ALFAGTV6.COM

[Greg Gordon]

Charts removed. They are a little misleading without all the associated text in the book so I felt it best to take them off. Thanks for the input everyone. Based on the feedback here, the charts will remain about the same.

Greg,
www.hiperformancestore.com

[MALDI]

Seems clear to me.

One question: why in the last graph do they use 30/70 for methanol but 20/80 for ethanol? Why not the same values for both? Since ethanol is more hydrocarbon-like than methanol (having an additional CH2 group) shouldn't you use more water, say 40/60 water/ethanol? On the other hand being of a higher molecular mass must increase its octance rating so you would use less water. Perhaps including the octane numbers for pure alcohols would be informative.

[Greg Gordon]

Hi Maldi,
Thanks for the response. It seems clear that you understand the charts which is what I am concerned about. The text in the book addresses all those questions.

I will cover the issues briefly here:
It's important to keep in mind that the data (not the charts which are mine) was created by NACA and the were working with a wartime avaition point of view.

1. In the last graph they used a 70% methanol vs an 80% Ethyl mix because those were the mixes needed to prevent any risk of freezing particles at 40,000 feet over Germany in December. In practice they usually used a 50/50 mix of each and the results are pretty much the same. There are cases where ethyl alcohol (denatured alcohol) and water is a better choice. That's covered in the book.

2. I don't want to get into the octane numbers of methyl alcohol and ethyl alcohol for a few reasons. All the different ways of rating octane will add some confusion and I don't want to turn this into a chemistry book. The water injection section is already huge, taking up a solid 20 pages of text, which will be about 50 pages once pictures are put in and editing is done. Plus, the anti-knock capabilities of each mixture are related to issues other than just octane rating of the alcohol.

Greg,
www.hiperformancestore.com

[Mats]

I see the histograms but Ihave no idea what you're trying to tell with them...

[Greg Gordon]

Hmm, that's not too good.

[5yearplan]

Sweet, I'm glad you are writing a book. Me and a friend have actually read alot into water injection after he stumbled across it on the magical world wide web. Then we had to try to convince another friend of it's feasibility and history. He fails to believe that it is effective AND reliable AND consistent. But that is another story. At any rate I am glad you are going to lengths to experiment with water injection and the like. Can't wait for the book. Also I found the graphs easy to read, but I've read WAY to many graphs, and studied up on the subject so I may be at a slight disadvantage. I'm sure if the font was a little bigger, and there was an ample introduction that would help. Now I just want to see more, any idea when the book will come out.

[la_strega_nera]

at 40,000 feet over Germany in December

Late 30's - early 40s research? Inverted 12cyl perhaps?

[Greg Gordon]

5yearplan:

Water injection is effective, consistent, and reliable. I hear the reliability argument against water injection a lot. However it just doesn't hold up. There a far greater chance of damage from a failure in the fuel injection system than in a water injection system. Think about the number of moving parts, sensors, etc. This book should be out in Nov. There is a lot of misinformation on water injection out of the web.

Ben:

Most of the reports from NACA were made in the late 30's and early 40's. That's when there was a lot of govt. interest in squeezing all the possible power out of piston engines. After that NACA became NASA and got sidetracked by gas turbines and rockets.

The 12cyl engine used in the V-12 test was an Allison. The inverted V-12s were usually DB601s and 605s. I don't have any tests of those engines.

[5yearplan]

The only feasible argument as to reliability of water injection system would depend on what system you bought, I've heard of water injectors leaking and causing problems.

Hi Maldi,
Thanks for the response. It seems clear that you understand the charts which is what I am concerned about. The text in the book addresses all those questions.

I will cover the issues briefly here:
It's important to keep in mind that the data (not the charts which are mine) was created by NACA and the were working with a wartime avaition point of view.

1. In the last graph they used a 70% methanol vs an 80% Ethyl mix because those were the mixes needed to prevent any risk of freezing particles at 40,000 feet over Germany in December. In practice they usually used a 50/50 mix of each and the results are pretty much the same. There are cases where ethyl alcohol (denatured alcohol) and water is a better choice. That's covered in the book.

2. I don't want to get into the octane numbers of methyl alcohol and ethyl alcohol for a few reasons. All the different ways of rating octane will add some confusion and I don't want to turn this into a chemistry book. The water injection section is already huge, taking up a solid 20 pages of text, which will be about 50 pages once pictures are put in and editing is done. Plus, the anti-knock capabilities of each mixture are related to issues other than just octane rating of the alcohol.

Greg,
www.hiperformancestore.com

What else will the book entail? I am quite intrigued... You will have to get me a signed copy It's too bad you don't want to get into octane levels I don't think it will turn into a chemistry book, but then again I haven't read the book... I think if you refer to octane as a rating of autoignition resistance, as opposed to "the same octane rating as a mixture of 87% (by volume) iso-octane and 13% (by volume) n-heptane." It would help get rid of the chemistry aspect. I know there are different ways of rating octane, but I am only familiar with three. The PON for us Americans and RON for those of you across the pond are the ones I have the most experience with. At any rate, how about a chart of the total effective compression (given a constant temp) on an engine and octane rating required to prevent knock. For those of us who want to run higher CR and then boost Also, how long is the book going to be in it's entirety, and what engine(s) besides the v12 did you use for the test?

