Ron Pope Motorsports                California Custom Roadsters               

Switching from 10% ethanol to 100% petroleum gas

roadmonster

Member
I've run ethanol blend in my car for nearly 10 years and recently switched to 100% dead dinosaurs for several reasons. Holley carb went 5 years before rebuild, then 3 years, then 2 years. Fuel pump leaked after 9 years. Blend is 93 octane and real gas is 87. I had reduced my CR with laminated steel gaskets to prevent knock, but I didn't think the engine would tolerate 87 after being used to 93 for so long.

Big surprise, no knocking at all on 87, but it took a long time for my car to "get used to" the new gas. It sputtered, stumbled, and died, exhaust note changed, etc. But after several tankfuls, it really settled down and now seems to run better than ever.

Even now, if I run it hard, the idle will creep up to 900-1000, only to return to normal 750-800 with normal driving.

My question is: Why so much difficulty adjusting to BETTER gas?
 
Ethanol is crap. I know for a fact it had me rebuilding my carb a few times. The junk inside was a crime, but it's all we have in Houston and surrounding areas. Hell, probably the whole state.
 
Unless there's moisture or corrosion from the ethanol, I can't understand why an engine would need to get used to it. Perhaps a timing, jetting change, carb adjustment is in order? I hate ethanol. I have had more issues related to bad fuel, moisture, corrosion, etc from that crap. The only places to get actual gasoline around here is a marina, airport, or cam2 at one station, and they are all at least four bucks a gallon.
 
I live in the area with the cheapest gas in the US and 100% gas is fairly common. 2 stations less than 1 mile away. As for adjustments, I tweaked idle mixture and timing, but went back to where it started (where it should be). It really runs great on the same tune as ethanol except for the one quirk of speedy idle after enthusiastic acceleration. I hope that will settle out too.

Real gas here is $2.30-$2.40 (87 octane) and 93 ethanol blend is about the same.
 
Ethanol is crap. I know for a fact it had me rebuilding my carb a few times. The junk inside was a crime, but it's all we have in Houston and surrounding areas. Hell, probably the whole state.
It seems to pour from gaskets designed for real gas. Old-school carbs and fuel pumps leak like sieves.
 
I live in the area with the cheapest gas in the US and 100% gas is fairly common. 2 stations less than 1 mile away. As for adjustments, I tweaked idle mixture and timing, but went back to where it started (where it should be). It really runs great on the same tune as ethanol except for the one quirk of speedy idle after enthusiastic acceleration. I hope that will settle out too.

Real gas here is $2.30-$2.40 (87 octane) and 93 ethanol blend is about the same.
That could relate to fuel temp. Perhaps after a brisk run fuel is getting hot or overpressurized and overpowering the needle valve or simply vaporizing and richening the idle mixture. I've had issues with the fuel boiling in the carb bowl and getting through the vents, into the carb and creating a rich idle scenario, even the vapors from it can cause this. Fuel expands as it heats. The ethanol is less susceptible to this. Just a thought. Do you have a fuel pressure gauge installed? The old school trick was wooden clothes pins clamped to the fuel line to dissipate the heat. I'm sure that would be an attreactive addition to your ride, lol! Just kidding! It seemed to be more noticeable in cars with solid steel fuel lines. A section of rubber was reported to allow some expansion. The issue was heat, and cooling the fuel, i.e. dissapating the heat is the cure.(if that is your issue) Im jealous of your real fuel availability and cost. The ethanol reeks havok on my equipment, especially two stroke, and it doesn't store well. Anything that sits seems to have fuel related problems.
 
In my '37 Chevy I use the Ethanol Free because it sits in the garage a lot of the time. I also use it in all my 2 cycle lawn tools. My riding mower, with its 24.5 horse 4 cycle motor, also uses the Ethanol Free fuel. However, the T requires high test so I bite the bullet on that one.

Jim
 
That could relate to fuel temp. Perhaps after a brisk run fuel is getting hot or overpressurized and overpowering the needle valve or simply vaporizing and richening the idle mixture. I've had issues with the fuel boiling in the carb bowl and getting through the vents, into the carb and creating a rich idle scenario, even the vapors from it can cause this. Fuel expands as it heats. The ethanol is less susceptible to this. Just a thought. Do you have a fuel pressure gauge installed? The old school trick was wooden clothes pins clamped to the fuel line to dissipate the heat. I'm sure that would be an attreactive addition to your ride, lol! Just kidding! It seemed to be more noticeable in cars with solid steel fuel lines. A section of rubber was reported to allow some expansion. The issue was heat, and cooling the fuel, i.e. dissapating the heat is the cure.(if that is your issue) Im jealous of your real fuel availability and cost. The ethanol reeks havok on my equipment, especially two stroke, and it doesn't store well. Anything that sits seems to have fuel related problems.
 
