Is 89 octane OK?
- Thread starter ODDferkOUT
- Start date
e30s only need 87 unless you have a chip. Anything else is probably a waste of money. In fact when i first bought my car i was running 91 and every once in a while when i floored it, it wanted to stall. Use 87 now with no problems. No performance difference other than it won't try to stall every so often.
UNLESS... you have a chip, i don't think your car should run better on 91 over 89.
Heres an article that explain high octane fuel...
Date: Thu, 13 Jan 2000
From: "Derek van Veen" <derek@dagazgroup.com>
Subject: RE: RE: Fuel Costs
Simply put, the octane rating of a fuel determines the propensity to explode
rather than simply burn when mixed with air and ignited. Exploding is bad.
Burning is good. The higher the octane, the more resistant to exploding.
If you are running too low of an octane for your motor, you will get
pinging. Pinging in its extreme form is also known as detonation. The
fuel/air mixture is igniting all at once and exploding instead of igniting
as a flame wave. The resultant "bang" is very hard on the pistons, head,
rods, and cranks. I've seen bent rods, cracked heads, pounded-out crank
bearings, cracked piston skirts, and chainsawed crankcases (*really* bad
thrown rods!).
In an overly-simplistic nutshell (sorry JC!), chipping a motor will usually
advance the ignition timing, adjust the fuel/air ratio, and modify several
other highly proprietary and secret things to increase performance. Among
the main factors in detonation are (1) heat; (2) compression ratio; (3)
octane rating; (4) fuel/air ratio; (5) ignition timing. Modifying any of
these factors can either increase or decrease the propensity to detonate.
Advance the ignition timing and you increase the potential to detonate.
Retard the timing and you decrease the potential to detonate. You can
balance these factors by modifying some to offset others. If you increase
the fuel/air ratio and advance the timing, you can raise the octane and end
up with more-or-less the same propensity to detonate as the non-modified
motor. Alternately, you could lower the compression ratio, but this would
cause a loss of horsepower and efficiency and undo all the gains of
modifying the mix and the timing.
also
*snip*
Date: Thu, 2 Dec 1999
From: "Renny Lutz" <ren@elp.rr.com>
Subject: Re: [uuc] 100 Octane fuel
*snip*
High octane fuel
is a waste of money except for the following situations: Very old motor
designed to run on higher octane fuel stock, Modified compression on
your stock engine, seriously advanced timing on stock engine, turbo or
supercharger on engine and you want to run higher levels of boost, or
engine with lot's of miles that has carbon deposits built up in the cylinders
which creates hot spots or raised compression which leads to detonation.
The higher the octane the less energy in the fuel, lower octane fuel burns more
explosively and quickly.
*snip*
Heres an article that explain high octane fuel...
Date: Thu, 13 Jan 2000
From: "Derek van Veen" <derek@dagazgroup.com>
Subject: RE: RE: Fuel Costs
Simply put, the octane rating of a fuel determines the propensity to explode
rather than simply burn when mixed with air and ignited. Exploding is bad.
Burning is good. The higher the octane, the more resistant to exploding.
If you are running too low of an octane for your motor, you will get
pinging. Pinging in its extreme form is also known as detonation. The
fuel/air mixture is igniting all at once and exploding instead of igniting
as a flame wave. The resultant "bang" is very hard on the pistons, head,
rods, and cranks. I've seen bent rods, cracked heads, pounded-out crank
bearings, cracked piston skirts, and chainsawed crankcases (*really* bad
thrown rods!).
In an overly-simplistic nutshell (sorry JC!), chipping a motor will usually
advance the ignition timing, adjust the fuel/air ratio, and modify several
other highly proprietary and secret things to increase performance. Among
the main factors in detonation are (1) heat; (2) compression ratio; (3)
octane rating; (4) fuel/air ratio; (5) ignition timing. Modifying any of
these factors can either increase or decrease the propensity to detonate.
Advance the ignition timing and you increase the potential to detonate.
Retard the timing and you decrease the potential to detonate. You can
balance these factors by modifying some to offset others. If you increase
the fuel/air ratio and advance the timing, you can raise the octane and end
up with more-or-less the same propensity to detonate as the non-modified
motor. Alternately, you could lower the compression ratio, but this would
cause a loss of horsepower and efficiency and undo all the gains of
modifying the mix and the timing.
also
*snip*
Date: Thu, 2 Dec 1999
From: "Renny Lutz" <ren@elp.rr.com>
Subject: Re: [uuc] 100 Octane fuel
*snip*
High octane fuel
is a waste of money except for the following situations: Very old motor
designed to run on higher octane fuel stock, Modified compression on
your stock engine, seriously advanced timing on stock engine, turbo or
supercharger on engine and you want to run higher levels of boost, or
engine with lot's of miles that has carbon deposits built up in the cylinders
which creates hot spots or raised compression which leads to detonation.
The higher the octane the less energy in the fuel, lower octane fuel burns more
explosively and quickly.
*snip*
