Another MPG thread E85 vs. pump fuel (my tests this weekend)

[turboglenn]

Well, i used my trip to KC to test pure highway MPG on E85 on the way there, and knowing i wouldn't find it where i was for the trip home i took the latop so i could map the new 1000's out on pump fuel and see what i could get out of them. ( I've never ran pump gas since getting the 1000's)

I filled up on E85 less than a mile from the interstate. I got on the interstate and headed to KC (supposed to have been non-stop) I had to deal wth a few miles of slow rush hour traffic (20-30MPH for about 4 miles) and then when the car broke the Alt belt outside of saint joe it was pretty much shut off and left off till i got new belts on and resumed highway speeds. Then i finished the trip to the hotel.

We made less than 5 miles of in-town driving while in KC and that was looking for gas to leave on (we stayed in a hotel right by the park and interstate so we didn't need to drive much) I got right at 200miles from 11.197 gallons This equals only 17.8 MPG!!!!!!! JESUS THAT"S LOW! Especially for 3 hours of straight highway.

On the way back i added those 11.197 gallons of 91 octane to the remaining total of what was in teh tank ( i think it holds 13.7 IIRC, i'll have to look in my other thread where some one posted tank capacity)

The ride home was non-stop, 198 miles and i used roughly 7 gallons of pump fuel, that equals just a slight over 27MPG highway!!!! Wow! i never expected there to be that much difference in long highway pulls, i expected minimal differences, seriously. I only had about a 2MPH change in in-towen driving at most, barely noticeable at all and made it well worth the extra consumtion for the price of it being so cheap. But on the highway i think i will always use pump gas and just have water injection ready if needed for higher boost/timing situations. In town on pump i average between 16 and 17MPG, on E85 i average about 14-15 MPG.

Please post what you have noticed/gotten on either fuel and please try adn keep it ALL highway and ALL in-town numbers only please. Mixing the driving doesn't give good results (in-town really doens't either, but i interested in your numbers as well)

I'm mainly interested in non-stop highway runs where the whole tank or at least a majority of it was burned at one speed non-stop

Funny little side note/story... NOT TOPIC RELATED. I had checked the timing mark on the pulley this am becauise of my fiasco with the damper coming off shredding the belts on my trip and the cruise method in which i re-installed it. You lock the timing through the software in the haltech to set base timing, i had it locked at 10* BTDC. Well the timing marks were okay so i shut off the car, unplugged th haltech and put the laptop away.

Well while at the circus today i ran into an long time friend and ex-DSM'er ( had a 91 talon TSI for a while) We needed a part for his car because when he came over i noticed he had a vacum leak and the car was running badly. I offer to drive him to O'reilly's in my mitsubishi and give hima tase of boost but for some reason when i layed into it the car just fell on it's face, built boost and just didn't go anywhere. I tried getting in it a few times and was just shocked at how slow my car felt, even part throttle loads werew awefully dogish and i was ashamed of my car, litterally!.

So as we're driving I asked myself "Is this just because pump gas sucks?"

Thejn it hit me... "No dumbass it's because you've got the timing locked at 10* BTDC!!!" had a good laugh on myslef.


Moral of the story...Even when you think you're doing something simple that you've done a thousand times and couldn't possibly screw up, make sure to slow downand double check yourself because you're going to miss something every damn time, but on a mtoor rebuild you'll remember every last bolt, zip tie and drop of locktite

[bacalhau16]

Its funny because its very true. Just when you think youve got everything, your still forgetting something. Sucks!

Interesting thread with the E85 vs. pump gas. very interesting.

[->PrOjEcTGS<-]

Glenn, You have to remember that you are using roughly 30% more E85 than you would be on pump gas to get the same amount of work out of it. I know you understand this. But, that's why it's required to have HUGE injectors for E85. That equates to low MPG. Just one quick calculation puts you right there at 17.5mpg. 25mpg x .30 =7.5 now take 25-7.5=17.5MPG. That's just an estimate.

