I'm converting to alternative fuel, E-85

[Tims Toy 500]

As the title says... I'm converting to E-85. I need a little help. I've looked around on USMB, but haven found the info i need. (Just a lot of political stuff .)

 

So here's what I know. E-85 has a stoichiometric value (air fuel ratio) of about 9.8 to 1 and Gas is 14.7 to 1. The carburetor meters the fuel with the jets. The number stamped on the jet refers to the diameter in hundredths of a millimeter (0.01mm). A 155 main jet, for example, has a hole of 1.55mm in diameter. Larger numbers make the engine run richer (more fuel). Simple stuff...

 

Using some math we can figure the area of the jet ( π r 2 ) and use a ratio calculation to get my new jet size.

So take my 106 jet; the radius of 1.06mm is 0.53mm (1.06/2). Times it self, 0.53 x 0.53 = 0.2809 (r 2 ). Next, 0.2809 x π = 0.882473 mm2.

A 106 jet has a surface area of 0.882473 mm2.

Now, ratio calculation: 0.882 x 14.7 = 12.9724... 12.9724 / 9.8 = 1.3237

I need a jet with the area of 1.3237.

Reverse the ( π r 2 ) formula and it turns out, I need a 130 jet to replace the 106.

Drill out my jet to 1.3mm and presto! I have a Hitachi carburetor capable of running E-85.

Not so simple... Feel free to check my math.

 

Here are my questions... The Hitachi has eleven jets. Which ones do i drill out? Only the primary jet and the secondary jet (someone mentioned)? AND how do I identify which one is the primary and which one is the secondary? Are those the ones on the bottom of the float bowl? Or do I drill all eleven?

 

[skishop69]

You can't use E85 with a Hitachi carb or very few carbs I am aware of. You also can't use it with a dated fuel system. It will eat up your rubber lines, the float for the level sender in the tank, the float in the carb, the plastic check ball for the accelerator pump and the accelerator pump itself. I deal with E85 vehicles regularly, and it takes special lines, plastics and other materials to protect against it. Many of the parts you need to change are not and never were available for the Hitachi. You're also looking at a minimum 20% horse power loss due to lower BTU's of E85 on a already small horse power engine. Last thing: If you use E85 in this fuel system, you WILL destroy it.

[Tims Toy 500]

If you use E85 in this fuel system, you WILL destroy it.

Says the guy with the quote above his avatar "If it ain't broke, you're not trying." Challenge accepted. LOL! 

 

My apologies folks, I was hoping we could skip to answering the question.   Without a long back story... I felt my post was getting to long. So here we go:

 

I failed to mention that this is my project / toy and have no defined timeline to complete it. I just like to tinker with it. If get advice and make some mistakes alone the way, then I'm learning. That's why I'm here. So, yep, I know I need to bend new stainless steel lines AND get different flex lines AND update the fuel pump AND find a suitable brass carb float AND not worry about the sending unit that hasn't worked since the Y2K scare... 

 

Like any project car, we all pick a starting point for improvements. Some go right for the full-on lift, 6 lug conversion and complete EJ swap , while others may start with simply waxing the new find. Me; I happened to already have the craptachi apart for a rebuild and thought "while I'm here..."  "I've always wanted to..."  "Oooh, Then I can go for the boost to compensate."  But here I am, doing one thing at a time. 

 

Yes, I've pondered getting & re-jetting the Weber everyone talks about here. (Nice write-up Loyale 2.7 Turbo.) Until I saw the price of one... Hmmm, the mini drill bits in the tool box are looking much cheaper. And if I mess it up then I'll get a Weber.

 

I admit I'm a little hardheaded. Like the title says "I'm converting to alternative fuel." It is going to happen.

 

Thanks for your input skishop69. All good things to consider. I'll tackle them eventually and hope to post the solutions here.  (Off topic. Puyallup huh? How was the fair this year?  )

 

Please, no more naysayers...  (And I just killed my own thread )

Thanks!

[skishop69]

Ok, so one last nay say and I'll move with advice. You will loose horsepower and fuel economy with this and most likely not be happy with the end result.

 

On to some help. You'll first need to look up the BTUs for gasoline and E85. Do the math and figure out the percentage of power loss in BTUs with E85. Use that percentage in your above math (which is theoretically correct) to figure your new jet sizes. You'll have to drill out the slow (pilot) and fast (main jets) for both the primary and secondary circuits. The jets in the top under the air bleed jets are the pilot jets and the two in the bottom are the main jets. The rest are air bleed jets and do not follow a linear based increase like fuel jets do. I've long since forgotten the size relationship between them, so you'll need to read up on it to make sure you get them to the right size. Depending on the size change in the fuel jets, you may not need to change them.

 

All of that work should wait until you can source a brass float, E85 resistant accelerator pump plunger and check ball. The check ball will be tricky because it has to be plastic of some kind. A metal check ball is too heavy and will hinder fuel flow into the pump chamber.