Those running flex fuel get in here :)

[FFBOS]

Takes a bit for separation to occur in the tube, but usually I see that within a minute.

 

[Blkout]

Yeah Mike got me away from thinking in terms of AFR last year. Lambda actually makes things a lot more simple.

That's what Curt says too.

 

[fubar569]

I wonder how close mine actually is on the eth%.

It's about time to get the laptop out anyways on days off.

 

[Speedy!]

Takes a bit for separation to occur in the tube, but usually I see that within a minute.

I tested this at the pump and after a minute or two it showed about 93% on the beaker. I left it in the tube and looked at it again back at the shop an hour later and it showed 90%. I'm just curious if something changes over time and the initial reading is the most accurate. I may leave some in there a few days and see how it changes.

 

[Speedy!]

Left some E85 in the beaker for a week and once it settled it never changed.

Almost done with the tune I believe. Just some fine tuning then start mixing down to 93 to double check things.

Crazy how some of the calculations work. More complex algebra than I would have expected.

 

[fubar569]

And here I thought I'd never use algebra outside of school.

 

[hellno]

Just ran a data log in 50 deg F air with measured E90+ that the car reads as 97% ethanol to test the fuel system. Beaker read 95% a couple minutes after filling it while at the pump, and 90% an hour later when I got back to the shop and took a look. I figure this is about a worse case scenario. Anyone know why the reading changes over time?

Car made 17.5psi, 2.20 pratio, 1800-1900 aircharge injectors tickled 85% DC right at the 6500 RPM shift point. Fuel pump DC 78% and 81psi fuel pressure.

A little over head left on these ID1000 injectors but that's all I'd want to see personally.

Now put 21 degrees of timing in that gomango and let er rip

 

[Speedy!]

Now put 21 degrees of timing in that gomango and let er rip

Man, I don't think mine can take that much. I've got tested E87 in the tank and I'm seeing a tick of stkr here and there way below that. I've not adjusted my knock sensors very much but I'm pretty sure it's real knock. If I take a half or degree of timing out in those spots it goes away.

Mike fattened it up a bit, and I fattened it up some more and I'm still seeing it.

Got a little more testing today and a new toy so we'll see.

 

[hellno]

Man, I don't think mine can take that much. I've got tested E87 in the tank and I'm seeing a tick of stkr here and there way below that. I've not adjusted my knock sensors very much but I'm pretty sure it's real knock. If I take a half or degree of timing out in those spots it goes away.

Mike fattened it up a bit, and I fattened it up some more and I'm still seeing it.

Got a little more testing today and a new toy so we'll see.

My knock Sensors are turned off if it’s a knocking it’s a rocking

 

[hellno]

But I am in the process oh getting another motor ready I pick up a redeye motor I’m going to upgrade it

 

[Speedy!]

Ok, timing advance is finalized on full E85. I played with fueling a bit, richer, leaner, and it definitely likes to be a bit richer on E85 so I have lambda setup .81 - .82. On gasoline I run .83 - .84 for comparison. I think the cooling effect of the ethanol and more volume of fuel helps keep detonation at bay

In the end I'm able to run about 3 deg more timing in the high torque curve areas and 4-5 deg more timing in the upper RPMs than the Shell 93 octane I run. I honestly expected a bit more like 5 deg in the high torque curve area and 7 in the upper RPMs based on everyone's praise of E85, but I've tested this thoroughly and this is it for my car. I added a degree at a time until I got knock and backed it off and the knock went away so it's for sure real STKR.

Some dyno information was recently shared with me on a car being dialed in on race fuel, and for each degree of timing it picked up 12.5(ish) horse power and about the same torque. Using that as a reference I'm picking up 37.5hp in the torque area and 50-60hp up top. Not bad for $1.60 a gallon fuel I'm within about 1.5 deg of my race gasoline tune for timing advance and that fuel is rated at 107 octane R+M/2.

We got a cold front today that's dropping temps unusually low for this time of year and I'm gonna run one more WOT test Saturday morning to check injector DC in 30-40 degree air. So far the highest I've seen is 85% in 50 degree air.

 

[Christian Dionne]

Ok, timing advance is finalized on full E85. I played with fueling a bit, richer, leaner, and it definitely likes to be a bit richer on E85 so I have lambda setup .81 - .82.

Have you tried Lamda around 0.73? I've had success in turbo cars with it that rich. Haven't tuned HC yet, just wandering if they respond the same. I would think having dual plugs, would let you get close to peak power stoich.

 

[Speedy!]

No, that's really rich. Mine dropped a significant amount of STKR going from .84-.85 down to .81 to .82. I tried .79-.80 with no further reduction, so I eased it back to put less stress on my injector DC. I've since been told that on a 800rwhp car 12.5 hp per degree of timing is a very conservative number and that 15-18 is more the norm.

 

[FFBOS]

Interesting you are seeing knock with that boost and timing. As I mentioned before there are a lot running around at 20-21psi with 20+ degrees on pump e85.

 

[Speedy!]

