big difference between 91 and 93 octane

[Moparal]

 

I made the mistake of putting 7 gallons of 91 octane in my car and had to back off the timing 4 or more degrees to get the ping out. I need to put my half inch fuel sending unit in, so I cant add any extra.

So what I am doing is backing off on the distributor and running all 3 carbs as much as possible untill I can take the sending unit out, then go get some good gas. And yes there is a major big difference in performance when you retard the timing.

[AprilsPink72Cuda]

Awwwe man, that sucks!  At least it was only 7 gallons, that wont last too long, lol.

[moparmaniac59]

Hi Al,
So why are you taking the sending unit out!! At least you didn't put diesel in it. I almost did on my car when I was distracted talking to someone. I even had the nozzle in my hand!!



                                                              Matt B.

[Moparal]

Matt, Im in the shop now doing your stuff.  I am taking the 3/8th unit out because the gauge part doesnt work right. It is brand new. Once you use 3 gallons or so, it just drops off to almost 1/4 on the gauge. I want something more accurate. Dave70 sold me his 1/2 unit , it was new. I dont really need 1/2"  but the price was right

[RabidScott]

Highest we can get here in Kalifornia is 91 octane.   

[Moparal]

I went with around 10.5 to 1 comp, so I need it with steel heads. Chevron sells 93. A store 6 miles away sells 110 at the pump. I think its like 650 a gallon tho.

[MEK-Dangerfield]

Al,

  This is something OldSchool turned me onto.

Come on over to the dark side...    Nothing like a lead substitute.


http://www.kemcooil.com/products.php?cId=4


  Mike

[Moparal]

I saved it to my favorites     I already installed hardend seats, so it can run on unleaded, but it does need 93 oct to be able to run good timing and keep the ping down. Thanks for the link

[67vertman]

The octane rating is a measure of the resistance of gasoline and other fuels to autoignition in spark-ignition internal combustion engines. High-performance engines typically have higher compression ratios and are therefore more prone to engine knocking, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design.

The octane number of a fuel is measured in a test engine, and is defined by comparison with the mixture of iso-octane and normal heptane which would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of iso-octane in that mixture is the octane number of the fuel. For example, gasoline with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.  Because some fuels are more knock-resistant than iso-octane, the definition has been extended to allow for octane numbers higher than 100.

 

[Moparal]

The octane rating is a measure of the resistance of gasoline and other fuels to autoignition in spark-ignition internal combustion engines. High-performance engines typically have higher compression ratios and are therefore more prone to engine knocking, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design.

The octane number of a fuel is measured in a test engine, and is defined by comparison with the mixture of iso-octane and normal heptane which would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of iso-octane in that mixture is the octane number of the fuel. For example, gasoline with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.  Because some fuels are more knock-resistant than iso-octane, the definition has been extended to allow for octane numbers higher than 100.

 

    Alls I know is if it isnt 93 it goes ping n clatter

[67vertman]

   Alls I know is if it isnt 93 it goes ping n clatter

Yep, it sound pretty much like the two marbles rolling aroung in my skull.          

[Chryco Psycho]

same here 91 max or ethanol blend 93 , the 91 makes more power & milage

[moparmussel]

i am dealing with fuel problems now! tried to start the cuda and got nothing but a few pops through the carb.smelled the fuel and it smelled terrible! had stabil in it from storgae,now so flat i put some on the picnic table and tried to light it and it would not burn! draining the tank and fuel lines this weekend,then fresh fuel and plugs,just not sure how to empty fuel bowl with out filling the oil pan with bad gas.

[moparmaniac59]

i am dealing with fuel problems now! tried to start the cuda and got nothing but a few pops through the carb.smelled the fuel and it smelled terrible! had stabil in it from storgae,now so flat i put some on the picnic table and tried to light it and it would not burn! draining the tank and fuel lines this weekend,then fresh fuel and plugs,just not sure how to empty fuel bowl with out filling the oil pan with bad gas.

So what if the picnic table lit?? Did we have marshmellows & hotdogs???

                                                   Matt B.

[ksierens]

What about putting some octane booster in the tank?  I haven't used it but I think you can get it at you auto parts store. By us, Turbo Blue is also about $6.50 a gallon, but oooooh how I love the smell!