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e85 conversion #4514758
09/13/17 02:36 AM
09/13/17 02:36 AM
Joined: Aug 2014
Posts: 607
WA
SnowDrifter Offline OP
SnowDrifter  Offline OP
Joined: Aug 2014
Posts: 607
WA
I'm trying to evaluate if it would be practical or even feasible to convert my rig to flex fuel (2005 Tahoe w/ 5.3). I've tried searching and got answers ranging from different injectors (32lb vs 26lb) and the associated reflash to different fuel pumps, soft lines, gas caps, and fuel composition sensors.

I'm at a dead end with my research and have yet to find any reliable info.

Anyone here know anything about it?


2005 Tahoe - 135k
2003 Forester(the swagger wagon) - Rehomed
1999 Passat - Rehomed
Re: e85 conversion [Re: SnowDrifter] #4514769
09/13/17 03:16 AM
09/13/17 03:16 AM
Joined: May 2012
Posts: 5,539
Fort Lauderdale, FL
DoubleWasp Offline
DoubleWasp  Offline
Joined: May 2012
Posts: 5,539
Fort Lauderdale, FL
The sensors make sense. E85 is rarely exactly 85% ethanol, so you would need something to be able to make adjustments according to alcohol content.


07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio
Re: e85 conversion [Re: SnowDrifter] #4514809
09/13/17 06:10 AM
09/13/17 06:10 AM
Joined: Feb 2003
Posts: 7,539
Jupiter, Florida
Cujet Offline
Cujet  Offline
Joined: Feb 2003
Posts: 7,539
Jupiter, Florida
Interestingly, some people find that their non flex fuel vehicles run just fine on E85. I don't know whether your setup is one of those without any issues.

Just a quick search and I found that your vehicle may in fact be flex fuel, without any badges or indication that it is.



QUOTE from link below: "I believe all tahoes of that style are e-85 capable"

http://www.gmtruckclub.com/forum/threads/do-all-00-05-z71-tahoes-accept-e85-fuel.22622/

And according to the old list at ethanol.org, your vehicle will run on E85. 5.3L Vortec-engine Suburban, Tahoe, Yukon and Yukon XLs http://www.walleyecentral.com/forums/archive/index.php/t-41121.html

Last edited by Cujet; 09/13/17 06:16 AM.

People who count on their fingers should maintain a discreet silence.
Re: e85 conversion [Re: SnowDrifter] #4514853
09/13/17 07:17 AM
09/13/17 07:17 AM
Joined: Jun 2003
Posts: 17,494
Deplorable in apple valley, ca
Chris142 Online content
Chris142  Online Content
Joined: Jun 2003
Posts: 17,494
Deplorable in apple valley, ca
Gm shows 2 different vin numbers. The "T" is not e85 compatable I understand and the other is. I do not know where the difference lyes.


02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
Re: e85 conversion [Re: SnowDrifter] #4514857
09/13/17 07:32 AM
09/13/17 07:32 AM
Joined: May 2012
Posts: 1,591
The land of USA-made Subies!
SubieRubyRoo Offline
SubieRubyRoo  Offline
Joined: May 2012
Posts: 1,591
The land of USA-made Subies!
Snow, unless you are getting the e85 for SIGNIFICANTLY cheaper than 87 octane, it will be a lose-lose situation. E85 has about 30% less energy than gasoline, so your mileage will go down accordingly. You don't appear to have a turbo or supercharger, so the cooling effect of the vaporization temp of e85 will be wasted as well, and if your engine is otherwise stock, the roughly 105 octane will hinder combustion as well.

If you're insistent on doing it, yes, you will likely need significant fuel system upgrades to deal with the corrosive nature of ethanol, and you will need injectors that are roughly 50% larger. This isn't including getting your ECM tuned to deal with the additional fueling requirements, and unless your truck had been flex fuel from the factory, fuel composition sensors will probably be waaay more expensive and involved than would ever be worth it. IMHO gasoline has been the primary mover of cars and light trucks for over 100 years for a good reason- it's energy-dense, readily available, and pretty cheap. That's still not going to change anytime soon.

Re: e85 conversion [Re: SnowDrifter] #4514864
09/13/17 07:46 AM
09/13/17 07:46 AM
Joined: Sep 2016
Posts: 513
Vienna, VA
TinyVoices Offline
TinyVoices  Offline
Joined: Sep 2016
Posts: 513
Vienna, VA
For a stock daily driver I would not bother with it. You won't save the money it's going to cost you to set the truck up for e85. You will get worse fuel mileage on e85.

The season people convert their modified cars (turbo cars) to e85 is because you can make more power with a simple tune and you can get it at most gas stations. For your situation, I'd say it's not worth it.


1993 Toyota MR2 Hardtop N/A - 160k miles - Valvoline Max Life 5w30
2006 Toyota Matrix XR AWD (Fiancee) - 130k miles - Valvoline Max Life 5w30
Re: e85 conversion [Re: SnowDrifter] #4514893
09/13/17 08:37 AM
09/13/17 08:37 AM
Joined: Sep 2015
Posts: 5,955
Kalifornia Kollective
BrocLuno Offline
BrocLuno  Offline
Joined: Sep 2015
Posts: 5,955
Kalifornia Kollective
E-85 is a street racers dream. But to get the benefits, you need enough compression to make it worthwhile ... Even w/o boost (turbo, or blower) you can make E-85 work, but it means building an engine for alcohol. You wanna do that ...

I had an issued E-85 Flex Fuel truck at work. Running a basic gasoline motor of roughly 9:1 compression on E-95 was a waste of money and fuel. Sure, it ran OK, but got something like 2/3 the normal mileage, so range was way down. The fuel cost was about the same with the savings on the pump price. Not worth it.

