: Premium unleaded???


rtroast
06-14-2005, 11:13 AM
I just bought a 2005 Tacoma 4x4 Double Cab with V-6.
Is it absolutely necessary to use premium unleaded gasoline vs regular unleaded?

jtaco1
06-14-2005, 11:37 AM
Look through the Owners Manual and see what they call for, that is what you should use because that is what the engine was designed for. I had a problem with mine when I ran the high test stuff, my truck was running way rich and could not burn is, so my tailpipe got really black. I have switched over to regular and it is much better, along with being cheaper.

J-Man
06-14-2005, 01:08 PM
i doubt its necessary, or at least it shouldnt be. Run the cheapo stuff and see what happens. see if you notice any hesitations, knocking, or whatever. I highly doubt you need to. Could just be the oil companies .02 wanting you to spend more $$$.

Texan1983
06-14-2005, 01:15 PM
just wondering, on my 02 v6 it says to use premium fuel right on the fuel cap. is that what i should be using?

J-Man
06-14-2005, 01:34 PM
uh, no. Only if your running a supercharger on models before 04 should you be filling with 91. Other than that, your wasting $$ and not burning the correct fuel for how the engine is programmed.

atwinda
06-14-2005, 01:48 PM
your 05 was designed to run on at least 91.

GangusKhanh
06-14-2005, 01:50 PM
I tried 87 and 89 octanes, and my engine was knocking and pinging like crazy. 93 is the only thing going int he tank right now.

pportera
06-14-2005, 02:38 PM
89 here or i get pinging
93 is a waste for any car, unless its blown or shooting nos. Or of course if u have a motor with higher compression.

i think 89 is best all around

PaulH
06-14-2005, 02:42 PM
Mine is so new, I'm still on the tank the dealer provided when I picked the truck up. The owners manual says to use 87, but recommends 91 for increased performance... what does that mean? The 4.0L has a 10:1 compression ratio. I will call my salesman and ask what octane they put in it. This should be interesting.

remelad
06-14-2005, 03:27 PM
2005 recommends at least 87 octane, its in the owners manual. I have tried all 3 grades and I get the best mileage & performance on 87 with no pinging whatsoever.

TacoMike82
06-14-2005, 07:00 PM
I've run mine on 87 and 91, no pinging with the 87 and no performance difference. Save the money.

EndersTaco
06-14-2005, 10:12 PM
I am at and around sea level all day. Around here most of the 05 taco's ping on the 87. I run a high quality 89 (Wawa gas, seems more consistant that the others around here) and get my most consistant gas mileage (16-17 in town, 18-19.67 on the road) and I drive in an inspired fashion!

rtroast
06-15-2005, 09:39 AM
Thanks to all. I guess I will just see how 87 (which is what the dealer most likely put in) performs. If it starts to ping or lag, I'll have to upgrade.

Thanks

Mikevr007
07-25-2005, 03:17 PM
In searching for more info on this I found out that on the '05 V6, Regular unleaded will work (obviously), but for optimal performance and fuel mileage, 91 is recommended.

Which brings me to a question.
In the 2003 Factory Service Manual, under New Features for the 5VZ-FE Engine, it lists "91 or more" for the Research Octane Number.
Does anyone know if that is true for the 2004? I'm guessing it is.
The operator manual says 87.

Thanks!

absolut taco
07-25-2005, 03:25 PM
At CostCo, where I fill up, I have a choice of 85 and 91 octane. I have never used less than 91. I think you should use the best gas you can get for your Toyota.

Dick Foster
07-25-2005, 03:26 PM
This should have been posted in the newbie folder, that is what that folder is there for. Your post has nothing at all to do with 4X4.

Dick Foster
07-25-2005, 04:04 PM
That's better.
You only need to run premium if the owners manual says so. I ran the middle grade befor the SC. If you have the SC then you must run premium. Just fuel is up with the recommend fuel and listen for knock. If you hear consistant knock and ping with the same grade of fuel of different brands then kick it up to a higher grade of fuel. If the engine was designed to run on 85 and does so without ping, then buying premium fuel only wastes your money.

Mikevr007
07-26-2005, 07:23 AM
I really thought some anal person here (other than myself) would explain this. So, if no one else is going to, here it is. Please take note of the very last sentence...

"The most important characteristic of gasoline is its Research Octane Number (RON) or octane rating, which is a measure of how resistant gasoline is to premature detonation ( knocking). It is measured relative to a mixture of 2,2,4-trimethylpentane (an octane) and n- heptane. So an 87-octane gasoline has the same knock resistance as a mixture of 87% isooctane and 13% n-heptane.

There is another type of Octane, called "Motor Octane Number" (MON), which is a better measure of how the fuel behaves when under load. Its definition is also based on the mixture of isooctane and n-heptane that has the same performance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the 'headline' octane that would be shown on the pump is the RON: but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the "roaD Octane Number" or DON, or (R+M)/2. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel, the "normal" gasoline in the US and Canada, would be 92 in Europe."

zosimov21
07-26-2005, 07:55 AM
So we can run the cheapo stuff here and it will be the same as running high test in EU?

absolut taco
07-26-2005, 09:08 AM
If the engine was designed to run on 85 and does so without ping, then buying premium fuel only wastes your money.
There is an article in the latest Car & Driver that suggests higher octane gas will leave less gunk on your fuel injectors meaning they will go longer before needing to be serviced. I'm not saying C&D is always right, just sharing some info...

Screehopper
07-26-2005, 10:39 AM
Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel, the "normal" gasoline in the US and Canada, would be 92 in Europe."

I knew about the other stuff, but the last paragraph is new to me.

No wonder when I was in New Zealand it was 92 (Premium) and 96 (Ultra Premium). But their choice of words for premium and ultra premium made it sound like their gas is superior to the fuel in the States.

In terms of diesel I know they have better stuff than we have here in the States. USA - Now hurry up with the ULS [ultra low sulfer] diesel.

J-Man
07-26-2005, 11:18 AM
There is an article in the latest Car & Driver that suggests higher octane gas will leave less gunk on your fuel injectors meaning they will go longer before needing to be serviced. I'm not saying C&D is always right, just sharing some info...
Higher octane gas does not mean its cleaner. The higher the octane number means its less explosive gas, or less prone to knocking under load, running higher test gas in vehicles that are designed for 87 means that the engine is not burning the gas completly which can lead to worse performance and leaving deposits and gunk where as if you run 87 in the vehicle thats designed for 87, it burns efficiantly - sp?

Its also important to give the vehicle a "mexican tune up" as my buddy in baja once told me - just drive it at 5-6k rpm's for 20 minutes and no more build up inside the engine. ;)

Dick Foster
07-26-2005, 11:22 AM
Yep.

TACODOC
07-26-2005, 01:05 PM
I've been running 87 octane since new, I'm sure the dealership "free tank of gas" at purchase was 87 as well. No problems with 87, truck runs fine and hauls ass :D