Advice with E-85 and dsmlink

[livedsm4g63]

So i have found an E-85 fill up station close by my house and i was thinking about switching over. Since i live in michigan and we have some cold winters i was thinking about doing a 50/50 mix with e-85 and 93. The thing is i have 950 injectors right now and Im seeing about 70% duty cycle. Do you think i will be maxing them out? Im thinking myself that i will be around 90%, however if it stays up that high wont i burn them out?

Also, i was wondering about cruise tuning with E-85, would it be the same as tuning for gas Stoic (14.7), just with e-85 Stoic(9.8526)? I know i have to calculate for my certain mix, and know what kind of e-85 it truly is.

And final question, why is stoic richer when your octane goes up?

Thanks in advanced for the help

 

[jrohner]

Since i live in michigan and we have some cold winters i was thinking about doing a 50/50 mix with e-85 and 93.

I have no issues starting when it's double digits below zero in the winter. Mixing makes it hard to get a consistent tune; I used to put 3 gallons of E85 in with every tank for extra octane before I switched to E85.

The thing is i have 950 injectors right now and Im seeing about 70% duty cycle. Do you think i will be maxing them out?

It looks like we have somewhat similar setups, and I had no issues with 750's. IDC's are OK to look at, but the number doesn't always mean much; I don't know about link, but on other tuning systems people have often logged 120-130% with no fueling issues, however that works ~~~.

Im thinking myself that i will be around 90%, however if it stays up that high wont i burn them out?

No. The injectors have fuel constantly flowing through them, so they have a pretty good 'cooling system'. I've logged more than 85% IDC on a stock 1G before.

Also, i was wondering about cruise tuning with E-85, would it be the same as tuning for gas Stoic (14.7), just with e-85 Stoic(9.8526)? I know i have to calculate for my certain mix, and know what kind of e-85 it truly is.

Unless you change the stoich fuel setting on your wideband, the afrs will read like gas -- 14.7:1 stoich even though it's actually running stoich for E85. The wideband doesn't know what fuel you're running, you have to tell it. So you'll shoot for something like 12:1 at WOT.

And final question, why is stoic richer when your octane goes up?

Octane has nothing to do with stoich. Stoich is based on the fuel.

 

[livedsm4g63]

wow, thanks jrohner, that about answered all of them

I think i just may run straight e-85, just so its more consistent.

The main thing i had to know was for cruise tuning, but if all i have to do is still shoot for the 14.7 thats easy enough

Have you ran leaner then that with e-85 to pick up some better gas millage?

 

[Calan]

...The main thing i had to know was for cruise tuning, but if all i have to do is still shoot for the 14.7 thats easy enough

Have you ran leaner then that with e-85 to pick up some better gas millage?

Unless you have custom ECU code or a simulated WB signal that let's you change the switching voltage, you don't have much choice. The ECU is going to try to maintain 14.7 no matter what, until it runs out of fuel trim adjustment.

Or you can lock the ECU in open loop and change your target AFR's to whatever you want...but it takes a lot more tuning and you have to stay on top of it.

**********

I'm running a 50/50 mix at the moment, but I definitely have a better and more consistent tune with straight E85. But I'm also on a high-compression stroker which is extremely finicky (or possesed..depending on how you look at it ). When I was 2.0L, tossing 2 or 3 gallons of E85 into a tank of 91 made a huge difference and wasn't too hard to deal with even with just a MAF-T.

As long as your airflow is accurate and you know the gas/E85 ratio, it's pretty easy to compensate for it... at least with ECMLink. I can't speak to other tuning methods.

On your IDC question, it's dependent on how much boost you run. If you start maxing the injectors, back the boost down a bit until you can go larger. You can also gain a little bit of wiggle room by raising your base fuel pressure if you have an AFPR.


EDIT:

Duh. Didn't even absorb the fact that your thread title said DSMLink

 

[livedsm4g63]

Oh alright

As far as figuring out what class e-85 is at the station. (Such as e-70, e-78, or e-85) How would we figure that out. I just talked to someone from the station and they had no idea what was going on. I have seen that 1992 Talon Tsi AWD Project has a table, but i wasnt sure if there was another way of figuring it out for the specific location. Or does everyone just tune as if it is true e-85?

 

[ramsack]

i have a 9:1 non-turbo bottom end and was gonna try to go for e-85, but that chart makes me decide otherwise and maybe go low in compression just so i can stay on pump gas and not have to have different tunes for months of the year.

 

[Calan]

I actually test it every so often... it's easy. I do this with a sample from the pump, and occasionally pull a sample from my fuel rail if I'm running a mix, to verify the ethanol percentage.

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You can pick up a cheap 100ml lab cylinder from the Discovery store, or Ward's...among other places.

I also have a spreadsheet that I created for calculating the SG, stoich, etc. from any combination of gas and E85. It allows you to enter the ethanol content of the E85 (as well as the gas), and has a tool for estimating the stoich based on a specific gravity measurement.

Stoich Calculator For E85 Blends

So far, the results I get from the spreadsheet match the measured results almost perfectly. It's just a matter of entering the new stoich into Link's global fuel calculator, and off I go.

 

[ramsack]

that is awesome! what is your take on the ethanol sensors that go in fuel lines? i was hoping to maybe buy an aem and maybe that could be made to work with something like that?