Now to compare how much it costs you per mile to run each fuel. I don't know what the price of E85 is but lets just say it is $3.00 per gallon. And lets say pump gas is $4.00 per gallon. 11.197 gal x 4.00= $44.78 to fill up on Pump gas. Now factor in that you will use 30% more fuel to go the same distance 11.197 x.30=3.3591, 11.197+3.3591=14.556 gallons of E85 14.556 x 3.00= 43.66 Now take your fill up price and divide it by 200miles. $44.78 / 200=$.2239 per mile for pump gas. $43.66 / 200=$.2183 per mile for E85. That's a whopping $.0056 that you are saving per mile. BTW, that's half a penny guys.

That is the only reason I have not gone to E85 yet. The cost will be pretty much a wash when it's all said and done. But the performance gain you get is awesome! Hopefully all my numbers are correct and you can understand my chicken scratch.

[turboglenn]

projectGS, i guess i was just a bit more off guard since i can get roughly the same mileage in town giving up only a mile or 2 per gallon if it's all city driving (neither fuel gets very much MPG in town )

[turbo addict]

I haven't had the mirage on a road trip but in town I am still getting around 20-22mpg on e85.

[urbanrcr]

I was thinking about switching to e85 in my cars 87 buick t-type and my talon which i run pump and meth in currently. Im sure with meth and 93 im in the same octane range as e85 if not better (e85 is 100-105oct if im not mistaken) and i don't sacrifice gas mileage. Thanks for sharing the information.

[KGB Pilot125]

Here is an interesting thought, what if a guy were to run the lowest otane and meth injection? I wonder if there is an improvment in MPG then? I know in my 4 Runner I get the best MPG using shell 87 I have ran 91 and 85 both the 85 it felt a little sluggish going over vail pass and going through loveland pass. 91 was a lot more but got me less MPG. I cant wait to try it in the talon.

[turbo addict]

Originally Posted by urbanrcr

I was thinking about switching to e85 in my cars 87 buick t-type and my talon which i run pump and meth in currently. Im sure with meth and 93 im in the same octane range as e85 if not better (e85 is 100-105oct if im not mistaken) and i don't sacrifice gas mileage. Thanks for sharing the information.

Even though it is rated at 105 it has a detonation resistance much higher. I run between 30-35psi on a e316g with just e85 no meth.
And my timing is higher than when I was running 110 leaded.
Just my personal experence.

[turboglenn]

turbo addict.. you need to bring that mirage over and let me check it out.. You got a list of the mods, management or anything like that online? I'm very interested in seeing how you're getting such great mileage and wouldn't mind studying your fuel and spark curves if you're okay with that.

[turboglenn]

I started tuning the WOT parts of the new 1000cc injector pump gas map and man, i miss my E85 already, so much less power on pump gas, BUT there is a lot of better throttle response and a TON easier starting which area few nice perks Just thought i'd throw that in here too since it's an ethanol vs. pump thread. I mean at the same boost i honestly feel like I'm losing about 30 horses at the same boost level on pump I know I'm running less timing, but there's a definite benefit to that E85 over conventional fuels that i can't quite put my finger on other than the timing gains.

[bastarddsm]

17.5 thats somthing I really didn't want to hear.. I was hoping to hear 20-22 mpg highway.. What did you have your closed loop a/f set to?

[DsMWookie]

You have to take into consideration how good his tune is also. I currently get 30+mpg on my built motor on the high way. So his current 93 numbers seem to be a bit low, at least compared to what I get. I generally cruise at about 80MPH when on the interstate. Also I run a FP3565HTA so it may have to do with me hardly ever hitting boost to accelerate or atleast not hitting large amounts of boost. (less fuel,more timing, yada yada)

[turboglenn]

Originally Posted by bastarddsm

17.5 thats somthing I really didn't want to hear.. I was hoping to hear 20-22 mpg highway.. What did you have your closed loop a/f set to?

