Subtopic	Posts		Updated
	Tire Noise	1		07/08 04:11am

By Scott A. Keen (Scottkeen) on Saturday, July 07, 2001 - 11:03 am: Edit

eom.

By Jake on Saturday, July 07, 2001 - 11:16 am: Edit

I use whatever I find, occasionally run a tank of hi-test through it. Fuel additive every month or so. No problems with carbon or sticky valves. But, I also run it pretty good, I don't dawdle. Truck has 227 thousand miles and no oil burning no problems.

By Scott A. Keen (Scottkeen) on Saturday, July 07, 2001 - 08:01 pm: Edit

Wow, that mileage is great! So, you say you use regular, mid, whatever, and occassionally premium?

I may have to try this, and get some fuel additive too. I can only hope to attain such mileage.

By john on Sunday, July 08, 2001 - 04:09 am: Edit

Does the vehicle "require" premium? Don't most specify premium?

By Glenn Guinto (Glenn) on Monday, July 09, 2001 - 10:26 am: Edit

I heard horror stories from people that try to put regular in an effort to save some money. They ended up having all sorts of problems. That's why I've been filling up with Premium ever since. It hurts a lot in the wallet- specially when my daily driving used to be 50 miles of stop and go driving. Just my 2 cents.

glenn

Jake, what year is your rig? That's pretty amazing that you have such high mileage!

By Paul L on Monday, July 09, 2001 - 02:57 pm: Edit

87 octane with some additive every 3K mi. My 95 Disco gets 16.5 MPG. Can't argue with that...

By Redsrover (Redsrover) on Monday, July 09, 2001 - 03:25 pm: Edit

I'm all for saving money. But ounce for ounce, gasoline in the US is the least expensive fluid you will put into your Rover. Mine get BP or Texaco 93.

By Jake on Monday, July 09, 2001 - 07:00 pm: Edit

My truck is a 94. I am the third owner. I don't try to save money, just from my understanding of the internal combustion engine, an engine like in our truck does not really require hi octane. Hi Octane, is used to reduce precombustion (pinging) in vehicles with hi comprssion. If our truck is tuned right, it should not require any hi octane, as it is not a high compression engine, nor does it have a combustion chamber that requires hi octane, like a hemispherical combustion chamber. Complete fuel burning is what prevents carbon: keeping your truck tuned and giving it a heavy foot now and then keeps out the trash. It helps to give it a little fuel additive now and then to clean the injectors. I have put everything from Bp to Kroger nameless gas in it and it runs the same on all of it.

By jcw on Tuesday, July 10, 2001 - 03:24 am: Edit

Agree with above. I've run 87 octane in my '94 Disco for a couple of years now, with no problems. Change the plugs regularly & there shouldn't be any problem. Did a test between premium and 87 for mileage...found no difference. Of course, if it pings a lot, go to higher octane and/or additives...but check the plugs and the timing.

John

By Leslie on Tuesday, July 10, 2001 - 03:56 am: Edit

Back from my (stupid) street-racing days:
As a rule of thumb, you should run an octane to match your compression... If you have an 8.5:1 compression on an engine, you should run at least an 85 octane; if you run a 10:1 engine, you should run 100 octane. The Rover 4.0 V8 engine is 9.35:1, so you should run 93.5 octane, ACCORDING TO the "rule of thumb".

Now, with that said.... The Rover manual itself says that you should run "premium unleaded", but then says "octane rating of 90 or 92". Now, unlike old musclecars, we're running around with these computers controlling our engines. On the musclecars, you would get your engine tuned, and would want to run the fuel that you have it tuned for. The computers on our Rovers, though, are essentially retuning the engine constantly, based on what's going on in there. So, the old rule-of-thumb, while good, doesn't have to be strictly obeyed when you've got a computer helping out. So, Rover doesn't HAVE to have 93.5, the computer is set for a 90 to 92 range. Now....

Around here, Premium is 93 octane, regular is 87 octane, and mid-grade is 89 octane. But, that's the "minimum". If a gas supplier gets busted w/ a lower than advertised octane, that fine hurts. So, they ensure that the octane is at least that minimum, but! Usually, though, instead of taking the time to measure it to get it down to that octane, they will go w/ generalizations to get it close but ensure that they stay above the minimum advertised. So, if you go to a pump, 87 octane will probably be around 88, 93 octane may actually be up around 94 or so, and 89 octane is probably going to actually be 90 to 91 octane.

I guess I'm seeming to ramble, so here's my point: While the manual says "Premium" in order to ensure an octane level above the computer's normal range, mid-grade octane is actually right at the computer's operating range. SO.... I personally use mid-grade, and also stick w/ the same brand. And, as mentioned, it does help to ensure that the engine doesn't 'always' operate in the same rpm range. Usually, cruising town or to work, my rpm will be very close to 2000. But, get into it about once a day or so, let the engine run on up past 3, maybe even 4000 rpm... just to help move anything starting to build up on out of there.

