First start of the day usually takes 4 or 5 tries. Im running e85. I didnt want to change any tables without asking as im not sure if its fuel or air issue. It starts normally and pretty quick when its hot. Its not necessarily a "cold" start also. Its about 60 today and it was hard to start. Any suggestions are appreciated.
Is it IAC controlled? Does it have a huge cam or stock?
Just curious, mine is huge cam, e85, IAC controlled, and IAC count is through the roof on cold start up, normally fires off 3rd or 4th try.
what vehicle is it? on mine it was a bad fuel pressure regulator up on the fuel rail
Originally Posted by Gregski
02 silverado turbo 5.3 small cam fuel pressure is fine
Startup Airflow
First in the Scanner add these Channels:
Idle Desired RPM
Idle Desired Airflow
Idle Startup Airflow
To make changes in the Editor go into: Engine \ Idle \ Airflow \ Startup
and modify the following two tables:
Startup Airflow Initial (double the values under the corresponding temps)
Startup Airflow Delay (double the values under the corresponding temps)
and see how the engine responds, doubling may be too much so you may back off a little, or it may need even more air
Fuel will be the main factor here. Ethanol needs a lot enrichment for cold starts. Crank spark will need adjustment as well. I wouldn't touch airflow (yet) if you are just trying to get it fired up. Startup and friction airflow come into play after the engine is running...they manage the start flare and return to idle. You should be able to get a nice healthy run-up without touching any airflow.
Alcohol evaporates more slowly when cold.
i.e. spray some alcohol/gas on a table and watch it evaporate
only the vapors, fumes, evaporated component can burn in the combustion chamber
So the instant it is injected cold, none has vaporized. When the engine is hot its like spraying a stream of fuel onto a hot frying pan- instant vaporization.
But when cold the alcohol just forms a puddle on the intake valve and kinda sits there.
Try to imagine it happening and this will cure your cold start issues because as you understand the relationship between heat, time, energy input to the alcohol it will begin to form a plan to get that engine started.
we control these variables:
1. pre-heat the fuel or engine's intake air & pathway. It would help vaporize the fuel more easily.
2. Allow a prime-pulse to all cylinders followed by a brief period of delay or waiting for the fuel to evaporate before trying to crank the engine.
3. Create enough air velocity/turbulence during cranking of the air intake pathways to assist with vaporizing the fuel more quickly.
I'm going to say #2 is the most useful. #3 means there will be some delay to starting based on the port volume and cranking rpm and all of that whereas with #2 enough alcohol evaporates and then intake turbulence will no longer be as important or even relevant. #1 is done in the supreme northern regions of ice cold weather.
Only for ethanol, and dependent on the concentration. An alcohol like methanol is a totally different beast.
In chemical makeup and reactivity, Methanol and Ethanol are practically identical. Ethanol has 2 carbons, methanol has 1.
Both are powerful solvents
Both evaporate quickly compared to water
Both contain the same functional group -OH
Methanol is lighter because it is missing 1 carbon so the vapor pressure is higher, it can evaporate more quickly.
Similar to the difference between butane and propane, they are essentially identical, plus or minus 1 carbon is a subtle difference.
The main difference I see with methanol is that it is highly toxic. Methanol turns to formaldehyde when it comes into contact with alcohol dehydrogenase enzyme.
My background is chemistry, I use both 100% methanol and 100% ethanol in my lab. The ethanol I use for tissue dehydration and sterilization, it is safe to touch and inhale by accident.
Methanol I use for immunohistochemistry and high perf liquid chromatography, do not breath or touch the toxic methanol.
All of that said, it is interesting to bring up methanol as a solo fuel on HPtuners discussion forum. I have not seen anybody running a 100% Methanol fuel'd dragster here with an HPtuners ECU. And I do not imagine it would be cost effective or easy to use a factory ECU like that either. So I just wonder why you feel the comparison was important. nevertheless I hope you are more aware how similar they are now at least
I won't comment on their lab applications...not my area. But for vaporization and combustion at a minimum, methanol and ethanol are very different. The polarity of the ethanol molecule causes it to tend to stick together at high concentrations, which is why it's hard to start when cold...doesn't vaporize well, like you said. There is a reason methanol is used for supplemental injection to cool an intake charge and ethanol isn't. I suppose it wasn't totally pertinent...but not all alcohols behave the same, especially in an engine
For this platform it is almost certainly fuel, as mentioned in the snippet quoted. While the OEM cranking spark may not be 100% ideal for e85, OEM cranking fuel will have to be changed, and that will likely chase away this gremlin by itself.
