E85Forum.com

Dennis Krawchuk · Joined: 15 Feb 2011 Posts: 4 Location: Algonquin, il.

Hi guys, I'm new here so please excuse any dumb questions. This may be 1. How much E85 can be mixed with 100 octane gasoline with out having to go thru major carb alterations? I curently drive a sbc 383 with alum heads, 11:1 cr, lunati cam and an air gap manifold. Any info would be great.

Dennis

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Welcome to the board.

I will let the carburetor wizards give you definitive information but can pass on some reference points to consider.

Part of the answer of course depends on how "lean and mean" your current jetting is. If your mixture is fat to control detonation, you have more latitude for added ethanol than someone that has spent time pushing the mixture towards the lean limit of good performance.

When Brazil was considering switching to an ethanol fuel economy they ran tests on cars of the period to find out what level of added ethanol would work in unmodified cars. As I recall they result of their tests was that up to 22% ethanol could be run in all currently available cars (almost all of them running carburetors) without making any changes in the fuel system or the tune.

That was one of the reasons they set one of the alternate fuel blends to be 20% ethanol by volume.

http://en.wikipedia.org/wiki/History_of_ethanol_fuel_in_Brazil

This is probably your best base line for what works in almost all cars with out any fuel system or tuning changes.

Some cars will be more tolerant of higher ethanol percentages depending on what the engine needs. Ethanol's high natural octane and cool combustion, makes many of the high performance V8 engines quite happy even on blends of pump premium and E85.

Larry

Dennis Krawchuk · Joined: 15 Feb 2011 Posts: 4 Location: Algonquin, il.

Thanks for the reply. The major reason I'm thinking this way is cost and performance. Currently I use a 100 octane gasoline and this being a street vehicle (1960 Apache 10 truck), I'm concerned about what the cost of fuel is going to be this summer, last year we were paying as much as $5.69/gal. I bought the engine from a guy getting a divorce about 20 years ago, who cared about the price of gas back then? This could really get to be a long story. Any way I have what I have. If I'm going to do a complete carb rebuild or not, I still haven't determined that yet. The carb I have now is BG speed demon 750. Sad

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

If all you need is 100 octane, I would bet your engine would be fat dumb and happy on 3 gallons of E85 in every 15 in the tank.

3x.85=2.55 gallons of ethanol content on summer blend E85

12x.10 = 1.2 gallons of ethanol content in 12 gallons of E10 pump premium, would give you a total ethanol percentage of 3.75 gallons of ethanol out of 15 gallons of fuel or about a 25% ethanol blend.

The calculated octane for that blend would be in the very high 90 octane range somewhere near 97 octane. Since high ethanol blends have higher effective octane than the normal octane measuring methods give, I would be surprised if the engine did not like it just as well as the 100 octane you are currently running.

Larry

Dennis Krawchuk · Joined: 15 Feb 2011 Posts: 4 Location: Algonquin, il.

Thanks a lot Larry, I'm on my way to figure out the advantages of E85. The cost savings is already got my attention and if the performance end is just as interesting I maybe tearing my Barry Grant apart. I don't know what the changes involve yet, but by days end I'll know if it's something I can do or if I need someone with more precise equiptment than I have.

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

If you are thinking of going all the way to E85 in that BG carb and this is not a daily driver year round then seriously consider sending that carb out to a carb rebuilder such as Mark Sullens: http://marksullense85.proboards.com/index.cgi?

The reason I say to do this rather than doing it yourself with conversion kits from some of the carb parts providers is 2 fold;
1) what Mark charges is not a whole lot more than the kits
2) he has a ton of experience with his own and other folks racing on E85
3) time is money too- it will take you a while to figure it out and dial in your tune.
4) a good carb rebuilder will be available by phone to help should the calibration need a tweek
5) recently at least one of the metering kit makers has been sending out improperly calibrated kits- problems in the metering blocks that have stumped some pretty knowledgeable tuners- Mark does his own so this is not a problem.

If you want to keep this carb for possible future use on gas and are considering a new E85 carb then look real hard at Eric: http://www.horsepowerinnovations.com/index.html

Understand also that if you go to full E85 that you MAY need to upgrade parts of your fuel system for added delivery or for best long term protection from corrosion (BUT NOTHING LIKE IS REQUIRED FOR METHANOL).

So how do you use this car- what are your goals for it?

Dennis Krawchuk · Joined: 15 Feb 2011 Posts: 4 Location: Algonquin, il.

Hi Alcohol, my truck is not a dailey driver. It is a fair weather ride. I use for s@%$s & giggles, cruise nights and when ever the time allows. It runs real nice, I haven't taken it to the track yet because if I break it I have no way to get it home. The rear tires are M/T Sportsman Pro's 33 x 21.5 x 15 and they are turned by a manual shift dialed in th400 with a Dana 60 narrowed 13" turning a 4.88 detroit locker completely built by Strange Engineering. Ya I'm an OLD school dumb ass that drives that on the street. I will take all of your advice and look into Mark Sullens. I also have 2 holley carbs doing nothing, maybe I could take one of those and have Mark tweek with it and just do a swap. As for the fuel supply system, it is all -8 ss with a Holley blue pump below the 20 gal. fuel tank. You guys on this forum are WAY helpful and I am very appreciative. I will also check out horse power inovations. After your post I don't think I would try the conversion my self, it's just notsomething that if I screw it up I could weld or machine the fix myself. Thank again I will keep you posted as to what the hell I'm doing.

Thanks,
Dennis

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

Sounds like a nice truck Dennis !

I sound like I am a salesman for Mark and Eric but I am not Laughing

Just saw too many guys try to do their own carb conversion and get really frustrated. Some nail it right off but it seems like a large % have a lot of trouble getting the tune right. Mark keeps files on all his calibrations and what worked and what did not for the last several years on different combinations (as does Eric). Tuning on E85 is so different than what the normal carb shop does they often have a lot of trouble.

It is helpful that your truck is a fair weather ride since it is a carb- E85 is 85% in the summer only and the Federal standards require station operators to change blends into fall (approx E78, winter (approx E70), and Spring (E78). With those blends for fall/spring (and even more so winter's 70% E) your carb tuned for E85 (85% ethanol) will go rich- pig rich in winter. My customers that race will barrel up summer blend in late August to finish the season and start next season. This keeps them from having to change jets.

Mark will gladly talk you thru this if you call him- he will not however post much on the web because other carb guys will "steal" the info. Larry, myself, or others here will also try to answer any more questions you may have.

BTW- these guys are over on the SE side of Chicago area- I do not know any of them but it looks like it would be fun to see them run (US 41 Track) http://proe85.com/index.php

jmarkaudio · Joined: 22 Oct 2010 Posts: 8 Location: Florida

Two things, first you don't want to mix leaded or metallic additive fuel with ethanol. The metallic additives used to boost octane in gas will LOWER the octane of ethanol. 100 octane unleaded is OK, however the cost of the conversion on one of your carbs will be more than offset by the savings with straight E85.

You can do one yourself, the hardest part is replacing the boosters on a 4150 style carb as the passages MUST be enlarged to get it to perform correctly and it requires a swedging tool to replace them. A Dominator is easier for anyone to do, with the right sized booster pins banjo's and inserts the rest can be done with the right sized drills. Of course you need to know what sizes to use, I'm real close to optimum on my 1150, a 1050 would be no problem getting someone a starting point. If by chance you have an RS Demon with removable boosters, you can modify those without replacing them. All of this depends on your ability to handle a drill bit and tap, and requires patience to do the job.

If you don't want to take the time or have the patience or... Mark or Eric's services are reasonable and worth using.
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Mark Whitener