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Can I just change grades of gasoline? - READ ONLY

21 messages,  Last post on Apr 06, 2002 at 9:08 PM

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What is this discussion about? Toyota Corolla, Engine

Messages Page 1 of 2

#1 of 21 change gasline by tonfada

Apr 02, 2002 (1:26 pm)

I am NOT a mechanic by any means, so please stay with me.
Since day 1, I have been feeding my Toyota Corolla (in the year of 1999, and I bought the brand new one.) with super gasoline (93), and I didn't realize that the car only needed regular gasoline (89) to run until last week. To save money on the gasoline, can I just switch the gasoline from 93 to 89? Or is it ok to switch it to regular gasoline? If ok, what do I have to do particularly to avoid any problems? Please let me know... Thank you.
 
James

#2 of 21 by Mr_Shiftright HOST

Apr 02, 2002 (1:33 pm)

Actually 89 octane is not "regular", it is often marketed as some type of mid-grade. Most regular I've come in contact with, on the West coast anyway, is 87 octane, which may not be enough for your car.
 
But sure, just put in what the manufacturer says, no problem, and save yourself some money, too.

#3 of 21 More than likely, 87 will work - by zueslewis

Apr 02, 2002 (1:45 pm)

check your owner's manual and follow the recommendation. Using anything but what is recommended does nothing for your car, only deflates your wallet.

#4 of 21 87 will work by arkainzeye

Apr 02, 2002 (6:15 pm)

i have the same car as you.. i have only used 87 octane. When i was in college i had a instructor that told me a story about his brother going to Penn State for chemical Engineering. and they had a lab project on gasoline. To make a long story extremely short. there was no real difference in the higher grade gasoline. Now if you have a high compression engine. "which you dont" then i could maybe see using 93-94 Octane. but other than that you'r just wasting money. i used high octane in my corolla and seen no difference in proformance. and the same thing went for my chevy tracker, ford rangers etc etc/
now if i maybe had a sports car, then i guess i may see a difference.

#5 of 21 The reason is that by zueslewis

Apr 02, 2002 (6:44 pm)

your ECM can't "read" any difference in octane, so no performance differences are seen. On a Corvette, for instance, 91 octane is required - if you use 87, it will run like junk. The ECM senses worse octane, not better, through several sensors.

#6 of 21 I... by britton2

Apr 02, 2002 (7:09 pm)

have a '01 Corolla - sometimes I put in 89 octane as opposed to 87 - I get about 2 more MPG using the 89 -

#7 of 21 There are other driving by zueslewis

Apr 02, 2002 (8:15 pm)

conditions contributing to your increased mileage - the octane difference is not capable of making that change - I mean no offense. There are many factors that effect gas mileage.

#8 of 21 britton2 by shipo

Apr 03, 2002 (7:51 am)

Unless your car has an upgraded ECM, it is more likely that you will see worse mileage with 89 than with 87. Also, unless an engine has either enough compression (the Corolla does not) to cause a hot enough burn, or the ECM is capable of firing the plugs early (unlikely, unless you changed your ECM), your engine will likely develop extra deposits in the combustion chamber and on the valve stems.
 
No matter how you slice it, you are better off using 87.
 
Best Regards,
Shipo

#9 of 21 Right on, shipo - by zueslewis

Apr 03, 2002 (8:28 am)

that "richer" fuel causes more gunk collection - bummer.
 
Weird question - I have an '88 Suzuki GSX-R 750 with a Keihin Flatside carb conversion, Yoshimura Carbon Fiber Duplex Exhaust, etc. Am I right by running the highest octane I can get? It's not injected and has no ECM, so wouldn't better fuel make a difference, quite contrary to injected and emissions controlled cars?

#10 of 21 I tried by krzyss

Apr 03, 2002 (8:47 am)

to find compression ratio for 1.8 VVT-i 130 HP engine in Corolla and I can't. Toyota does not believe that it is important information.
I suspect that it is high compression engine and using higher octane fuel gives you better milage.
 
Krzys
 
PS Manufacturers often say that engine requires regular gas but HP numbers are obtained using higher grade. Of course ECM (the computer, which controls engine) must be able to utilize higher grade.
 
PS2 Yes you can use the lowest suggested octane any time you want and if it is not available you can use higher or lower (I would suggest higher . ECMs are quite clever nowadays.

Messages Page 1 of 2

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