Going E85/Flex Fuel
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The day started off with a 6:45 AM departure from Charlotte with about 3/4 of a tank of 93. I was trying to plan it out to where I'd arrive at Carolina Dyno with as little 93 in the tank as possible, but I was a little too cautious on a stop in Wadesboro where I put in about 4.5 gallons. Ended up with around a 1/4 tank when I got to Wilmington, which was fine because Ben wanted to check everything out on the 93 tune before switching to E85. This is where the trouble started.
We knew we wanted to raise the base fuel pressure just a bit to help out with the E85 delivery, so we raised it from the stock 43-45 PSI to a modest 50 PSI using my AEM adjustable FPR. After a few pulls on the dyno, Ben noticed that something was wrong on the top-end as the mix was going too lean to continue the pull. He made another pull with me and another Carolina Dyno employee Randy watching my fuel pressure gauge on my rail. The fuel pressure barely made it up to the base pressure before beginning to plummet the higher Ben got in the rev range. We knew there was a problem, and Ben suspected the fuel pump.
We pulled the pump and inspected everything. All seemed well... the short fuel hose that connects the pump to the carrier looked OK, but we swapped it anyway. Ben also had a spare fuel pump carrier laying around that he graciously gave me so that would rule out the internal filter (and the general oldness of mine). Put it all back in and had the same issues. The more pulls he made the worse the fuel pressure dropped off, so we figured that the pump was on its way out and was getting worse the hotter it got. Randy just happened to have a Walbro 255 in the correct configuration at his house, so he ran home and grabbed that. Took the fuel pump BACK out, swapped in the new pump, put it all back together and she ran like a charm. Fuel pressure rose steadily with boost during every pull up to about 65 PSI max.
So finally after getting all that sorted out and getting the fuel trims reconfigured, we were able to get our 93 octane baseline. Due to the weather being pretty much the worst possible setup for boosted cars (hot and it had just rained so humidity was at 100%) the car was down about 25 HP from where it was back in the winter (394 WHP). So 370 WHP was my baseline for that day on 93 octane.
After making a run for some E85, we started draining out the 93 octane by running the car with a drain hose connected to the FPR return line. We got it as low as we felt comfortable with until the fuel started pulsing out the line and the pressure gauge was jumping around. Then we dumped in about 4 gallons of E85 which resulted in a final mixture of about E60 reading out on the gauge. Ben tuned it up for that concentration and then we dumped in the rest of what we bought which got the mix up to an E72. He doctored up his numbers for that concentration so we had two good data points and interpolated the rest of the concentration curves.
A final pull with the E72 concentration resulted in 410 WHP; a 40 WHP gain over our basline from a few hours before. We might have been able to squeak another 5 WHP or so if we had been able to get the concentration of ethanol up to a true 85%, but the pump concentration was most likely less than E80 anyway.
I plan on heading back sometime in the winter when its nice and cold/dry so we can see what my max output is at, but based off the 40 WHP differential today, I would expect to be in the 435 WHP range. The humidity is really the killer because I think I was seeing 3 PSI less boost than I was at my last visit.
Sorry Dagou, I didn't pay any attention to the torque curves along the way. Its a Honda; the torque-less wonder. It *may* have picked up 25 ft-lbs if it got lucky. I'll see if Ben still has the curves on his computer, but I'll be sure to save the curves from the winter pulls for you.
Ben also was able to lean up my idle/cruise AFR's when running a higher ethanol percentage, which should help me get a bit better gas mileage on E85 when just cruising around. Naturally the E85 tune requires more fuel when WOT, so those savings will likely get zeroed out and then some with the way I drive. Its still a bit unnerving seeing AFR's in the 15's under normal operation, but I'm getting used to it. Ben spent some extra time street tuning it like he did last time to make sure all was well under normal driving. He's always done a great job at making sure I was happy (and that he was satisfied) with the way the car was before letting me leave.
The trip home was uneventful besides me attempting to make it all the way to my local E85 pump on as little gas as possible to keep my concentration up, lol. I'm not too thrilled about have another "Whinebro" pump back in my car... I still had the soft top tray off the car when driving back home and once you're down to about a 1/4 tank that pump is nice and whiny. It does quiet down a lot with the tray back in and a full tank of gas though. I did discover that the second-to-last bar on the AP1 fuel gauge lasts a heck of a long time, much to my delight.
So, overall I am satisfied with this setup. I get to buy gas that is significantly cheaper than 93 octane; E85 was $3.36 whereas premium was a whopping $3.99 at the same gas station. The cheapest I can find premium around me right now is $3.62, so that's at least a $2.60 savings on a tank. I guess ethanol is better for the environment and all that s**t (like I care, lol). And I'm making ~40 more WHP to boot! But really I think its just a pretty neat setup that not many people have or even know about.