Around here there is no Ethanol free gas. Only 10% Ethanol. I'm running 93 octane with Ethanol but with every fill up I add "Carb defender" from Joe Gibbs. its suppose to protect the carbs from Ethanol. Only time will tell. I have to drive 30 miles to get Ethanol free gas. So I will do that when I get ready to store the car for the winter. run out the garbage and fill up with the good stuff.
 
I can get 90 octane, non ethanol, but it cost$3.30 plus. I buy it for all small engine and push rod toy engines. For the OHC engined toys, I buy canned gasoline, VP or Sunoco. If I have to add ethanol gasoline, I carry a bottle of Stabil, but still have some over the winter issues. I am trying some Seafoam, but you do not know it works until it doesn't.
 
I can get 90 octane, non ethanol, but it cost$3.30 plus. I buy it for all small engine and push rod toy engines. For the OHC engined toys, I buy canned gasoline, VP or Sunoco. If I have to add ethanol gasoline, I carry a bottle of Stabil, but still have some over the winter issues. I am trying some Seafoam, but you do not know it works until it doesn't.
Sea foam is good stuff. I have been using it to combat the woes of ethanol for the past couple years with noticeable results, especially in the first tank or two in the spring after storage. It has worked so well in a couple of vehicles that I was convinced that I was going to have to go through the carbs, but a couple tanks with sea foam and they were good to go. I have considered storing the smaller stuff dry. I have always stored things full to avoid condensation, but with the corrosion, oxidation, and moisture due to the ethanol, I may have to change my habit. I can get non ethanol fuel at the marina a mile from my farm, but it's pricey, like four bucks a gallon. That would be ok in one or two for winter storage, but I have several. I wonder what it would take to eliminate the ethanol from the fuel? Time for a chemistry journey.
 
Here are the octane levels of the gasoline components found in ethanol blends that are inaccurately, but "designated" as 87 octane E10, 88 octane E15 & 87 octane E15:
1) 87 octane 100% ethanol-free gasoline has its gasoline measured at 87 octane. Duh!!
2) Often reported in many website forums, inaccurate, but "designated" 87 octane E10(10% ethanol) ethanol-blend has its gasoline component measured as 84 octane.
3) Not reported often in website forums, inaccurate, but "designated" 88 octane E15 (15% ethanol) ethanol-blend has its gasoline component measured as 83.4 octane.
4) Not reported often in website forums, inaccurate, but "designated" 87 octane E15 (15% ethanol) ethanol-blend has its gasoline component measured as 82.3 octane.
In all ethanol blends, no gasoline or ethanol components have 87 octane, as designed 87 octane gasoline engines are prescribed to perform best.
Only 87 octane 100% ethanol-free gasoline is 87 octane.
 
I think he's complaining that ethanol raises the octane rating of lower priced fuel ????
Hey , Lifelong I know it's in there , as long as the price stays down and it works in my vehicles , that's fine.
AFA storage , I put the small tools in the shed , the tarp on the boat , the T in its corner , If I'm still around in the spring , , I'll put gas in them and go , never have had a problem !?!?
 
I think he's complaining that ethanol raises the octane rating of lower priced fuel ????
Hey , Lifelong I know it's in there , as long as the price stays down and it works in my vehicles , that's fine.
AFA storage , I put the small tools in the shed , the tarp on the boat , the T in its corner , If I'm still around in the spring , , I'll put gas in them and go , never have had a problem !?!?

Is that a bad thing if we pay less for higher octane fuel?
 
Is that a bad thing if we pay less for higher octane fuel?
Ethanol has less BTU's per gallon then gasoline and therefore your gas mileage
will be less. Yea, it's not much, but it is less.
 
Ethanol has less BTU's per gallon then gasoline and therefore your gas mileage
will be less.
As my post states, & other websites also show, accurate 87 octane 100% ethanol-free gasoline(E0) is 87 octane, as gasoline engineers prescribe for 87 octane low compression ratio gasoline engines. Once ethanol blends get to 10% (even less?) ethanol in the gasoline-ethanol mix, no gasoline component or ethanol component comes anywhere near 87 octane.
Therefore, 10% ethanol blend fuels, not only lack the 3% btu energy that gasoline has, ethanol blends also miss a lot of the power stroke of gasoline engines set for 87 octane. My last five 87 octane, low-compression ratio gasoline engines, while efficiently burning 87 octane 100% ethanol-free gasoline over 15(+?) years, gained 8%, 8%, 7%-8%, 7%, & 5% better MPG, than using (not burning efficiently) 87 octane 10% ethanol blend fuels.
Now, with the "ethanol in gasoline industry" pushing the use(not burned efficiently) of 88 octane 15% ethanol-blend fuel, only a wider percentage gap of MPG can be expected between E0 & E15, than I have indicated between E0 & E10.
 

     Ron Pope Motorsports                Advertise with Us!     
Back
Top