yea ive fiddled around with all different types of gas and 87 octane does the best on our cars, premium makes our cars into slugs

 

I have tried several types of 91 in my tC. I ran several tanks full in order to ensure the computer compensated. Like it had been said previously, I saw no improvement in either performance or Fuel Economy when temps do not exceed 100 degrees F. There MAY be SOME benefit when ambient temperatures climb the scale a bit. In the past I have noticed greater percieved low end torque when compared to 87 when its really hot out.

For most people who are not running F/I and/or not living in AZ, Cali, or Texas, you will likely not see any benefit unless you have a computer tune. Even then it may not be worth the extra 20 to 25 cents per gallon.

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hm,i never used the regular. Only premium and sometimes the plus ( middle one) when the gas was $4... btw i did not feel any difference between plus and premium.

 

The only benefit you might have is that there are more detergents in premium rather than just regular (especially if its shell). I have to use premium, otherwise I would have a decrease in motor performance, or blow my motor lol

 

Yes there are better detergents in premium, especially Shell V-Power.

There have been tunes available in the past for toyotas, GMs, and hondas that optimized the Ignition and Cam Phasing for maximun power. These programs/flashes required Premium in order to prevent timing from being pulled when knock is sensed.

We don't yet have these programs or flashes available to us, although soon we may have the ability to tune effectively using that currently "in testing" Dezod programmer.

 

Basically now that cars are ran on computers we do not need premium to ignite for more power unless we are boosted,the detergints in all the grades are about the same.Just use regular and pocket the money you save verse cost of premium.Now if you ran a carerated car with high compression then you will need premium to be able to retard the burn a bit to reduce pinging.......even gas companyies will tell you you do not need premium,they make it for cars like Vettes and such and boosted cars that need it and nothing more.

 

Running premium on a non-boosted tC is like blending your money into a smoothie, drinking it and ____ing it away later... don't bother.

The manual says 87. Run 87. If anyone tells you that you should do otherwise, they're an idiot.

 

i use chevron 87 and i commute a lot and i dont seem to have any problems.=]

 

i use premium to me theres not really a power increase but i dont know why but i feel like my gas last longer when i use it...

 

It's in your head. Trust me. Unless you're boosted, there is ZERO benefit. If there were our car would say to use a higher grade instead of the 87.

 

Yup, no reason for premium. I have used 87 since the day I bought it and have never had a problem. Used mid grade a couple of times and couldn't feel a difference. Just save your money and use 87.

 

yeah i kinda figured it was all in my head lol...

 

Simply put - look in the book and do what it says. There are a few cars that call for premium and you can use the midgrade but other then that - you do whats in the book. Now if you are boosted, you do NOT want to put anything less then premium in.

 

I put premium in my 2006 xa and it feels faster. I also noticed that the rev counter will not move a little up and down when I'm idling with premium vs regular. My xa could go faster on the freeway with premium and it felt like the engine was less stressed. Is there any potential problems that could result from using premium/91 in the xa?

Thank u

 

I've tried Premium for about a month but realized I was just wasting money. I've learned later on that it helps to have Premium when you're boosted. Just like you'll find online, the premium is to help resist detonation. Only buy premium when your car needs it or you're boosted.

 

I run 91 and I'm only on bolt ons. My tuner was able to pull a bit more timing but probably not worth the extra. As soon as I take off my intake manifold setup and emanage I'm for sure pumping 87.

 

We resurrected a thread where everyone with sense says to run regular.

Your car "seems" to run better only because you expect it to.

Running premium does not hurt your car. It doesn't help it either.

 

Tonythemouse, the needle moving at idle is most likely because your A/C is kicking on, the computer revs up the engine a bit right before the A/C clutch engages so it doesn't bog the engine when it kicks on... if it's not your A/C you sir have a bigger issue.

If your car is either tuned for higher octane or utilizes forced induction, you will need the higher octane. Otherwise, save your money and use it for more effective mods, like that gigantic shopping cart spoiler you've always wanted!

Also, Costco Gas isn't only shell. Costco purchases their gas in a (for lack of a better term) sale type fashion. Whoever is cheapest for them to get a shipment of fuel from at the time, they will buy it from. Most of the time they do purchase from top tier companies, however they do occasionally get shipments from other refineries that provide fuel for non top-tier stations.

 

Crap, I accidentally re-ressurected the old thread... can we get a mod to kill this thread please. lol