We knew we wanted to raise the base fuel pressure just a bit to help out with the E85 delivery, so we raised it from the stock 43-45 PSI to a modest 50 PSI using my AEM adjustable FPR. After a few pulls on the dyno, Ben noticed that something was wrong on the top-end as the mix was going too lean to continue the pull. He made another pull with me and another Carolina Dyno employee Randy watching my fuel pressure gauge on my rail. The fuel pressure barely made it up to the base pressure before beginning to plummet the higher Ben got in the rev range. We knew there was a problem, and Ben suspected the fuel pump.
We pulled the pump and inspected everything. All seemed well... the short fuel hose that connects the pump to the carrier looked OK, but we swapped it anyway. Ben also had a spare fuel pump carrier laying around that he graciously gave me so that would rule out the internal filter (and the general oldness of mine). Put it all back in and had the same issues. The more pulls he made the worse the fuel pressure dropped off, so we figured that the pump was on its way out and was getting worse the hotter it got. Randy just happened to have a Walbro 255 in the correct configuration at his house, so he ran home and grabbed that. Took the fuel pump BACK out, swapped in the new pump, put it all back together and she ran like a charm. Fuel pressure rose steadily with boost during every pull up to about 65 PSI max.
So finally after getting all that sorted out and getting the fuel trims reconfigured, we were able to get our 93 octane baseline. Due to the weather being pretty much the worst possible setup for boosted cars (hot and it had just rained so humidity was at 100%) the car was down about 25 HP from where it was back in the winter (394 WHP). So 370 WHP was my baseline for that day on 93 octane.
After making a run for some E85, we started draining out the 93 octane by running the car with a drain hose connected to the FPR return line. We got it as low as we felt comfortable with until the fuel started pulsing out the line and the pressure gauge was jumping around. Then we dumped in about 4 gallons of E85 which resulted in a final mixture of about E60 reading out on the gauge. Ben tuned it up for that concentration and then we dumped in the rest of what we bought which got the mix up to an E72. He doctored up his numbers for that concentration so we had two good data points and interpolated the rest of the concentration curves.
A final pull with the E72 concentration resulted in 410 WHP; a 40 WHP gain over our basline from a few hours before. We might have been able to squeak another 5 WHP or so if we had been able to get the concentration of ethanol up to a true 85%, but the pump concentration was most likely less than E80 anyway.
I plan on heading back sometime in the winter when its nice and cold/dry so we can see what my max output is at, but based off the 40 WHP differential today, I would expect to be in the 435 WHP range. The humidity is really the killer because I think I was seeing 3 PSI less boost than I was at my last visit.
Sorry Dagou, I didn't pay any attention to the torque curves along the way. Its a Honda; the torque-less wonder. It *may* have picked up 25 ft-lbs if it got lucky. I'll see if Ben still has the curves on his computer, but I'll be sure to save the curves from the winter pulls for you.
Ben also was able to lean up my idle/cruise AFR's when running a higher ethanol percentage, which should help me get a bit better gas mileage on E85 when just cruising around. Naturally the E85 tune requires more fuel when WOT, so those savings will likely get zeroed out and then some with the way I drive. Its still a bit unnerving seeing AFR's in the 15's under normal operation, but I'm getting used to it. Ben spent some extra time street tuning it like he did last time to make sure all was well under normal driving. He's always done a great job at making sure I was happy (and that he was satisfied) with the way the car was before letting me leave.
The trip home was uneventful besides me attempting to make it all the way to my local E85 pump on as little gas as possible to keep my concentration up, lol. I'm not too thrilled about have another "Whinebro" pump back in my car... I still had the soft top tray off the car when driving back home and once you're down to about a 1/4 tank that pump is nice and whiny. It does quiet down a lot with the tray back in and a full tank of gas though. I did discover that the second-to-last bar on the AP1 fuel gauge lasts a heck of a long time, much to my delight.
So, overall I am satisfied with this setup. I get to buy gas that is significantly cheaper than 93 octane; E85 was $3.36 whereas premium was a whopping $3.99 at the same gas station. The cheapest I can find premium around me right now is $3.62, so that's at least a $2.60 savings on a tank. I guess ethanol is better for the environment and all that s**t (like I care, lol). And I'm making ~40 more WHP to boot! But really I think its just a pretty neat setup that not many people have or even know about.
Joined: Aug 2011
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From: Myrtle Beach
thanks for the write up. Before you start a college fund with your saving per tank what is E85 miles per gallon?
With varying fuel mixes it really is going to be had to look your AFR and have it mean something. "Its still a bit unnerving seeing AFR's in the 15's under normal operation, but I'm getting used to it."
