I watched the video and it got me thinking that if I do run E0 gasoline in my klx250sf I will need to decrease my main jet size slightly due to the higher energy content of that fuel. Anybody want to weigh in on the proper new jet size? Currently I run a DJ140 MJ at 2N with DJ's needle running 10% ethanol gasoline. KLXSTER have a good answer? The guy in the vid claims 10% mixed fuel has like 0.96 the volume specific heat content that pure gasoline has. Which DJ main jet will flow 0.96 the amount of fuel that a DJ140 flows per unit volume of air?

 

You know, in "researching" for a less-than-helpful response, this topic became very interesting......

I did learn that "stoich" for E10 is about 14.2:1 and best power is about 12.2:1 ... Lets assume this is true...

(There is some debate on this, some info is puts E10 stoich very close to 14:1..)



I dyno'd with premium unleaded that certainly contained some ethanol as mandated by our "gooberment" - E10 is their target and perhaps it was, in fact, E10 that I burned on the dyno tests... HOWEVER, my AFR targets for the carb setup are targets for E0 !!!!!!

So your 22hp and 15.5 lb ft could be enhanced with nothing more than a tank-o-E0...???

But, more difficult is this question: With a E10 AFR of 12.8:1 at upper RPM's, what happens to that AFR with E0.. ???? This is giving me a headache...

What is apparent though, is that for 10% moonshine, you (and I) will be on the lean side of max power production with your/our current config..

So, that does translate into a jet change - E10 requires about .5/.6 :1 richer AFR than the numbers for E0.. That is one DJ jet size larger - for you, DJ140 to DJ142..

 

This E10 stuff was about to make me start drinking earlier than usual.. I ran my bike with a DJ150 for quite a while - convinced it was more powerful than anything I'd tried.. I even ran it a while after the Dyno showed it to be waay overfueled in the midrange and with a slightly less aggressive TRQ rise than the previous setup I had tested.. I was certain the bike actually performed better in the "real world".... The testing only revved to about 9250 , the DJ150 setup had risen to 12:1 AFR at that point... I bet the bike DID make that extra power above 9250 (to 10.5k) that I swear I was feeling due to it running a perfect (or very near perfect) AFR with E10 !!

(I eventually gave in to "science" and continued testing more "appropriate" setups..)

The problem with the CVK is in keeping the midrange from going horribly rich when the main jet is sized correctly for unlocking that amazing upper-mid and top end power.. So, while the 140/2n and 144/1n formulas are great power enhancers with appropriately modified bikes, perhaps E10 would make a bit mo-powah with 142/2n and 146/1n ...
Also perhaps my DynoButt was correct with the DJ150 main as the AFR on top was likely perfect for the 10% Corn Squezzins I was burning... Perhaps the DJ2152 kit with DJ150 main and the stock needle with full aftermarket exhaust system/MCM/lidless/at or near sea level ....?

FYI: to use my setups, adjust as neccessay for your altitude - see post 846 in the MCM thread for the "how to".. Direct link -https://www.kawasakiforums.com/forum...85/#post524526

Oh the horror - power left on the table...

 

From elsewhere on the web:

E-10 is 90% gasoline and 10% ethanol. The difference in jet size for "optimal performance" between gasoline and E-10 is very little.
Of the 10% that is alcohol you need to go about 30% richer - so 30% of that 10% is only 3% by weight. By volume (jet size is based on volumetric flow) alcohol is heavier than gas per unit of volume by 16% so by weight you are running less than 2% leaner jets when running E-10. That equates to less than one jet size for most small block applications when comparing gasoline to E-10. (assuming that the fuel mixture was dyno set with straight gasoline and then switched to E-10).
Most after-market performance carbs are set rich from the manufacturer so you may have to lean them out to get to either point.
Ethanol, when run straight, allows for more compression, there is 30% more liquid going into your engine which expands more and has a "latent heat content" which all adds up to more power potential than gasoline. (even though it has less BTU per gallon it pushes hard longer on the piston)
Nitro-methane (nitrated methanol) requires that a lot of liquid is poured into the engine because it has in the liquid more oxygen and only uses two parts atmospheric air to each part of fuel (compared to 12 parts air to each part of fuel for gasoline). Liquids expand more than gasses under the same heat and generate more power.

