thanks atomic. That's what I guessed but wasn't positive. That comparison is exactly what I wanted to see and this is why. I wanted to take timing out of the equation because running 93 with meth will allow you to increase the timing more than straight 93 w out meth. burning e85 alone allows you to increase the timing coming from 93. So leaving it alone, and somewhere in the middle of both fuels happy place would allow a more clear test.

The difference in amount of useful timing between the two is something I do not know. is it something like 2-3 degrees or even more going from 93meth to e85?

i.e.
93 pump = 15* timing
93 w meth = 17* timing
e85 = 18* timing

Does anyone has some numbers for this? What is your timing at with reg 93 pump, then what is it with meth? Do you have the power dif between the two also? How much more timing did you go up? I know the amount of meth and each trucks tune are variables but a number of degrees would be neat to see for the same truck.

I love these threads and I understand where you guys are saying you cant compare them without new tunes. I hear ya, I was just wondering about the fuels. I would hope no one leaves their 93 tune when spaying meth and again 93 w meth tune when switching to e85.

 

Jake i wanted to bring this comment over here from the other thread started yesterday. I'm interested hearing about the denser air charge based on nozzle placement before the throttle body. I know the meth needs to be placed up stream from the intake mani and IAT sensor so it has time to cool the intake charge and do its thing. But how far is too far? Is there a point where the charge would actual heat back up or lose its density? For example, would it be better to place dual nozzles directly after the intercooler or place them about 12"-18" before the throttle body? From what i've seen on this forum and over on tech, no once places there meth injection point directly out of the intercooler...

 

So no one has tried my leaf blower idea yet?

I did the math at some point and the air leaving my intercooler with 3" pipe is moving something like 250ft/s....find a leaf blower with similar output (170mph) and put a meth nozzle at the exit and see how far downstream you can no longer see meth vapor. Crude but should give you an idea.

I think a lot of you guys are underestimating the complexity of the issue as Jake alluded. X amount of timing wont always give you Y more horsepower. Normally you increase timing, then you reach mean best torque, MBT, at some ignition advance. If you keep increasing timing you will actually loose torque, and if you increase it more you will get knock. Point is, more timing isnt always better, and even if you arent getting knock you could have more timing than you need. This is when having a lot of time on a dyno comes in handy. But to make it more fun, the MBT timing will move around some with atmospheric conditions. So a perfect tune on Tuesday night all the sudden isnt so good Friday morning, but this may be splitting hairs.

So how much timing should you run? Well that depends on A LOT of things like compression ratio, cylinder head design, quench height, chamber volume, intake are temp, FUEL, afr, camshaft overlap, power adder type, plug heat range, and im sure some others. To complicate it, this moves around constantly, especially during a high-load situation like a WOT pass.

You really need to pick a fuel choice as one of the first decisions in a build and design your whole setup around that. Most stock engines are designed for pump gas, which is fine, you can clearly make big power with pump gas. To say swtiching to one fuel or another will add Z amount of power by letting you run X amount of more timing is a gross simplification of the whole thing.

 

From a simple heat standpoint, technically no nozzle placement is too far from the throttle body. If methanol is injected into the heated air stream and it undergoes a phase change from liquid to gas, it will absorb heat energy in the process regardless. Even if the nozzle was far enough from the throttle that the methanol changed completely from liquid to gas and began to heat up again from the charge pipes, there would still be a net loss in heat because the heated air gave up work energy to convert the methanol. Now for this to be of optimal use, the ECM has to be aware of it and inject more fuel accordingly. So the IAT sensor would have to pick up the temperature drop or the tune will be off and it could go lean due to the added air mass.

I'm not sure if this holds true for everyone who swears by methanol injection but generally, placing the nozzle too far from the throttle body is not desirable because it leads to an added transient fueling delay. Just like a fuel injector into a port on a cylinder head, some of the fuel injected into the air stream will impact the pipe walls as pressure rises. For a turbo's rather gradual pressure rise and a large amount of pipe wall area, this delay can be pretty extreme. If you have meth injection, the trend you often see for a constant boost level and meth injection quantity is the air fuel ratio gradually getting richer and the pipe walls become saturated with methanol. The opposite is true when you let off the throttle...it takes time for the methanol to all evaporate from the pipe walls, so the mixture can stay rich for several seconds.

I haven't come across it too much in research papers or books, but in my opinion, our combinations are not extreme enough to get a whole lot of benefit from injecting methanol after the TB or actually using it as a primary fuel and injecting directly into the port. The knock resistance from injecting methanol closer to the intake valve itself is very high, but I do not think these engines even on 20psi stand to actually gain much from that. In the end they are still passenger car/truck engines and have extensive research and modeling of the cylinder quench, flame propagation, etc. so they are already fairly knock resistant. A good tune and IAT reduction from enough meth injection further upstream should be plenty for our needs. Now a dragster that runs solely on meth and 60 pounds of boost and has giant heads...they will pick up more from port injected methanol

 

Might be why top fuel dragsters have 4 injectors per cylinder at different places along the intake tract...

 

They reap all the benefits lol. Bout time for you to add 24 more injectors, yeah?

 

SO IF I WANNA switch to e85 from my norm of 93 can i do so next time i fill up with no probs????

 

 

^^^^ yeah. Wtf

 

What did the five fingers say to the face?!?