IMHO, mi dos centavos, YMMV, etc....

-Leslie

By Ron on Tuesday, July 10, 2001 - 04:57 am: Edit

If you have a 94-95 you can time it to run off 87 fine, a 96 and up will run off 87 BUT 87 does not have as many additives and that is not a good thing as the 4.0s like additives for a variety of reasons. So with an early one if you are willing to sacrafice some power 87 is somewhat ok for a newer one I would not recommend it.

Ron

By J FromAndover on Tuesday, July 10, 2001 - 06:19 am: Edit

I use premium. I average 17.5 to 18 MPG. I'm going to test with mid grade as I know two people (moronic women who like the "pretense" of the vehicle) who use mid-grade for 2 plus yrs.

You guys actually sold me.
-J

By MA on Tuesday, July 10, 2001 - 07:05 am: Edit

I put regular gasoline(86 I think) in my disco1, but I also add 104 Octane Boost to it. I have been doing this for about a year now and have no problems. You just have to remember that every third fill-up you have to add the octane boost. I might start using premium($1.30 now!!) in it because of falling gas prices.

By Scott A. Keen (Scottkeen) on Tuesday, July 10, 2001 - 09:37 am: Edit

I can get either Regular (87) or Premium (93) at the Costco gas station, only -- no mid-grade available.

OK, so this leads to the question: Can I fill up half the tank with Regular, then the rest of the tank with Premium? LOL

By gp (Garrett) on Tuesday, July 10, 2001 - 10:36 am: Edit

well in that case it will only run good half the time.

By fritz on Tuesday, July 10, 2001 - 11:54 am: Edit

like your grammar. But seriously, I deem 89 to be a fair compromise between the incessant debate over inherent benefits of premium gas. On other cars ive owned (94 turbo mr2, and a turbo'd civic) i ran premium for fear of pinging, but in the disco i dont particullary feel that it requires it after all isnt it based off a 80s buick motor? I dont think they have premium in the jungles of africa.

By gasman on Tuesday, July 10, 2001 - 07:17 pm: Edit

FYI,

Just for you Colorado folks. Colorado has lax laws on fuel quality and our regular is like 83 octane, midgrade is 87, and Super is like 90. Basically, because of our legislation we pay for Super and get Mid-grade. Be careful in putting regular in your colorado car, rover or not. I didn't believe it either until I started looking at the pump.

Buy Colorado Mid-Grade.

By Leslie on Wednesday, July 11, 2001 - 03:48 am: Edit

Good point...
I remember when I drove through Colorado a few years ago noticing that they STILL had leaded gas, and all of the octane values were WAY low... didn't realize that it was a 'Colorado' thing, just thought it was a western US versus eastern US thing...

SO... when I said mid-grade, note what the mid-grade here is (previous post).

Also, regarding additives: used to, they were only in the Premium gas. Depending on 'which' gas station you're at these days, all of the octane levels may have additives, or maybe just mid and premium... doesn't hurt to check, if you feel that it helps that much. I think it's better to stick with a station that YOU know works... Not w/ the Disco, but another car I used to have, I had problems with it on certain brands of gas, but no problems on a specific brand. So, I migrated to buying only that brand, and haven't had any more troubles. YMMV, though, depending on where you are, may be a different brand is more dependable in YOUR town...

-L

By Ron on Wednesday, July 11, 2001 - 05:01 am: Edit

all isnt it based off a
80s buick motor?

Try early 60s

Ron

By Tate on Wednesday, July 11, 2001 - 05:07 am: Edit

I took a trip to CO last summer and noticed the low octane levels. I was rather curious about this until someone mentioned that at higher altitudes, lower octane levels were required for the same amount of pinging-reduction. In other words, the octane levels are reduced in proportion to altitude. Now, whether or not the _quality_ of the gas is different there, I don't know. From what I understand, octane has nothing to do with the caloric (energy) content of the fuel, just its resistance to predetonation (pinging), and possibly the brand's additive package. That said, I'm a firm believer in "good gas" vs. "bad gas." My friends often make fun of me because I'm picky about what brands of gas I use.

By jinwoo on Wednesday, July 11, 2001 - 06:22 am: Edit

So what brand is good gas, Pete?
Anybody has good or bad experience with particular brand?

We have 95 Discovery(my wife is a main driver) and always put premium at QT. Somehow price of premium at QT is just in bewteen mid to premium in other more well known name brands here in Atlanta and we just stick to QT and have had no problem at all.

Jinwoo

By Scott A. Keen (Scottkeen) on Wednesday, July 11, 2001 - 07:03 am: Edit

Good vs. Bad gas (ok, I know there's a joke in there somewhere about beans)

I don't like Shell gas. I haven't tried it in the Disco but my Honda and Miata hated the stuff. Sluggish, pinging, just terrible stuff. I tried it several times and had the same bad experience. I avoid Shell now.

