Fuel Switching To Corn?

Discussion in 'SN95 4.6L Mustang Tech' started by Nightfire, Aug 31, 2013.

  1. Alright so BASICALLY all I need to run E85 is a retune. Right now my fuel system consists of 60lb injectors, KB BAP, wiring upgrade, and Aviator 310lph pump. Im running about 15psi and am around 500rwhp (haven't had it dynoed yet).

    Would it be worth retuning for the corn and retuning more aggressively? OR am I pretty much at my limit fuel-wise regardless of running E85?
  2. stock block?
  3. The motor is forged.
  4. so, stock block??
  5. Oh, yeah the block itself is the stock block.
  6. The block is kinda a moot point. It won't be the limiting factor here.

    You'll need about 40% more fuel flow at WOT than an equivalent gasoline engine. You typically tune E85 to be a bit richer, hence you'll want even more flow. It runs more happily under rich conditions than gasoline and does.

    So some back of the napkin calcs... whatever the limit of a 42lb injector on gasoline is, that's probably your limit on E85. So around 500rwhp it looks like?

    As you can see, you'll want more injector if you are planning to run more boost. On the turbo forms I frequented before (2.3T), they would typically run 90-120lb injectors for E85. that would ensure you have plenty of capacity without too much difficulty tuning for lower flows.

    As for the fuel pump... It wouldn't surprise me if you quickly approach the limit of that 310lph pump too. I kinda recall the 255lph pump was good to 400-450rwhp on E85, so your 310lph may only be good for 500rwhp.

    Not much reason to run E85 unless you make the tune more aggressive to take advantage of it. Fewer stations have it, it'll cost a little more per mile than pump gas and you'll be stopping more often for gas. But with 105 octane and a really nice cooling effect, you can really turn up the wick.
  7. Alright so I suppose that simply switching to e85 now (without fuel system upgrades) is pointless. I might come back to it sometime down the road.
  8. Might be worth getting a dyno just to see where you are at with power and injector duty cycle.
  9. That is job #1 as soon as I finish breaking in the motor.
  10. The number is closer to 30%, but that's a moot point. He will definitely max that pump (probably already has). Rails and supply/return line will also be an issue. And we keep coming back to the stock block. E85 is also not as much of a easy switch as some make it out to be. In most areas of the USA, you're at a 30 minute minimum trip to get it from a gas station. It doesn't store as well as gasoline does so that becomes an issue as far as needing to purchase a test kit whether you are buying from a station or buying your own 55gallon drum. Just because it says E85 doesn't mean it actually measures as E85 - rarely does.

    Not trying to discourage you from the swap (I'd say go E98 if anything) but you need to be very knowledgeable about doing something like this.
  11. I run E85 in my supercharged 2012 mustang. Here are my thoughts on this.

    I think you will run out of fuel. I have a return-style fuel system on my 12' and i suggest switching to one with larger fuel pumps (I have twin walbro 465lph ones). The aviator pump might not like e85 too. Walbro 465lph ones work well with e85.

    Also, e85 ruined a few o2 sensors on my car because of the way they were positioned in the header. If your sensors are horizontal with the ground, you will most likely have issues with moisture (from the fuel) getting into them and ruining them. Thus, making your car run like crap. If the sensors are more vertical to the ground, you will be fine. I'm not sure this is a problem on new edge cars but better be safe than sorry.

    e85 requires around 20-30% more fuel, not 40%.

    E85 moisture also gets into your oil and dilutes it. You need to heat up your oil, run your car hard, to burn off the oil.

    and cold starts are not an issue and e85 is kinda iffy to get right when trying to tune the driveability of the car. It's not like a 93 tuned or race gas tuned car.

    I use the gas because it reduces detonation and is a safety net. You WILL be fine if e85 tests out to E70 or up(minimun of 70% ethanol). E70 has all of the detonation resistant stuff that E85 does so no worries there. If the gas is diluted down past E70, then you will have trouble with detonation.

    Also, him having a stock block has nothing to do with anything. The actual blocks are pretty strong. The internals are where problems come from.
  12. Yeah, Im not going to bother with it right now. A lot more complicated than I originally thought.
  13. Just a comment on the 40% number. Yes, to maintain the same AF ratio, it is closer to 30% more fuel for stoich conditions. I was saying that at WOT, you'll want to tune an E85 engine to be richer than an equivalent gas engine... hence I rounded up and said 40%. E85 makes peak power at a richer AF ratio than gas and generally tolerates much richer mixtures without loosing power like a gasoline engine would. Hence, take advantage of that fact, especially with a boosted engine. You'll have a safer tune and the benefit of additional cooling due to the fuel.

    Yes, the percentage of ethanol in E85 varies, primarily by season and your location. It can vary between around 90% ethanol in the summer down to 70% in the winter. My solution was simple... using the tweeker, I had two tunes. One for summer and one for winter. As the stations started making the switch over (it is gradual), I would flip the switch. The O2 sensors will compensate and adjust the long term fuel trims to a compensate adequately, even if you did nothing. Heck, I ran E30 in my GT without getting a CEL with no tune at all.