E-85 would be great stuff if it was not made from corn. If it was made from grass or other crops grown on marginal land, sure good stuff. But primary food crop conversion is not a sensible thing.

In Argentina and Brazil where they have a large amount of sugar cane refining by-products, it makes great sense. Here, not so much ...


Formerly in marine engineering. In an earlier life I owned my own petroleum tank truck, and hauled for the majors and independent's.
Re: e85 conversion [Re: BrocLuno] #4514909
09/13/17 08:50 AM
09/13/17 08:50 AM
Joined: Jun 2015
Posts: 4,284
New England
Virtus_Probi Offline
Virtus_Probi  Offline
Joined: Jun 2015
Posts: 4,284
New England
Originally Posted By: BrocLuno
E-85 is a street racers dream. But to get the benefits, you need enough compression to make it worthwhile ... Even w/o boost (turbo, or blower) you can make E-85 work, but it means building an engine for alcohol. You wanna do that ...

I had an issued E-85 Flex Fuel truck at work. Running a basic gasoline motor of roughly 9:1 compression on E-95 was a waste of money and fuel. Sure, it ran OK, but got something like 2/3 the normal mileage, so range was way down. The fuel cost was about the same with the savings on the pump price. Not worth it.

E-85 would be great stuff if it was not made from corn. If it was made from grass or other crops grown on marginal land, sure good stuff. But primary food crop conversion is not a sensible thing.

In Argentina and Brazil where they have a large amount of sugar cane refining by-products, it makes great sense. Here, not so much ...


I know that E85 is popular with Subie turbo modders, but I believe I read that they have to modify the entire fuel delivery system since they need to pump so much more of it in a given time than with gas?? I've never seen an E85 pump around me and there seem to only be a few in all of New England, so E85 is just an academic topic as far as I'm concerned.


2014 Forester XT, 90000 miles
Last Change;
M1 5W30 d1G2
Tokyo Roki 15208AA170 filter
Re: e85 conversion [Re: SnowDrifter] #4514936
09/13/17 09:21 AM
09/13/17 09:21 AM
Joined: Feb 2003
Posts: 7,539
Jupiter, Florida
Cujet Offline
Cujet  Offline
Joined: Feb 2003
Posts: 7,539
Jupiter, Florida
I have a turbo S2000 that I can run on E85, when I want. I have a stand alone computer that is easily configured to either setting.

However, I can easily put E85 in it and drive it home on the conventional gas program. Like most cars, the system operates in closed loop (relies on the (wideband in my case) O2 sensor) to adjust Air/Fuel. It only has lean operation difficulty when under boost on E85 and the Gas program.


People who count on their fingers should maintain a discreet silence.
Re: e85 conversion [Re: SubieRubyRoo] #4515732
09/14/17 01:06 AM
09/14/17 01:06 AM
Joined: Jan 2011
Posts: 571
Anaheim, CA
zorobabel Offline
zorobabel  Offline
Joined: Jan 2011
Posts: 571
Anaheim, CA
Originally Posted By: SubieRubyRoo

If you're insistent on doing it, yes, you will likely need significant fuel system upgrades to deal with the corrosive nature of ethanol, and you will need injectors that are roughly 50% larger. This isn't including getting your ECM tuned to deal with t

I've seen this corrosiveness mentioned a lot, but haven't run into evidence. In my mind, if the rubber can take E10, it should be able to handle E-85.
I do remember a Finn on this board blowing up his Saab engine on E-85-ish fuel.


1997 Maxima 188k, Edge 10w30, K&N HP-1003
2004 Corolla 193k, VWB 5w20 + SSS 10w40, MGL4967
Re: e85 conversion [Re: SnowDrifter] #4515736
09/14/17 01:29 AM
09/14/17 01:29 AM
Joined: Aug 2014
Posts: 607
WA
SnowDrifter Offline OP
SnowDrifter  Offline OP
Joined: Aug 2014
Posts: 607
WA
Looks like the cost/benefit isn't there for this one. Though for anyone interested, the major bits in the conversion require the following: L59 fuel injectors, flex fuel comp sensor ACDelco 12570260, and an ECU for an L59. Will likely need some other minor parts like fuel lines to connect to the fuel comp sensor too


2005 Tahoe - 135k
2003 Forester(the swagger wagon) - Rehomed
1999 Passat - Rehomed
Re: e85 conversion [Re: SnowDrifter] #4520684
09/19/17 08:24 PM
09/19/17 08:24 PM
Joined: Jul 2013
Posts: 1,753
Ottumwa, Iowa
jhellwig Offline
jhellwig  Offline
Joined: Jul 2013
Posts: 1,753
Ottumwa, Iowa
Originally Posted By: SnowDrifter
Looks like the cost/benefit isn't there for this one. Though for anyone interested, the major bits in the conversion require the following: L59 fuel injectors, flex fuel comp sensor ACDelco 12570260, and an ECU for an L59. Will likely need some other minor parts like fuel lines to connect to the fuel comp sensor too


It only takes around a 50 cent spread on these vehicles to make e85 more cost effective.

I think that 04 was the last year gm used the alcohol sensor but I may be wrong. They went off o2 trim after that. You shouldn't need any line upgrades as there wasn't a difference between flex and non.

I have no proof of this but I belieave the only difference between flex fuel vehicles and their non flex fuel twins in the mid to late 2000s is that the money wasn't paid to certify the emmisions for e85.


Sparks fly from my fingers.

1995 Chevy K2500 Suburban lt 5.7
2014 Toyota Sienna
1983 Chevy K5 350

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