The bottom line is that the difference in power between gasoling and E-10 is so slight that you would have to use precision jets, in half sizes to correct it and the difference in power output is less than you would get between two different days at the track for most applications. Those that keep records and re-jet for atmospheric condition would be the exception to this.
Paul

 

You're right about marine engines, especially outboards, being some of the finickiest applications for fuel. When I had an Evinrude outboard for a fishing setup, I used to keep up with this more. What I understand is that while it's true that ethanol fuel absorbs water more than non-ethanol fuel, the ethanol fuel also possesses an ability to keep the water absorbed into the fuel more in suspension, "dissolved", soluble, or whatever other term applies. This ability exists as long as the fuel is "good". By the time the water and fuel separate, and the water goes to the bottom of whatever, the fuel really isn't good anyway. It might fire an engine, but it's what we normally refer to bad gas at that point. There are some sources on marine sites that state this.

On the suggestion that FI engines aren't sensitive to bad gas or water separated ethanol, don't tell that to most fuel injectors. They gum up a lot like the jets in a carb in many cases.

 

Sorry Tax, I can't determine fact from supposition on your web findings.. But for tuning, I need "stoich", lean-best-torque, mean-best-torque, and rich-best-torque values for E10... If, as I have come to understand, these numbers are .5 to .7 "richer" than the numbers for E0, then that is one DJ jet size larger than my current carb setup "recipes"..

You have information on those values ?

 

Klxster, about your concern of not being at the best A/F ratio while you were on the dyno:

A lambda probe in fact measures the amount of oxygen present in exhaust gas. 0% oxygen means the mixture is stochiometric, positive means a lean mixture and negative (a deficiency in O2) means rich. It's the instrument that translates that to A/F, and it does it by assuming you're buring gasoline. So 14.7/1 means the mixture stochiometric, 12/1 is richer and 16/1 is lean. This is so even if you're burning E10 or whatever: if the instrument displays 14.7/1 it means the A/F is stochiometric. The real A/F might be 12.5/1 if you're burning E10 or something else. The instrument is just saying that there is no extra O2 in the exhaust, nor is there a deficiency (or unburned fuel).

The bottom line is that your dyno tuning is still valid even if you had E10 or such in your tank. At least this is what I expect, having used those wide band lambda probes with various fuels (CNG, hydrogen, propane) in engines in the lab where I was working in the not too distant past.

 

Always a pleasure to hear from you Ray.. And thanks - Nothing like real knowledge to bring enlightenment to us knaves... exhaust O2 content reported as a numeric A/F from an instrument calibrated for E0 will not be the actual A/F if running a different fuel... So, on such an instrument, achieving 12.8:1 (obviously with a wide band lambda) with E0 or E10 means combustion characteristics are identical.. Since 12.8:1 is generally accepted as lean-best-torque for E0, it would also be lean-best-torque with E10 on such an instrument. Also, I guess all instruments are calibrated to crunch thier lambda voltages for E0 - as a standard ... Doing otherwise would create mass confusion..

Do I have this understood now..?

 

Not sure who gave me the idea from reading different threads but today I drained my carb after the bike sat for several weeks in the garage with 10% Ethanol gasoline in the tank and carb. The bike started and ran much better than it does without draining the carb. Even just a few days parked had my bike running roughly for some time. This is better than driving to NC to fill gas cans for the bike. I think the pure gas will be great for the lawn mower though.

 

Yep.. Gotta drain-er if more than a few days.. E10 suks moisture into the bowl from da bowl vent lines - in case you don't know where/how the hard starting is comming from..