Author Topic: E-85 conversion for a supercharged carbureted street engine  (Read 3838 times)

0 Members and 1 Guest are viewing this topic.

Offline Milwaukee Midget

  • Global Moderator
  • Hero Member
  • ***
  • Posts: 6662
    • Milwaukee Midget Racing
E-85 conversion for a supercharged carbureted street engine
« on: August 04, 2008, 12:45:21 AM »
Non-LSR topic for sure, but I've been toying with the idea of converting my MGB over to E-85.  What attracts me to this fuel is that it's readily available here in Wisconsin and most places I travel to here in the midwest, and that the octane is 100+.

The car in question is my street driven 72 MGB, which is completely stock with the exception of the Moss Motors Supercharger kit.  If you're interested, you can view the kit at

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=37878 

I know I'll take a hit on MPG, but I sure would like to up the boost and keep some timing advance so it's a little quicker off of the mark.  Inconsistent premium fuel quality has also lead me down this path - with reformulated premium in my part of the state, I have no problems - but outside of the southeast quadrant and whenever I cross over into Iowa, I have to back off the timing a tick or two.

When it comes to alcohol, I'm dumb as a post, whether I'm fueling an engine or fueling another rant.

If I follow through with this, what do I need to be paying attention to on the conversion?  Any thoughts, experiences with E-85 or alcohol as a fuel?  What kind of air/fuel ratio should I be dialing in? 

I'm not committed to it yet, but any input would be appreciated.

Thanks. 

"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline hotrod

  • Hero Member
  • *****
  • Posts: 1231
    • Black Horse photo
Re: E-85 conversion for a supercharged carbureted street engine
« Reply #1 on: August 04, 2008, 01:11:22 AM »
It is very doable, and not difficult at all.

basically you need to add about 30% extra fuel flow. Use timing appropriate for a 105 -112 octane fuel, and you are good to go.

AFR's on a gasoline calibrated wide band will probably be about as below. These are what I run on my turbocharged Subaru WRX.

Idle it likes 13.8:1 or lambda 0.94
light throttle cruise up to 1 bar to 1.3 bar manifold pressure you can run 14.7 - 15.2 (lambda 1.0 - 1.03)
moderate acceleration boost up to 10 psig, 12.0 (lambda 0.82)
WOT max load 12.0 - 10.6 (lambda 0.82 - 0.72) depends on what the engine likes.

You might drop over on one of the E85 specialty boards and check in for some real world experience with the fuel.

http://e85forum.com/index.php (performance oriented forum)
http://e85vehicles.com/ (general e85 discussion and conversions - less technical/performance oriented)

Or you might find my E85 FAQ on one of the Subaru boards useful:
It is currently 67 pages long but the basics are in the first couple pages.
http://forums.nasioc.com/forums/showthread.php?t=803341


Given the age and origin of the car, you will want to replace all your rubber fuel hose with modern EFI rated fuel hose. It seems to be very tolerant of E85. Any rubber diaphragms like in fuel pumps or carburator accelerator pumps etc. that contact the fuel might need to be replaced. Cars manufactured after 1990 are generally fine with 85 but the earlier manufacture cars may have some issues with gaskets. Rubber/cork composite gaskets are one "do not use" material. Does your fuel system include any zinc or magnesium components? If so you want to replace them with other materials. Fuel compatibility is generally an over blown issue but it is something you should pay attention to on the older cars that might have pot metal carburetors etc.

The fuel itself is fantastic for boosted applications it is practically detonation proof at any reasonable mixture and timing on boost levels likely to be run on the street. It also with no other changes will give you a 5% 10% increase in midrange torque and power in most cases.

Larry


« Last Edit: August 04, 2008, 01:22:04 AM by hotrod »

Offline Dean Los Angeles

  • Hero Member
  • *****
  • Posts: 2370
Re: E-85 conversion for a supercharged carbureted street engine
« Reply #2 on: August 04, 2008, 10:53:29 AM »
Larry was spot on, as usual.

Ethanol will chew up and spit out the diaphragm in the fuel pump, will corrode zinc or magnesium to nothing. Rubber parts that are attacked look all bloated and puckered.

I saw an engine that ran methanol that had fuel sitting in it for two months. Their was a magnesium part that turned to powder. The outline of the part was the only thing left. Ethanol will have the same effect.

