I'm dying to get out of Miami tomorrow, but I don't have enough time or fuel to wait in line for 4 hours to get 93 octane. I have access to a large private tank of crap gas (87 octane, I think) that has no problem powering V8 Jeep Grand Cherokees and the like. Can I get away with mixing 5 or 6 gallons of low octane fuel with the gallon or so of 93 that's already in the tank? Will I be OK if I stay off boost? I am using stock ECU.

I have no idea how sensitive these cars are to bad fuel, if you can't tell.

Thanks!

 

I assume it would be fine once or twice, but not something you want to do frequently.

 

Yea i definitely agree.. Assuming you still have a good amount of 93 left in the tank, i think you should be fine. Ever think of running to a auto part store and getting octane booster??

 

Let me ask you this: Do you have access to Toulene (114 oct) or Xylene (117 oct)? Perhaps a few gallons from Home Depot/Lowes? You can throw in a few gallons of that stuff and raise your octane to "acceptable" levels. Just be careful when handling it (no plastic cups). People do it all of the time to raise their octane levels at the track.

 

I wouldnt even put that in a 944 turbo.

 

You can run 87 if you want. Keep it off of redline and do not lug it, basically do not run the engine hard. The knock sensors will watch out for you.

 

Yeap, the ECU's in modern cars will make the precautions needed to be safe. Just dont' make a habit of it.

 

actually the knock sensors used in OE systems are pretty poor. They only react to significant detonation (after it occurs) dial back the timing a little and wait for more to see if they have gone far enough...they suck because 1) they are reactionary and require det to occure before they kick in, 2) they only retard timing within a very limited window which is not always enough to prevent further det and 3) they are very poor at sensing highrpm det...oh and 4) often react to false stimuli from other engine vibrations.

That all said...if you are in a pinch and need to get the hell out of Dodge (or Dade) then 89 should be fine for a few gallons mixed on a short trip. keep it cool and donlt load the motor rapidly. Its not like you will blow your motor or anything, its just leads to massive pressure spikes in the combustion chamber that hammer your bearings and rings. I would do it in the same situation....

-dave w

 

Couldn't you use a bottle of octane booster from an auto parts shop? Octane 108+

 

That's what i suggested?!?!

 

Sorry missed that.... not a bad idea though if I say so myself.

 

the octane booster crap doesnt work. see if u can get your hands on some torco, that stuff works.

 

Noo i was just saying, nobody even saw i wrote that i thought it might be a good solution, guess not

 

You can add some Toulene (114 oct) or Xylene... do a search online to find ratio... be careful, and DO NOT get it on your paint.

Octane Booster is complete crap... may raise your octane from 87 to 87.3 or something insig.

If you have to run 87, don't get into much boost, and don't lug. And you get to your destination, run as much of the 87 out as you can, and refill.

 

It won't hurt the car, from what I read the timing will retard and you will just get rduced power.