I hate to sound like a nit pick but methanol as an aux injection (water/meth injection from an auxiliary pump) does little for charge cooling or engine cooling at performance airflow rates.I won't comment on their lab applications...not my area. But for vaporization and combustion at a minimum, methanol and ethanol are very different. The polarity of the ethanol molecule causes it to tend to stick together at high concentrations, which is why it's hard to start when cold...doesn't vaporize well, like you said. There is a reason methanol is used for supplemental injection to cool an intake charge and ethanol isn't. I suppose it wasn't totally pertinent...but not all alcohols behave the same, especially in an engine
I calculated the effects because I knew it wasn't much and needed to show that using a few different engineering tools,
here is a hand calculation for 100% methanol injected at a typical flow rate aux injection to a 400hp engine
IMG-6051.jpg
backed up by toolbox calc,
VERIFIED-CALC.png
the temp drop is negligible and becomes worse as engine horsepower increases above baseline, which is a naturally aspirated calculation (very low to begin with)
next here are heat capacities showing water superior to methanol for cooling as a temp differential before phase transition
heat-capafities.png
next, drag force involved with the nozzle injection
drag-force.png
When injecting fluid into fluid (air is a fluid) there are many losses associated with the nozzle that affect the energy of moving molecules, their organization, turbulence, temperature, viscosity, etc... many factors influence the outcome. The nozzle itself at high pressure/small orifice imparts energy to the incoming molecular mass which is itelf a form of heat, meaning when the nozzle breaks up liquid there is severely reduced cooling effect because the energy came from the nozzle and not from the surrounding air. A nozzle will heat the injected fluid at high pressure and any gas or broken up fluid molecules created as a result (high atomization = poor cooling) means that injected mass can no longer phase transition (liquid -> gas) which is what we need for a temperature reduction of methanol since it's heat capacity is poor to begin with.
The nozzle injection also disrupts the organization of fluid as it was flowing possibly laminar is now suddenly becoming turbulent, which is harmful to airflow rate and power production. Nozzles can be fitted at some exact position and orifice/pressure to minimize this effect but people never do that in automotive injection situations, they just drill some hole at a 90* angle or whatever and call it a day.
Next there is the issue that air molecules as a gas state and methanol molecules as a gas state both take up the same amount of space in classical physics, 22.4L per mole. That means for every methanol (or water) molecule that evaporates (phase transition which removes heat) you displace 1 molecule of air, thus density is dropping even as temperature is dropping.
I could keep going and showing the effects of water and so forth but the main idea here is that methanol as an aux injection system does very little for cooling intake air temperature, and generally results with a drop in power in any real world situation where the additional octane boost isn't called for.
methanol is indeed a powerful octane booster but that is the only benefit, there is very little to do with cooling at aux injection flow rates.
For example, user adds methanol inj and loses power
https://ls1tech.com/forums/dynamomet...o-results.html
Here is the entire discussion
https://www.corvetteforum.com/forums...post1602523881
All of that said, both ethanol and methanol do an incredible job cooling down the air intake pathways at high injection rates. There is negligible difference in their cooling ability at typical drag-racing eth/meth orientation injection masses, both can and will ice down the intake manifold.
To put this one more way, the closest molecule to methanol on planet Earth that I can come up with is ethanol. There is literally no other molecule or atom on Earth or in the universe that is more like ethanol than methanol. So it strikes me as odd that you say they are different when there is nothing else in the universe more similar than they are to each other.
To be fair there are other ways to look at eth and meth. For example we could say methanol has HALF the number of carbons as ethanol. That is a huge difference when we say it like that. HALF of something, right? That doesn't make a huge difference but because the weight is reduced by almost half, the methanol molecule can more easily get away from itself. The same way long chain fatty acids with kinks (butter molecules when they are not fully hydrogenated) can get away from their partners causing the butter to become softer and melt at lower temperatures.
Well if that's the case, I won't bother with my new methanol injection kit ><
I'll just concede this one man, you win lol.
well hang on!
There are great benefits to water injection for forced induction applications.
All of my cars get a turbo and a water injection setup for safety.
