|
|
Joined: Oct 2002
Posts: 365
CEG\'er
|
CEG\'er
Joined: Oct 2002
Posts: 365 |
Originally posted by Stazi the Aussie:
No, it burns slower.
Don't know was was meant by "hotter", but the higher the octane, the faster the combustion rate.
|
|
|
|
|
Joined: Jun 2001
Posts: 1,541
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Jun 2001
Posts: 1,541 |
Originally posted by IL Sean:
Originally posted by geoffct:
They automatically retard the spark (reducing power) if the ecu determines there is predetination (knock). Many modern cars do not audibly or noticably knock. The car can detect in less than 2 revs a knock situation, and correct it in the next spark.
I have been able to hear the knock when I ran 87 octain, so it wasn't able to retard the spark at all.
There is only a finite amount of timing that the PCM will take out when detecing knock. Also, the knock sensor is not the most sensitive sensor so I wouldn't depend on it in lieu of running the correct octane for your car.
Bottom line: Run the lowest octane you can get away with, without having any spark knock/detonation. Higher octane WILL NOT give you more performance, unless your current octane choice is too low to begin with.
|
|
|
|
|
Joined: Sep 2002
Posts: 3,632
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Sep 2002
Posts: 3,632 |
Quote:
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
"Cobb - It's not just for corn anymore!"
|
|
|
|
|
Joined: Oct 2002
Posts: 365
CEG\'er
|
|
CEG\'er
Joined: Oct 2002
Posts: 365 |
Originally posted by DemonSVT:
Actually the SVT Programming can "self tune" so-to-speak between 87 to 93 octane. (00 SVT's especially well with the newer PCM & programming)
I myself could notice a difference between cheap 91 octane and the normal 92/93 octane Amoco I run.
...all I wish was 94 octane was available at the pump here...  I sure could use it!!! 
I usually run 93 octane in my '98 EO. When I use 92, there's a slight loss of grunt, most noticiably at the lower-end.
Sunoco has 94 octane here. But I haven't been curious enough to pay an extra .12 - .15 per gallon to experiment.
|
|
|
|
|
Joined: Oct 2002
Posts: 365
CEG\'er
|
|
CEG\'er
Joined: Oct 2002
Posts: 365 |
Originally posted by SVTDriver1:
There is a reason why on the gas gauge itself, the message "Premium Fuel Only" is there. You go to the gas station and pick up the "premium" pump and pump it in there. I don't understand how you are saying higher octane (a measely one point) is so bad for the car. Oh well. I run 93, always have always will. I have never in my life heard a spark knock in my car. You may be getting some shidty quality gas.
SVT Driver 1
I'm pretty sure anything 91 or higher is considered to be premium grade.
|
|
|
|
|
Joined: Sep 2001
Posts: 155
CEG\'er
|
|
CEG\'er
Joined: Sep 2001
Posts: 155 |
96+ octanes usually have special additive which tend to damage cats and other parts. Lead being the most present for 110 octane. Sunoco Super blue(?) is an unleaded 104 I believe, but last I heard it wasn't doing good things with seals, read the disclaimer on the pump. I recall a 98 octane at marathon? but I do not know anything about it.
By excluding 96+ I was meaning to say any premium or ultra-premium gas at any altitude. Race gas is just too much for street cars, and is not worth the risk of cat/seal damage. Using higher octanes can ever hurt the actual engine block itself.
Geoff C. Turner
99 Black SVT -mine
99 Blue SE V6 ATX -mom's
96 Black SE MTX -sister's
All with 278mm front rotors
|
|
|
|
|
Joined: Nov 2002
Posts: 3,506
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Nov 2002
Posts: 3,506 |
Using full on race fuel, in a street car, yes, i can see it damageing the engine, but i thought we were refering to Higher octain pump fuel.....I know the 76 station by my house sell 100 Octain Street Race fuel as Unleaded....In my old car it ran great, when I tore down the engine to replace the pistons and rings, with forged, (becasue of nitrous and turbo) the combustion chamber was still pristine! I replaced all seals as well in the tear down...none showed any signs of ware.....But thats what i thought by higher octain you were refering to.
Roz
3.0 SVT hybrid...all the fixens...Track/Race ready very soon!!!!!! 20,000 + miles
|
|
|
|
|
Joined: Aug 2002
Posts: 3,732
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Aug 2002
Posts: 3,732 |
ima bout to go get some 94 octane, i got a chip coming tomorrow, and a little 87 left in the tank
Russell
Oval Port 3L Nearly Done
MTX75 w/ Homebrew Zetec FD and Torsen Complete
|
|
|
|
|
Joined: Oct 2002
Posts: 365
CEG\'er
|
|
CEG\'er
Joined: Oct 2002
Posts: 365 |
Originally posted by Roz 1999 SVT-C:
Using full on race fuel, in a street car, yes, i can see it damageing the engine, but i thought we were refering to Higher octain pump fuel.....I know the 76 station by my house sell 100 Octain Street Race fuel as Unleaded....In my old car it ran great, when I tore down the engine to replace the pistons and rings, with forged, (becasue of nitrous and turbo) the combustion chamber was still pristine! I replaced all seals as well in the tear down...none showed any signs of ware.....But thats what i thought by higher octain you were refering to.
Roz
Yeah, Roz, about 14 years ago, I also flirted with non-racing 100 octane in the slighly beefed-up, cast-iron block and head engine in my '85 XR4Ti (studs on the block, forged pistons, bored-out 20mm, conservative high-lift Motorsport camshaft, in-dash wastegate bypass for the Garrett TO3 blower).
It definitely gave the powerplant a kick in the pants and did no damage -- the engine and blower were in perfect shape when I traded the XR4 for my CSVT in '99 (I've been a die-hard Amsoil user for 15 years). But the $5/gal 100 octane available at that time from Superfuels was WAY too high-dollar for my wallet ...
And -- for the sake of getting back on the track the actual thread -- NO WAY would I go any higher than 94 octane in the unmodded engine of my '98 EO CSVT.
Did I mention Superfuels had a very brief lifespan?
|
|
|
|
|
