Premium Unleaded?? Do I really need to???

[Serg]

My owners manual for my 19995 Classic LWB says to use Premium Unleaded only... well that's fine and dandy for my M3.. heck it even gets 21 MPG when I romp on it.. However for my Rover (which gets a whopping 11-15mpg so far) I would like to use mid range or even regular unleaded..

Question is, will this hurt it?? I really can't see how since it is not a high performance engine... I just don't want to save a few bucks if it means engine problems down the line.

Serg

[Rangie Mark]

Bottom line is they run better that way and fuel economy is not a reason to buy a rangie

[Rangie Mark]

Otherwise you will get carbon build up on the valves .......$$$$$ :p

[Disco Mike]

Originally Posted by Rangie Mark

Otherwise you will get carbon build up on the valves .......$$$$$ :p

I agree with Mark, bad idea you run low octane gas, it will carbon up the engine big time and yes the MPG will fall off.
It hurts, but do it. In a short while you will find a cheap gas station, like Arco, that sells good gas cheaper.
Mike J.

[Serg]

No bigie... I use Chevron only anyhow, I was just wondering if the thing really needs to have Super Unleaded. No prob, thanks for the info guys!


Serg

[azpaquin]

FWIW, if you are looking to up your MPG, Change every oil in your car to synthetic and I mean everything. Lube your U's and CVs and get synthetic in the diffs. Less friciton is good. Do it yourself and save some cashish.

Get very good wires and plugs, 9.5mm or better. Do not go cheap.

I put in a Jacobs Ignition kit, that added 2 mi per gal and gives better burn to your plugs.

Then run the good gas.. long term it will be good for the fuel system.

I have 300k mi on my white elephant 1988 RRC and I have been getting over 15 mi per gall all day on the highway.

[OkieRover]

Last night's fill-up calculated at 15.5 mpg. My engine has 147,000 on it. I use Castrol 20w50 year around, changed every 3000 miles. I get the cheapest gas I can and use 87 octane. I try to remember to run a bottle or two of injection cleaner through it on every third oil change, just for fun.

[azpaquin]

Originally Posted by OkieRover

Last night's fill-up calculated at 15.5 mpg. My engine has 147,000 on it. I use Castrol 20w50 year around, changed every 3000 miles. I get the cheapest gas I can and use 87 octane. I try to remember to run a bottle or two of injection cleaner through it on every third oil change, just for fun.

That's awesome 15.5 gal. What is in that Rover, the 4.2? Isn't that the higher compression engine?

[OkieRover]

To say I am blessed with this engine would be an understatement.
It's the 4.2. Not sure about the compression.
Other than me overheating it once or twice due to a clogged radiator I have tried to be good to it. My Rangie had 86,000 when I bought it in 2000.
The worst mileage I have gotten was 13.9 the best was 19. That 19mpg was a highway trip in October 4 years ago. I drive a mix of city and highway with highway being 50 miles of my daily trips.
I wish I could afford a 300Tdi.

[lrmaniac]

Hi

oakie, you said "I wish I could afford a 300Tdi."? Why?
Are they a lot more expensive there in the US? Or is Diesel fuel more expensive hen petrol?

[azpaquin]

Originally Posted by OkieRover

To say I am blessed with this engine would be an understatement.
It's the 4.2. Not sure about the compression.
Other than me overheating it once or twice due to a clogged radiator I have tried to be good to it. My Rangie had 86,000 when I bought it in 2000.
The worst mileage I have gotten was 13.9 the best was 19. That 19mpg was a highway trip in October 4 years ago. I drive a mix of city and highway with highway being 50 miles of my daily trips.
I wish I could afford a 300Tdi.

huh. maybe you could get more MPG out of it with some mods. I am doing some more mods as we speak and I will know the outcome after a long drive I will be doing in the next coming weeks.

[OkieRover]

Originally Posted by lrmaniac

oakie, you said "I wish I could afford a 300Tdi."? Why?
Are they a lot more expensive there in the US? Or is Diesel fuel more expensive hen petrol?

Yes. A 300Tdi will set me back a minimum of $9000(US). I know a fellow here doing a conversion and he is laying out something like $13,500(US) I believe. Diesel fuel right now is 10cents less than petrol. Today in Oklahoma it's $1.68(US) for 87 octane petrol.
I don't know why they are so expensive but they are.

[OkieRover]

Originally Posted by azpaquin

huh. maybe you could get more MPG out of it with some mods. I am doing some more mods as we speak and I will know the outcome after a long drive I will be doing in the next coming weeks.

Let me know what mods you do and if they work. If I got 17 or 18 I would be in heaven.

[Serg]

Originally Posted by OkieRover

Let me know what mods you do and if they work. If I got 17 or 18 I would be in heaven.

Sheesh..I'd be happy with just for an average 15mpg!!

Serg

[Mr Tj]

The short-bore V8 aluminium block is pretty high compression, hence you'll pretty easily get the dreaded knocks with anything below premium gas.

Also, bear in mind that European petrol starts at 90 octane, and goes up to 98/99 octane at the pump, as opposed to US 'cheapo' gas that is lucky to get to 92/93.