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E85 vs water/meth info

G

gambler87

New member
Does anyone have any hard info (datalog), comparing e85 to 91 pump gas with water meth on our engines

Looking for iat readings vs ambient, and egt info for both fuels.

If not I'm thinking about running tests on my engine this spring to see which would be better.

I've read alot of articles and no not one that I have read has given cylinder pressures, egts, iat info. And I can't find anything that compares both of them on the engine platform

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e85 is worth about 60 more hp over piss gas in mine.

s1x cam tog headers gen5 2.8 e85 60# injectors 105# springs ti retainers stock heads stock tb 330whp/400wtq

IF you have e85 in your area the hell with meth run e85!

Edit i see your in MN e85 is everywhere I live in Grand Forks ND.

E85alllllthesc3800s!!
 
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E85 for the detonation mitigation water meth for the cooling of the iat.both have sprayed jobs that they do well.

If you have a tuner I would recommend you make the swap to e85
 
might be interesting to see the differences if you are inclined. not everyone has access to E85. another thing to consider would be testing the actual differences of different water methanol ratios. most people recommend a 50/50 blend, but other people do 100% methanol.
 
I run a 70/30 water/meth ratio by weight.

I still see no one with hard info just people saying it's better.

I've done research on supercharger pulley size on gen v for boost vs iat temps, and I've done the research on water meth ratios. U want to run the least amount of methanol in ur mixture with still having zero kr all the way through the shifts. Water cools better and doesn't affect afr. So the more water the better iat temps.

I just can't see how e85 is that great of a fuel. U don't get the gas milage of pump "piss" gas. And it doesn't give u the octane that water meth does. And u have to use it all the time.

I get 27 mpg on my grand prix just cruising. 3.0 pulley, gen v, 1.95 yt rr, 4" airraid intake, ls4 maf, 42# injectors, SD headers. That's on 91 non ethanol.

The friends that I know don't get that kind of milage out of e85 and u go through it faster than pump gas.

U only use water/meth when u go into boost. I'm a boost happy person and I will drain a 3 quart tank in a little over half a tank of regular gas. I pay 99 cents a gallon for distilled water and I pay $35 for a 5 gallon can of m1 meth. So that's $40 for 10 gallons. $4 a gallon. $8 for every tank of regular gas. I average 330 miles per tank of gas daily driving 60 miles round trip every day to and from work

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Expect a 30% decrease in mpg atleast.

You might get 20-22mpg on the freeway if you are lucky.

Also, lets keep in mind here that introducing fuel sooner in the intake increases cylinder air charge density, so you can get more air into each cylinder before the intake valve closes. E85 does most of the heat absorbing once it gets into the cylinder. So, adding fuel sooner or later each have their own benefits and help make more power, but they do it in different ways
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Fun question, heres an extremely simplified explanation...

Gasoline contains 46.4 MJ/kg of energy, methanol is 19.7 MJ/kg, ethanol is 30MJ/kg. Lets remember e85 is 85% ethanol and 15% gasoline, so e85 would be (.85*30+.15*46.4)=32.46 MJ/kg. Lets also assume 20% of your fueling with the 93/meth combo comes from the meth, so on an energy basis, 93/meth energy content is (.2*19.7+.8*46.4)= 41.06 MJ/kg.

Already something should be obvious....you can make the most power, energy wise, on pump 93! e85 only has 84% of the energy content of straight 93 and 93/meth is only slightly better at 88%. This is of course ignoring the effect of detonation. Also dont forget this is based purely on just burning the fuel, not necessarily how much the engine can utilize of that (which is where timing comes into play).

Now, lets say you want to run your engine at 0.73 lambda for e85 and 0.78 for 93/meth. Stoich afr for e85 is 9.0:1, 93 is 14.7:1, and meth is 6.47:1. Dont forget our fuels are mixed! E85 is going to be (.85*9+.15*14.7)= 9.855 and 93/meth is (.2*6.47+.8*14.7)= 13.05.
So 0.73 lambda for e85 is going to be (.73*9.855)= 7.19:1
0.78 for 93/meth is (.78*13.05)=10.18.
0.78 for straight 93 is (.78*14.7)=11.45

AFR is air to fuel ratio, ie, the amount of air needed to completely burn 1 unit mass of fuel. So if we keep our airflow constant (just playing with fuel, remember?) then we are going to use [1- (7.19/10.18)]= 29.4% more fuel with e85 than 93/meth...but is that more energy available?

Just for comparisons sake our turbo moves 40kg of air (about 800hp worth).
Straight [email protected] lambda (40/11.45) = 3.493kg of fuel for the air given.
93/[email protected] lambda (40/10.18) = 3.929kg
[email protected] lambda (40/7.19) = 5.563kg

Using our energy content from earlier:
Straight 93 (3.493*46.4) = 162.08 MJ
93/meth (3.929*41.06) = 161.32 MJ
e85 (5.563*32.46) = 180.57 MJ
Keep in mind we are richer with the e85, at 0.78 (truly apples to apples), it would be 168.82 MJ.

