Turbocharging? Vacuum? Too much thinking. Smart people unite

[teoman]

Water injection reduces NOX. I am not sure if it is just the reduction in temperature or some chemical reaction, but I wonder if injecting it in to the exhaust would have any use whatsoever.

[RustyLugNut]

Originally Posted by Enki

I don't fear lean mixtures; every one of the tunes I ran on my car utilized it; there's just diminishing returns past a point where you wind up giving more throttle to maintain the same speed and as a result the fuel consumption doesn't drop any more. I found this to be 15.5 AFR on my car, while others run their cars as lean as 17:1; somehow, I still have the best miles per tank on a mix of ethanol vs anyone on pump gas and leaner mixtures.

The only thing I'm "afraid" of is people bolting a turbo on to their car expecting one result and ending up buying a new engine because their understanding of how it should be done is incomplete.

The thermodynamic conditions are such that you produce the exothermic oxidation of nitrogen. This is why you get elevated temperatures in this AFR range. At about 18:1 AFR and beyond, you see a significant drop in NOx production and a resultant drop in combustion flame front temperature. Hot NOx is highly corrosive and erodes valves and rings quite rapidly.

Throttling losses are your enemy. Driving with the throttle as wide open as possible is the goal of lean burn. If you can get past about 70-80% throttle opening you will have some power underfoot to vary your cruise somewhat and retain most of the benefits of minimal pumping losses. A turbo only helps by providing additional turbulence and heat. Yes, you will reach a plateau based on your current variables, and that is when you need to start changing those variables. If your engine management doesn't allow you to advance your ignition enough, you will have to increase your intake temperature and use lower grade fuel. Yes, lower octane fuels that have a tendency toward pre-ignition are preferable for very lean burn situations. Studies are even using diesel as an admixture.

[ecocruze]

So driving like a hypermiler with a turbo gasser. Basically never touching boost I should be ok with running WAI with intake temps up to around 150°f correct? If I get a jump going from 100-120° up to 140-150° I should get around 4 mpg more. Similar to jump from 70-80° up to low 100°. Really wouldn't want to burn up my engine tho lol. I'm over 60 mpg yet so obviously I don't use boost much.

[RustyLugNut]

Originally Posted by 14'ecocruze

So driving like a hypermiler with a turbo gasser. Basically never touching boost I should be ok with running WAI with intake temps up to around 150°f correct? If I get a jump going from 100-120° up to 140-150° I should get around 4 mpg more. Similar to jump from 70-80° up to low 100°. Really wouldn't want to burn up my engine tho lol. I'm over 60 mpg yet so obviously I don't use boost much.

WAI and heavy boost don't play well together unless the fuel management has ready adjustments built in.

My wife drives like the little maniac she is in her Turbo Fiat Abarth 500. When we blast up to Las Vegas in the middle of the night, the car returns 34 mpg indicated at whatever atrocious velocity she is traveling at. In the hot daytime, the same trip and velocity return 38 mpg indicated. Desert temps go from sub 70 night time to 100+ deg F daytime. Yes, some of the gain is due to air density and aerodynamics. Most modern turbo vehicles have adjustments for warm air. However, your constant WAI may mean reduced power at full throttle.

[ecocruze]

Boost never really reaches over 5 psi even if I get on it a little. I'm gentle haha want the car to last for 200k miles. Not concerned with power. Eco forum here lol no need for power.

[ar5boosted]

Originally Posted by teoman

Water injection reduces NOX. I am not sure if it is just the reduction in temperature or some chemical reaction, but I wonder if injecting it in to the exhaust would have any use whatsoever.

I've heard that too.

My understanding of how it does this is simply by reducing the temperature of the combustion chamber. I don't think it would do anything but make steam come from the exhaust :-) Somebody could report you for having a smoky car :-(

As I understand them lean-burn engines is that they are mechanically-reinforced engines designed to operate at higher temperatures and pressures than 'normal' engines. The unfortunate chemical result of this is higher NOX levels which makes nitric-acid that kills forests.

Filling up with water is a bother. I was running 50% water and 50% fuel which meant carrying around 20L of water and filling that twice as much as I was filling the fuel. General consumers wouldn't go for that.

[teoman]

%50?

That is a lot. How did you come up with that number? And did it work?

[Enki]

I think he/she means a 50/50 mix of water/methanol for water injection alone; not pump gas.

[ar5boosted]

Originally Posted by Enki

I think he/she means a 50/50 mix of water/methanol for water injection alone; not pump gas.

No I really did mean 50% fuel, 50% water.

So if I drove 200km and used 20l of gas/fuel, I would also use about 20l of water.

Originally Posted by teoman

%50?

That is a lot. How did you come up with that number? And did it work?

Yes it worked - of course. Lot's of water fillups, more than gas stops.

Originally Posted by Enki

he/she

He. Sorry about the ladies bottom. It's a Japanese drawing. I'm an ugly fat middle aged man :-)

[Enki]

So you mean you injected water (unmixed) at the same rate as you were consuming fuel right? I ask because I'm pretty sure that putting water in the gas tank is a not so great idea. Lol.