In a cast piston application, water injection is priceless because it is the only thing that can aux cool the piston in an engine without piston oil squirts.
This is what water injection was originally intended for, cooling the combustion chamber components. Adding methanol was an afterthought, 50/50 is a tasty spritz of octane boost to allow safety from both water cooling and improving the behavior of 93 octane pump gasoline fuel.
It's a great feature that helps us avoid switching from gasoline to E85 flex fuel, which would have us upgrading our fuel system dramatically at high power outputs (1000+rwhp we need 3x walbro 450s for example)
The system can be used different ways. And there are some pitfalls to be aware of
1. to be effective at cooling the CC and piston, liquid injected water has to make it past the intake valve before it transitions to a gas state.
2. aux pumps are wear items, they need routine maint and replacement. They can and will fail or clog at any instant.
3. the aux systems tend to leak, nothing is truly trouble free
#1 is a big problem for us because most of our intake manifold are designed to be DRY flow style. There may be liquid distribution issues causing some cylinders to receive more or less liquid water. It can be difficult or impossible to tell if every cylinder is receiving the same mass of liquid.
Thus, positioning of the nozzle, features of the pumping/pressure system, and even valve and primary injection timing can affect the outcome of aux injection.
#2 is an issue all meth users will eventually face. There are threads strewn all over the internet where people "swear they will never use meth injection again because the pump turned off and blew their engine". I could post a few but I'm being lazy rn.
#2 isn't a big deal if you know how to tune an engine properly. By that, I mean simply, tune the engine as if the methanol/water isn't even there. Run the engine in the safe range for the primary fuel for the majority of the time and there won't be any issue.
In other words, use pump fuel safe timing and get all of your a/f ratio from the primary injection.
I will discuss using methanol as a 'scramble' feature at the end
#3 This is why I prefer to use 100% distilled water in my systems and NO methanol. I don't mind the leaking, anywhere, when the system is only leaking water.
Remember methanol is extremely toxic to touch and it can burn with an invisible flame. Even in 50/50, the alcohol component can leave and collect in a tight space, causing an explosion. I am sure you can buy superior fittings and run leak-free type of setup, just like you can run safety valves, check valves, warning lamps, etc... But once you add the cost of all that extraneous additional hardware, wiring, complexity of the system, it takes up extra space, it costs extra... you might as well have just converted over to flex fuel system by that point.
In other words, the great thing about aux injection of water is that the system is very simple and cost effective in the first place. Adding all the hardware and expensive leak-free fittings/lines and safety stuff goes against the simplicity nature of such an additional system to our vehicle. IMHO
Finally lets talk about using methanol and water to actually push beyond the limits of pump fuel, and how to do this without suffering the same fate as so many others.
The reason most users who have had engine failure while using methanol (when the system fails) is because
A. they tuned the engine to rely on the methanol (timing, usually)
B. they thought it was a "set it and forget it" type of system, which is untrue- the pump requires service and replacement, at least that.
So how can we be safe and avoid those two pit-falls?
For A, we already discussed using pump fuel safe timing and get the fuel from the primary source not the aux injection.
In other words, get the extra power by using additional BOOST pressure, not IGNITION timing.
When the pump fails to inject methanol and the octane of 93 drops back to 93, if the engine was timed for 100+ octane then it will immediately "explode" (pressure spike) and blow a headgasket or put a hole somewhere.
On the other hand, if the system was timed properly when the methanol fails, the cylinder may only begin to start heating up. Which means when that warning light comes on (either meth or EGT related) you will have a window of opportunity to notice and shut things down before catastrophic failure.
For B, you must maintain and/or replace the pump regularly, and pressure test the system, check for leaks, check for clogs, most systems have a "test" setting to help with this.
And finally, the main thing of all, "do not set and forget" the system. In other words, have a "high boost" button on your boost controller and TEST the methanol system just before using it at high boost. Then, make your runs (racing or whatever). And when done, shut it back down to "low boost" where the methanol or water aux injection isn't a key player in the safety of the engine.
----
note
If you are NOT forced induction based then the aux injection systems are only good for cleaning the carbon out of the cylinders, they won't add power.
5.3/4l80e/turbo playthrough
https://www.corvetteforum.com/forums...ge-budget.html
cancer research
https://www.mdpi.com/2306-5354/10/1/96
Did ya ever figure this out?
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