Goingnowherefast

iTrader: (1)

Hey guys,

So obviously there's a lot of talk about E85 and how to physically set the car up for it. But I want to make this thread to talk about the tuning aspect of it. My question is this: I have an MTX-L wideband. As you know this measures Lambda and then it converts it to gas AFR. E85 has a different Stoic value than gas. So my assumption is that when you change from gas to straight E85, the gauge will have no way of knowing that it is indeed running E85. This means that it will display gas AFR values (which if it's running correctly should be 30% more volume I.E seeing like 10-12 AFR instead of 14.7 would be normal).

What I would like to know:
1. In Megasquirt, I have the AFR table setup to run correctly on gas. Since the gauge will still be reading gas values, and therefore telling megasquirt the gas values, will I even have to change the AFR table at all? Won't Megasquirt try to target those AFR values (say 14.7 for argument). I.E it will throw enough fuel to hit those values? Meaning all that would need to be done is some VE tuning.
2. If that assumption is incorrect, what exactly needs to be done in Megasquirt to get set up for E85?
3. Is there a way to change the Innovate gauge to read E85 Stoic values so the values don't look weird?

Thanks for the help in advance guys.

Background on car:
-FBO 1.6L (No AFM)
-MS3 Pro
-Innovate MTX-L Wideband
-RX7 550cc injectors

18psi

iTrader: (76)

You're making assumptions, and overthinking it.

1)The MTX-L will give you the afr reading you need to see. No need to convert anything, or change anything, or adjust anything. You simply keep using it just like you did with pump gas.
2) update req_fuel and the appropriate startup tables
3) again, overthinking.

It actually amazes me how many people overthink this. This is the one case where overthinking is counter productive.

slowcarfast

My understanding is that the your gauge will measure in lambda (the ratio of actual AFR to stoichiometry for a given mixture) then converts that ratio to a number. Whatever the fuel, stoich will always be a lambda ratio of 1 and show up as 14.7 on your gauge (unless you change it). There's no need to change afr targets. I was super anxious about things not working when i switched, but I pulled up to the pump, filled up, added 35% to my fuel table, and drove away letting VEAL do its thing.I didn't change anything else.

Edit: 18psi beat me to it. I didn't even change my startup settings, but my startup sucked as a result, it started and ran though.

18psi

iTrader: (76)

/\ Yup.
Except you want to change req fuel and not ve table, because that will update lots of other things and not just the fuel table.

slowcarfast

I also had just changed to much bigger injectors so my gas tune/req fuel wasn't really dialed in. I do not recommend this approach, but hey, even with that stupidity it still worked.

Goingnowherefast

iTrader: (1)

Thanks for the replies guys. This forum is absolutely badass. So much good information here.

So I actually ended up pulling my RX7 injectors in exchange for some new FF640cc injectors. I'll throw the car on E85 per your guy's advice and report back here with findings! (and maybe before/after dyno's)

hector

Just curious, why wouldn't you want to run a flex sensor?

Goingnowherefast

iTrader: (1)

Yep, you guys were right. I was 100% overthinking it.

Tonight I drained the fuel, added 5 gallons of E85, changed req fuel and manually changed some VE fuel values and it's running like a champ now on E85. I'm making a how-to video of how a complete idiot like myself (equipped only with a Miata with E85 compatible fuel components and Megasquirt) can change their car to E85. This will include the Megasquirt changes too.

StanTheMan

just have a question.
It may also be irrelevant since I'm running MS2PnP
I assume you mean changing the required fuel. In my case that would mean my injectors would go from 6.0ms to 8.2ms. that's easy enough as that would also take care of all the start up adjustments.
but that doesn't take into account the extra spark timing you can use with E85 without running a Flex fuel sensor

and yes I'm probably over thinking one part & totally misunderstanding another part.

I currently run 2 separate maps one for 93 & another for E85

Goingnowherefast

iTrader: (1)

Your thinking is correct. The req fuel simply changes the injector time in ms. It does nothing to change spark timing. I am planning on doing what others have said is safe (Increases timing 2-3 degrees across the map and eventually dyno tuning it). But it seems that even when changing the req Fuel you still need to do a lot of VE table tuning to get everything dialed in correctly.

MX5RACER

What about any physical changes to the car to run E85? Do most people not worry about the E85 eating the almost 30 year old steel fuel lines, ballooning the 30 year old rubber lines and cleaning all the years of varnish from the fuel tank?

Goingnowherefast

iTrader: (1)

So here's the things I've done and I'll break it down to what's needed and what's recommend:

Needed:
-New Injectors and Seals (I chose the MT.net love child: The FF640cc's)

Recommended:
-New Rubber lines (I replaced all my old rubber lines with new Ethanol capable lines
-DW200 Fuel pump (Ethanol rated)
-Replacing Fuel Pump after a tank of E85 use (Should be done on old cars anyways)

chicksdigmiatas

iTrader: (11)

That is complete bullshit I think. Maybe myself and my friend were lucky (we switched to E85 at about the same time). I still have the same rubber hoses from 1995 going to my fuel pump. (Not that I would recommend it, but hey, it is what it is) I will upgrade soon, as I will need it, but the whole E85 devours your fuel system thing is complete hogwash. Here is what I did. I was one of the earlier E85 folks IIRC.