So using straight 93 as the baseline
Straight 93 = 100%
93/meth = 99.5%
[email protected] = 104.2%
[email protected] = 111.4%

SSSSOOOO.....*based purely on the fuel consumption*, running e85 slightly richer in place of 93/meth will give you 12% more power everything else being equal.

The HUGE caveat to this is all things are NOT equal. Remember how we are injecting a lot more mass of e85? Well that fuel displaces air, so all the sudden you cant push in as much air because some of the volume is fuel, so you volumetric efficiency goes down. By volume e85 is displaces roughly 6% more volume than gasoline, so your gap just shortened by that much. E85 burns cooler than 93, so from a thermodynamic standpoint your engine is now a less efficient heat pump. Also e85 is harder to ignite, ie, you need a stronger ignition system, this is a parasitic loss on the engine, unless you dont run an alternator. The flame front speed of e85 is slower, so using the same timing map of 93 will not allow the engine to fully utilize the power stroke. There are many more things to consider, but this hits the high points.
Click to expand...

Just some things I've read in the past.

I doubt you will find hard data on anything 3800 related, I don't know of anyone installing temp sensors past the blower and EGT in the cylinders to compare the two. In short, the reason people run E85 instead of the intercooler is because of the cooling the fuel can do in the cylinder. Allowing you to increase timing and increase cylinder pressure at the same time within reason.
 
Rule #1....you don't use E85 for economy....period. I get about 18, Blueguy gets about 22 on a stock engine. Mine's a little more....aggressive.

I experimented with the water/Methanol ratios quite a bit, and settled on 100% on a DO10 nozzle for the best, and because I used a progressive controller I could adjust from there. It did what it was supposed to do, which was to kill the KR...but it just didn't push the car faster on the ET's like I wanted. I had to be cautious on when to dial in on when the boost came in, adjust the PE tables constantly with the heat etc, it was just a pain in the ass in the end.

With E85, I don't worry about when to adjust my pe for temps anymore, the car doesn't care about when I stab the throttle. When I push the pedal down, it goes from A to B, and I never have to worry about if I'm running low on my meth tank.

Back in 09, Dave (TEP Dave) and I ran together at a track in south Missouri, we were going back and forth on our kits, nozzles, etc. He had a Snow Performance setup on his XP 2.6 pulley setup, and the fastest he could pull times with were in the 12.20 range (he's got a 86 Cutlass G-body L67 swap)
I had an XP 2.6, 2.8, 3.0 setup that I jacket with on my mixes, and the best I could put down was a 13.1 on anything..I put in a can of Torco that I had, immediately clicked off a 12.95....then another 12.90.
We both came to the conclusion that while the meth injection did what it was supposed to do, it just didn't provide the HP gains that we wanted. You can run a lot off boost with no predetonation, but it was just crudding up the intake charge, and adding too much humidity to overcompensate for what fuel I was pulling to make it worthwhile.
We both took the kits off, sold them, used that money to buy bigger injectors and fuel pumps, and proceeded to go full E85 and I haven't looked back. I have a station that's about 5 miles from my house, but on the way to work that I stop at a couple times a week, and I too commute about 60 miles a day.
Bottom line, they both work, but it's easier for me to use E85 over Meth now....just my two cents.
 
Reptile where did u have ever ur nozzles placed? I hear that direct port water meth is the way to go.

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Five finger, is the 6% volume based on a 1 to 1 figure or does that take into account the offset (more) e85 u have ever to run compared to pump gas?

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gambler87 said:
Reptile where did u have ever ur nozzles placed? I hear that direct port water meth is the way to go.

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I have been looking for several months, and I can't find anyone that has run direct port. Closest would be Javi running two nozzles under the blower.
 
Yeah I still don't see how e85 wins, u have to fill both, but u get better mileage with water/meth injection and can still run the same or actually more octane, and u can still start ur car in the winter.

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E85 is just better at it's job inside the cylinders than running pump gas with alcohol injection. It has the ability to do more, let you run more compression and boost, aswell as spark and less likely to knock.

Sure both allow you to do this but E85 is just better at it.

E85 has a much greater latent heat of vaporization than gasoline, cooling the intake charge and thus increasing its air density-rather like intercooling or water-alcohol injection. We've all seen Sprint cars and Alcohol dragsters frosting up after a good run. Ethanol has much the same property, just to a lesser degree. On some engines the resulting power increase could be as much as 5 percent. And when we compare the performance potential of E85 apples to apples-that is, to other retail pump fuels-really there is no comparison. With a pump octane of 105 instead of 87 to 94, you can run more compression, more boost, and more spark advance without damaging the engine with knock, and make more power.
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Just another blurb I've found in tons of articals.
 
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