Mixing E85 and pump, with AEM EMS, suggestions???

[andy4g63]

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I just found out that I have locally E85, so I want to mix it with a straight 93 octane, but I don't want to change the tune right now. Car runs perfect with 93, just wanted make it a little higher octane, without retuning the car.I have AEM EMS and it is relatively easy, but I am not capable of doing it.Would I be able to mix or not???

Thanks,Andy.
All my mods are in my profile.

 

[JayRolla]

You will have to completely retune. If your not adding boost or timing than you wont see any difference. If you go 100% e85 and add boost and timing than it will be worth it.

After looking at profile I would upgrade to 1600cc injectors and boost that turbo to 35psi and lots of timing with e85. I will be gettting an hx40 for my next turbo.

 

[matthewdesigns]

To bump octane an appreciable amount, you'll need to mix in a high enough percentage to throw off your tune, I suspect, since e85 requires roughly 30% more fuel than pump gas. I tried a mix before I went to a setup to handle it exclusively, and I really didn't see much of a difference other than running out of fuel on my already maxed out system.

What octane are you shooting for? In round numbers, 10 gallons of 93oct + 5 gallons of e85 = 97octane, 13gal 93oct + 2gal e85 = 94.6 octane...just simple math to figure that out. If you add 1/3 tank of e85, you'll probably need to bump up your fuel delivery a bit to stay at a safe WOT afr. If you just add a couple of gallons to a tank, then you'll probably be OK, but what good, really, is a 1.5 octane increase going to do for you? If you are close enough to the "edge" that you need the 1.5 octane for safety, then you probably ought to dial everything back a little anyway.

Why not learn how to use the EMS and jump in to e85 wholly? You might as well figure it out and retune for straight e85. Add about 30% to your fuel delivery as a starting point, and go from there. You will not be disappointed!


Edit: What takes me 3 paragraphs, Jason gets done in 3 sentences .

 

[gsxrtalon]

By mixing e85/93pump you'll never get a stable octane level which in return will make it hard to get a consistant tune. I would either suggest go straight e85 or stay on 93pump. If you have a pump with e85 close by then I say go straight E85, its only going to make tuning easier and make it easier to get all you want out of your setup. IMO

 

[SonySlave]

Agreed. Either stick with 93 or go straight E85. Mixing even a little bit of E85 into your 93 will throw your fuel off significantly and there's no telling whether your mixture will always be the same, leading you to have to adjust settings all the time.

Also, according to your mods, you have an in-tank 255 and an inline 044 with 1000s. What are your IDCs like right now with 93 octane? The E85 is going to increase those IDCs significatly (about 30-35%), so a set of 1600s may be in your very near future. I was getting about 60% IDCs with my baby 50-trim at only 18psi with 1600s and a single in-tank 255HP pump. Something to seriously think about.

E85 is sooooo worth the change. Trust me!

 

[gsxrtalon]

^^ Agree about the fuel pump/injectors upgrade if switching to e85. I have a single in-tank 255 with FIC 1050's and at 20psi with my gt35 and straight e85 Im seeing 60% IDC's. 1600's are in my near future along with another 255FP.

 

[dsmmatt28]

I have done this man. Im running straight e85 now though. More boost and more timing. I could only do this when I was on E. I put 3 gallons of e85 and the filled the rest up with 93!! You wont have to change anything. You will be able to run more boost!!!

 

[gsxrtalon]

Mixing e85 and pump WILL causing you to run richer. Your fuel(globals) WILL need to be adjusted if you continue to run mixed gas and this goes back to why its a bad idea because you'll never get your trims just right because of the changing octane levels........

 

[gsxtasy]

Mixing e85 and pump WILL causing you to run richer. Your fuel(globals) WILL need to be adjusted if you continue to run mixed gas and this goes back to why its a bad idea because you'll never get your trims just right because of the changing octane levels........

Leaner, not richer.


Are you running cell by cell or a boost comp map or...? Switch it up and add a percentage of fuel to your entire map and watch your wideband. AEM isn't that hard, don't be afraid of it and just start playing with it, don't blow anything up though.

 

[KGB Pilot125]

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I just found out that I have locally E85, so I want to mix it with a straight 93 octane, but I don't want to change the tune right now. Car runs perfect with 93, just wanted make it a little higher octane, without retuning the car.I have AEM EMS and it is relatively easy, but I am not capable of doing it.Would I be able to mix or not???

Thanks,Andy.
All my mods are in my profile.

With the AEM you could do a couple of different things to increase fuel with out having to change the entire tune. you could add a rotary switch that could add or subtract 25% fuel using I believe uses one of the egt inputs or something, I dont have my manual or notes here in my hotel. The other thing you could do is use the wideband feedback and make it so the ecu can add or subtract 25-35% fuel to keep you in your AFR target. I have not messed with the rotary knob but have messed with adding subtracting fuel using the target afr and works pretty well. I dont know what you do to add timing though which you should do to get the most out of the E85. For boostif you are using the AEM to control it you could wire in a Hi/low swtich, I got one of the Econ/power switches from an auto for mine I just need to figure out how to wire it.

 

[andy4g63]

First of all, thanks for the replies everyone. My schedule is pretty screwed, so was not able to respond untill now. I was thinking of putting roughly, 9gal of 93 and 3 gal of E85. This is about 97 octane, which is nice. About IDC, I am seeing about 80-84% IDC at the redline.
Gsxtasy, mentioned that the mix will go leaner, this is actually good, cause in the upper rpm's from 7500 to 8300RPM, AFR"s start getting rich and I am ending with 10.8 AFR at redline, and 11.4 to 11.2, gradually dropping as the RPM increase, so I could go a little leaner. Timing is very conservative, about 13* at redline.

If the E85 adds like 30-35% more fuel, adding only 30% E85 to 93 octane, will be like 10%, I can deal with that. Only want to rise the boost to about 25PSI if car allows me to do so, without knocking.

Learning and trying to understand AEM is not that hard, but believe me, there is no time. I have family and a kid, just can't ignore everything and deal with the car/ which I am or was doing anyway/. I am 39 years old and sure that you guys, most of you are much younger.

On the other hand the E85 I found "locally", is about 35 miles each way and I can't go there every time, nor have a place to store it, if I get more in some containers.

Thanks, again and if anyone has anything more to add or share, you are more than welcome to do so.

 

[JayRolla]

Ahh that sucks. I would love to see what that turbo at 40psi and 18* timing could do!!!