premo gas in stock car?

[5000Audi]

i just read a f/s post on a car being sold and it said its been ran on premium gas when the engine has not been tuned for it?

Is there a gain into doing this? since the engine from factory is tuned for regular 87 gas...

so lets say a 2000 civic with a stock engine running on 87 vs 91.. is there any gain in going to 91 without a tune?

[Tarrantula]

Nothing you would probably notice. Just better mileage.

[badatusrnames]

Octane rating is a measure of the "anti-knock" properties of a fuel.

Higher octane doesn't give you more power on its own, but it allows you to make more power in that it enables higher compression and cylinder temps without your engine being destroyed.

Especially at Calgary's altitude, there is really no sense in running a stock, NA car tuned for regular with 91.

[Joe-G]

I don't think that its a good idea. If the engine was designed to run on lower octane, then put in 87.
If it was designed to run on premium, you should always put in premium gas, although you may be able to get away with regular, since higher end vehicles can usually adjust to the lower octane at our altitude.

The higher the octane, the higher temp it will take to ignite the fuel? and the more compression it can take...Something like that, but don't take my word for it...

[5000Audi]

ohh ok.. so by this one guy saying its been ran on premo since he has owned it really dont mean a thing? just means more cash out of his pocket then..

i know how the premo works for the engine knock since i drive a turbo'd car but i just wondered about a stock n/a engine...

[sr20s14zenki]

Depends on the compression ratio, what kinda car is it. My wife's maxima calls for premium, but it has a 10:1 compression ratio. Alot of high end hondas call for that as well, but they are also 10:1 or more

[Joe-G]

Well, i think it can do some damage as well?
I noticed that when my mom started putting premium in her SUV which required regular (thinking it was better for the engine), i noticed that the engine sounded like shit, and timing seemed to be off.

[5000Audi]

the car i seen post this was a 98 honda prelude SH...

[sr20s14zenki]

Nope, it wont do damage.

Octane actually PREVENTS burn, thats how it is more stable for higher compression/boosted engines. It cant pre-detonate if the fuel isnt as volatile. I love the myth, that octane can make your car faster, LOL. If your car is meant to have premium and you are running regular, your knock sensor is telling your computer to pull timing so you wont destroy the engine with pinging. If you put premium in THEN, youll notice in that situation lol


And yes, that prelude would require premium, i believe it is 10:1 for compression

[5000Audi]

what if a guy were to fill up his car with premium gas.. 94 and dumped in 1 bottle of octane booster....would that up the octane levels enough to need a tune for the car?

[sr20s14zenki]

Nope, wouldnt matter. High octane is there for when you NEED it, if your engine doesnt require it, it wont do shit.

Now, if you took out your pistons, which are prolly like 8.5:1 in a turbo car, and put in 9.5 or 10:1 pistons, then you would need more octane.

[5000Audi]

so octane booster is pretty much a money grab for the companies?..


or would it take 87 up to like a 91?

[sr20s14zenki]

LOL i read a comparison once. That STP shit you get at a gas station that claims 1-5 points...yah, try .1 of a point.

the NOS stuff you get at canadian tire, it will give you 1 point, or a little less.


Cash grab, get the real thing, its better

Apparently toluene makes a wicked octane booster too, its a cleaner you get at home depot.

[badatusrnames]

Originally posted by sr20s14zenki
LOL i read a comparison once. That STP shit you get at a gas station that claims 1-5 points...yah, try .1 of a point.

the NOS stuff you get at canadian tire, it will give you 1 point, or a little less.


Cash grab, get the real thing, its better

Apparently toluene makes a wicked octane booster too, its a cleaner you get at home depot.

Yeah if you read the fine print on the octane booster label, it mentions that each point of octane increases they scream about on the front corresponds to only a .1 point increase in the actual octane rating.

Toluene works good too, I think its octane rating is ~130 (not sure on what scale RON, or MON though).

You can crunch the numbers to figure out how much you need to add...

[rusich]

On my 3.5L v6 RAV4 engine, premium fuel decreses gas mileage by about 3L per 100 kms.

[sr20s14zenki]

Thats strange....^^^^^

[powerslave]

Originally posted by 5000Audi
the car i seen post this was a 98 honda prelude SH...

They require premium.

[A790]

Originally posted by Tarrantula
Just better mileage.
It does the opposite actually.

[gpomp]

i'm too cheap to put premium in my car, will my engine explode on lower octane gas?

[powerslave]

Originally posted by gpomp
i'm too cheap to put premium in my car, will my engine explode on lower octane gas?

Probably not.

[Canmorite]

Originally posted by A790

It does the opposite actually.

I noticed that too. Over about 2500 kms of driving the same route on 91 octane, normal driving, I was using 9-10L/100km. With 87 I got 8-8.5L/100km over the same distance :dunno:

[CivicDXR]

:repost:


http://forums.beyond.ca/showthread.php?s=&threadid=219246&perpage=20&highlight=&pagenumber=2

To summarize, if your owners manual says use premium, use premium. If it doesn't, don't waste your money. Even if you think your car is modded enough that it needs it (N/A mods unless you've changed your compression), it probably doesn't...