A reaction in which all components are completely consumed is considered to be stoichiometric (stoich). For gasoline/petrol this mixture is approximately 14.7 parts air, to 1 part fuel (14.7:1) for E85 this ratio is approximately 9.7:1 (note these ratios are approximate based on theoretical data assuming perfect laboratory samples, these ratios may vary slightly due to variations in regional and seasonal blends of fuel.)
Guess you need to start looking at Lambda:
"Note about Lambda vs AFR
You may have noticed in the table that Air-Fuel Ratio has an equivalent value called Lambda (λ). Lambda is representative of the stoichiometric ratio where a λ=1 will always be stoichiometric, regardless of the fuel in use. Other ratios are simply defined as a ratio in relation to stoich. For example, a ratio of 11.76:1 would be: 11.76/14.7 = 0.8. This simplified measurement is very useful, in fact, most oxygen sensors actually read in values of lambda, as they are actually measuring the ratio of free air in the gas mixture, and thus the ratio in regards to stoich. This simple process allows vehicles to also quickly adjust to differing fuel types. Most modern flex fuel vehicles that run on both E85 and petrol/gasoline have done away with the expensive alcohol sensors and rely on the oxygen sensor to determine what the mixture of fuel is and reference the appropriate map accordingly."
Great job making this happen! Now what is next?
With varying fuel mixes it really is going to be had to look your AFR and have it mean something. "Its still a bit unnerving seeing AFR's in the 15's under normal operation, but I'm getting used to it."
A reaction in which all components are completely consumed is considered to be stoichiometric (stoich). For gasoline/petrol this mixture is approximately 14.7 parts air, to 1 part fuel (14.7:1) for E85 this ratio is approximately 9.7:1 (note these ratios are approximate based on theoretical data assuming perfect laboratory samples, these ratios may vary slightly due to variations in regional and seasonal blends of fuel.)
Guess you need to start looking at Lambda:
"Note about Lambda vs AFR
You may have noticed in the table that Air-Fuel Ratio has an equivalent value called Lambda (λ). Lambda is representative of the stoichiometric ratio where a λ=1 will always be stoichiometric, regardless of the fuel in use. Other ratios are simply defined as a ratio in relation to stoich. For example, a ratio of 11.76:1 would be: 11.76/14.7 = 0.8. This simplified measurement is very useful, in fact, most oxygen sensors actually read in values of lambda, as they are actually measuring the ratio of free air in the gas mixture, and thus the ratio in regards to stoich. This simple process allows vehicles to also quickly adjust to differing fuel types. Most modern flex fuel vehicles that run on both E85 and petrol/gasoline have done away with the expensive alcohol sensors and rely on the oxygen sensor to determine what the mixture of fuel is and reference the appropriate map accordingly."
Great job making this happen! Now what is next?
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Joined: May 2002
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From: Raleigh, NC
on a normal wideband gauge setup for gas, 1 lambda = 14.7 gas = 9.7:1 e85, so if you "pretend" its gas thing work out about the same. AFR at low load on most hondas can be as lean as 16:1 with gas and usually you can get away with a touch leaner on e85 before it starts to drive funny.
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Yeah, Ben actually leaned up my 93 octane idle to 15 too for the same reason. Car has been running great thus far. I'm tweaking a little bit of transient throttle stuff while the car is still cold (because my drive to work is < 10 minutes), but otherwise its great.
I'm not really sure what's next yet. I told myself that I wanted to do a V8 swap in 2015 because I would love the experience. We'll see if my wife has the patience for that process or not, haha.
I'm not really sure what's next yet. I told myself that I wanted to do a V8 swap in 2015 because I would love the experience. We'll see if my wife has the patience for that process or not, haha.
Joined: Aug 2011
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From: Myrtle Beach
"Sorry Dagou, I didn't pay any attention to the torque curves along the way. Its a Honda; the torque-less wonder. It *may* have picked up 25 ft-lbs if it got lucky. I'll see if Ben still has the curves on his computer, but I'll be sure to save the curves from the winter pulls for you."
25 ft-lbs is a shit load, people die for a 8% increase in torque, especailly in our torque-less wonders. I cannot beleive that doing dyno pulls has become so common place for you that you do not even save the curves. YOu have come a long way.
25 ft-lbs is a shit load, people die for a 8% increase in torque, especailly in our torque-less wonders. I cannot beleive that doing dyno pulls has become so common place for you that you do not even save the curves. YOu have come a long way.
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LOL! I know. Well I knew the numbers themselves would suck this visit anyway because of the weather. I was more concerned about how it drove versus the numbers this time around. Come winter I won't be that way.