I use Exxon or Mobil if I'm in a rush, but if I've got time, I go over to Price Club / Costco and get their gas. It's pretty cheap relative to XOM. I'm in Northern Virginia, where XOM charges about $1.93 for premium, whereas I was just at COST last weekend and got premium for $1.59

By Tate on Wednesday, July 11, 2001 - 07:37 am: Edit

I've had good luck with the BP/Amoco/Unocal brands. Sometimes Mobil if I have to, but I try to stick with Amoco as much as possible. Some of the pumps even have windows where you can see the gas that's going in--it's quite clear. I agree with Scott--there's something bad about the Shell gas in Northern VA. I put some in the Disco once (premium) and it pinged quite a bit. A gas anecdote: My dad put 60k miles on an 89 volvo using whatever cheap gas he could fine. At that point, he gave it to me (my first car). The injectors were clogged and it didn't run well. After cleaning the engine out, I ran nothing but Amoco and BP (regular) for another 100k miles with no other engine fouling problems. That's what made me a fan.

By britdaz on Wednesday, July 11, 2001 - 05:17 pm: Edit

I am living in CO and have a 96. The only problem I have had, was when I used the lowest grade. On drives up into the mountains on weekend ski trips the engine would make a strange humming noise. Not had any pinking though. I currently use the mid grade at whatever gas station has the best price.

By Leslie on Wednesday, July 11, 2001 - 05:42 pm: Edit

I used to not have any problems with, then began having trouble with Unocal/Union76... actually killed a carb on a Jeep I had. At that point, I switched to Exxon.

I wouldn't mind Texaco if need-be, but pretty much use Exxon. The Food City gas stations around here have some Gas-n-Go stations now, and since they're new, I haven't had any trouble w/ 'em.

A big point that can affect the quality of the gas you get isn't the quality of the gas that is going into the station's tanks, but the age of the tanks. Older tanks can leak, not only fuel out but also water in, which contaminates the fuel. To counter this, some older stations will add alcohol as a drying agent. I try to keep away from 'old' pumps.

Actually, the reason why the Union 76 gas killed that carb was alcohol-related. The fuel pump on that particular model actually required the fuel to act as an internal lubricant... not a problem with real gas. The alcohol blends, though, weren't heavy enough to provide the neccesary buffering and the fuel pump began shaving its internals... I found bits of metal shavings inside the fuel filter that was just before the carb. Evidentally, enough fine metal bits got into the carburetor, and wreaked havoc. {At the time, I didn't know what had happened... it was years later when I described what had happened to a mechanic that he explained what had happened, because he had seen a dozen other cases of the same thing with that particular Jeep. Alas... that Jeep is long gone...

I digress.....

Exxon... although I'm 'politically sore' at them over the Valdez, their gas has never given me a problem, and there is a very handy station on my way to and from work, with the best prices in the entire area... so I stick with it.

Anyway....

-L

By Norm Orschnorschki (Norm) on Thursday, July 12, 2001 - 04:53 am: Edit

From what I've read, using low octane gas in the 9.35:1 motor causes predenontion damage and overheating at the cylinder wall which can be fatal to the aluminum block. Check the RPi website under V8 problems. However, the 8.12 and 8.13:1 motors were made to run on regular gas.

Norm

By jcw on Thursday, July 12, 2001 - 05:03 am: Edit

I've done about 50k on my '94 (130k total) on 87 octane. No ping, except occasional brand-related. I regularly check the plugs (change every 15k). Detonation damage will typically leave tiny balls of metal on the plugs...nothing on mine.
To each his own.

John

By ARog on Thursday, July 12, 2001 - 07:11 am: Edit

Again....a 94...96+ are the ones that would have problems with using lower grade gases.

By Leslie on Thursday, July 12, 2001 - 07:30 am: Edit

If I was in Colorado and defining "low grade", I'd whole-heartedly agree.

Being elsewhere, though, and using "mid-grade", not regular... I don't "think" there'd be a problem. (YMMV, etc., disclaimers all applied!)

Norm, you're right, for the same reasons that my rule-of-thumb was created around... for a carbureted, non-computer-controlled vehicle: a 9.35:1 compression engine on 93.5 octane, and a 8.13:1 engine on 81.3 octane, if you don't take the rule liberally... but it IS meant to be taken liberally, with a proper amount of forethought.

The computer on these critters can easily compensate within a given range, and probably should be able to handle regular unleaded fine. Using premium instead of regular is keeping the computer from having to adjust the ingition as much towards limiting predetonation. I choose to use mid-grade because it is as close to the specified octane range as premium is, and isn't costing me an extra 10 cents per gallon.

Again, YMMV... if you're not comfortable with that, don't do it.

-L