ERC 110 octane fuel at Speedweek?

[coloradodave]

Did anyone else have a hard time getting a good plug reading using this gas at Speedweek? We really struggled with it.

[doug odom]

Four of the first six people I talked to had burned a piston. I don't know if it was fuel or air pressure but it sure was giving people that should know better a big fit.

[bvillercr]

Four of the first six people I talked to had burned a piston. I don't know if it was fuel or air pressure but it sure was giving people that should know better a big fit.

I'm sure it was a mixture of both or the lack of.

[SPARKY]

I was told that it is imposible to get ALMOST ANY  plug reading with it which was my experience

[wobblywalrus]

The plug insulators always look white to me.  I cannot jet the ERC 100 using plug readings.  They always seem similar to a lean mixture on an engine running normal gasoline.  I look down through the plug hole with a light to see the top of the piston.  Nipple brown is the color that I want to see on the crown.  Any pitting is a sure sign of a lean mixture.

[jl222]

The plug insulators always look white to me.  I cannot jet the ERC 100 using plug readings.  They always seem similar to a lean mixture on an engine running normal gasoline.  I look down through the plug hole with a light to see the top of the piston.  Nipple brown is the color that I want to see on the crown.  Any pitting is a sure sign of a lean mixture.

  We used the ERC 110for years and always had white insulators, but could tell not lean from other pars of plug,
 we switched to the A8C 118 OCT I believe and have color, still had piston problems [ skirt ] but don't no why yet.

    JL222


               

[jimmy six]

Looking at the top 2 threads of the plug have always told me what was happening. The base of the porcelin needed a tan ring to be right on. Always used 118...............Good luck

[SPARKY]

I wish I could remember the gentlemans name but we had a "fuel lesson" in impound. He explained that you wanted a fuel with a high octane rating if you had lots of compression and were concerend about detonation; that is why we run 118 A in Ratical.

 A fuel with this characteristics burns slower, because it has a higher 90% vaporization temp and has additives. 110 has a fairly high 90% temp I was told.

Otherwise you wanted a fuel with a lower 90% vaporization temp which will burn faster.

With his recomendation we switched to 108 from 110.  He also told us we would be amazed at how much more jet we would need.  We were running a 165 moved up to 168 then 172 and were planing on trying a 178, we were getting better indication on the plugs but we hadn't seen any indicatin of off idle richness---we were running faster into an increasing quartering headwind. We decided to go home from impound on Thursday am rather to wait out the storm as we were just bumping our on weak record.

[coloradodave]

That's great information guys, thanks a bunch

[dieselgeek]

Used the 118 in our 12.5:1 N/A engine, plugs were hard to read (what I'd expect for such an inappropriate fuel choice).   But, switched to the 114 equivalent and the plugs looked the same - little or no heat, clean white porcelain.  But we picked up 5mph with no other changes.

O2 sensors seemed to be working correctly.  I leaned it out from the above two passes, which were in the high 11s AFR (way too rich), to 12.2:1 AFRs and we picked up another 5mph.   Crew chief was pretty scared/concerned about the way the plugs looked - no good reading, but no aluminum on them either - he asked me to fatten it up on the 4th and final run, so I ran it in the high 11s again.  There was plenty of soot in the exhaust, the car slowed back down 5mph, plugs still looked clean & white.

After getting home and taking the engine apart, the report is "engine still looks brand new" (not sure what all that means, but, apparently we can trust our O2 sensors and lean on it a little more next trip).

[Stan Back]

I think if youda checked with Rick Gold, he'd have recommended the 110.  Cheaper and probably more power yet.  We followed his recommendations to Impound 5 times with about the same compression.

Stan

[dieselgeek]

I think if youda checked with Rick Gold, he'd have recommended the 110. 

Rick was adamant, twice, that we run the 118.  He seemed concerned that this engine had been hurt the previous 2 years.  The engine did best on the dyno with C25.  We learned the hard way not to simply ask for the "C25 equivalent, or similar"   

[JimL]

Short note of my personal experience with fuel choices:

1.  If your intake tuned length is very short, AND you're looking at spinning pretty fast, AND your cylinder head is aluminum, the 90% distillation temp is worth paying attention to.  Lower 90% temp gasoline means it takes less time and heat to get vaporized.  Higher 90% temps, in some engines will lead to white porcelains on your plugs, but black sooty exhaust and sometimes melted pistons as you try to figure it out.  This can happen when all the fuel doesn't burn on time (gives a lean primary burn, followed by a long flame period at lower pressure...and into the exhaust, leaving the black soot).

2.  In 2000 we tried running our 2 liter ModRoadster on a "heavy" fuel (high distillation temp and lots of BTU per unit).  The car was running 102-103 mph, plugs were white, and the side of the body had 3 feet of soot trailing the exhaust outlet!  We went back to the fuel truck, took out the heavy fuel (high 90% distillation temp), and put in the 118 octane with low 90% temp.  We went straight back in line, changing nothing, and ran 183mph, leading to a 181 record that stood for some time.

3.  90% distillation temp is the temperature at which 90% of the initial volume is fully vaporized.  I used to use Core Referee Lab, at Long Beach airport, for fuel testing (customer cars issues).  They told me that 400-440 degree 90% distillation is about 1/2 and 1/2 gasoline and deisel (when folks goof up at the pump).  If you need to run on the rich side, high 90% temps could give you trouble.  The folks at the fuel trailer were very helpful in showing me the temp charts for the available fuels (last year and this year).  I had no jetting difficulties, and both years bumped up records.  The fuel I chose had the lowest distillation temps.

Lots of chemistry needs to happen in milliseconds.  Hope this helps,
JimL

[SPARKY]

Jim---thanks

[joea]

..80 mph gain by only changing gas...wow