The closed loop AFR was set to around 400mv on the narow bad, that left teh afr's bouncing between 15.5 and 16.2:1

Originally Posted by DsMWookie

You have to take into consideration how good his tune is also. I currently get 30+mpg on my built motor on the high way. So his current 93 numbers seem to be a bit low, at least compared to what I get. I generally cruise at about 80MPH when on the interstate. Also I run a FP3565HTA so it may have to do with me hardly ever hitting boost to accelerate or atleast not hitting large amounts of boost. (less fuel,more timing, yada yada)

The E85 tune was spotless, the pump gas tune was crude, but teh cruising AFR's were right on. But, being that i can't run sequnetial on my car without a different ignitor (from a turbo-II Rx-7) i give up some mileage to running in batch fire mode. I run around 16:1 cruising...about 13.5:1 under light accel, and then under low boost about 13.5:1 richening up towards 12.5 by 10psi....I was cruising at 80mph the whole way with the cruise control on, it was a hilly trip with me hitting about 5-7psi up every hill with the cruise controling the gas.

My car has never gotten great mileage (at least in town) with the bigger injectors and haltech EMS, so don't take my numbers to heart if you're running a stock ECU or DSMlink, AEM EMS or anything else that operates in sequential mode as your mileage will be slighly higher than mine by maybe a few MPG. I have consistantly gotten up to 32 MPG on the highway on pump gas when on 720's with a perfect tune before teh E85 ocnversion. And remember my pump gas fill up still had 4 gallons of E85 blended with it from not draining the tank when i filled up to come home. so the 27mpg can't be taken as solid pump gas data, i was just noticing how much better it was even being only about 75% pump (and if my tank capacity or % of pump gas is wrong, i don't need corrected, i've been drinking and am not to worried about being scientific with it)

[dsm-onster]

Originally Posted by turbo addict

Even though it is rated at 105 it has a detonation resistance much higher. I run between 30-35psi on a e316g with just e85 no meth.
And my timing is higher than when I was running 110 leaded.
Just my personal experence.

Other than cooling the cylinder better which is why you could pour on more boost, the detonation resistance is the same. Octane is the measure of detonation resistance.

[jrohner]

My last trip I did 21.3MPG, which is around what I usually get on the highway. This was with my new BC 272 cams and huge FMIC with a closed loop AFR of about 10.6:1 (about 16:1 gas AFR). Speed ranged from 63 - 70 mph the majority of the time depending on various speed limits (60's most often).

Back when I was in fwd mode (trans issues), and SMIC and stock cams, I was getting up to 20 in town, and 22 mixed hwy with some town. This was because I couldn't get on the throttle until 3rd gear (even 3rd gear it spun). At the time I was running 11.7:1 AFR (about 17.55:1 gas AFR)

Back when I was running gas, stock 14.7:1, and AFC tuning, the best I got was 25 point something on the highway. I usually got about 18-20 in town.

[wishihadatalon]

Best 93 numbers were 33mpg for a long highway drive. The afr is around 14.7.

Best e85 numbers are 28 on the drive back from the shootout. The afr for that was 16.2. I increased timing a little for this, but after reading some different things on burn rates and what not, I should have decreased it ~2 degrees.

[jrohner]

Originally Posted by wishihadatalon

Best 93 numbers were 33mpg for a long highway drive. The afr is around 14.7.

Best e85 numbers are 28 on the drive back from the shootout. The afr for that was 16.2. I increased timing a little for this, but after reading some different things on burn rates and what not, I should have decreased it ~2 degrees.

How are you getting that good of mileage? I see you have megasquirt, could something with that be the reason? What is your ignition timing cruising?

[KGB Pilot125]

Originally Posted by wishihadatalon

Best 93 numbers were 33mpg for a long highway drive. The afr is around 14.7.

Best e85 numbers are 28 on the drive back from the shootout. The afr for that was 16.2. I increased timing a little for this, but after reading some different things on burn rates and what not, I should have decreased it ~2 degrees.

Do you run a Cat. Converter? I think that is really great to see some "lean burn" type tuning on here one thing that I have read about lean burn is it will destroy a cat in no time running that lean, IE hot. If you have a EGT what were the temps like while cruising?

[wishihadatalon]

Originally Posted by jrohner

How are you getting that good of mileage? I see you have megasquirt, could something with that be the reason? What is your ignition timing cruising?

Tooning haha. I have zero reason to get into the throttle on a long cruise. Set the cruise, rock the A/C (yep