About to go E30, but confused how to refill my pupu

[csmaan12]

Okay, I'm having trouble finding this. I looked at the fuel mixing cheat sheets and all that, and maybe I'm looking in the wrong place.

I got my Stratified E30 Flash Tune ready to go, driving my car to 1 bar left to follow the initial instructions on the first fill up (4 Gallons E85, and the rest with 93). I'm confused though, when I need to fill up again, usually at 2 bars, how much do I have to fill up of each to achieve the same mixture? Or should I just keep driving to 1 bar and do the 4 gal E85 and 93 the rest, each time I fill up?


Thanks..

[speedfreak44]

Their tune is still somewhat conservative, drive to 1/4 tank and fill up 3 gals E rest 93. If you go over or under its fine but I would lean toward extra E vs extra 93.

[csmaan12]

Originally Posted by speedfreak44 Their tune is still somewhat conservative, drive to 1/4 tank and fill up 3 gals E rest 93. If you go over or under its fine but I would lean toward extra E vs extra 93.

Cool that's exactly what I wanted to know, thanks. I figured it's a little more lenient, but I also don't want to blow anything up.

[jtday]

The tune is designed to run anywhere between 30ish percent and 40ish percent. It's not really ideal to fill up X gallons of E, then top it off with 93, although it wont hurt anything. If you're an anal retentive guy like me, you will need to fill up with the exact amount of E and an exact amount of 93 every time. I shoot for the low end and run a 30.68% mix. So when I fill up, I never actually put in a full tank of gas.

I'll put in either:

2 gallons e85: 5 gallons of 93 or,
3 gallons e85: 7.5 gallons 93.

The math is as follows assuming you're doing the 3:7.5 fill-up:

(3(0.85)+7.5(0.10))/14.5 = .3068 ~ 30.68%

I have a gen1 so my gas tank is 14.5 gallons as you will see as the last number in the calculation above. This is only if you want to be super accurate about it. I find it helps with fuel trims if you are more accurate.

[speedfreak44]

When I ran their flash tune my trims were all less than 5% despite never following exact math

[Enki]

Don't top off. Keep the ratio the same; document how many gallons it takes at whatever marking your fuel gauge is at and use that as the basis for your ratio according to the cheat sheets.

[csmaan12]

Originally Posted by Enki Don't top off. Keep the ratio the same; document how many gallons it takes at whatever marking your fuel gauge is at and use that as the basis for your ratio according to the cheat sheets.

Hmm, I'll do this. My first fill up when I was ready to flash it was 4/9 with the fuel light on.

Originally Posted by speedfreak44 When I ran their flash tune my trims were all less than 5% despite never following exact math

Good to hear there is leniency in it. Mine right now are -1.56/4.69, although the first like 40 miles they were -9/6, then it changed to -7/4, then eventually it evened out to -3/3 and now its holding consistently at -1.56/4.69. I took a log today I'm going to send them once I complete the rest of the steps.

Originally Posted by jtday The tune is designed to run anywhere between 30ish percent and 40ish percent. It's not really ideal to fill up X gallons of E, then top it off with 93, although it wont hurt anything. If you're an anal retentive guy like me, you will need to fill up with the exact amount of E and an exact amount of 93 every time. I shoot for the low end and run a 30.68% mix. So when I fill up, I never actually put in a full tank of gas. I'll put in either: 2 gallons e85: 5 gallons of 93 or, 3 gallons e85: 7.5 gallons 93. The math is as follows assuming you're doing the 3:7.5 fill-up: (3(0.85)+7.5(0.10))/14.5 = .3068 ~ 30.68% I have a gen1 so my gas tank is 14.5 gallons as you will see as the last number in the calculation above. This is only if you want to be super accurate about it. I find it helps with fuel trims if you are more accurate.

Thanks, if I end up being too lazy to math things then I'm going to follow your steps except mine was a 4/9 initial fill up. So I'd have to adjust to that. Apparently my gas tank is 15.9 gallons though on the pu.

[Enki]

It is lenient, but over time the disparity will grow significantly if you always top off; If you're always doing say 3 and 8, over time the mix will dilute further (which is exacerbated by not draining the tank to near empty).