[Greg Gordon]

The book has some information on supercharging history. The various types of superchargers, and pros and cons of each. There is information on choosing the right size supercharger. For example a lot of space is taken up by the pros and cons of turning a smaller supercharger fast vs a big one slow for the same level of boost. There is of course pulley and drive ratio information, including a chart for pulley sizing. A fair amount of space is devoted to intercooling. I explain how to make it quiet or loud. Of course I cover bypass valves and blow off valves and so on. Oh, and of course water injection and fuel injection information including every L-Jet secret I know to get an L-Jet car to survive at 10psi and run pretty well. Personally I am converting my cars to modern injection, so of course there is info on that also.

Regarding octane. As you know, water injection has an effect very much like using higher octane fuel. I do have an explanation of just how much an effective increase in octane can be expected with various quanities of water. This data comes from NACA not me. They had an unlimited budget for testing stuff to destruction. They had top engineers and scientists working with the best equipment. I could not possible hope to approach the accuracy of their testing so I am content to use their numbers. They used the Allison V-12 as well as various single cylinder liquid cooled and air cooled test engines. My personal testing is far less scientific, and I didn't test anything to destruction. I do explain how far I pushed it. The only engine I used is my 2.5 Alfa V6.

I think the best way to present the data is to describe the effect on knock-limited boost rather than octane. In other words if at 5psi you can't add any more boost without knock, or retarding the timing, that's the knock-limit. How much more can you raise the boost with a given water/fuel ratio? That's the question I try to answer.

[5yearplan]

I understand what you are trying to say, I guess I just explain water injection as helping to raise the octane of the gas (loosely) as well as absorb heat. Given that when you use water inj. (once again temp. is a constant) you raise the amount of energy it takes to ignite the new mixture, thereby raising the overall octane. Two ways to say the same thing. So the next book will be on turbos right? If you need an engine for experimentation purposes, I could donate one...

[Greg Gordon]

Yup, it's two ways of saying the same thing. I am trying to put it in a way that you can see on a boost gauge.


A lot of this book is relevant for turbos. For example a lot of the intercooling, bypass valve, fuel injection and water injection information is directly applicable. However turbos have a lot of different issues that I don't touch on. I would have to learn a lot more before I could write a book on turbos. As it is, if I write another book it will deal with the more advanced supercharging topics I can't fit into this one. For example compound supercharging, A/C cooled intercoolers, software, and super high speed valves for water injection etc.

[5yearplan]

I'm sure it's been touched on before but what water injection system do you use?

[Greg Gordon]

Here are a few samples of the book. Obviously I am taking these samples way out of context, so give a break on the seemingly incomplete statements. the first one deals with the octane issue.

From the water injection chapter:

"Injecting water into the engine’s intake system has an effect that’s very analogous to using higher-octane fuel. Just how much of an effect does it have? According to N.A.C.A., a lot. They came up with the following numbers. An engine normally requiring 100-octane fuel can operate satisfactorily on 80-octane fuel with a water/fuel ratio of .6:1. That same engine could be run on 88-octane with a .4:1 water/fuel ratio or 94-octane with a .2:1 ratio. If we assume that this effect will be the same with pump gas then 93-octane fuel with water injected at a .6/1 water fuel ratio will be effectively 116-octane!"

A little blower history:

"Since the rest of this chapter will deal with supercharging an Alfa V6 with a Roots supercharger it will get fairly technical. Before we dive into that I would like to give a little more history of the Roots design, and discuss the important changes made in the most modern versions.
Roots is always capitalized because it’s the name of the inventors, the Roots brothers. They invented it in 1854 and as I wrote earlier they were trying to make a better water wheel to power a mill. I think it will actually work in this application because when the belt is removed from a supercharger and the engine is started, the supercharger will spin pretty fast as a result of the air moving through it. However apparently it didn’t work well enough and they abandon this application. It was then discovered that it blew air very well and was used on a number of applications where large volumes of air needed to be moved.
The first automotive company to seriously use the Roots supercharger was Mercedes. It’s interesting to note that Mercedes tried various other types of supercharging first including a piston type and a vane type but couldn’t get the results they needed with them. In October of 1919 they had the first road test of a Roots blown car. This early Roots car was really loud (I will discuss Roots noise later), the noise was described as ear-piercing. However the performance was so good that Diamler decided to bet the entire Mercedes racing reputation on the Roots supercharger. This was risky because Mercedes was doing well in racing and the Roots supercharger was largely unproven. What seemed like a gamble at the time paid off in a big way. The supercharged Mercedes was so successful in racing that within four years every significant European marque adopted the Roots supercharger.

The Roots became a standard feature on most big Mercedes from about 1924 until the Second World War. They used a fairly complex setup, even by modern standards. They mounted the supercharger vertically and drove it off the crank with bevel gears. It was connected with a clutch and only engaged at full throttle. When the blower engaged the car became very loud, and power increased by 50%, that’s a good amount even by modern standards.

It’s fascinating to note that today a lot of effort has been spent trying to make the Roots blower quieter. In fact I have done some work in this area myself! However people in the 20’s must have had a different view of mechanical things because the scream of a Roots blower was viewed as a sound of technology, status, and wealth, and the owners of Roots cars were proud of the sound.

I read one account from Prussia in the mid 1930’s about a son of the local baron who would signal the approach to the village’s main street by engaging the blower on his big Mercedes. This signaled the locals to clear the streets because he came through town at great speed. Apparently the locals were grateful for the warning cry of the blower!"

Greg,
www.hiperformancestore.com

[Greg Gordon]

I am using Coolingmist's system. I am a technically a Coolingmist dealer.