Switching to E-85

[Deaf Bob]

I know E-85 has higher octane..
Requires rejetting of the carb and air-bleeds...

What else?
What rule of thumb to go by on re-jetting?
Same for air bleeds? Less or more?
Will the stock mechanical pump suffice?

Electric pumps need to be in their own box if in car...Or built into the tank ( gas tank is a boat tank with bigger outlet tubes and vented located behind the driver. ) Sounds crazy but it IS the safest place for it..

I am hoping with E-85, the cars will run cooler.plus race gas is pretty spendy. Need 15 gallons a derby minimum for 2 cars. (oil coolers get punctures as do radiators.) A buddy just went to a bought E-85 carb With one derby on it, and one of the first ones out, we never got to see how it runs hot. It ran smoother, but he never tunes his engines.

We run NO alternator. 2 truck batteries with bolts (group 31or 32? Like semi trucks) about 900 CCA's each. We turn on the radiator fan 5 min into the "race" to save battery juice..untill they blow the breaker or fuse.. Wired as 12 volts. Some guys run 24 to their starters, we do not, as it is like playing Russian Roulette as to when they gernade (they WILL blow! )

Any thoughts will be appreciated

Deaf Bob
We run radiators, sometimes they don't get poked, sometimes they do...

[Deaf Bob]

Realized this is in the wrong thread...

[JOES66FURY]

PM Thumpin455...he is the E85 guru here.

[Mater]

what joe said. thumpin knows whats up with e-85

[Thumpin455]

Thanks guys. First things first Bob. What carb you running, and what engine? Compression, cam specs, etc?

Its a bit more involved than just rejetting, you have to open up some passages to flow a bit more fuel. I did a Qjet for a bud in Nebraska so he can run E85 on his figure 8 car, but he hasnt tried it yet. Maybe next month when I am home I can dial it in for him. So far as we know only two people are modifying Qjets, me and a friend of mine in South Carolina. Lots of people do Holley, and I can do those too, I just like Qjets and figuring things out. You need to open up the idle passages, main circuits, transition circuits, and get a bigger shot from the accel pump. Each carb is a bit different in what you need to do, and how much you need to drill it, so the carb design makes a difference.

You know how when you run an engine too rich on gas it gets REALLY hot and things start to glow? Well that doesnt happen with ethanol, but if its way too lean it can get warm, but usually they stop running before anything melts in a naturally aspirated engine. If you are running derby with it, then you can run it richer and the heat will help you make more power, also if it stalls then it will start easier if its hot. On cool nights when it isnt warmed up you could run into a no start issue, but how often do you derby when it is colder than 60F? The extra fuel cools the engine so losing the water isnt such a huge deal, you will get more run time out of it without water due to much less waste heat from the fuel. It will also make more bottom end and midrange power than gas will, though you might not notice it on dirt.

As for the rest of the fuel system, if it is made up of modern parts, not 35 year old rubber hose, it should handle it no problem. You could have a problem with varnish and deposits left by gas clogging the fuel filter and pump, because ethanol will clean that crap out real quick. It clogged the pick up sock on one of my cars that had seen nothing but race gas since the mid 90s, so now I have to drop the tank and clean the crud out of it. It needs a bigger system anyway, so its getting a cell and new -8 lines. All the safety stuff you use for gas works with ethanol, except ethanol itself can be extinguished with simple water while the gas in E85 cant. Still it shouldnt be a problem. A half gallon of E85 swished around in the tank and left for a few days should get most of the crud out, its a really nice solvent for that stuff and carbon deposits in engines.

I havent done any two barrel carbs yet, but I have a few I might mess with this year. If you are running a Holley or a Qjet all I need is a quality rebuild kit and the carb, I will convert it for you for the cost of shipping. I test them on one of my engines that is similar to the one its going on before I send them out, the one in Texas works pretty good as do the ones in Nebraska that have been installed. Really need my bud to try that carb, would save him a ton of money on fuel this year.

[Bamfster]

Todd, you should do a full tech article here. I have a spare 700 dp that I would like to learn to tune E85 on, even though the fuel isn't really available around here. I like to learn new stuff and if it ever does become popular here, i'll be 1 step ahead.

[Thumpin455]

Well I have a Holley, and might do a Demon 850 this year too, if I can ever get the camera to shoot in macro I can show what needs to be done. The proper way to get the tune right is a wide band, but you can make it run real easy without one. You need the WBO2 to fine tune it to get the most power and mileage out of it, not to make it run. The stuff is stupid easy to tune and get it to run and make great power.

Interesting thing. This week ethanol is going for $2.20 a gallon on the CBOT while gas is $3.39 last I checked. If you have to run race gas due to compression, ethanol should be looking VERY attractive right about now. Hell even for low compression engines its looking good, provided the stations arent simply gouging the price because they can.

[Bamfster]

And that is precisely why I want to try it .... 105 octane. But, like I said, it's not readily available around here.

[Deaf Bob]

E-85

Don't want you to think I disappeared...
Worked 11 hrs today...
Next derby is April 16 in Pasco WA (4-6 hr drive) getting the car done..
I will take you up on the offer to set up the carb.
I need to get the cam specs from the kid...it is his motor that needs the octane..(11.5-1 or 12-1. Depending on the math..;-((. )
Carb is a Holley 500 cfm 2 barrel.. (4's kick in at the most inoportune moments sometimes)
Fuel line from tank to pump is half inch braided line for fuel..no 35 year old rubber
We run the better stuff... Pays off in the end..

I know some guys do, and many have the concept that derby is just junk to made run for one or 2 shows... We use the same motor/ tranny combos in all our cars.
Each kid has their own combo with the son running the more "built" motor..

This old man is beat... Heading to bed! Being 58 (almost) sucks! Lol...

[Thumpin455]

Got your carb yesterday, going to tear it down tonight and have a look. Havent messed with one of these in a long time, but they are pretty simple. When I make the changes I will shoot some pics of the process, and probably make a video of it running too. Going to need an adapter plate, I dont have any 2 barrel intakes. Not a problem, I can build one pretty easy.

[Deaf Bob]

Glad you got it....
Will put the return postage in the mail...