xspsi6

iTrader: (31)

Oh wow! I honestly can't believe this thread so go ahead and argue your misinformation all day and I will just leave it at what I posted before

Oh and btw I cut 1.59-1.65 60fts everytime out and run high 10's everytime out so fyi it hooks

JamesBond1

How can it be misinformation if the information is from the Lexus ES300 book/manual? Just saying.

Great, I’m really happy for you. Just don’t kill yourself because I can just imagine how much you tuned your car

Ahaha. Alright, we'll just leave it like that

p.s....It was nice to meet you!

adreano17

because you are pushing that much HP from a supra, it clearly has to be tuned and modded. of course you cannot run 87 on a modded car, because with modded parts, you will really kill your car. 91 oct is for performance, therefore it does need it. any way, you cannot hurt your car if higher octane is used. it is just wasting money in some cars, but if the manual says what you can do, you cannot dispute the engineers. i run 87 in my stock, and i used to run 91. its barely any difference. if you are a racer like yourself, invest in sunoco racing fuel. but us here....in the es department can do 87 (cost efficient), 89, or 91 (slight increase in stock power). just my 0.02 cents worth.

BoostedE21

For any new people reading this thread, Don't listen to Supra guy. He's undermining calculations and parts designed by hundreds of engineers that get paid hundreds of thousands of dollars for something that he learned "tuning his supra."

When I work with Megasquirt, I tune the ECU to run at a specific octane rating, usually 93 or 110. So the car, at that point, is "designed" to run at that octane level. Anything less or anything more, and it won't run properly. Because I only tuned it to run at one exact octane level. There's no flexibility, because I don't want it - I just want to run one type of fuel, so I don't have to tune it for multiple and install the respective sensors to detect it all. I'm sure he does the same with his Supra.

The stock ES, on the other hand, has knock sensors that help allow the engine to change the timing as necessary to account for different octane levels. It can adjust way more than necessary in both directions. Consider that the programs used in the ES ECU are the same ones used in Toyotas all over the world, including places like Venezuela, which is known for having some of the lowest octane gas (and lowest prices) in the world. And they run fine there. Granted, it does cut back power - but it can account for it.

Since it's all digital, the computer can adjust timing on a huge scale to account for bad fuel or excellent fuel. It's not inflexible, as that guy seems to assume.

JamesBond1

Very well said BoostedE21! That is what I wanted to say too I just have a hard time trying to explain it, however, you explained it brilliantly

12340987

"Premium" fuel is for "premium" cars with "premium" prices. High compression engines do require high octane fuel to prevent detonation, but those are rare. Manufactures will state a car produces more horsepower (and mileage) just because they use premium fuel for the rating. Premium can increase gas mileage and appears to increase power, because you can have a leaner (more efficient) burn.

xspsi6... What is it you do to the ECUs exactly? Leaner burns = cleaner burns, how would that increase carbon deposition?

Go to lexus.com and toyota.com. The 2011 v6 Camry and 2011 ES350 have identical drivetrains (Unless that has changed recently.), yet the 350 produces 5 more HP. Why? The fuel grade.

What would be nice is to pay attention to MPG every time you get a different tank of gas, and figure out if it's really worth it. I've posts that say the increase in mileage actually saves $1-$3 per tank.

Brockton

I just bought a 2008 ES 350.

Based on these forums, thew first thing I looked for in the manual was what gas grade to use.

Answer in the manual: 91.

R1R

Actually, the 2011 ES350 now has a new fuel recommendation of 87 octane, and now produces 268 HP, the same as the 2011 V6 Camry. But your were correct, the fuel grade use to make up the 5 HP difference. I think it was a smart move by Lexus to make the change, as it lowers fuel costs for their owners.

Brockton

http://www.edmunds.com/advice/fuelec...3/article.html

http://www.scientificamerican.com/ar...tion-premium-g

http://www.consumerenergycenter.org/...s_premium.html