Is it needed to use premium gas. 93 octane? is the low grade ok? The JZ motor isnt considered a high performance motor, so would premium gas be needed?

Mike

 

I think some will disagree with your ...The JZ motor isnt considered a high performance motor... comment.

Short answer: your car was engineered for it, and I think this is addressed in your OM, sotry to use 91 as often as possible, but if not, the computer will adjust the timing for lower rated octane.

You won't be saving much over the long haul by using lower rated fules, so why bother?

I mean, its your car, obviously, but the higher octane is what the OM calls for, and usually the higher octance fuels contain helpful detergents.

 

the better fuel you use the less problem you'll have later on and the better performance you going get ..

i remeber long long time ago when i used to get my dad's car.. back then we used to fill up our car with '93 and that was '88 or '89 car .. it was somewhere in '95.. and it wasn't performance car either

besides like dex said.. you not going save much ... so why bother? 'cause you going spend all those money back on fixing your car..

and the most important thing this car was designed for premium gas and nothing lower then that, it says so in your manual and probably on dash board as well.

so i would not use anything else besides 93 if i were you..

 

You must be a fool if you are willing to spend many, many thousands on a car to try and save $200 over the course of a year...

 

Yeah did you get your car on a 60month lease with 5000 miles a year so your payment would be low? If you can afford the car, you can buy the required fuel for it.

 

Higher octane gas has more controlled burn characteristics, allowing the engine to run higher compression, with more aggressive ignition timing. This means you can get more power out of the engine.

If you switch to regular, the engine may start knocking, the knock sensors will pick it up, the computer will retard ignition timing (essentially lowering compression in your engine). The end result is that to avoid damaging your engine, the computer will de-power it a little.

So, in the end you're going to get more performance with the same fuel economy or same performance with better fule economy if you use the premium fuel over regular.

This negates any financial advantage you are expecting from using the regular even further (not worth to me, for example).

Your choice on the gas you want to use, though....

 

Your mods probably cost the equivalent of at least 10 years of savings from going from Premium to Regular. But if you want your car to go slower, go for it.

 

Come on now guys, play nice. He has a decent question.

Mike, I think you have the answers you need to formulate your own decision.

 

I was going to continue to use Premium anyways, just getting some opinions on the subject.

thanks for the imput

Mike

 

Sorry to bring this thread back, but what if the car (not Lexus)calls for regular unleaded?

Assuming the car has an auto knock sensor would it be better for the engine to run, for example, 89 octane instead of 87?

Would doing this just be throwing money down the drain?

 

Go with what the manufacturer recommends.