This is why I recommend filling via the 1/4 tank method (calculate mix per 1/4 tank and use that ratio to fill up).

[jboss23]

Hey bud, Ive personally been running E30 now for about 15k+ miles. The first couple of fill ups i was super anal about the correct ratio, but then that got real old real quick. Your "suppose" to run 4gal of E per tank of gas. After about about 1k miles on the E tune i got lazy and now i go anywhere from 4-5 1/2 gals of E per tank. My LFTS stay +/- 3 at all times, my AFR's are spot on, my fuel pressure stays between 1870-1920 at WOT, and in that 15k miles i have never seen knock above 1.2. Alota asshats here say im dumb or what ever, but what i say is that 15k+ miles on E, and I just swaped my turbo, and the K04 is still picture perfect. Just sold it to some chump for 400$. So I say to you and take with with a grain of salt.... dont go under 4gal per tank and dont go over 50/50 and you'll be right as rain.

[Enki]

He can go over 50/50 if the car is prepped for it.

[Vansquish]

Originally Posted by jboss23 Hey bud, I've personally been running E30 now for about 15k+ miles. The first couple of fill ups I was super anal about the correct ratio, but then that got real old real quick. You're (deleted, """)supposed (deleted, """) to run 4gal of E per tank of gas. After about about 1k miles on the E tune I got lazy and now I go anywhere from 4-5 1/2 gals of E per tank. My LFTS stay +/- 3 at all times, my AFR's are spot on. My fuel pressure stays between 1870-1920 at WOT, and in that 15k miles I have never seen knock above 1.2. A (inserted space) lot (inserted space) of asshats here say I'm dumb or what(deleted space)ever, but what I say is that I have gone 15k+ miles on E, and I just swapped my turbo, and the K04 is still picture perfect. I just sold it to some chump for $400. So I say to you, and take with with a grain of salt, (deleted, "....") don't go under 4gal per tank, and don't go over 50/50 and you'll be right as rain.

There, that's better.

Also, learn your fucking homophones.

[g00s3y]

Originally Posted by jboss23 Hey bud, Ive personally been running E30 now for about 15k+ miles. The first couple of fill ups i was super anal about the correct ratio, but then that got real old real quick. Your "suppose" to run 4gal of E per tank of gas. After about about 1k miles on the E tune i got lazy and now i go anywhere from 4-5 1/2 gals of E per tank. My LFTS stay +/- 3 at all times, my AFR's are spot on, my fuel pressure stays between 1870-1920 at WOT, and in that 15k miles i have never seen knock above 1.2. Alota asshats here say im dumb or what ever, but what i say is that 15k+ miles on E, and I just swaped my turbo, and the K04 is still picture perfect. Just sold it to some chump for 400$. So I say to you and take with with a grain of salt.... dont go under 4gal per tank and dont go over 50/50 and you'll be right as rain.

So much stupid is in this post.

Asshats aren't calling you dumb. People who are smart and educated on this platform are calling you dumb, because you have said a lot of dumb shit. And you come off as some toolbag who can't complete a sentence properly. Still hitting 22.8 accurately all day every day?

OP, listen to the more educated people in this thread. You want to try and be as accurate as possible when filling up. Does it need to be absolutely perfect, no, the ECU can adjust to allow for some leeway with the ratio.

[rfinkle2]

[biggman026]

OP - as a general principle, yes it is ideal to fill up with exact ratios of E85 each time.

In practice, is it really detrimental if you are not being perfectly precise with the ratios? No. When I fill up, I put in 4 gallons of E and then top it off with 93. If I make it to the gas station within 10-15 miles of my gas light turning on that will generally mean I'm putting in about 10 gallons of 93 (I wait till the gas light comes on to fill up). If I can't fill up right away (only 2 gas stations in town have E85 and they are inconveniently located) it can be as much as 11 gallons of 93. My trims are close to zero (+/- 2 or 3) regardless of whether I put in 10 or 11 gallons of 93. The ratio of E85 to 93 varies by less than 2% between putting in 10 or 11 gallons of 93 (28.5% compared to 26.6%). That simply isn't significant enough to affect your trims or alter your knock threshold.

