E85 L20B

[JumboFett]

Hey y’all,

Is anybody out there running E85 in their 620? If so, would you mind sharing a breakdown of what you did to make it work? Thank you 🙏 

[datzenmike]

 You can only run about 10% ethanol in a carbureted engine which is jetted for gasoline but will run if diluted with up to 10%.  E85 is for EFI engines designed to work on 'FlexFuels' where the air fuel mix is electronically calibrated to add more of the lower energy containing ethanol.

[JumboFett]

59 minutes ago, datzenmike said:

 You can only run about 10% ethanol in a carbureted engine which is jetted for gasoline but will run if diluted with up to 10%.  E85 is for EFI engines designed to work on 'FlexFuels' where the air fuel mix is electronically calibrated to add more of the lower energy containing ethanol.

Oh fer sher. I’m aware that I’d have to re-jet my Weber to be much richer, as well as use a higher flow fuel pump, I’m just curious to know if there’s a pump/jet combo that’s known to the community. I’d also likely have to increase compression to 11+:1 to get any significant increase in power. 

[datzenmike]

As long as the supply of E85 is available and cheaper then yes. Propane was a big thing decades ago and there were conversions. Does anyone run propane or LPG today????

[JumboFett]

24 minutes ago, datzenmike said:

As long as the supply of E85 is available and cheaper then yes. Propane was a big thing decades ago and there were conversions. Does anyone run propane or LPG today????

Only with diesel, but unlike propane as an automotive fuel E85 has continued to grow in availability. Renewables and EV are the future, I just wanna keep my options open. 

[Dusten]

5 hours ago, datzenmike said:

 You can only run about 10% ethanol in a carbureted engine which is jetted for gasoline but will run if diluted with up to 10%.  E85 is for EFI engines designed to work on 'FlexFuels' where the air fuel mix is electronically calibrated to add more of the lower energy containing ethanol.

 

I disagree it's for EFI.  It's for anyone who wants more power than pump 92/93 can support and has the ability to dial in afr.

 

Add a wide band to a carb'd rig, and jet it appropriately.

Typically e85 needs 30% more fuel than 92 octane to support the needed afr.  

 

My concern is e85 that is hard on rubber.  You'll need to replace all the lines with ptfe lines and run e85 safe carb.  Any unanodized aluminum will corrode and any rubber in the carb will degrade.  

 

I don't think you'll gain much power for the cost of making the truck compliant.  

 

My e85 tune in my lightning is about 125hp more than my pump gas tune. 

But I turn up the boost and timing.  

19lbs and 11* on 92

23lbs and 17* on e85

 

On a motor that isn't going to see much gain from a few degrees timing and doesn't need the added benefit of how cool e85 runs, it really doesn't make sense to swap.

 

If you built a high compression l20b with a cam and some headwork. Id say go for it.  

[datzenmike]

... or turbo.

[Dusten]

If you're going to go through the effort to fab a turbo exhaust manifold and source a reliable blow through carb for an l20b just go EFI.  

[datzenmike]

E85 is not 85% ethanol. It can be, but is somewhere allowed to be between 51% and 85% ethanol, so, so much for accurate jetting between tank fulls. EFI Flex fuel vehicles can easily run perfectly on this and straight gas and are self adjusting for mix and ignition timing. I think flex fuel engines also run higher compression ratios that the 8.4 of an L20B

[Dusten]

4 hours ago, datzenmike said:

E85 is not 85% ethanol. It can be, but is somewhere allowed to be between 51% and 85% ethanol, so, so much for accurate jetting between tank fulls. EFI Flex fuel vehicles can easily run perfectly on this and straight gas and are self adjusting for mix and ignition timing. I think flex fuel engines also run higher compression ratios that the 8.4 of an L20B

 

 

I'm aware.  I run it exclusively and have for years.  You can buy e85 in barrel.  My local station runs e80-e90.  I've never seen less than 80.  

 

My tune is basically safe to e70 and I test each tank.  Few stock ecus can run flex fuel.  

[paradime]

18 hours ago, Dusten said:

 

I disagree it's for EFI.  It's for anyone who wants more power than pump 92/93 can support and has the ability to dial in afr.

 

If you built a high compression l20b with a cam and some headwork. Id say go for it.  

True words, but I think these points need more for a practical context. From a NA L20, at very least you'd need 11.5:1 compression, before seeing any power gain over pump 92 gas. One of ethanol's  biggest benefits is nock suppression. NA drag cars are running 16:1 on e100, but that's with a billet alloy custom designed and built engine. 

 

Real power gain from e85 comes from forced induction. Under enough pressure it has as much as 107 relative oct, but doing 12 psi right on an L20 is serious $ and requires tons of peripheral upgrades, monitoring, and control tech that needs addressing. If you're hell bent on running e85, for a draw through turbo setup I'd recommend a plate efi system. It's worth every penny, because it would make your life SO much easier.  On our SR20 swapped 510 with flex fuel capability, my brother and I have been running e85 from a barrel for over a decade. IMHO that stuff is the bomb. Although this has likely more to do with it's tune, but at 22 psi there is at least a 25% power difference between 98 race gas vs Ethanol, and even with reduced timing, gas runs much hotter. 

 

 Either way, the L series with same side intake exhaust, and comparatively poor flow characteristics, it's not an ideal platform for e85, and certainly not the most cost effective way to get power out of them. 

 

That said, it would be an interesting challenge to make it work.