It must be unfathomable for you guys to understand cylinder pressure Forget the boost, it takes X amount of cylinder pressure to make Y horsepower. Doesn't matter the boost. A supercharger is simply an engine that provides air. The supercharger at X amount of speed will provide Y amount of air which SHOULD equate to similar horsepower..... the same X/Y will make different amounts of boost depending on what it is feeding...why is that so hard to understand??? Procharger doesn't understand this, I don't understand why people even buy that crap product. All they will tell you when you call is it will make X amount of boost... they don't have a clue how to correlate that to horsepower. I tire of listening and even thinking about having a conversation with many of you folks because generally it is futile, but I am in the mood tonight. Argue with me while you can, I have to go to the track in a few hours where there is no talking about it.

Getting as much dynamic cylinder pressure as possible is the goal. Running it detonation free on a limited fuel octane is the challenge. Hell, on 116 octane leaded racing fuel 1200 HP+ NA is achieved every day at the strip.

If you go into their blower spec section it will give you air flow specs. and how much boost the compressor is capable of making.
If you guy's want to know how to get big numbers (with any fuel) what you want to do first is find out how much power you want to make and then convert this to how much CFM it will take to get the job done.
It takes at least 1800 CFM to make 1400 HP
So why would anybody buy a supercharger that only flowed 1400 CFM and then tried to make 1400 HP. This is where most people have it totally wrong. They then try to keep turning up the boost to make the HP, but what they needed was more air flow from the blower. Boost has nothing to do with it.
FYI------
Procharger blowers flow
D1 1400 CFM
F1 1500 CFM
F2 2300 CFM
F4 4300 CFM
It takes about 2000 CFM to make 1600 HP, so an F2 can barely make this because you have to think about all the air losses you have through all your plumbing.
Thinking about making power from a CFM standpoint instead of a MOTOR standpoint you will see this is why so many different combinations of engines can make the same power levels with out having the same parts, but having the same blower. I have personally seen 3 totally different sized engines with 3 totally different fuel systems that had CI differences of at least 100 CI all make within 100 HP of each other with the same sized turbocharger. Keep in mind every one of these engines had different brands of turbochargers, they just were the same size with roughly the same airflow ratings. The intercooler is a big part of making big power and living to tell about it later, but the number one thing in my book is airflow.
First find a supercharger that will flow enough air to get to your targeted HP level (with air to spare),find an engine that can live at this power level with all the parts that go with it. You must account for every thing that is needed at the power levels and cyl pressures. Then find a way to get this air cooled down to a manageable level, then supply enough fuel (and then some) to get the job done. Then the most important part , find someone that can tune your engine at this power level that knows what he's doing.This is the guy that can tell you what octane fuel you need to make you motor live.
As far as Prochargers being crap. I don't normally use Prochargers, but when I have they have always moved enough air to get the job done at the power I was trying to make. As far as do they understand how to make big power, They probably don't. All they do is make the air, (WE) have to make the power.

[QUOTE] Forget the boost, it takes X amount of cylinder pressure to make Y horsepower. Doesn't matter the boost. [QUOTE]

RichardCranium, I'm not going to argue with you, I can tell from your posts that you know what you're talking about. Keep talking, this thread is a good one, and although there's always some friction we don't usually lose a thread in the Tech section.

I am very interested in your thoughts on cylinder pressure vs. detonation. Not the cylinder pressure after ignition that pushes the piston down, but the cylinder pressure before ignition.

I may be wrong, but I think of the energy in the intake charge in two forms, pressure and temperature. Pressure is a form of potential energy and temperature is the result of kinetic energy. If the total combined energy of these two is too high, the fuel detonates on its own without spark, too soon and without a smooth, relatively slow flame front that the piston can handle. If I remember my chemistry this total energy is called activation energy.

Intercooling works because it removes some of the temperature, allowing more pressure before you reach the total energy that triggers detonation. You can cram in more air mass because of this additional pressure allowance, and therefore make more power. What are you thoughts on this?

Spreadport heads flow better, so you can get the same cylinder pressure before ignition with less boost, which means less temperature. In this way using these heads has a similar result to using intercooling; it allows you to pack in more air before you reach the detonation limit. But because of the relative cost of big intercoolers vs. spreadport conversion, we will probably see bigger intercoolers used first.

So far from the information I have gathered on boat engines, the limit on pump gas with Roots blowers is about 1100 HP, with screw comprressors and centrifugal blowers it's about 1200 HP. After that it takes increasing amounts of octane. I believe centrifugal blowers can operate on pump gas at more than 1200 HP simply because their mounting position allows room for a massive intercooler on top of a modified tunnel ram intake. Adding spreadport heads to this mix will be the ultimate.

NOBODY: "Right On!" to everything you just said.

