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Discussion Starter · #1 ·
So, now I'm looking at converting to E85 on my 383 even sooner... FJB!
I had been pondering the Sniper or FiTech throttle body injection, but have also been looking at the ATM Innovation E85 carbs.
The EFI will require a new electric pump, return line, another sensor installation, etc., which are reasons that I'm considering just going with a carb for now. Also, I've just recently installed a dual wideband AFR gauge that I bought some time back.

So I'd like to get more info and opinions to see if there are things I'm unaware of when running E85 with a carb.
I saw something somewhere that mentioned needing to run a return line even with a carb, when running E85...
Any info on that, as well as any other considerations with E85 would be appreciated, especially as it relates to limitations of carb vs. FI.

Thanks!
 

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I know nothing about E85 carbs but a long time ago I tried to run a blend of E85 aand premium gas , a 2:1 ratio to start, didn’t work, I keep adjusting ratio, finally I was back to straight gas. I tried blending just because I needed higher octane, I was trying to stay mostly gas. I could not open the idle circuit enough to idle. I also see you plan to buy carb set for E85, so you should be good, enough storie time.

I have been fighting with Sniper EFI for last few years, it is not just plug and play, no way no how, to run E85 in it I think you would need a custom unit, unless Holley offers an e85 unit. Reason I say customone is because the injectors would need to be larger flow units, because of it taking more fuel volume to make engine run, it might be a combo of higher pressure and larger injectors as well.
A few things I learned on this sniper swap, on old car is, lots of good grounds are needed to help eliminate noise. Also old car alternators are a big source of the noise and they cannot keep up with the power needs of electric fuel pumps, electric fans, injectors and computers at least in idle conditions. Newer alternators provide clean power a decent amount in idle conditions. So. you might need to adapt a newer alternator, technology wise to support electrical load.
I am sure either system can be done, it’s all going to depend on how much time and money you want spend setting either system up.

Oh and if you go efi, plan on running the distributor unit that works with efi unit, if Holley it will be hyper spark. If you do you might as well get the ability to control the timing as well, with the distributor in the loop you will be running basically 94,95,96 GM truck technology, on old car.
 

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E85 requires more fuel be delivered to the metering unit. This is the result that the stoichiometric mixture with alcohol requires more fuel than gasoline. So EFI requires a different programming to add duty cycle to the injectors and may also require a higher flow injector and or higher pressure pump as more fuel needs to be supplied in the allotted on time of the injector.

A carb needs to be rejected to perform the same effort of increasing the amount of fuel available to the engine. That is going to touch on larger jets sizes from fuel metering to air correction and probably the locations and amounts of number and sizes of the bleed holes of the emulsion system.

Obviously the fuel pump and system needs to be sized to deliver about 40 percent more fuel for E85 compared to gasoline up to an E10 blend.

The pump for EFI excluding the low pressure (20psi) systems used by the OEM TBI systems of about 30 years ago, the high pressure systems (40-60psi) both OEM and aftermarket use an electric pump that needs to be cooled while the pressure and volume need to be managed at a constant value regardless of the rate of consumption. There are two ways of satisfing the cooling and pressure/volume requirements by either plumbing an peak flow pump that runs all with plumbing that includes a bypassing regulator and a return line for the unused fuel fraction. The other method is called Pulse Width Modulation (PWM) which uses a pressure sensor to a computer that rapidly switches the pump motor between lengths of on to off time ratios to manage the pressure, this trades the regulator and return line for a sensor and electronic module. The OEMs went from bypass systems (1985-1995) to PWM in 1996.

Given modern fuels have pretty low vapor points to make port and direct injection systems happy the old time engine driven and mounted fuel pump can be given to vapor lock problems more so than the pre EFI days, so going electric with the pump mounted by if not in the tank pretty much eliminates vapor lock issues when feeding a carb.

To meet your needs with a carb on E85 you need a high volume pump with moderate pressure. A way to get that is a high volume low pressure type pump for low pressure EFI mounted adjacent to the tank with a bypass regulator under the hood with a return line to the tank. This insures that at from idle to WOT the fuel pressure is constant regardless of tge volume being consumed by the engine because the installed system is sized to supply more fuel than the engine will ever consume therefore the pressure to the carb or to an EFI is always constant. Engine driven pumps can and do run out of fuel up on the top end because they run out of time to draw a full chamber capacity at WOT unless you oversize the pump which brings you back to the need for a bypass regulator and return. The OEMs did this on carbs with mechanical pumps near the end of production use of carbs to get better fuel ratio stabilization in their constant battle of optimizing fuel economy with power with emissions. So they got to the point of discovering that stabilizing the fuel flow at the carb reaped benefits in all of these categories plus got rid of vapor lock issues.

By far most of my builds over the last couple decades use electric pumps, preferably in the tank, with bypass regulation and return lines.

Bogie
 

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Discussion Starter · #4 · (Edited)
Thanks for the feedback.
I forgot to mention that my current fuel pump is an Edelbrock Quiet Flo electric pump, mounted inline, just in front of the rear axle.
It is rated at 120gph/454lph, and 6.5 psi max.
I just did some research, and according to what I saw, it looks like the flow would be enough for up to 500HP on E85, if the info I saw is correct. This would obviously only be used for carb...
However, I also ran across the apparent fact that pump E85 can vary considerably in its Ethanol content.
So I'm assuming that this would not work with a carburetor...
I'll have to see if the EFI handles that any better.

