How Are The Conversions Going? Inquiring Minds...

[EyesofThunder]

What everyone forgets is there is more O2 present, so despite less energy, there is more O2 so more of the fuel gets burned and therefore can have the potential to make power, if it doesn't get burned like gasoline, then we end up with less power. Hence why E85 typically has a 5% more hp output than gas in NA applications. Probably more like 10% in boosted.

But I am seeing in the order of 50% loss in mpg on the 3800 and 25% on the LT1. The 3800 is 8.5:1 and the LT1 is 10:1, but another 25% loss? Seriously the 3800 gets mpg almost what the LT1 gets, the LT1 is in a 5000 lb car and driven a bit harder, and is a 7000 tow package car. The 3800 SC is driven by the instant fuel economy gauge (which the FW doesn't have) and is a 3800 lb car. My guess is compression is a huge factor in E85 use. I do know heating the fuel and air coming in is a GOOD thing for E85 and economy.

I do need to get some fuel and see how much % is in it. I am thinking it is not E85, but more like E70 right now. Everytime I try to set the fuel to 9.78:1 or so, it runs way rich, it always seems in the 11:1 range for the pump E85.

The problem that I see with E85 compared to race gas is consistency is poor, race gas is much more consistent. You never know what you are going to have from tank to tank.

 

[bsdlinux]

In regards to fuel mileage- Most of the numbers quoted on the net are from the newer flex fuel vehicles and almost all of them are NA. They typically have a higher compression ratio than our TRs or even your SC3800. The key to getting great mileage and power from E85 is to have a NA engine well over a 13.1 compression ratio. Obviously we can't build our boosted engines with that much compression.. so we are kind of in a trade off situation.. mileage or power

Most flex fuel vehicles will lose anywhere from 10-20% of their gas mileage from using E-85 and these cars were designed for it.

EYES - Ok your LT-1 came stock with around 10.4:1 compression. Your SC3800 somewhere around 8.5:1. There you have it.
Your compression ratio on your 3800 is killing your mileage just like it does on my TR. So yes compression ratio is a big factor with fuel economy using E-85.

Having a warmer air intake temp is a good thing for E-85. This is exactly why I run a 195 stat in my TR.

I've had excellent luck with E-85 here in Texas in regards what I get everytime out of the pump. My BLMs are always in line with the numbers I would see in the previous runnings with that same mix of whatever I was trying to do. I've ran straight E-85 and damn near everything else in between. BTW I was using 87 + E85 mixes with excellent results :biggrin:

E-85 vs racing fuel or even alky injection. There is a board member here that has done testing between 93 and alky and just E-85 in the same car. The results were about 8% more power in E-85's favor. These tests were backed up using other cars as well. So E-85 is a better power choice than 93 and alky. However I would choose the 93 + alky for the daily driver.

Some have claimed the same results or close to the same when using 93 + alky vs RACE gas. If E-85 has been shown to make more power than an alky injection car then obviously E-85 is a great race gas alternative as well. I would call it a no brainer :tongue:

 

[FreeJack]

I have been experimenting with E-85. I had a 75% Gas to 25% E-85. I have been gradually moving to a higher concentration of E-85. Well I finally got to 75% E-85 to 25% 87 octane gas. I suddenly found my BLMs really high! Around 150! I added for Gas and the BLM went back down to normal 128-134.

Any ideas why E-85 would raise BLMs???

Thanks

 

[EyesofThunder]

The nature of E85. Simple answer: It has a high content of O2 in it, something gas has none of. So 100% will raise BLM's to around 180. So you MUST use larger injectors. Do NOT mess with E85 on a boosted engine without fatter injectors. You are flirting with a box of holey pistons..... Not and engine block with them....

I have been experimenting with E-85. I had a 75% Gas to 25% E-85. I have been gradually moving to a higher concentration of E-85. Well I finally got to 75% E-85 to 25% 87 octane gas. I suddenly found my BLMs really high! Around 150! I added for Gas and the BLM went back down to normal 128-134.

Any ideas why E-85 would raise BLMs???

Thanks

 

[FreeJack]

I am 60lbs mototrons are they too small?

 

[EyesofThunder]

Depends on how much fuel the engine needs with gas.

Watch your Injector Duty cycle. If it is getting up on 80% or higher, stop running it and get some larger injectors. I almost ALWAYS run a datalogger when I am running E85.

I found on my LT1 with E85 and stock LS6 injectors (same flow rate as stock LT1, 24 lb/hr) and when I got over 80%, I noticing some odd things in how the acceleration rate of the engine. It slowed momentarily between 80-85%, once over that it started picking up again, and didn't lean out on the NB O2's up to 116% duty cycle. (please don't say they are static, they aren't it is much more complicated than that). Don't do this on a boosted engine, I did it on a NA engine that can tolerate it

So the answer is datalog, and find out what the engine is needing. 60's I would think would be plenty for a mid 13 sec car on E85 , but probably not much more than that. I haven't studied how much fuel the TR's are running, but that makes sense based on the calculations I have seen.

I am 60lbs mototrons are they too small?

 

[FreeJack]

Does TurboLink show the injector duty length? If so where?