    The twEECer worked well for me. It has 4 different settings, so with the flip of a switch, I can fill the car with gasoline, E85 or any combination there of. I'd have a setting for gas, and 40%, 70% (winter) and 90% ethanol(summer). BTW, I have an E85 station about 4 miles from home (which happens to be between work and home)
    #13 bhuff30, Sep 5, 2013
    Last edited: Sep 5, 2013
  14. Forgot I was in the modular section and not the 5.0 section - LOL on the block comment.

    If it's testing out at E70, the worry is the octane. If you're tuned on E85 and you fill with E70 and don't test it and adjust the tune accordingly, kiss your fancy new forged pistons goodbye.
  15. Not necessarily. If you have a good tuner, who knows how to tune for e85, you can fill up on e70 and be alright.
  16. What, if he leaves 6 degrees of timing out of your E85 tune "just in case" (and therefore a ton of power and throttle response)?
    If you have a spot on 93 tune and you go fill it up with 87 and put a window in a piston, nobody is going to say your tuner "doesn't know how to tune."
    trombonedemon likes this.
  17. This is a conversation between me and 04sleeper on SVTP. Apples to oranges with your 87 to 93 comparison, that is extremely different than the e70 to e85 comparison. I would imagine you have never ran e85 before? and if e70 is such a lower octane than e85, why havent I put a window in my block yet? I've filled up on gas that had an ethanol content lower than 80% multiple times, granted it was above 70% too. You're talking about a tuner that has absolutely no idea what he is doing tuning for ethanol.

    Originally Posted by jymboslice
    Hey man, I saw your post about E85 in the distillery and have a question.

    Is there a difference in the octane or ethanol rating in E85 during the summer months when compared to E85 in the winter months? I heard that E85 is actually like E70 in the winter months. Basically, is there any difference in E85 in the winter months compared to the summer months - is what I'm wondering.

    I'm looking at getting an E85 tune in the springtime and am wondering if I should wait until the summer to get the tune.


    The Octane rating of E85 does not drop off until you get to about the E50 mark. Depending on the supplier of E85, they may choose to lower the ethanol content down to E70 for winter months. This is done for easier starting in cold climates. But adding more gasoline will raise the cost of the fuel so sometimes they don't change it. Here in Texas they do not change to Winter blend.

    If you would like to test the amount of Ethanol it is pretty simple.

    You can buy a simple Ethanol tester like this one.

    Here's a thread on testing it.

    First time testing E85

    If your tuner knows what he is doing, tuning for winter blend will not be a problem come summer time.

    You won't see much of a power difference between E70 and E85 either. Both will make around the same.

    Let me know if you have any other questions.

    Originally Posted by jymboslice
    Hey, thank you for the response. I appreciate it!

    My tuner will most likely be Amazon or JPC racing, I would guess that they know what they are doing?
    Both tune, but I am not sure of their experience tuning E fuels. I would check into making sure that whoever you choose is comfortable tuning E85 as there are many differences.

    I'm going to get one of those Ethanol testing kits and test the E85 in my area.
    Good idea. I recommend keeping one handy and testing on a regular basis to help you understand your area.

    So, if I were to get an E85 tune right now (Using E85 available right now/Winter in MI) I would be ok to use the same tune for the summer blend of E85? All depending on if the supplier changes the ethanol content to E50 or not. I'm not sure if that makes sense or not, this is the first time I've been messing around with E85.

    I would not need two tunes - one for the winter blend (E70, depending on if the gas station switches) and one for the summer blend (Normal E85), right?

    Thanks again

    You tuner should have the ability to provide you one tune for both E85 and E70. If you test the fuel and you actually have E85, then if you fill up with E70, your car will just run a tad richer and won't harm anything.

    If you test your fuel and see you have E70, then tune it a bit on the rich side to begin with and come summer blend you will still be fine.

    One of the great things about E85 is that it has a very wide "Sweet Spot" when it comes to A/F.

    Your tuner should know all of this. (Hopefully)
  18. I have dyno and track experience with E98, E85, and E70 and one customer with E98 on a road course. As a general rule of thumb, a car tuned on E85 runs a half point richer on E70. Not internet folklore, not conjecture, not should-be, would-be. Actual measured wideband.

    If you are running fuel X and you switch to fuel Y, especially with an octane change, you are leaving something on the table without a retune. Sometimes this means leaving a bit of power out that you could have, and sometimes it means making holes in pistons.
  19. How much is that something, though? If it's 10 horsepower at an 800 horsepower level, most people aren't going to be too concerned about that.
  20. It's not always horsepower - often it is throttle response, idle quality, drive ability, off-boost or tip-in power, power under the curve, etc. Granted, it's not always a huge difference that you can boast about your peak HP in your signature on your favorite car forum to get all the high schoolers with bolt ons to adore you, but if you have a built motor/power adder/fuel system/etc,etc,etc build (read = $$$) and you are not willing to invest certain moneys to protect your investment, you're a fool.