 

[spartan69x]

You should be able to ask a manager or someone at the station what the true mixture is, if not they can make a phone call and find out, or at least should be able to.

 

[Calan]

what is your take on the ethanol sensors that go in fuel lines?

They are really expensive.

Zietronix makes one...not sure if Tom has figured out how to utilize it with ECMLink yet... and I have no idea what kind of support there is with other software.

EDIT: I believe Wes (member SOADweskey) is running one. Shoot him a PM, or maybe he'll pop in here and share his opinions on it.

You should be able to ask a manager or someone at the station what the true mixture is, if not they can make a phone call and find out, or at least should be able to.

In my experience, even when they know... they don't know. The only true way to find out how much ethanol is in anything that comes from a pump is to test it. And it really is so simple to do that it's almost routine for me now, even though it doesn't need to be done that often.

I think people really over complicate the E85 blend thing. You can use something like my spreadsheet above or just a calculator to get close to the stoich... and then just watch the fuel trims in ECMLink and tweak the global until they are back to what they were before filling up. Takes about 15-30 seconds...That's it.

 

[livedsm4g63]

Nice, that spreadsheet makes it super easy and so is the test. I wouldnt mind checking it everytime just to be certain. And like you said. 15-30 seconds and your off.


Would you mind explaining how you would go from stoich afr to the global %. Im confused for the first step after i have the new stoich. I dont understand what to multiply my 950's by in order to get their e-85 flow.

 

[Calan]

BTW - Ignore the last two cell comments that mention adding the values to ECMLink's AFRatioEst properties. Those AFRatioEst properties are obselete now in the latest version.

 

[livedsm4g63]

Let me know if this is correct.

So i will want to take the stoich for my blend, divide it by 14.7
Then multiply that by 950 to get what the e-85 flow is
Then take 450 divided by the e-85 flow, then minus 1

And thats my global?

And has anyone seen a difference in pulse widths? or do they usually leave them the same?

 

[Calan]

Ehhh...I just plug the stoich and injector size into the global calculator in Link and click "Calculate". You can get there with the formulas listed on the ECMLink wiki, but I'm too lazy for that. I worked it all out when I made the spreadsheet, and then tried to forget about it.

But seriously, there's basically two ways to go about it. You can figure the global for gasoline at your injector size, and then multiply that by a "fuel factor" that represents the additional fuel that is required when you run E85 (or E78, E100, etc). Or, you can calculate the actual stoich ratio of the blend, and use that. I prefer the second method because it is more accurate since you are working with a known stoich value, and it's easy since Link has the calculator built in. You are really doing the same thing either way; the fuel factors mentioned on the wiki are just ratios derived from the stoich of pure gas and pure ethanol.

And, I leave my deadtime alone.

 

[livedsm4g63]

i would have done the same. I was going off a different calculator i found on here and for some reason i thought it was the one you posted

I like yours a lot more. Its very similar to the other one but you did more work to it. I like it. I like it a lot!

that is awesome! what is your take on the ethanol sensors that go in fuel lines? i was hoping to maybe buy an aem and maybe that could be made to work with something like that?

I was able to find out that straight from the dealership the sensor alone is $800. those crazy people. The part from zeitronix doesnt come with the sensor. However i have found a place online that sells a replicator. Not sure if it would work though but id rather pay $162 instead of $800 any day
Flex Fuel Replicator

I prefer the second method because it is more accurate since you are working with a known stoich value, and it's easy since Link has the calculator built in.

I dont have version 3. i only have v2

 

[ramsack]

i see those sensors on ebay for $200-$300. i guess i could always get lucky and spot one in a junk yard. that zeitronix thing is just a gauge.

 

[Calan]

I dont have version 3. i only have v2

Download the V3 app. It works with the V2 chip, and you should be using it anyway just because it has a lot more features and is easier to use than the V2 app.

 

[rts91tsi]

Oh alright

As far as figuring out what class e-85 is at the station. (Such as e-70, e-78, or e-85) How would we figure that out. I just talked to someone from the station and they had no idea what was going on. I have seen that 1992 Talon Tsi AWD Project has a table, but i wasnt sure if there was another way of figuring it out for the specific location. Or does everyone just tune as if it is true e-85?

If your refering to the Citgo station on Pickard St, their e-85 is 70% ethanol.

 

[livedsm4g63]

If your refering to the Citgo station on Pickard St, their e-85 is 70% ethanol.

Theres a fillup at the shell station on broomfield and mission .Thats where ill be filling up.

 

[rts91tsi]

Nice, multiple fillup points around Mt Pleasant. I'll definatly try to make it out to a Tuesday at ABC.

 

[livedsm4g63]

Hopefully by then i will have found the tools needed to test the e-85, so we can figure out what % it truly is

 

[cody92talon]

wow this really helps me to prepare to switch to e85 thumbs up fellow dsmers

 

[bertrenolds]

So the specific gravity of E85 is 0.796? Need to know to set my AFRatio est in dsmlink.

 

[snowborder714]

I'm guessing you're either running v2.5 (or older)? If you're running v3, then upgrade the firmware and you won't have to set that for AFRatioEst.

 

[bertrenolds]

yea I'm running version 2.5, I'm just making sure so when I start running E85 I can get the correct AFRatio est. So is it 0.796 if I'm always running E85?