Regular vs Premium gas - what's the consensus?

maxcattum

Disco II and LR3 are specified to require premium gas (92). I have a 96 Disco I and have been using regular (87) for the last 8 years without problems. What's the experience in the community running Disco IIs and LR3s on regular?

MaxCattum

british_rover

The knock sensor will just retard ignition timing slightly. You probably won't even notice the slight drop in gas mileage or any drivablity concerns. If you tow on a regular basis then using the 91-92 octane would be a good idea.

dandrews1

I've actually been putting 95 octane gas in my 2006 LR3 HSE... is there any issues with using better than spec gas?

/DA

british_rover

Check out this post.

Fuel

The LR3 does have variable cam phasing but not variable valve timing. Using higher octane gas is not going to cause any problems but you probably aren't getting much of a benefit out of it.

maxcattum

Are the compression ratios for the Disco I 4.0 L engine and the DISCO II 4.6 L engine similar? Since I've been "successful" running my DISCO I on 87 Octane, I'd like to do the same with my DISCO II. I'm not towing anything - this one is mostly for cruising and city (my DISCO I is my offroad toy - can't get any decent resale value for them these days, so I may as well keep it).

Thanks for your feedback - MaxCattum

british_rover

I will look it up for you and let you know. I just got to find one of my old Disco tech books.

lrguy44

Here at altitude (above 4000 feet) it has been common practice to use Regular (85 octaine) for years. It was even in a owners manual for a 97 Maxima that I had. Read an article somewhere that it was not recommended anymore, but dealership and customers have not had problems. By the way Rover - I was off 3 1/2 months medical but had to come back in time for Master's cruise.

chomondely

2006 LR3, V6, 10k miles. I live in Houston, Tx, sea level fairly level.
I just switched to regular gas. I get about 19-19.5 mpg with regular, the same as premium. Mostly highway, 73 mph. I would switch back to premium if I towed a trailer or needed full throttle acceleration.
No drivability problems at all with regular.

hdominguez

Based on the feedback from the guy from Houston ... is it ok for me to use regular gas for an 05 LR3? I don't want to do it if this will cause long term problems or issues.

Hector
Austin, TX.

bobw3

Does it really matter? Normally premium gas is $0.20/gal more than regular. If you drive 20,000 miles/year at 25mpg, that's 800gal times 20 cents a gal more = $160/year, or about $3/week more in gas costs, or 0.01% of the cost of buying a $30K vehicle...we're not talking big bucks here! It's about the difference of getting 23mpg vs 25mpg using 20,000 miles/year at 25mpg = 800gal vs 23mpg = 870gal which is about an extra $160/year.

So you could look at the difference between using premium and regular gas the same as gettin 25 vs 23mpg, but for some, that difference is enough to buy another vehicle. I guess if everything else were equal between two vehicles except one costs $160 more per year to operate because it's less fuel efficient or requires premium gas, then I'd go for the one not costing the extra $160/year, but there are usually a lot of other differences between vehicles (in my opinion) more significant than this issue.

maxcattum

Interesting analysis and point taken.

Unfortunately our Discos don't get 23-25 mpg but rather 12-14mpg. Being in California, the delta between regular and premium is more along the $0.35 / gal. So we're looking at $400-500 / year. My question was: can I pocket that without damaging the engine in my 2003 Discovery? (I know I'm ok doing that with my 96 Disco - have been driving on regular for 8 years without problems)

Thanks for all the replies - looks like nobody has had a real bad experience going that route.

MaxCattum

british_rover

I know plenty of people that put regular in their Discos and the only consequence seems to be a tiny drop in MPG.

Try it out for a few tanks and see how your mpg drops.

The knock sensor will retard timing if necessary so that should protect your engine.

If you are going to tow or use the Disco off-road you should put premium in it as you are straning the engine more.

55396

Here is a very good explanation of octane ratings in fuel and how it has nothing to do with the energy content or quality.

http://tech.vtxoa.com/index.php?action=artikel&cat=3&id=22&artlang=en