E85 fuel with carbies

[brook308]

Anyone out there tried to run e85 on their carby car?
I am looking at running e85 to help with detonation on a dellorto blow through turbo.
Any input would be appreciated.
Cheers
George

[Duk]

Me thinks you'll want to get the carby bodies, especially the float bowls, hard anodised.

[brook308]

Me thinks you'll want to get the carby bodies, especially the float bowls, hard anodised.

It's for racing only so I'd be prepared to flush the system with unleaded fuel after each event.
So the e85 would only be used over a 24 to 48 hour period.
Just checking to see if someone has tried this on carbies.

[Duk]

Then it comes down to tuning to compensate for the lower energy density of E85.

[brook308]

As a precaution I have immersed a carby in e85 to see what happens over the next couple of weeks.

[Duk]

As a precaution I have immersed a carby in e85 to see what happens over the next couple of weeks.

I was just thinking (dangerous, I know........... )...................

Fully immersed, there probably won't be much oxidation of the carby body. I'm thinking that it would be the small passages that have fuel flowing thru them when the engine is running. When that fuel flow stops, the passages will still be wet with fuel, but now air will get in there and potentially start the oxidation process. If that's the case, it'll be the oxidation in the passages that may block a passage or flow with the fuel to go and block a jet or an emulsion tube.

Perhaps a simple dunk and allow to air dry, would be more telling than simply plonking it in some E85 for a couple of weeks???

[brook308]

As a precaution I have immersed a carby in e85 to see what happens over the next couple of weeks.

I was just thinking (dangerous, I know........... )...................

Fully immersed, there probably won't be much oxidation of the carby body. I'm thinking that it would be the small passages that have fuel flowing thru them when the engine is running. When that fuel flow stops, the passages will still be wet with fuel, but now air will get in there and potentially start the oxidation process. If that's the case, it'll be the oxidation in the passages that may block a passage or flow with the fuel to go and block a jet or an emulsion tube.

Perhaps a simple dunk and allow to air dry, would be more telling than simply plonking it in some E85 for a couple of weeks???

Good thinking, I'll also just fill a carby with e85 an then let it sit to emulate a sitting car.
This would not be typical if I drain and run bp98 after each meeting. Only problem would be having to change jetting to get the car to run on bp98 each time.

I had a look at my experiment today, no damage so far, plastic floats ok, plastic inlet filter ok, nothing has started to dissolve yet.

Drilled out some spare jets in preparation for e85.
Mains were 160 now 200, with 230 air correction
Idles were 55 now 60
Pumps were 35 now 40

Will test with wide and a/f meter and see how the sizes go.

[brook308]

So my carby soaking in e85 for a week showed no ill effects, all parts ok.
Tested the float level of e85 vs bp98, the float was about 1mm higher in e85 so not a big difference.
Started and ran the car on the above jet sizes, now I just need a dyno session to get the mixtures right.
The car free revs well with the up sized jetting.
All my fuel hoses are relatively new, so is the fuel pump and my tank has also been cleaned when I foam filled it so there shouldn't be too many years of petrol contaminates in the system. As a precaution I ran 5 litres though the system via an electric pump for about 20 minutes before starting the engine.

[carlo rossi]

Really if you own an Alfa WHY?
sell the car if cant afford the fuel
otherwise the ethanol will chew up all things rubber
as I have been advised

[Darryl]

Really if you own an Alfa WHY?

BOOST!

Charge cooling and knock resistance. Should work. Hard to know which "rubber" parts are made out of what exact polymer (they are unlikely to be natural rubber) to know what resistance to ethanol actually is... Interesting experiment - we need to know... FWIW, for an "accelerated" test you could try heating - what could possibly go wrong?!

[brook308]

Really if you own an Alfa WHY?
sell the car if cant afford the fuel
otherwise the ethanol will chew up all things rubber
as I have been advised

Looking for feedback from people with experience not opinions.
Read the 1st post, this is not about saving a few bucks on fuel.

[brook308]

Really if you own an Alfa WHY?

BOOST!

Charge cooling and knock resistance. Should work. Hard to know which "rubber" parts are made out of what exact polymer (they are unlikely to be natural rubber) to know what resistance to ethanol actually is... Interesting experiment - we need to know... FWIW, for an "accelerated" test you could try heating - what could possibly go wrong?!

Cheers Darryl,

Did some tuning today, with my original jet estimates,I was off the mark.
With 200 mains, 230 AC and 65 idles the A/F was too lean, low rpm was 14:1 high rpm was 16.5:1.
Ended up with 245 mains, 230 AC and 75 idles, low rpm is 12:1, high rpm is 13:1.

Testing was done free reving and some paddock runs, need a dyno session or track now to make sure all is ok.

I was surprised how much the jets had to be opened up to get to 12:1 with E85.

Also when I had the float chamber open the rubber gasket I have had swelled with the e85.
The rubber float chamber gasket is unique to force fed dellortos, usually this is a fibre gasket.
So on a stock carby gasket kit the e85 should be ok in the short term at least.

I have flushed the e85 with bp98 in till I get a chance to test again.

So to summarise I have increased the idle jets from 55 to 75, a 37% increase
Main jets from 160 to 245, a 54% increase, these increases didn't quite match those I had researched.
I haven't been able to find any dellorto DHLA e85 conversion info, only Holley etc.

Don't really care to much for economy, just want 12:1 or there abouts through the rev range and some more detonation protection. Also cooler running on E85.
[/list]

[Duk]

Jet numbers are the hole diameter, aren't they???

If so, when crunching numbers for jet sizes, you should be working on the hole's cross sectional area rather than their diameter.

Your idle jet is now 1.859 times larger.

Your main jet is now 2.345 times larger.

[brook308]

Jet numbers are the hole diameter, aren't they???

If so, when crunching numbers for jet sizes, you should be working on the hole's cross sectional area rather than their diameter.

Your idle jet is now 1.859 times larger.

Your main jet is now 2.345 times larger.

Yep, jet sizes are diameters, so that's correct the percentage increase is much greater when you calculate the jet area.

Don't worry it surprised me, my 1st set of jets were supposed to be 40% larger in area but they ran way too lean.
I was starting to think that it would be impossible to jet the dellorto's to provide enough e85 to get to 12:1.
But unless my Innovate Wideband sensor is telling fibs I have to drill the jets out that much to get close. Even at these sizes as the RPM increases the mixture gets leaner but at worst it's 13:1.

The car runs 50/50 water methanol injection on boost so this should bring the 13:1 down to 12:1 hopefully at high revs and boost.

[LaStregaNera]

I think a problem you might run into is that E85 is not consistently 85% ethanol, it moves around a bit depending on time of year - this will knock your jetting around. Of course, not a problem on a wideband equipped injected car.