I took an extra FPR and a couple other fuel parts and let them sit completely submersed in E85 for about 4 months. Nothing happened. I figured it would be fine.

I put in a walbro 255 and new sock while draining the tank. This was before the new "E85 compatible" pumps. (On a side note, after finding out there was such a thing, I contacted walbro to see if my earlier "non e85 pump" would implode or something, and they stated it should be fine, just decreased life. Here I am 7 years and 50k later....) There was a tad of rust or something at the bottom of the tank. I rubbed my fingers across it. It seemed like it wasn't going anywhere. Buttoned it back up.

New fuel lines under the hood, because they were chewed up. 190k FPR stayed in place.

Took req fuel and cranking PW and multiplied by 1.3. The cranking PW was spot on, and the VE was fine when near stoich, but was overly lean in vacuum, and overly rich in boost. Maybe I miss scaled, but VE analyze live took care of it.

You just read your AFRs like you were tuning for gas, it is that easy.

I did all this on a OG MSPNP. Complete piece of garbage megasquirt. Now with a MS3x going in, there is a flex fuel sensor in my future, so I don't have to map out E85 stations for road trips.

I'm with vlad. It requires very little overthinking, and is as simple as changing parameters in your ECU as long as you have the little supporting hardware required.

I bumped my timing 4 degrees. It hasn't pinged heat soaked with heavy hooning in 95-100 degree heat. I am not going to dyno tune until I get a new turbo.

Goingnowherefast

iTrader: (1)

Yeah I'll also add that Evo guys have been running stock lines in Evo's since they found out that E85 gives them like 40whp extra haha. There's countless threads that have investigated damage to the old rubber fuel lines and found nothing. It's a good thing to do in practice, but the "E85 fears" seem to be really overblown.

MX5RACER

Not that want to be a snob towards a certain brand, not sure I am going to risk a fire with 30 year old fuel lines and Ethanol use from the word of someone who bought a Mitsubishi... lol.

JK, in all seriousness, When was the oldest Evo available in the States, 10 years ago? Not sure E85 use has been going on long enough to use the data from EVO's yet.

The problem of Ethanol use and rubber/steel lines corroding is real. Anyone who has any small engines like weedeaters or edgers can tell you that. The Ethanol does dissolve those lines and gum up carbs etc. my concern with the Miata fuel lines are the steel hard lines under the car. There is a coating that lines the inside of the fuel line and protects the steel from normal fuel. The Ethanol is known to dissolve this coating and the steel line will start to rust from the inside out. When they rust out, the fuel is pressurized and can spray fuel under car leading to a serious fire.

I guess I am looking for the data to either prove or disprove that theory. It looks like at least one person has not had any issues, which is great to hear.

Goingnowherefast

iTrader: (1)

I guess I'll be the one to say it, but you'll probably never get the data to prove or disprove that theory. The ancedotal evidence is in however, and there simply isn't E85 cars burning up on the streets or racetrack in masses due to your theory.

Also to your point, you know there is ethanol is your gas tank right now right? Modern pump gas has around 10% ethanol in it, so we've all been running E10 for about 5-6 years now, and no-ones cars are burning up.

MX5RACER

You are correct we have been using gasoline with a maximum of 10% ethanol content the last few years. But 10% is not 80%, there are studies out there about extended E85 usage and possible negative affects on cars. Recently, they were discussing increasing the amount of ethanol in normal gas to 15% max, but this was rejected with the reason being possible damage to cars.

This is is not my theory, but a widely subscribed theory by people both smarter than me and by people dumber than a box of rocks. The truth probably lies somewhere in the middle. I am just trying to find out where that middle ground actually is.

.one lane

Here is what I replaced to run E85

- Replaced old shitty rubber fuel lines with new rubber lines (Gates Barricade. It was available from my local auto store)
- DW200 fuel pump
- Flow force injectors
- 5x Racing adjustable fuel regulator (increase flow rate for injectors)

Been running strictly on E85 for over a year without issues.

psyber_0ptix

iTrader: (4)

I had one fuel injector go funny after using e85. After cleaning, it seems to work fine now.

I had already replaced my fuel lines to -6AN when I did the 1.8L tank swap, but I seem to remember that there's more of an issue for non-ethanol compliant submersible fuel hose to the fuel pump degrading and swelling than the external rubber hoses.

StanTheMan

i changed the fuel filter a few times.
My original NA6 injectors were running at over 90% Duty cycle so I changed them to Chinese copy Rx8 but after taking the original 27 year old injectors out found they were all gunked up.
6AN fuel lines....cause i liked the look of steel braided fuel lines......
fuel pump is only a few years old but a stock replacement
changed all the injector seals since the injectors were out.

I have another question.
Is my thinking correct here?

In standard setting for the flex fuel sensor it adds 13deg to your timing.
85% of 13 is 11. So that means a felx fuel sensor would add an additional 11 deg to timing with E85 ( less depending on mix) unless you have table switching activated.
I undersatnd in MS2 you just run the Flex Fuel sensor by itself.As the table switching function does not work together with the Flex fuel sensor
With MS3 you can make the table switching work with the Flex fuel sensor and it is a much better option.