I have been using 87 without issues, but I seen someone post run 91 or better. I did a 50/50 mix of e85 and 87 and it seems fine. It gives higher octane and I save about $40-$50 a month over premium if my calculations are right. It didn't change my milage either. If this is a bad idea, let me know. I cant afford an engine right now.

 

So you save $40 a month by using the completely wrong gas for your Disco You are loosing 1.5 to 2 MPH, have less power and torque, on 87 octane you are carboning up your valve just $1500 in a valve job some where down the road and there is not a part in your fuel system that handle ER-85, it will take out fuel pump, injector seals, your fuel rail and again effect your engines performance.
If you can afford to maintain your truck as it was designed then drive it less or by a V.W.

 

E85 is about 95 octane, so if you mix it 50/50 with 87, you are still getting 91 octane.

 

E85 is introduced into a non E85 system in most cases nothing will happen except the car may run a little sluggish. That's the best situation, E85 is alcohol and alcohol can damage rubber components and erode fuel injectors. So in rare cases you may have to have a portion of your fuel system repaired

E85 is actually 105 octane. it can burn much hotter than regular premium gasoline and is very corrosive it is a bad idea and will cause you some problems it may not take prolonged use either.

 

Higher octane does not mean it burns hotter. Now e85 is less dense, and if you don't get enough of it, you will run lean. That might cause it to burn hotter... This is the only real concern about e85... running too lean.

Also, the reports of e85 being 105 octane are from "experts" that measured it incorrectly. Click here for more info, page 29.


Most fuel systems since the early 80's are designed to run on at least 10% ethanol, so the injectors, o-rings, fuel lines are all designed to work with ethanol.

Lots of people in the midwest mix e85 with regular gas with no issues at all. I've ran up to a 1/4 tank of e85 and the rest premium in my old 96 D1 with no issues.

 

Besides the fact that e85 doesn't have as much energy as gasoline, and the fact that e85 can absorb massive amounts of moisture, you're running it in a fuel system that wasn't designed to run any significant quantity of alcohol. All you're doing is ruining the plastic and rubber parts of the fuel system that aren't compatible with ethanol, and setting yourself up for an almost laughably expensive fuel system repair bill somewhere down the road.

Then again, we can never have enough parts trucks. Feel free to carry on!

 

Running the wrong fuel octane will not cause carbon build up on the valves, all it will do is cause the ECU to retard the engine timing because the Disco was designed to be ran on 91 octane or higher motor fuel.
It also will not cause lower MPG, because the ECU will retard the engine timing to compensate for the lower octane fuel.
You may notice reduced MPG or engine performance while towing heavy loads or at high speeds.
These engines are computer controlled and fuel injected, which means the ECU controls how much fuel the engine gets, and it will only give it as much fuel as it needs.
The ECU will also use the knock sensors to adjust the ignition timing to keep the engine running at optimum efficiency and performance.
You will however get carbon buildup if you are running worn out spark plugs and or spark plug wires because weal spark will not burn the fuel/air mixture correctly.

My experience with E-85 in a non E-85 car, it kills the fuel pump and fuel injectors.
In my Carmy it killed the fuel pump, in the Volvo it killed the fuel pump and fuel injectors.
It will also set off the check engine light because it runs to lean and the O2's will read that its running to lean and they will throw a fault code.

Your best bet is to use the fuel that is recommend by the manufacture and stick with that unless its a emergency, then use whatever you can get.

 

I once had a square peg, and tried like hell to get it into a round hole, just couldn't get it to fit though.

Maybe there is a reason, but why would you want to do it? to save maybe $0.10 a gallon?

I'm not a technical person, more logical.

 

You will get less MPG's, you will get less power, you will damage your fuel system and you will save a few bucks in the short term.

 

I'm just going to leave this here:

Gasoline-ethanol E15 blend could damage cars: AAA - MarketWatch