DETONATION control

T

thedevilmakesthree

Daily Driver
i was wondering some other things for detonation control.
heres a few i think i know. let me know if you know others, or if they work....anything you know about them
using higher ocatne fuel
water methonal injection?
Retarding timing?
Also propane has a high octane rating but it doesnt have as much engergy as gasoline, has anyone run dual fuel?
Not sure but doesn't lead added to the gas help?

thanks
 
Let's add to that -

Individually timed fuel injection to each cylinder
Injecting atomized fuel into a closed valve
Vapor density vs. temperature
Octane vs compression

Regarding lead... I believe it had a dual purpose, as a catalyst and as a lubricant.
 
ha a little over my head.
Thanks for the add-on.
Is lead legal for street use? my friends dad added lead substatute to his old boat.
Any one know anything else bout water methonal injection.
 
I made a WI system for my Volvo - using some Aquamist components, and a much cheaper Shurflo pump. Mine is set to engage over 18psi boost; I use it primarily for when I go to the track & dyno testing. Don't really need it otherwise.

Not sure it's worth the time & money on a stock X. Much cheaper just to tune it right & run the highest octane you can buy.
 
Lead substitute will kill O2 sensors...

Why is it you want to run lead or lead substitute on the street?

As far as water/methanol injection, the water displaces some of the fuel/air, therefore reduces power. Methanol has a fairly low energy content in itself (you have to run more than twice the amt of methanol thru an engine to make equivalent power as gas), but it will tolerate huge amounts of CR. Therefore, there is more energy in a gas/air mix than in additives like water or methanol.

However...

Injecting a mist of methanol or water condenses the intake charge by a property of physics known as "latent heat of evaporation". Basically absorbs heat of of the A/F charge, making the charge denser and cooler. Cooler charges are less prone to detonation, and could I suppose in theory actually contain more energy than a straight AF charge, due to their greater density.

Methanol is pretty corrosive tho, so special hardware (SS tank and lines) are best if you go that route.

Pete
 
did it work well?
What if you had really high compression. or highish compression and a few lbs of boost?
Where do you get the methenol. does it run out fast?
lets say you had a high comp motor. with a turbo but the wastegate was constantly open so it just vented the gas past the turbine. intil you switched it, then the WA system went on?
What kind of volvo?
 
alright, does only water injection work? what is the ratio of the mix? 50/50? if the methonal/water is only used at detonation control not alot of it would be used as fuel right? so you would still get alot of gas/air mixture.
My car seems to run better on very humid days.
 
Just how high is your static CR...

thedevilmakesthree said:
alright, does only water injection work? what is the ratio of the mix? 50/50? if the methonal/water is only used at detonation control not alot of it would be used as fuel right? so you would still get alot of gas/air mixture.
My car seems to run better on very humid days.
Click to expand...

and how much boost (if any) are you running? Seems to me you would have to have a very highly modified engine for this discussion to even come into play - are we discussing theory or an actual problem?

Pete
 
Cars perform better at lower ambient temps. I'm surprised you find yours running better with high humidity.

The WI system (I use windshield washer fluid when I use it, plastic lines are all from Aquamist) is practical for high boost turbo charged motors, for the reasons Pete mentioned - lowers the intake charge temp. Can't see it being any value on a NA X1/9.
 
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