Water meth boost raise levels

[Veteran]

If you run a FI with 91 octane, you are normally capped at 7psi as a safe level to stay away from detonation.
I googled what a water meth system would increase the boost safety limit to, but cant find a definitive answer.
Any have a clue ?

Sponsored

 

[raptor17GT]

It's been used since ww2 to aid raising boost, have a search for Frank Walker water injection

 

[Zrussian13]

I run 1/3 bottle of boostane per tank and Lund told me I'm good up to 10lbs but I don't plan on pushing it past 8-9lbs. I added water meth too but I still wouldn't push it farther than that.

 

[WildHorse]

It's been used since ww2 to aid raising boost, have a search for Frank Walker water injection

Remember though that mid-late WWII American fighter interceptors were also using 140+ octane fuels. But here's a good article

 

[K4fxd]

140 octane??

Quick google.

" Fighter planes like the Spitfire, Mustang, Thunderbolt, Hurricane, SeaFury, Lightening, Hellcat, and Corsair all ran on 100 octane gas. This allowed the engines that powered them to attain stunning performance. The famous Rolls Merlin began the war producing just over 1,000 horsepower."

https://www.google.com/search?client=firefox-b-1-d&q=ww2+fighter+fuel+octane+rsting

 

[Jackson1320]

I ran 16psi on my coyote with water meth no problem

 

[K4fxd]

I added water meth too but I still wouldn't push it farther than that.

Engine masters did a dyno test and found straight meth worked the best.

 

[WildHorse]

Engine masters did a dyno test and found straight meth worked the best.

Hard pass on the straight meth. 50/50 <- is what the germans used. the Americans found the corrosive nature of methanol detrimental to safe engine operations.

 

[Jackson1320]

Engine masters did a dyno test and found straight meth worked the best.

No. Engine masters did a test and found that straight meth provided the most power but that doesn’t mean best

 

[K4fxd]

Engine masters did a test and found that straight meth provided the most power but that doesn’t mean best

We have a different opinion of "best"

 

[raptor17GT]

Hard pass on the straight meth. 50/50 <- is what the germans used. the Americans found the corrosive nature of methanol detrimental to safe engine operations.

For sure the engines in the war did get more maintenance than your average FRP motor but here's the link I meant earlier. The Germans injected water directly into the cylinders but the allies put it in pre supercharger intake to get a bigger benefit. Can't read the link fully on my phone but during testing WI was pumped into engines so much that water poured out of the lower cylinders yet zero damage to engine though power was way down. Obv if you tune with this you'd better make sure you know when you run out otherwise kaboom

https://www.google.com/url?q=http:/...cQFnoECAYQAg&usg=AOvVaw20uQkuDv5279iz0t1QZdC8

edit - the other thing is to make sure you use the right alcohol type, do you want to add extra fuelling or are you using WI purely to control detonation? Another consideration for sure. I had always thought WI was a band aid to proper tuning but it turns out it's not so although it obv can be used as such. Just another tool in the box to be used or misused

2nd edit:

Water injection worked by reducing cylinder inlet temperature, thereby delaying the onset of detonation. As the water evaporated in the induction passages of the engine, it providing a prodigious amount of cooling to the fuel charge due to the latent heat of vaporization of the water. Cylinder inlet temperatures went from about 350qF to about 100qF. This increased the detonation margin to the point that up to 150 inHg of manifold pressure could be used. When water injection was in use, the engine was markedly smoother, and the interior of the combustion chambers stayed extremely clean with no carbon or varnish build-up on the piston crowns, valves, or ring packs. Frank remembers that “There was no hard carbon whatsoever. You could clean the top of a piston down to bare metal by wiping it with a cloth”. German engineers tried water injection (Wassereinspritzung) on their gasoline engines, but with limited success.

Germans, who were very good at building highprecision pumps, had perfected direct fuel injection for their large aircraft engines. German engineers injected water directly into the cylinders as well. Since the water did not have time to evaporate and cool the induction air, the large cylinder inlet temperature reduction was not achieved. Frank learned of this while reviewing a report on a captured German aircraft engine.

