| Author | Message | ||
     Blake Monchilovich (Azblake) Member Username: Azblake Post Number: 53 Registered: 02-2003 |
Hi, '94 D1 with the distributor. How many degrees to compensate for the cheaper gas? | ||
| Leslie N. Bright (Leslie) Senior Member Username: Leslie Post Number: 2085 Registered: 02-2002 |
Don't. Gas prices are coming down, keep running better gas.  -L | ||
| Blake Monchilovich (Azblake) Member Username: Azblake Post Number: 54 Registered: 02-2003 |
I've been running the 87 since I got it and put the timing to 6 during a recent tuneup. As I understand the octane is only an indicator of how fast/hot the fuel will burn during combustion, not necessarily an indicator of quality? I've ran 20k+ miles without an issue but had recent concerns about heat and know timing can play an issue. I do run premium through my other car, but it is a small dispalcemant turbo and heat/knock is a big issue. Plus, over $2/gal is criminal. Just looking to see what other people are doing. | ||
| Todd Nash (Nash) New Member Username: Nash Post Number: 10 Registered: 02-2003 |
A couple of months ago I was getting 14mpg with 87 and 16mpg with 93. This worked out to 11.2 cents per mile with 87 and 11.4 cents per mile with 93. Bottom line, the good stuff was just as cheap in the short run. Plus, I may be reducing trouble for the long run. Anyone else have this situation? | ||
| Dan Armbruster (Dan_armbruster) Member Username: Dan_armbruster Post Number: 60 Registered: 04-2003 |
I just switched from 87 to 92 and I have noticed a moderate difference in gas mileage, I just hope the gas starts to go down. | ||
| Reed Cotton (Reedcotton) Member Username: Reedcotton Post Number: 69 Registered: 01-2003 |
Blake, You are right about one thing. Octane ratings have really nothing to do with quality. They are closer to what temperature the gasoline will ignite. Lower octane=lower ignition temperature. Higher octanes were developed for higher compression engines to reduce pre-ignition. Higher octane gas also has more energy per volume. Engine manufacturers send alot of time calculating the proper gas to use in a particualar engine, and they really aren't owned by the oil companies. Running a low octane gas in your truck, for long periods of time, will have long term effects on the engine. You may not always hear the ping or knock that is happening, but each time it does, it shortens the life of the engine. Sometimes to the point of catastrophic failure. (bent rods, broken pistons, etc...) I agree though, $2.00 per gal (more like $2.30 here) sucks!!! | ||
| Leslie N. Bright (Leslie) Senior Member Username: Leslie Post Number: 2091 Registered: 02-2002 |
Dang! Premium here is down to $1.54.... $1.39 for regular for the Roo.... -L | ||
| thom mathie (Muskyman) Senior Member Username: Muskyman Post Number: 255 Registered: 11-2002 |
sure about this one? here we go again | ||
| Blake Monchilovich (Azblake) Member Username: Azblake Post Number: 55 Registered: 02-2003 |
So can't you adjust for the preignition by changing the timing slightly? I just don't know what to listen for when doing it. | ||
| Joseph C (Condorwatch2) New Member Username: Condorwatch2 Post Number: 12 Registered: 03-2003 |
I never noticed any difference. Ran high octane for first 50K. Thought it might be just burning money. Switched to 89 octane. Same crappy fuel efficiency and performance for next 50K. Engine still going at 130K. Actually the higher octane is probably important for more advanced performance modified engines like in some modified BMWs. But apparently not for my somewhat unsophisticated D1 engine. | ||
| Reed Cotton (Reedcotton) Member Username: Reedcotton Post Number: 71 Registered: 01-2003 |
Muskyman- Actually I am not sure about that one, Octane-wise. More energy may be released but it may be more to the fact that the fuel/air mix is allowed to ignite at a higher pressure. I doubt that Octane itself (or Octane substitute) actually ads power by itself, other than modifying the flash point of the gasoline. But it has been over thirty years since I did any definitive stuy on the subject. Higher the engine compression ratio, the higher the octane needed, unless other means of preventing detonation are used. -Reed | ||
| Dan Armbruster (Dan_armbruster) Member Username: Dan_armbruster Post Number: 62 Registered: 04-2003 |
I really dont understand this tech talk, so is it really necessary to pay for the higher octane or is a poor college kid pissing money away? | ||
| John Hamblin (Jhmover) New Member Username: Jhmover Post Number: 10 Registered: 02-2003 |
I got told by the service rep at the dealer that they recomend the high octane because they're afraid detonation will cause problems with the cylinder liners. Frankly, I run mine on the cheap stuff, I never hear any pinging and I've noticed no difference in gas mileage. I haven't bothered with the timing because I don't hear any pinging. Why pay the gas companies anymore than you have to? | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 150 Registered: 10-2002 |
Oh man... I think Todd N probably has $ figures about right as far as savings on running 87 octane. If you don't drive your rover that much why bother running low octane? And if you do commute alot of miles (and have only 1 vehicle) then why not buy a used street motorcycle (make mine BMW) and save on fuel and maintenance and come out ahead? You're driving a v8 powered brick with two full time axles under power and thinking about incremental mileage savings? At that point think diesel and keeping your vehicle for a lot of miles. Yeah, higher compression is usually the reason for higher octane requirement but have you compared a mid-eighties domestic v8 timing to your rover? Most run stock timing retarded. IMHO Land Rover ran 6 degrees advanced and a correspondingly properly curved distributor to maximize performance for (relatively) small displacement with standardized 8.13 comp ratio and thus required higher octane fuel. Personally I'd only bother if I was stuck in Mexico with only low octane fuel avail then I'd back off the timing as needed to keep from detonation and accept the crappy loss of power. My $.02 | ||
| Dan Armbruster (Dan_armbruster) Member Username: Dan_armbruster Post Number: 63 Registered: 04-2003 |
Thanks alot guys maybe ill switch back to 87 my next fillup. | ||
| Brad Russell (Bradnc) Member Username: Bradnc Post Number: 233 Registered: 03-2002 |
According to my OBDII on my 97 my engine ignition is advanced 26 degrees. Now, I know this isn't possible in terms of the degree scale we think of, so does anyone know how this is measured and how advanced my engine is? |