Makes me wonder how de-sensitized their knock sensors are. Mine start to intervene at anything at or around 1 volt of knock sensor activity. I'd think it were false knock based on what everyone else is saying, but the STKR goes away when I take the timing back out so seems real to me. I tuned the knock sensors on race gas last summer myself to eliminate what I thought was false activity. I'm likely overly cautious but it's making plenty of steam for the street so I'm not inclined to mess with them much. For a street setup I'd prefer a lot of safety margin especially considering this will need to work for 93 as well as E85.

I did one final injector DC test yesterday in 35 degree F air. The injectors tickle 90% DC right at 6500 RPM so they're definitely approaching the limit in that kind of air but not maxed out. It'll be rare I'll be giving it the beans in 30 degree temps as traction is a challenge at that point, so I'm good with where they're at for now. That was the first time the car has really scared me in a while. WOT in 4th and the tires started to skip around and hunt for traction at about 100MPH, I puckered up a bit but got the test done LOL. After the pull I'm slowing and an unmarked Federale pulled in behind me for a minute. I was like OH BOY. They pulled around and took off and I hit the next exit and back to the shop and made sure I hadn't had a heart attach in Mexico.

Now to start mixing down to 93 and cross checking timing and fueling as the ethanol content changes.

 

[FFBOS]

Makes me wonder how de-sensitized their knock sensors are. Mine start to intervene at anything at or around 1 volt of knock sensor activity. I'd think it were false knock based on what everyone else is saying, but the STKR goes away when I take the timing back out so seems real to me. I tuned the knock sensors on race gas last summer myself to eliminate what I thought was false activity. I'm likely overly cautious but it's making plenty of steam for the street so I'm not inclined to mess with them much. For a street setup I'd prefer a lot of safety margin especially considering this will need to work for 93 as well as E85.

I did one final injector DC test yesterday in 35 degree F air. The injectors tickle 90% DC right at 6500 RPM so they're definitely approaching the limit in that kind of air but not maxed out. It'll be rare I'll be giving it the beans in 30 degree temps as traction is a challenge at that point, so I'm good with where they're at for now. That was the first time the car has really scared me in a while. WOT in 4th and the tires started to skip around and hunt for traction at about 100MPH, I puckered up a bit but got the test done LOL. After the pull I'm slowing and an unmarked Federale pulled in behind me for a minute. I was like OH BOY. They pulled around and took off and I hit the next exit and back to the shop and made sure I hadn't had a heart attach in Mexico.

Now to start mixing down to 93 and cross checking timing and fueling as the ethanol content changes.

The guys who tune e85 setups a lot, Curt, Barth, etc use the timing I describe. From what I was told they don’t mess around with the sensors. Maybe they will chime in at some point.

 

[Speedy!]

Haha, I wish but I doubt they're gonna come in here and tell me how to tune the car. Mike's worked with me on it and he knows what he's doing, so I dunno but I'm way below 20 degrees of spark advance and if I add one more degree the car just takes it right back out as STKR. I'm still a novice tuner so I could be missing something with E85 fuel that's special, but I've treated it like I did gasoline other than richening it up a bit more and slowly adding timing until I got knock and backed it off a degree.

Having said that I can't run 20 degrees of timing on my race gasoline either that's rated at 107 octane unleaded with these specs:

Octane – R+M/2 107
Motor Octane 100
Research Octane 114
Specific Gravity 0.723
RVP 6.7
Oxygenated 9.6%
Unleaded Yes
Stoich Ratio 13.04%
Color Blue

 

[Speedy!]

Well, final update on this thread, I gotta start a new one with the results. I was missing something that's a bit unique to E85. I've now got more power in the car than is really practical for the street, so I'm turning it down a notch LOL.

For those interested in the end I was about 9 degrees more timing than on 93 and zero STKR and could have put more to it I think. Pretty crazy. I've now backed that down a tick and it pretty much matches my race gas tune I had been using at the track. Pretty awesome for $1.53/gallon.

 

[Bboyd]

Well, final update on this thread, I gotta start a new one with the results. I was missing something that's a bit unique to E85. I've now got more power in the car than is really practical for the street, so I'm turning it down a notch LOL.

For those interested in the end I was about 9 degrees more timing than on 93 and zero STKR. Pretty crazy. I've now backed that down a tick.

I’m thinking of going to e85! did u tune it?

 

[fubar569]

Speedy pointed me in the right direction when it came to errant ethanol inference and I've got things fairly straight now...only so much you can do with 1200/1300+ cc on pump gas though and if you keep it within 10% inference you're doing good.

I'm about 3-7% at the low end...3% or so at ~50% ethanol and back towards 8-9% at 75% ethanol. All within the margin.

Tight fuel trims and accurate injector data is ABSOLUTELY 100% essential when running inferred flex. Hell or any other time.

My E85 only tune is a good bit more aggressive than my inferred flex. It's much closer to that 20* mark mentioned earlier give or take a couple.

I'd love to get it to a dyno now to see what it makes.