lines come into and go out of. it is there to determine when e85 has been added to the fuel, and help switch the ecu into a e85 mode. this is because e85 requires more fuel than gasoline. anyways, these blocks corrode from inside, and split open, causing a no fuel pressure situation.


so IMO, in a performance scenario, i love e85. it allows much higher boost levels to be achieved. but you must upgrade your entire fuel system to handle the e85. in a DD scenario, i honestly don't like it. it can cause way too many problems since most fuel systems have aluminum in them somewhere.

jkeifer3

I don't think adding ethanol makes anything cheaper as I don't trust the oil companies to pass along any potential savings to the consumer. In fact, adding ethanol only drives the price of corn (and corn products) higher.

7No

iTrader: (1)

Korn and ethanol.

Sullen0313

e85 additive honestly only makes gas more expensive. i can find it here and there without, and it's generally about $0.05 cheaper than with it.

IS350atWOT

iTrader: (1)

On pure gas, I got a smidge worse (about .5 mpg). On my first tank back on e10 though, I'm getting the best ever. I think I may set a record.

I bet you're right. I'm getting way too good mpg's right now (about 27). I bet it's just relearning the fuel.

lobuxracer

iTrader: (2)

This advice is a time waster. The engine was designed to run on California's crappy 91 with oxygenates (read ethanol), so there is zero advantage to running 94 and zero advantage to mixing them. Some of our California members actually have better mileage than those of us with 93 at the pump.

crazymikie - You must live in (or near) California. Most of the rest of the country DOES have 93 at the pump. Just one of the small reasons I left The People's Republic of California for Georgia four years ago. The Supra loves it here, and got a miserable 12 mpg on Cali's crap 91 even after running pure distilled and Red Line Water Wetter for coolant (this made 92 tolerable and maintained my normal 18 mpg).

Your fuel trim on ethanol-free fuel will fix itself for short term pretty quickly. It's the long term fuel trim that hurts you - it takes awhile to sort itself out. I suspect you got LT headed in the right direction, then switched back to ethanol and leaned out just a little, so you're seeing the impact of a leaner mixture (closer to ideal than factory) because factory maps run a bit rich to protect the engine against bad fuel or a minor fuel system failure. They'd rather run a little rich than buy you a new engine because it ran too lean.

crazymikie

Wrong on both counts. I live in MA (and we have 93 here).

Also, and as far as it being a time waster, I disagree. Since no one has hacked the ECUs in these cars yet, no one knows how they work. I can tell you in Subarus, there is a global scalar which can pull back timing across a broad range of load/rpm sites in the maps. If an inferior fuel is used in the car, it will adjust the global scalar to compensate for it (like the case with CA fuel). In fact, it wasn't uncommon for turbocharged Subaru motors to audibly knock after resetting the ECU while running inferior gas, while the ECU was relearning and sorting everything out.

I don't know the quality of fuel in BC, but if someone is interested in trying, it can't hurt. I don't think there will be tons of power to be made, but if anything, you would probably notice it up top, under WOT. This is where timing is most advanced (you have to start flame propagation earlier to compensation for the shorter window to try and achieve complete combustion) and cylinder pressures are the highest so unstable fuels are more susceptible to pre-ignition.

Just because it will run on CA 91, doesn't mean it will run ideally.

IceIridium

iTrader: (2)

So Lobux, in your opinion, there would be no difference if I use either 91 with ethanol or 94 without ethanol? If not, I'm going with 91 cus it's cheaper! (by about 3 cents/L. )

lobuxracer

iTrader: (2)

You're letting your misunderstanding show. There is a LOT of knowledge about how the ECM works. There is just no knowledge of how to change it.

No, you are polar wrong about advance. At WOT, you are at MINIMUM advance because the cylinder pressures are very high and flame propagation is at its best. Advance compensates for rpm and for lean mixtures at part throttle. Way back in the days of mechanical devices you had two elements to timing - centrifugal advance to compensate for the reduced time of each cycle as rpm increases, and vacuum advance to compensate for engine load. The greatest advance is actually under high vacuum (part throttle) and can exceed 65 BTDC degrees in some engines. The best engines have very little advance because their combustion chambers don't need it.

