87 octane at 14*

coopdog123

greased lightning
Just wanted to weigh in on this. For a long time i was under the impression that 14* on a stock engine was simply to much advance to run 87. Then here recently, guys start comin out of the woodwork sayin they run 87 without mishap. So im happy to say i tried it and the truck runs pretty much the best it ever has, which is comforting considering it has 180,xxx miles and that would seem to indicate that at least carbon buildup isnt a problem yet. No detonation that i can hear at WOT. So yeah, i got that goin for me, which is nice
 
I have had several of these trucks and the couple degrees never felt like much diff no matter what anyway. Def no wow factor. Your not gonna do this "mod" and walk away saying wow what a diff... Cause there's not . Plus with nitrous I keep it at 10* for 75 shot 8* for 100 shot. I always got a 75/25 mix of 110 in my front tank. I've never put 87 in my truck... To me it's like me having to drink cheap beer.... I won't do it!
 
well i definitely wont be spraying on 87, but if its more efficient this way then there is no reason for me to run anything higher until i up my compression.
 
I agree i just always put the premium stuff in my rides. However I have a 2006 chev van w/ 4.8l. It has 212k on it. Always have used 87 per my bosses request. I got van w/ less than 80k. However the other day I was in a hurry and accidentally pushed 93 instead. I just filled it anyway. Erased my engine codes. I'm on a half tank now and still no code. It would normally throw CEL and it would read "multiple cyl misfires" within a day or so. So far so good. The van has had just about everything changed to get code to stop but never tried using good gas. I think things just run better on better gas. Could just be me idk?
 
Yeah, it can work. At least for some. We have 3 trucks that are drivers right now and two of them are blower trucks, the third is getting ready to have its blower reinstalled. Our octane rating for premium (ethyl, high test; remember those terms ?) is 92. Base timing is set at 10 degrees for them and they always get premium. The spread in this state is usually 10 cents higher for each grade above regular. So it costs 20 cents more a gallon for premium over regular. Our local pricing is $2.999 for regular, $3.199 for premium. So lets say I take 25 to 27 gallons on a fill up with both tanks really low. The difference comes out to $5.00 to $5.40 for a fill up. Granted ours aren't daily drivers as some are but for me that's just pocket change. Not worth testing the pistons for 5 bux. He!!, I even mix 101 race gas with our 92 when I race the '95 during the season just for a little "peace of mind" at the track. Consistency is more important than quick in bracket racing for me.

So, for me I'll leave a little on the table for those 8 pistons rather than get towards that "edgy" area for those same pistons. All that said, it's just a little Powerdyne only seeing 6 PSI at the top end of the track. Guess I'm conservative....

Scott
 
It's quite surprising actually the difference that can physically be seen on a cylinder head when someone uses lesser quality/lower octane fuel. I've gotten to the point where I can tell what fuel someone runs by looking at exhaust valves. If you've seen what I have you would never ever run anything except Shell or Sunoco premium. As far as timing? IMO, a broad statement of "set it at 14*" is well wrong. Each engine wants to see different timing for that sweet spot. Will bumping timing help? In most cases yes. Some it actually hurts. Setting timing by ear takes a lot of experience listening to engines and knowing what your hearing. After years of doing it in my personal life and years of running engines on dynos and engine stands I am just recently being able to hear what an engine is doing. Detonation will also not always be able to be heard. Be careful. If it was me and I was set on running 87, I would leave my base timing at 10*. The minor if any performance you gain from it isn't worth the damage you could be doing. "We" know that on most small block pushrod engines all in timing is gonna want to be somewhere between 32 and 38 degrees ignition timing depending on what heads, fuel and compression you have.
 
I had to switch from Shell to Conoco 93 octane on my L, Shell just wanted to ping intermittently. This never happened prior to E blend fuels. I can now run 100% gas from Conoco, the trade off is $.80 higher per gallon of 93 octane, 87 is currently $2.66/ gal and 100% 93 is $3.46/ gal.

Shell is currently $2.68, $2.88, or $3.08 depending on octane. Until a few weeks ago, Shell was always about $.15 difference between octanes.

On a side note, my 2011 5.0 F150 with 3.55 gears is getting 21.8 to 22.2 hiway mpg on 89 octane E blend Shell. It likes to ping on 87 octane Shell. Moral of this story, Shell is no longer the best gas in Arkansas. Personally, I have always preferred Chevron or Conoco.

Lastly, running 87 octane with 14 degrees timing is a risk I'm not willing to take. It only takes one bad tank of gas to ruin your day. Additionally, there can be up to a 2 octane differential between each fuel grade. You could get 85 octane some day and never even know it.
 
Last edited:
Local gas stations or what some refer to as "No Name" fuel brands have the minimum amount of detergents required by the EPA, better fuel brands like Conoco, Chevron, Shell have higher amounts of detergents to keep your valves clean.

I recommend trying 3 tanks of different fuel brands to determine which runs best in your vehicle. And, stay away from fuel additives unless absolutely necessary. Running quality fuels will keep from having to run additives, the exception being occasional assistance with E blend fuels.
 
Interesting this all came up, ive been running citgo 87 in my 302 ranger for the last month or so and ive been noticing its been hesitating more and more even when i shift. I chalked it up to the weather change.

You all have a 10 cent difference between grades? here around chicago theres about a 50 cent difference between 87 and 93
 
By the time spark knock is audible, the piston's already losing material. The saving grace on these antique boat anchors is that they're built fairly stout for NA applications, and you get away with rattling it for a while without much incident. On the flip side, I've seen forged mod motors come apart at the race track NA over bad tunes. I had a guy call me over to his pit one day to ask about his tune-up, and with three passes on his car it was already too late.

Would you like to see a chart of what a 4* bump in base timing will command in the spark table before being modified? I can create the image for that after work. I'm ***uming that you don't have access to that chart since you're playing with base timing and not changing the tune.

Four degrees is a little aggressive for regular fuel, but there are MANY factors that will influence what you can get away with, including what your modifiers are doing based on your weather, altitude, and engine temps. I'd actually guess that if you're going to knock, it'll be in the mid-range under moderate load with that application. Probably the main thing saving it is the factory tip-in setting.
 
Interesting but I will never try 87 on my built lightning but may be possible retarding the timing that low but also retarding the timing not only at WOT but below that, blown engines are required to use premium gas, but is good to mention that twin turbo Ecoboost Pick ups does use 87 on stock set up, but never when a tune is modified for more aggressive timing...
Be careful what kind of boost you run will be pretty riski making 12 or more psi and still running 87.........good luck
 
Yes, Matt. Post a chart. I'd like to see that. FWIW, Gas is cheap, engines are not. If you need to cheap out on fuel to drive your lightning, you can't afford the truck.
 
Stock timing in black text.

gen_1_stock_timing.jpg


Plus 4 degrees in the red text.

gen_1_plus_four_timing.jpg



Of course this is the base table, before the manipulation from adders...
 
Every one has differing opinions on it. Based on my experience with low compression and iron heads your wasting money on higher grade fuel period. No gain in performance cleanliness etc. But hey it's your money.
I do run 93 in my 04 MACH1 however it has alum heads 10.5 compression and requires it. Or 12 ecoboost however does not require it as per the owners manual and it too runs fine and no knock on reg unleaded.
 
Well my most frequented gas distributor is on the top-tier list, so it looks like i really only need to worry about pre-detonation at this point
 
I remember my 05 ranger actually recommended BP gas in the gas door. I never used it but started after some time and gained 1 to 1-1/2 mpg switching.

I agree that there are differences.
 
Back
Top