Ethanol/Methanol/E85 Carb Conversion

[Stainless1]

I think we are glad the E85 is actually Ealmost90... my guess is we might want to blend in a little race gas to hit 85... and try to hold all we use about that number. 
Yes we discussed Methanol as well.... one step at a time.

[generatorshovel]

A/F sensors do not like Alcohol (for long), although there are options,,
https://www.fueltech.net/collections/sensors-valves/products/wb-o2-sensor-alcohol
Plug reading lets you know if your tune contributed to your engine failed,,
http://www.wallaceracing.com/plug-reading-lm.html

I also started with the X 2.5 jetting plan, but ended up going way bigger, with ALL jets, including drilling the carb passage the pilot jet feeds thru.

[wobblywalrus]

Lots of testing was done over the years on a Triumph Bonneville using various fuels.  It was done on the dyno using as scientific a procedure as possible considering the time and money available.  The jetting was set to provide the richest mixture that made good power.  The timing was set to make the most torque at the least advance.  The fuel air curves were measured using the dyno operator's lambda sensor stuck up the tailpipe.  Often there was another lambda sensor attached to a bung in the header pipe.

It was important to use multiple sensors.  The header bung sensor was always problematic and comparison with the tailpipe sensor showed this.  It would have been a disaster if the header sensor readings were used to adjust the fuel/air mixture in some cases.

All sorts of gasolines were compared, a heavily oxygenated ERC race gas developed for the Australian market, Sonoco Standard, Sunoco Supreme, a highly oxygenated Sunoco leaded gas, and Sunoco GT260 Plus which is used now.  Some Sunoco Supreme-toluene-nitropropane mixes were also tried.

The last mixture showed no advantage on the dyno but it launched the bike to some insane speeds in actual use.  This is something I cannot explain.  Otherwise, none of the fuels gave any significant advantage after the mixture and timing were optimized for each one.  This is something else I cannot explain.  Many people see performance differences with varying fuels.

The latest version of the Dynomation computer based engine tuning program can look at the use of different fuels.  One project for next winter is to model the performance using the various fuels I tested and to see if the virtual results match what we saw on the dyno.  It will be a lot of work but the results should be interesting.

     

[ggl205]

Age old problem, WW. What looks good on the dyno does not always work on track. Of course, it works the other way, as well. Just too many variables a dyno can't deal with.

John

[Sporty Dan]

Ross, any more updates? How much boost are you running on the dyno with the E85?

[mc2032]

No updates.  Hope to get a few main jets drilled out today or tomorrow pending Stainless' availability.   Boost has been around 11 maybe 12 psi.

[wobblywalrus]

VP sells leaded E85 race fuel. 

[mc2032]

Without reliable o2 sensors, I pulled the plug on E85 for now.  First couple of partial pulls, the AFRs were waaaay too lean, to the point we lost part of one electrode.  Do not know if it was burned off or just the plug.  Bore scoped the cylinder/piston top and no visible damage.  One problem to be solved is the S&S carbs (both of them) float bowls flooded at any pressure slightly above gravity.  Purolator/facet fuel pump has good flow and apprx 5 psi pressure.  Holley regulator w/ alcohol diaphragm, set to make the 1-15 psi gauge needle just move off of zero would make them overflow.  Will have to google if e85 is less dense than gasoline or if the floats are compromised.  In the past, the needle/seats would hold 2- psi static and 1.5ish at idle.
So, will unmount the bike from the dyno and get ready for august.

[Queeziryder]

Were you using the S&S Alky carb, 'cause this has a weir so that the float bowl overflows and returns to tank.
The SG of Ethanol/Alky is very different to Gas, and we could never get the bowl to seal.

HTH

[mc2032]

Carb is/was a Super E we modified for an alcohol discharge tube (great big).  Experienced a bunch of what looked like reversion.  Carb was spitting fuel out the front even w/ the turbo pulling air in.  May have been flooding/overflowing w/ the fuel pump/needle & seat issue.  But that should have taken the AFRS to rich.  Dunno.  Have reached out to S&S to see if there are alternative floats but don't think so.  Part of the disconnect was the guy on the bike.  This style of carb has three circuits, idle, off idle/mid range and main.  I was not pinning the throttle each and every time.  I would see AFR's go waaay lean, get scared  and forget that to get to the main jet circuit the throttle needs to get open, and open faster.
But still, we found a few horses left in the barn from last year and will try to spur his old nag into at least a high lope in August.  Now to find those old gut hooks from my junior rodeo days.

[Doc B.]

Gasoline's specific gravity is about .74 and ethanol's is about .79 (more dense). So in theory your float would be riding a little higher in ethanol. Not sure how that relates, but there you are.

[salt27]

Ross, we had the same flooding issue on our bike.

My solution was to put a tee in the line on pressure side of the pump and add a valved return line back to the tank.

The valve would be open reducing presure for idling and warm up and closed once underway.

The bike would sputter a bit thru the first two gears and then clean out and rip.

I believe the fuel demand of the engine at speed alleviated the flooding.

Kind of hokey but it worked for us.

  Don

[mc2032]

This system is set for bypass now.  Pump to a tee, one leg to carb the other to regulator and return to tank.  I used the pump to drain the tank and put the tank return line into the fuel jug.  Really good flow and pressure.  We took both bowls off the carb and hooked the fuel line from the pump to check if the needle was seating.  yep, pump on, at little to no back pressure from the regulator, the needle held.  Just a bit more pressure and it overflowed.  Press down on the float and plenty of fuel flowed into the bowl (visually).  Have reached out to see if there float alternatives, but right now it will work as is. Vanity wanted to see some pressure on the 5 dollar liquid filled pressure gauge.  Spares box is full to spilling.

[salt27]

Yeah, our spares box is quite full too.

With my hair brain ideas about one of every three things I buy or build seems to work.   

  Don

[wobblywalrus]

Another thing that helps is to rubber mount the carbs so they do not jiggle and to isolate them from engine heat.  Either can cause mixture problems that are hard to diagnose.