Initial tests were with plain tap water from the East Hartford municipal water supply. Later, when flight tests were pondered, alcohol was added as an antifreeze agent. Three alcohols were tried: ethyl, methyl, and isopropyl. Along with the tank car of ethyl alcohol came U.S. Treasury Agents and instructions that the engine was not to be run without a Treasury Agent being present. After a couple of weeks, the Treasury Agents retired to the Engineering Office where they drank coffee and flirted with the engineering aides and secretaries. They found no one was interested in drinking their alcohol and were tired of the heat, noise, and confusion of the test cell. It was discovered that a mixture of about 50 per cent ethyl alcohol was required to prevent the water from freezing at high altitudes. Once tests on the ethyl alcohol were complete, a similar battery of tests was run on methyl alcohol. There was virtually no difference between the two alcohols. On the drive home for dinner, Frank considered not even running tests on the isopropyl alcohol, thinking that “alcohol was alcohol”.

Later that evening, he started feeling guilty for not completing the battery of tests on isopropyl alcohol and went back to the test cell to begin the last of the tests. To his utter amazement, Frank could not even get take-off power when using isopropyl alcohol. The engine ran terribly, missing, , spitting, shaking, and spewing flames thirty feet long from the exhaust stacks. At midnight, Frank gave up having reached the conclusion that the isopropyl alcohol was useless.

At 8:00 AM the very next morning, Frank’s telephone rang. It was his boss, Bill Closs. W. J. Closs was called “Bouncing Bill Closs” by his employees because of how he walked with a spring in his step. Closs said “There is a C-54 outside waiting to take me to Europe where they are about to ground the entire P-47 fleet. The pilots are afraid to use water injection because every time they do, the engine blows. I haven’t a minute to waste. Tell me how the alcohol testing went last night.” Frank quickly related the story of the miserable failure of isopropyl alcohol. Two days later, Frank got another telephone call from Closs who had just returned from England. There he was met by a General and a whole bevy of Colonels, Majors, and Lieutenants who all wanted to know “What the hell are you going to do about these P-47 engines?” Closs said, “What kind of alcohol are you guys using?” “What difference does that make?” barked the General. In typical military fashion, the General turned to the Colonel, the Colonel to the Major, the Major to the Lieutenant, and the Lieutenant to the Tech Sergeant, each repeating Closs’ question. The Tech Sergeant said “De-icing alcohol, Sir!” ”What kind of alcohol is that, Sergeant?” bellowed the General. “Isopropyl, Sir!” said the Tech Sergeant. “Well, there is your trouble, General”, said Closs, “you must use a mix of either ethyl or methyl alcohol. Isopropyl just won’t work”. Frank believes there were many such serendipitous events that occurred during World War II that allowed the Allies to prevail.

Frank did not know it at the time, but the isopropyl alcohol would not work because it was making the mixture too rich. Alcohol had been added to water in sufficient quantities to keep it from freezing, about fifty percent by volume. Any flammable material has a minimum and maximum amount that can be mixed with air and still burn. These amounts are called the Lower Explosive Limit, or LEL and Upper Explosive Limit, or UEL, respectively. While the mixes of methyl and ethyl alcohol were both below the LEL of each compound, the mix of isopropyl alcohol was not. As a result, the isopropyl alcohol was trying to burn, making the mixture too rich to run very well at all. One interesting test that Frank ran in conjunction with water injection development was called a “drowning test”. Here, the amount of water was increased beyond what was required to suppress detonation. Eventually the amount of water was increased to the point that water was pouring out about half the cylinders, but the engine was still running. Finally, when power had dropped to about 600 HP the test was terminated. There were no ill effects to the engine.

 

[Zrussian13]

Engine masters did a dyno test and found straight meth worked the best.

No argument there. I run a 50/50 for safety. Lower flash point. I like to cruise around with my little girl and she loves riding in the Mustang. If it was a full blown race car it might be a different story.

 

[Veteran]

I ran 16psi on my coyote with water meth no problem

What fuel were you using ?

 

[Veteran]

Thanks for all the replies, but there Is still no definitive answer to how much extra boost a water meth will allow Before detonation kicks in .
So let’s say 91 Octane allows 7psi safely. That’s at best 570 whp.
not bad at all , but let’s be honest 700/750 would be a lot better and still manageable by the drivetrain.
To get to say 700 whp you’d need 12/13 psi boost.
All above based on a centri.
So will the water meth curb detonation for a extra 6psi above the 7psi 91Oct limit ?

 

[WildHorse]

So will the water meth curb detonation for a extra 6psi above the 7psi 91Oct limit ?

Absolutely not.

Sponsored