E85Forum.com

dangstang · Joined: 28 Feb 2010 Posts: 3

I have a 351 stroker (11.25+/-.25 comp ratio) that runs great on a 60/40 mix of 110/93 or a 60/40 mix of 93/toulene(114) I am looking for a potential e85 mix in which I can utilize my gas demon carb. I am willing to tune the carb ( jets, pumps etc.) I guess what I am really asking is (generally speaking) what % of e85 can my gas demon support in a homebrew with just tuning mods. Might be willing to go to specialized metering blocks or any other non-permanent mod that will allow me to run a significantlly higher % of E-85. I do want to be able to change the carb back to "gas only" easily, if I want to.

Alcohol · Joined: 17 Apr 2007 Posts: 634 Location: Central Wisconsin

I'll leave the carb part for Thumpin, Drag Chevette, or others. When you say homebrew- do you really mean homebrew hydrous ethanol or the more common US fuel grade spec annhydrous (dry) 200 proof ethanol? If you intend to use homebrew of 190 proof or a lower proof (more water) then Thumpin is going to need to advise you. At some increased level of water in lower proofs you will not be able to blend it with gas at all since they will phase separate. Some home brewers will use zeolite to dry it beyond the 190 proof level.

You will want to define your ethanol type (proof) before folks can give you good answers.

Thumpin455 · Joined: 04 Oct 2008 Posts: 227

Depending on what your engine wants and the jets in the carb it has now, you can get a varied amount of capability by splash mixing. Splash mixing is adding E85 to your tank along with gas from another pump. Its a trial and error thing with a carb, just like tuning for best power or ET. Every engine will want something different.

There will be a point where if you add more E85 to the tank the passages in the carb will be too small and it will go perpetually lean. The carb just wont flow enough fuel to run straight E85 and larger jets wont fix the problem. Finding that will require you to add a certain amount of gas, then a certain amount of E85 and find out what the engine likes with the biggest jets that actually make a difference. That is why you dont see too many flex fuel carbs, its either one or the other and varied amounts of gasoline or ethanol will make a difference in how it runs and what it needs.

The carbs I set up for ethanol, be it hydrous that I make or E85 I get at a pump, are dedicated to that amount of ethanol. If I want to run straight gas or 10% then I switch carbs. Its too much hassle for me to figure out how much ethanol is already in the tank and how much gas might be in it. So I do one or the other and forget about splash blending. Besides if you can get E85 nearby, and you make the switch to it in your race gas compression engine, you wont want to switch back provided you get the carb right. There is a big difference between it runs and it runs right or good.

Homebrew usually refers to someone who makes ethanol fuel at home from various plants and it is most often a hydrous ethanol since you cant get all of the water out. You can mix it with gasoline, but if you let it sit for a day or two it separates the gas from the ethanol. More water makes it happen faster as does a smaller sample, its all about percentage and how much of each is in the fuel.
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1970 Pontiac GeTOh 455 with a Qjet.
1998 Pontiac Formula LS1 on yeast pee.

dangstang · Joined: 28 Feb 2010 Posts: 3

Just trying to ascertain if pump e85 mixed with 93 or 93/toulene mix is a viable alternative using my demon. Was hoping that maybe someone else may be using something similar with a mildly modded carb. Trying to curb the costs of toulene and race gas and the hassel of going to the speed shop and paint store so often. I know going all the way with a complete e85 carb conversion is really the cats meow on this site and if I had more compression it would be done already. Thought maybe with my mediocre compression I could use a gallon or 2 and reap some of e85's benefits.

dangstang · Joined: 28 Feb 2010 Posts: 3

OK not looking 4 a homebrew so I guess I could call it a ghetto mix.

Thumpin455 · Joined: 04 Oct 2008 Posts: 227

You dont need high compression to run E85, the point is you can if you have it. Smile

I am running it in a 9:1 455 and it still has all the benefits like running cooler, allows more timing, makes more bottom end/mid range, etc.

If you go through the carb specs sticky at the top of this section you can get the info you need to convert a carb yourself. The big expense is a numbered drill bit set and a pin vise to hold the really small bits. Pick up an old Holley at a swap meet if you dont have one and go through it, Then you can try it out and simplify your life so you dont have to run to the paint store to go racing. Smile

_________________
1970 Pontiac GeTOh 455 with a Qjet.
1998 Pontiac Formula LS1 on yeast pee.