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Sc400 Premium Fuel?


Skizz

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you can run lower grades, but the car itself is tuned for 91, and a lot of lexus owners have had problems with poor idle, acceleration and all around performance when running lower grade gas.

It'll run on mid-grade and even regular but you'll notice a performance and a fuel mileage drop off. Don't know about you, but I would only do it in an emergency because I wouldn't want the performance deficit (hey, thats what these cars are all about!) and I certainly wouldn't want to run the risk of damage a steady diet of regular (for example) might pose to my car. If you're looking to save money, its most likely a very dubious investment to make.

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The way I understand this, your high compression car will protect itself from pinging when run on lower grades by retarding the spark when it detects knocking. If your knock sensors are not working, your car may not have this protection. That could cause damage to rings, pistons, rods, etc.

I could be wrong but I don't want to take that chance.

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Hi all,

I know the car says premium fuel only.

I was wondering if you can get away with mid grade or even regular.

Is this a performance issue? Or will it actually do harm to the car?

Thanks!

Your choice of words are in conflict with your choice of cars. In choosing a Lexus, you should not be thinking of "getting away" with anything. These are beautifully designed and engineered cars. There are many owners who mod their cars. That usually means an increase in performance in some regard, not a decrease as you are suggesting. My advice is, unless you plan to mod your car, stay with the oem specs.

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When fuel was up around $4 a gallon I tried "cheapin out" , not a good idea, engine started being fussy, missing, funky idle, poor acceleration. Ended up costing more in the long run, because I had to spend for a bottle of octane boost.

Stick with premium fuel

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When fuel was up around $4 a gallon I tried "cheapin out" , not a good idea, engine started being fussy, missing, funky idle, poor acceleration. Ended up costing more in the long run, because I had to spend for a bottle of octane boost.

Stick with premium fuel

yeah i didi the same except i didn't have any probs.

i would fill up with reg then use some octane booster save bout $15 on fill up

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When fuel was up around $4 a gallon I tried "cheapin out" , not a good idea, engine started being fussy, missing, funky idle, poor acceleration. Ended up costing more in the long run, because I had to spend for a bottle of octane boost.

Stick with premium fuel

yeah i didi the same except i didn't have any probs.

i would fill up with reg then use some octane booster save bout $15 on fill up

Dunno about your area, but here there was only a .20 cent difference between regular and premium, even at bone dry it amounts to only about $4.00 per fill up, (give or take a few pennies) about the same price as adding a quality octane booster. A "six of one half dozen of the other" kinda situation.

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  • 3 weeks later...
Hi all,

I know the car says premium fuel only.

I was wondering if you can get away with mid grade or even regular.

Is this a performance issue? Or will it actually do harm to the car?

Thanks!

No harm will occur if you run mid-grade but pay attention to the engine pinging or a lack of performance/power (accel on

hills, etc.) and gas mileage. Also do not drop from premium to regular. Go from premium to mid-grade and if you want then

step down to regular.

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