That obviously doesn't apply if you fill up from different points, e.g. sometimes you get gas when your gas light turns on, sometimes you get gas when you're at a quarter tank, etc. If you vary the points from which you fill up, you need to consistently use exact ratios because topping off with 93 will result in very different ratios each time.

So basically, if you want to do it "right" then yes, always fill up using exact ratios. But if you want to do it easier (and fill up less often because you're actually filling your tank) just top off with 93.

[twincitySPEED6]

Over the summer I ran Stratified ots for e30? (4 gallons of e).
I got used to a good feel for how much farther I could drive with the gas light on. So I pretty much always filled from nearly empty. I only could experiment this, as I pretty much drove to the same places every week.
After a while instead of topping off with 91. I just did 4 gallons of e and 9 of pump. For the sake of consistency.

Was I doing it wrong too? Would like to know for future references.

[Voltwings]

i dont understand why this is so hard? Just always fill up with a constant ratio.

4 gallons in a Gen 1 works out to damn as no different 25%, and in a Gen 2 is 25%.

Therefore, every time you go to the pump its 1 gallon of E85 for every 3 gallons of 93, which works out to 25% ... simple.

If you have half a tank, that's 7.5 gallons you need to fill up. You can do 1.5 and 4.5 for 7 gallons. Close enough.

I can get my tank damn near full every time doing this, and my ratio is always perfect, and i dont have to wait until my tank is empty to fill up.

[littleloogy]

Turn on one e85 and one gas pump and put a funnel in your fill neck. Then put the e85 on the first click, and put the gas on the 3rd click. That's the most accurate way for sure.

[sxman]

Originally Posted by littleloogy Turn on one e85 and one gas pump and put a funnel in your fill neck. Then put the e85 on the first click, and put the gas on the 3rd click. That's the most accurate way for sure.

Loogy taught me this a while ago and it's saved me damn near 15 seconds of math/fill up.

[csmaan12]

I think I figured out a ratio on my last 4 fill ups. I've been doing 1/4 tank fill up, which is 11 Gallons.

So 3.5-3.75 of E85 and 7.5-7.25 of 93....am I doing it right? Given that at 1/4 tank I have about 4.5 Gallons left. After fill up LTFT starts at .78/4.69 and settles after a couple miles to -.78/4.69 and stays that way until next fill up pretty much.

[Malbosia]

There are ethanol calculator apps on iTunes and Android. Search google play for "e85 Mix Calculator" if you want to keep it exact.

You should do a test on the e85 and the gas your using to see how much E comes pre mixed from the gas station to make sure your adding the correct amount to keep it exact. The gas station's ratio changes with the seasons depending on how far north or south you are.

Using a cheat sheet such as the one rfinkle posted above is a good way to go as well.

[csmaan12]

Originally Posted by Malbosia There are ethanol calculator apps on iTunes and Android. Search google play for "e85 Mix Calculator" if you want to keep it exact. You should do a test on the e85 and the gas your using to see how much E comes pre mixed from the gas station to make sure your adding the correct amount to keep it exact. The gas station's ratio changes with the seasons depending on how far north or south you are. Using a cheat sheet such as the one rfinkle posted above is a good way to go as well.

Sweet, I think I got the grasp of it, and it should be E70 during winter time where I am. So I should be at E33 with the ratio I posted above.

Just curious how do I determine how much %E I have left over in the tank before fillup. Is it always assumed to be E10?

[Enki]

Or he could use one of the three I've made and have been available for a couple of years now.

[csmaan12]

Originally Posted by Enki Or he could use one of the three I've made and have been available for a couple of years now.

Yeah I'm using those ones at the moment, and they're very helpful, but there's something in my head that just doesn't click for some reason.

By the looks of it, I should be adding more E at the pump and less 93, because I'm basically doing the math based on the fact that I need 11 gallons to get from 1/4 to full. BUT according to the sheets, an E30 mix can be achieved (with E70 winter blend) by mixing 4/7 which I was slightly off.

Now am I wrong to top off, or is it okay if I know exactly how much I need from a certain fuel level to achieve top off. For example, needing 11 gallons from 1/4 - Full...therefore using 4/7 mix?

[Enki]

Use the HTML version on your phone which does remix calculations for you.