Thanks

 

[termn8rbuick]

i bought 10 galons of e85.started my car i put the 10 in and the idle smoothed out.it s normally rich.filled the tank up with 93.about 5 galons.so far so good.i turned the fp up to 46.set my maf trans. to 12 degree rich,and rich idle.also added a small bottle of marvel mystery oil.so far ive ran 21 pounds of boost 0 det.already went back and got 10 more.

 

[termn8rbuick]

ive got 55lbs.inj,223 223 cam,t66 turbo

 

[EyesofThunder]

I don't know directly, I just calc it in Excel.

DC = Inj PW * RPM / 1200

So just calculate it if it doesn't already.

Does TurboLink show the injector duty length? If so where?

Thanks

 

[FreeJack]

What is Inj PW?

Thanks

 

[EyesofThunder]

Injector Pulse Width. The amount of time the injector is commanded to be on.

Injector Duty Cycle: Duty cycle is the proportion of time during which a component, device, or system is operated. In the case of a fuel injector, if the injector is on for say 12mS, and off for 12mS, the total cycle is 24mS (I have no idea how long the actual cycle is, this is simply an example), so if the injector is on for 50% duty cycle. On for 18mS and off for 6mS, then 75%, etc. But we have another factor in an engine, it is a 4 stroke engine, and we have to factor in rpm. So that is why there is a formula for it. The ball park is not to exceed 85% max duty cycle, as most likely you are spraying fuel on a closed intake valve.

So in an engine, if we are on for 12mS, @ 3000 rpm, our duty cycle is 30%.

What is Inj PW?

Thanks

 

[FreeJack]

I see!

Thanks for the valuable information. I will have to crank up turbo link and see if there is any information I can grab!

Thanks!!!

 

[EyesofThunder]

And a comparison:

PW RPM Duty Cycle (calc) %
18 3000 45
18 3500 52.5
18 4000 60
18 4500 67.5
18 5000 75
18 5500 82.5
18 6000 90

As we see, rpm increases, same PW, DC increases. So you can see better how they are related. So if you are at say 85% DC at 5500 rpm and you start to increase your rpm, say some mods, new short block, etc, you can easily exceed DC on the injectors and risk going lean. OR if you are already close on DC and you start dumping in % of E85, you will for sure exceed 85%. I have seen 116% on my LT1. (Remember we have a 4 stroke engine, so DC can actually be calc to 200% before the injectors are truly "static" or open all the time, but over 100% DC they are most likely open 100% of the intake stroke and the compression stroke. Somewhere I am sure there is more settings that setup min BTDC open degrees and max degrees so the injectors shut down and not spray at a closed valve. I know the SC 3800's do, LS1's and a few others do have it. So cam change does affect the theoretical 85% number, but it is still a very good rule of thumb to not exceed. Playing with holey pistons sucks....

 

[FreeJack]

Thanks for the info. I will research my car. That may explain for the high BLMs at highway speed. It seemed to not be that bad with a 50/50 mix.

 

[EyesofThunder]

Note that when the BLM is >128 at the time you enter PE mode the PCM dumps in extra fuel, figuring that there is something wrong and it is running lean and starts to try to protect things.

So monitor things carefully with a WB O2. On the LT1, the BLM's can be locked, keeping this from happening, not sure on the 3.8L Turbo.

Thanks for the info. I will research my car. That may explain for the high BLMs at highway speed. It seemed to not be that bad with a 50/50 mix.

 

[b4black]

What everyone forgets is there is more O2 present, so despite less energy, there is more O2 so more of the fuel gets burned and therefore can have the potential to make power, if it doesn't get burned like gasoline, then we end up with less power. Hence why E85 typically has a 5% more hp output than gas in NA applications. Probably more like 10% in boosted.

E85 has no O2 in it. It has oxygen, but that's not the same as O2 in the air. The oxygen in ethanol is more like the oxygen in CO2. It's there, but just taking up room and not aiding combustion.

Think of the oxygen in ethanol as bread cumbs in meatloaf. It's just filler.

If you need more O2, run more boost. That's the point of the turbocharger.

The 5% 'more power' in NA applications is just peak HP. It's a function of the higher octane and most modern cars having knock control. Overall, the power is down ~30%, hence the loss in MPG.

 

[EyesofThunder]

I didn't do so well in Adv Chem.

Ethanol is: CH3CH2OH
I can't find gas, but IIRC it has no O in it at all. Neither has O2. So having O has to be better than none right?

E85 has no O2 in it. It has oxygen, but that's not the same as O2 in the air. The oxygen in ethanol is more like the oxygen in CO2. It's there, but just taking up room and not aiding combustion.

Think of the oxygen in ethanol as bread cumbs in meatloaf. It's just filler.

If you need more O2, run more boost. That's the point of the turbocharger.

The 5% 'more power' in NA applications is just peak HP. It's a function of the higher octane and most modern cars having knock control. Overall, the power is down ~30%, hence the loss in MPG.

 

[bsdlinux]

I didn't do so well in Adv Chem.

Ethanol is: CH3CH2OH
I can't find gas, but IIRC it has no O in it at all. Neither has O2. So having O has to be better than none right?

Short answer is yes. However the extra oxygen is not what makes E-85 a power making fuel for our cars.

B4BLACK said it all the oxygen is just filler in this case ; I wouldn't even consider it mentionable.