| Author |
Message |
    
Bryan Weiss
| | Posted on Tuesday, May 14, 2002 - 01:13 am: | 
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So I have heard both ways as far as the discussion over using the dealer and manual recommended 93 octane as opposed to 89 octane.
This is kind of in regards to the other thread dealing with fuel economy. Someone mentioned it being better with 89 octane.
Anyone else experience this? Are there other issues to using 89 over 93?
Anyones opinions? |
Carter Simcoe (Carter)
| | Posted on Tuesday, May 14, 2002 - 01:38 am: |
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tried 89 once and it knocked BAD, don't plan on doing it again. |
Scott Tschantz (Scott)
| | Posted on Tuesday, May 14, 2002 - 02:28 am: |
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I used 89 for a few years and I would get a check engine light for miss fires I changed to 92 and have not had the light back on and the milage improved I get 330 miles on a full tank on the highway I also put magnecore wires in at the same time so it might be those. hope this helps Scott |
Tomo (Tomorover)
| | Posted on Tuesday, May 14, 2002 - 08:53 am: |
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I've been using 87 octane for the 3 years I've owned my '95, and never had any problems (that I'm aware of!). If memory serves, I switched to compare gas mileage between regular and premium. First tank after switch, mileage dropped a couple of mpg. By the fourth tank after the switch, mpg was the same as it had been before, so I've used it ever since. Never knocked on mine. |
Danno
| | Posted on Tuesday, May 14, 2002 - 08:53 am: |
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i've used 87 for almost 5 years. tried higher octane, but didn't notice any improvements.
also the key word is "recommended"
in my SAAB, it's recommended that i use 92, but i use the car for work, where i'll go through a tank of gas in a day, and so i'll use 89 on the days i know i'll drink the whole tank in a day. no difference, but i think i may get a wild hair up my ass and try 105 octane 
there was a magazine article in Motor Trend (i think) that tested a few cars that were to run 92, but they tested with 87 and 92. the only major difference came in the BMW M3, which lost alot of power from what i recall. and that the modern vehicle with the computers did a good job for compensating for the octane values.
Scott, i had the same problem. i thought it was bad gas, but it was due to the stock wires arching to metal. |
JEspelien (Superj)
| | Posted on Tuesday, May 14, 2002 - 09:18 am: |
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Pump octane is not the only thing differentiates premium fuels. The brand name refiners also use a different package of additives/detergents in their premiuim fuels. This is a cut and paste of a response I posted in another thread. "The mechanic in question is correct in encouraging you to run premium fuel, if you have a 1996-1998 4.0 liter and the premium has Techron in its additive package. Chevron chemical's Techron used in various premium fuels has been PROVEN to help prevent the formation of carbon deposits in the ring groove and on the exhaust valve. Since 89 pump octane fuel is all that is needed to prevent detonation in most 4.0 liter GEMS engines you can also just add Techron to your 89. There is also lots of combustion research showing retarded timing on port fuel injected motors CONTRIBUTES to exhaust valve deposits by raising the exhaust temperature unnecessarily. Heck maybe retarding the timing and running 87 would be a good way to alleviate newer Rover envy if you have a 94-95 3.9 because then you too can drop $2000 on a valve job you didn't need." |
Greg French
| | Posted on Tuesday, May 14, 2002 - 11:15 am: |
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I have been running premium ever since I owned it (97 Disco 4.0)
The other day I was taking a trip that I knew would use the whole tank in a weekend, so I put in 87 just to see what would happen.
It knocked, smoked, and had a noticable loss of power. I found I had to put the pedal all the way to the floor to get up hills from a stop.
Since then, I have run 3 tanks of premiun as well as gas treatment and fuel injector cleaner through, but it still knocks pretty loudly when I first start it.
I DO have L.I.S. (Leaky Injector Syndrome), so it has always run bad when it is first started, but the knocks started only after I used the 87 octane.
Hope this helps.
Greg |
98roverdisco
| | Posted on Thursday, May 16, 2002 - 12:47 pm: |
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My 1998 4.0 seems not to care much--in unofficial seat of the pants testing...There MIGHT be a tad more oomph with 92--hard to say if it is real or my wishful thinking! Mostly, my truck seems to like certain stations. My regular local station's gas usually results in the smoothest idle. Milage for any grade or brand is pretty consistent: Highway at 70mph = @330 miles to a tank. Town or off road thrown in means 10-15% less--depending on my heroics with the throttle.
On the subject of Techron: I am a former BMW tech. When I was active, BMW recommended Techron as a regular treatment. We sold the stuff for about $7 a bottle (with BMW labeling--you could buy the same bottle at Chevron stations for about $2.50!!)
BMW said it was mainly naptha--(lighter fluid, to most of us). To be plain, I never found it to make a damn bit of difference. we called it "sanke oil" and sold it to yuppies who believed you could play home chemist and make great mechanical changes.................FWIW |
98roverdisco
| | Posted on Thursday, May 16, 2002 - 12:49 pm: |
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Um, "snake oil"--I'm really not that dumb, I just try to type too fast.......... |
JEspelien (Superj)
| | Posted on Thursday, May 16, 2002 - 02:46 pm: |
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Naptha??? This is a quote from the official SAE response to the EPA in 2001 during the discussion period on ULEVs regarding new fuel formulations and their possible effects on increased engine deposits "the current state of the art treatment is the additive polyether amine (PEA). Developed by Chevron and originally introduced in 1980, today it carries the company trade name TECHRON®." This paper was signed by combustion engineers from every manufacturer that sells cars in the U.S. |
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