The importance of sizing the compressor to the job and trying to operate within the most efficient range for that compressor cannot be overestimated. If your compressor is too small and/or you did not account for extra restrictions of the ducting, you are starting off two steps back.

How far back? In our original flow bench work we produced the following results:

750 Holley - 1000 CFM @ 28"H2O

Same carb inside Vortech
carb box with pipe - 643 CFM @ 28"H2O

Same carb inside Vortech
carb box with intercooler and pipe - 545 CFM @ 28"H2O

Same carb inside Rtech
carb/intercooler box with pipe - 765 CFM @ 28"H2O

To enclose the carb and use an intercooler you cannot avoid some additional restrictions, but the Rtech flowed 40% more air than the typical remote mount intercooler setup. Later on this design added 85 HP on the dyno without spinning the blower any faster. On the water, a later design added 8 mph. Even though intake pressure (boost) increased by 3 psi, intake air temperatures were reduced by 25F.

Now think about the intake ducting being used by the drag racers with intercoolers in the passenger seat or even the trunk. We hope to get well beyond the 1200 HP limit by taking this design philosophy to the extreme. More to come in the next month.

Quite grouchy arent we?

Will we be able to get to 90 degree air on the back side of the intercooler when water temps are 85?
Do we add an AC compressor & cool our water down or is the benefit not worth the HP drain of the compressor?

The one thing I have gotten from this thread is having forgotten about water injection. In the old days we had to use water injection to help keep from seeing detonation. If I remember correctly there was a graph I saw somewhere that showed adding more fuel keep away detonation to a point. When water was added less fuel was needed & you were able to increase the cylinder pressure way higher before detonation set in, then with just more fuel. I am going to have to go back & dig thru some old turbocharging books.

Cooling effectiveness is a percentage of the temp difference betwee the hot side and the cold side, and 90% is an excellent number to achieve in practice. If air is leaving the blower at 300F, which is about right for the pressure ratio involved here, and both air and water temp are 85F. The best outlet temp you could hope for is about 106F.

Any articfical cooling is good for a matter of seconds at the heat rejection rates involved and not something you can sustain in a boat. Water injection is more sustainable, but if you tune for it and then lose the injection for some reason, you're in trouble. I like the idea but would want to see it introduced through it's own port injectors and controlled by a computer that also had a knock sensor.

Fast says this about knock sensors "Solid valvetrain components, open exhaust systems and many other high-performance engine components inherently create noise that a knock sensor can perceive to be spark knock, even if the engine is running properly. The end result is that power output can be unnecessarily reduced."

As far as lose water will be just like running lean on fuel, so that problem can be handled. I like your idea of computer controlling the water.

Tomcat:
Although I have to admit that most of what you said in your most recent post is beyond my expertise, it makes a lot of sense to me.
It is drastic oversimplification, in my view, for someone to say that an engine is just an air pump and the more air you put in it the more power you make and that boost is boost, etc.
All things being equal on a given setup, this is true (till you exceed the flow limitations of the blower) but you can't compare 10lbs of boost from a roots blower to 10lbs of boost from a centrifugal, since the two have different methods for moving the air and the latter is almost always the more "adiabatically" efficient as, pound for pound of boost, it doesn't heat the air as much as as a roots type and this generally means the oxygen content in the air fuel charge is higher. After all, the oxygen in the air is what augments the fuel burn, not the other gases (nitrogen etc.). Simply put, the ideal is to get a relatively denser cooler (and consequently) more oxygen rich air into the cylinder and this not only makes more power (provided the right amount of fuel accompanies it into the cylinder) but the cooler intake charge helps to offset detonation and this lowers the octane requirement in any given fossil fuel motor. For example, the primary difference between SAE "Motor" and "Research" octane ratings for gasoline is the air inlet temperature on the same test engine with air inlet on the "motor" test being higher, (like 300 degrees I believe) therefore the motor octane rating is always lower than the Research rating.
I agree that the trick is to find someone who can tune it all (jetting, timing, cam sizing and phasing etc. etc.) to make real power and it is a hell of a challenge to make 800+ hp without a lot of testing and sophisticated equipment.
That's why we like having guys like you around, to tell us where we went wrong!!!

On that note, any idea what a 750Holley/Demon flows under say 8-10lbs of boost? The reason I ask is that Procharger recommends a 750CFM carb to like 950hp, and, if memory serves, I believe you once mentioned that Dean Nickerson used 750CFM main bodies/carbs with success. I have a 870CFM carb (The old Bastard that you helped me figure out!) and a 750 Race Demon and I'm leaning toward the Demon but I wondered if it might be a restriction at say 850hp on a 509cid?

This is a great topic and its guys like you that help guys like me become more educated. On that note! Is it possible to have to big of an intercooler? Such as my M1 with an M5 intercooler. It seems like it would take more air to start building pressure in a larger intercoler.