Is premium unleaded gas/petrol recommended for a gen5? - Toyota Nation Forum : Toyota Car and Truck Forums

SportivOZ · 10-04-2003, 03:54 AM

Sorry for being so technically challenged,.....I am using a 98% petrol/gas for my gen5,....is it any better than the standard unleaded (91% or something)?

I just want to know since the price difference is quite big in terms of annual use. Is it just marketing hype? Or does it really make a big difference in the long run.

Any mech techy's here can that can clear this out? Ta!

Daffunda · 10-04-2003, 09:15 AM

I know that it makes a difference between regular 87 and premium 93. It says so in the manual also. I don't know why you would want to put in even higher grade gas. I can actually feel the difference, so it really works.

Kooter · 10-04-2003, 10:29 AM

I use 89 (research) octane gasoline in my '04 XLE V6. Every once and a while I will use 93 octane.

I used to have a '97 Lexus ES300 as well as a '97 XLE V6 (same engine) and if I used only 87 octane gasoline it would stumble under heavy load. (The knock sensors would detect engine knock and retard the timing as a safeguard, which caused the stumble if too low octane was used.)

If your engine is a 4-cylinder then 87 octane is all you need. Using a higher octane will not enhance performance and may even offer less performance...plus it costs more for the higher octane.

I would use 87 octane in the 4-cylinder engine and 89 octane in the 6-cylinder engine.

Kooter

1200mk · 10-04-2003, 02:51 PM

87 for inline 4s, the manual says 87 can be used for the v6s as well but if you want more performance they recommend premium (91)

thisdj78 · 10-05-2003, 07:26 PM

Quote:

Originally posted by Kooter
........If your engine is a 4-cylinder then 87 octane is all you need. Using a higher octane will not enhance performance and may even offer less performance...plus it costs more for the higher octane.

I would use 87 octane in the 4-cylinder engine and 89 octane in the 6-cylinder engine.

Kooter

Really? I have a Gen 4.5, 4 cyl and my manual says to use premium unleaded for optimum performance. So you are saying it will actually decrease performance?

I've been using nothing but premium since the day I got the car

TypeZer0 · 10-05-2003, 07:36 PM

do you kno if the gen 3's would retard the timings if it senses knocking?

djprefix · 10-05-2003, 11:16 PM

The manual will always say to use premium. An octane rating is just how hard it is to burn, so the higher the octane the less risk of detonation. But you'll make the most power out of the lowest octane you can run. It's easier for you engine to burn and will burn more quickly. I say run 87 unless you're going to be flooring it all the time or something like that. There's really no point in running 93.

thisdj78 · 10-05-2003, 11:42 PM

Quote:

Originally posted by djprefix
The manual will always say to use premium. An octane rating is just how hard it is to burn, so the higher the octane the less risk of detonation. But you'll make the most power out of the lowest octane you can run. It's easier for you engine to burn and will burn more quickly. I say run 87 unless you're going to be flooring it all the time or something like that. There's really no point in running 93.

Well, I do alot of freeway driving, so I'm always flooring it,

kenratboy · 10-06-2003, 01:03 AM

My cars (see sig) book says anything is fine, but a hi-octane (91 or better) will give you added preformance. I use 87 octane, and want to try some 91 (we don't have much 93 or above in Nevada, or Cali for that matter.)

Will it make a difference?

Nick · 10-06-2003, 01:06 AM

performance, no, but you'll get a bit better gas mileage, especially if you do lots of hwy

kenratboy · 10-06-2003, 01:10 AM

Quote:

Originally posted by Oldman
performance, no, but you'll get a bit better gas mileage, especially if you do lots of hwy

Hmmm, me likes this high octane thing

I do over 2/3 highway driving. What does it do for highway driving?

Nick · 10-06-2003, 01:16 AM

give you an extra 30-40 miles per tank

kenratboy · 10-06-2003, 01:33 AM

Quote:

Originally posted by Oldman
give you an extra 30-40 miles per tank

Hmm, that would almost compleatly offset the added cost...

Aussie Ed · 10-06-2003, 02:16 AM

i only use 95+RON pulp in my gen 4.5

its better if you want to keep your injectors clean and if you are going to dyno tune it, you may get a few extra kw after a few mods.

i feel that my car runs better with higher octane fuels.

so yeah, i'd personally recommend using pulp thats 95RON+ in any new car or anything that you are wanting to mod in the future or that has been modified.

vkeks05 · 10-06-2003, 04:05 PM

Quote:

Originally posted by Oldman
but you'll get a bit better gas mileage, especially if you do lots of hwy

What's the technical explanation for this?