FJB! (n)
 

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There's a lot of E85 BS all over the internet so don't read too much on google.
Your pump is fine.
HP innovations and Mark Sullens are the two carbs guys to talk too. Pick one and listen to them, not your buddies, not the internet, not the fluff in magazines and TV. Trust me on that deal.
Pump E85 does vary to a degree, more on that later, but it's also not really a problem UNLESS bracket racing and chasing 10ths.
 

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Discussion Starter · #6 · (Edited)
Thanks for the info jonhsongrass1.
As long as it runs fine on the pump E85, that's good enough.
They finally officially closed AutoClub Dragway in Fontana, so I won't be chasing much... just want it to go fast when I tell it to...
My tank sending unit has a 3/8" nipple... I'll have to ask the E85 carb guys if I'll need bigger line for up to 450HP on E85. (383 with 230/236 HR cam).
 

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Along with Eric Neifert @ Horsepower Innovations and Mark Sullens E85 Carburetors, ....add Mark Whitener @ Lightning Racing Carburetors to the list.

Like Johnsongrass1 posted, anything between E75 and E90 will run about the same unless you are chasing hundredths on the ET slip.
Very forgiving fuel in that respect, much like straight Ethanol or Methanol.

There are simple testers you can get to carry in the truck, to test % at the station before you fill up.
 

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Discussion Starter · #9 ·
I have been fighting with Sniper EFI for last few years, it is not just plug and play, no way no how, to run E85 in it I think you would need a custom unit, unless Holley offers an e85 unit.
The Sniper and FiTech units are E85 compatible... however, you have to buy the higher HP rated units to get a lower actual HP with E85.
So, the 600HP unit is only good up to 425 or 450... so for more than that, you need to get the 800HP unit.
 

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Discussion Starter · #10 ·
Along with Eric Neifert @ Horsepower Innovations and Mark Sullens E85 Carburetors, ....add Mark Whitener @ Lightning Racing Carburetors to the list.

Like Johnsongrass1 posted, anything between E75 and E90 will run about the same unless you are chasing hundredths on the ET slip.
Very forgiving fuel in that respect, much like straight Ethanol or Methanol.

There are simple testers you can get to carry in the truck, to test % at the station before you fill up.
Thanks Eric!
It looks like an HP Innovations carb is just about $75 more ($740) than a comparable ATM Innovation one ($666.67)...
Any opinion on the ATM carbs? I guess the knowledge is as important as the carb itself.
LRC doesn't have a website, so I'll have to see if he does anything in that price range... his FB page has some nice stuff, but looks $$$$

XRB Series E85 Carburetor | ATM Innovation

Products and Serivces | Horsepower Innovations

(20+) Lightning Racing Carburetors | Facebook
 

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Lots of companies filling the market demand on E85 but Eric at HP and Mark are the only two I trust because E85 IS ALL they do. Nothing else at all so they specialize in it's uniqueness and aren't just filling a market desire. Mark is my go too because he is literally a little under 20 minutes from my house with traffic. Mark is at the shop 6-9 every evening if you wanna call and chat. Eric likes texting and email, always very responsive.
 

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Mark Moderates the FB page and is active there. He still takes calls and emails from the web page. His pricing is very depenadant as each carb is custom to suit the one application. Cookie cutter pricing doesn't cut it. Log into Facebook
 

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Discussion Starter · #14 · (Edited)
Wow, Mark's Facebook page made me realize that there could be much more to running E85 than I thought.
The discussions that I saw seemed very much "serious drag racing" focused, and gave me the impression that running E85 could be more precarious than I thought... starting issues, timing issues, etc. Varied opinions as well.

So my situation is mostly street driving, with some 1/4-mile runs for fun... maybe some Street Legal Drags. No "daily" driving, just for fun.
Compression is ~9.5:1
Ignition is an MSD Street Fire distributor... no timing control.
Simple inline 120gph electric pump, no return line.

Am I fooling myself thinking that I can just bolt on an E85 carb, tune and go?
Would I just be creating headaches for myself, or would my situation be less problematic than the serious drag racing scenarios seen on Mark's FB?
Just trying to ascertain if a carb will be less hassle than EFI implementation, before I start discussing carb specifics with an E85 carb builder.

Thanks for any feedback on this.
 

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You missed this in my post 5.
"Pick one and listen to them, not your buddies, not the internet, not the fluff in magazines and TV. Trust me on that deal."

Yeah, most guys on the FB are serious straight liners chasing brackets and even heads up style running gobs of NO2, Forced induction, etc.....
There are also a whole lot of guys and gals using E on the street too. It's really pretty easy to get along with. Refer back to what I said at the beginning of this post or shoot me and PM if you prefer.
 

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If that's the soul question, EFI on ethanol if at all possible. Also, a good carb isn't much difference than EFI when set up right, it's hard to tell the difference.
 

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To me; just me, I feel like there really is not much gain for the money in a gussied up TBI. If you're going to go EFI? its port efi or bust. So if you're a carb/distributor guy? Stay carb and distributor. If you're just 'over' tuning carbs and swapping springs? Then get a tablet and learn something new. I love EFI and I doubt I'll ever go back, unless I did a really traditional build
 
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