I discovered the effects on rubber when I dumped some old fuel in the gas tank of my truck. It sorta stopped running.
Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
Just remember . . . It isn't life or death.
It's bigger than life or death! It's RACING.

Offline hotrod

  • Hero Member
  • *****
  • Posts: 1231
    • Black Horse photo
Re: E-85 conversion for a supercharged carbureted street engine
« Reply #3 on: August 04, 2008, 05:55:29 PM »
E85 is much less aggressive than regular racing methanol but it does have mild corrosive effects that sometimes bite folks on classic cars. On the newer cars we have essentially zero issues with fuel system compatibility since they are all designed to run 10% ethanol. U.S. spec E85 now contains corrosion inhibitors, and they closely control fuel acidity from sulfur and acetic acid that can show up in home brew alcohols. The gasoline fraction unlike racing methanol seems to act to pacify metal. The ethanol plants use plain everyday mild steel tanks to hold their ethanol prior to shipment and blending.

We even use non-ethanol rated after market electric fuel pumps with no problems in our conversions, and it does a marvelous job of cleaning the fuel tanks they look like new tanks when you take the inspection cover off. Several of us have years of use on full E85 conversions with no modifications to the fuel pump or fuel system and no problems of any kind.

Denver Colorado was the first U.S. City to mandate ethanol added to fuel to fight ozone, and carbon monoxide pollution in 1988. At that time I had a 1968 VW, and about 2 weeks after the conversion I found a puddle of gasoline under the car when I came out in the morning to go to work. The 20 year old cotton reinforced rubber fuel line off the tank had decided it did not like ethanol and was dripping like a leaky faucet. I replaced that hose with over the counter fuel line from NAPA and never had another problem with it.

I have heard of some classic car buffs having problems with the fuel pump diaphragms and accelerator pump diaphragms on old cars that still had OEM fuel pumps and carburetors parts. Once those were replaced with modern after market replacements no problems as the newer rebuilds have parts intended to be exposed to ethanol added fuels.

They briefly tried a similar mixture to E85 called M85 that was a mix of 85% methanol and gasoline but it did have major problems with fuel compatibility which is why it is not seen much any more.

Larry

Offline Milwaukee Midget

  • Global Moderator
  • Hero Member
  • ***
  • Posts: 6662
    • Milwaukee Midget Racing
Re: E-85 conversion for a supercharged carbureted street engine
« Reply #4 on: August 04, 2008, 09:02:30 PM »
Thanks, Dean and Larry -

Let me pump this vast well of knowledge a little further.  The fuel pump is an electric SU which has always been problematic.  Is there a pump that either of you would recommend?  I think I need ~5psi - need to look that up.

Changing out lines should be no big deal. 

FYI - The carb is a modern SU (oxymoron) HIF44 that has worked well with a 10% blended fuel for 3 years.  It has no accelerator pump. 

You mentioned zinc and magnesium - I'll follow through on that, but I think the body of the carb is an aluminum die casting.  Are brass fittings an issue?

Anything inside my supercharger I need to concern myself with?

Grateful for the help!

Sincerely,

Chris 
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline hotrod

  • Hero Member
  • *****
  • Posts: 1231
    • Black Horse photo
Re: E-85 conversion for a supercharged carbureted street engine
« Reply #5 on: August 04, 2008, 09:19:32 PM »
Brass fittings do not seem to be a problem, at least no one is reporting issues in that regard.

Most of the turbo import crowd use the walbro GSS-342 pump which is a high pressure EFi pump. It is the same pump used in the Dodge viper.
Although it is not rated for ethanol it seems to have an acceptable lifetime in the real world. I sent one back to Walbro for analysis after 35,000 miles of use and about 3-4 years of E85 usage and they were surprised to find very little sign of wear.

I would suggest you check to see if Walbro makes a replacement pump for yours and give that a try.
As mentioned earlier, cars manufactured after 1990 all are ethanol compatible in order to handle 10% fuel ethanol blending, so if your fuel pump is used in any modern manufacture car a new over the counter replacement would probably work okay.

If you have a good relationship with a local NAPA car parts outlet, see if they will let you browse through their fuel pump catalog, or order an Airtex fuel pump catalog for you. It has good appendix info in it showing pictures of fuel pumps and common usage for them and you can probably find a modern car that has essentially the same packaging. If all else fails a new after market "inline electric fuel pump" would work, just install it near the fuel tank so it is pushing the fuel and you should be good to go.

At least that is where I would start.

Larry