I can also tell you from direct experience, too much advance kills pistons. Quickly. When I tuned bike engines, I always looked at retarding the timing from the factory setting because I was always increasing compression which meant I needed LESS time to get to peak pressure (which needs to happen 7 degrees ATDC no matter how you slice it). Adding timing means there is some other problem you're failing to address - like lighting the mixture before it auto-ignites which couldn't possibly be the best thing for any engine.

Finally - Please read carefully - Lexus DESIGNED the engine to run on 91 octane. Unlike the 2JZ which was designed to run on 93 and ran like total crap on 91, the 2UR-GSE was intended FROM THE FACTORY to run on 91 octane. If this were not true, the California members would be posting about their horrible gas mileage. They're not, because the configuration delivered by Lexus works AS DESIGNED on California's crappy fuel.

It would truly be a marvel if we could get a tune for 93 octane and more aggressive cam timing to take advantage of better fuel, but all the OEMs use California fuel as their design standard because it's the worst stuff available and also the largest market for cars in the US.

7No

iTrader: (1)

91 works fine here in CO too.

crazymikie

I should have been clearer- if you were to start at 2000 RPM and floor it and pull all the way up to redline, advance should drop until peak torque and then will slowly advance as the efficiency of the motor and cams drop off. You could run flat timing all the way up to redline, but you'd probably be leaving power on the table. My point was that of all of the places the car would likely be pulling timing, up top, at WOT would be the place it would be most noticeable, if at all.

Absolutely agree. Timing is a crutch for poor volumetric efficiency. On boosted motors, I would gladly run another pound or two of boost before resorting to using timing to make power. You end up getting sharper spikes in cylinder pressure by advancing timing more and more. And yes, once you add more boost or lean out fueling, I'd agree that you'd definitely need to remove timing. When I had my Subuaru, I was running water/meth/nitromethane injection, which happily supported around 25 PSI on a 16g turbo on a stock motor for almost 80k miles. I pulled that motor to put a JDM spec motor in there with a larger turbo, but even at 80k miles, the compression was almost factory-new numbers. The timing I ran on that motor was just enough to keep EGTs in check.

My point was not all 91 octane is the same and sometimes OEMs don't account for what CA peddles as 91. If you look at some of the aftermarket reflashing tools, the will have separate mappings for CA/NV 91 since it's worse than the rest of the country. And, yes the OEM configuration works, but the question is could it work BETTER on their fuel. If someone were curious to try, I'd be very curious to see the results.

IS350atWOT

iTrader: (1)

Just so everyone knows, the ethanol-free and e10 gas I used in my little experiment were both 93 octane. Most name-brand stations around here like Shell, Exxon, and Citgo jump from 89 mid-grade to 93 premium. They don't have a 91 grade. 91 is usually found at "discount" gas stations like Wal-Mart and Valero. I like 93 because I get about 1 mpg better on 93 octane vs 91 octane. But I would think it could also be the quality of gas rather than the higher octane rating that yields better mpg.

d1trainee

iTrader: (2)

The only problems i see with runinng e10 is that E85's stoichiometric value being 9.765:1 and 91's stoichiometric value being approx 14.5:1. Basically, in my head, that means it takes a higher volume of ethanol to run an engine. so essentially, again in my head, 10%E in my 91 is like a watered down drink. If 91 is available for the same price as e10 i would go for 91oct.

IceIridium

iTrader: (2)

Okay I filled up with 91 octane with "up to 10% ethanol" at Chevron and have been driving with it for several days now. Here's my impression so far.

I can't wait to get rid of this **** and get back in my 94!!!

Regular mode feels fine. But Sport mode feels like 1/2 Sport mode now. It certainly lacks that extra "kick" it had before even at slight throttle. Before, if I was in heavy traffic I had to make sure Sport mode was off because if I wasn't careful I'd suddenly lunge towards the car in front of me but now I can have Sport mode on all the freakin' time.

No idea if it's the ethanol doing it or the octane rating, but it sucks.

Now I just hope that after I burn off this crap and fill up 94 the computer will correct itself back and it will be fun again....