Hardcore:

Yes, I think it is possible that you are too rich. I know those insulators are white, we've seen that too. But I've seen Nickerson's personal boat engine on the dyno deliver 900 - 1000 HP with BSFC numbers of 0.6 and the plugs look white to me. He doesn't seem concerned and I realize I don't know anything about reading plugs!!

The other way I look at it is the total metering area. For example, the jets and single power valve in an HP500 carb have a total metering area of 0.0251 in2. Although this is an 800 CFM carb not the 850 you have, I would expect it too work just fine on your 509.

Now if you had a 50% increase in air density, you would need a total metering area of 0.0251 X 1.5 = 0.0376 in2. Your carb with 90s and 0.080" PVCRs would have a total metering area of 0.0456 in2: way too much. If it has 0.060:"PVCRs then the total metering area would be 0.0368 in2, which is almost a 50% increase, just about right.

Once you measure the PVCRs you will know what your total metering area is, and be in a much better position to know what to do next.

Air flows through the carb because the pressure above is greater than the pressure below. It doesn't matter if it is atmospheric above vacuum, or boost above vacuum or even boost above less boost. At WOT, when you see 5 psi on the boost gauge, you probably have no more than 6 psi in the carb box. This 1 psi differential is plenty to flow the required actual CFM. Four barrel carbs are rated at 1.5" Hg which is about 3/4 psi.

As discussed above it is the increase of velocity (or to be more exact - the velocity pressure) inside the venturi that results in the reduction in static pressure which at the nozzles. The greater static pressure in the fuel bowl pushes the fuel through the metering passages. This happens whether the engine is supercharged or not.

The real problem is the increase in the density of the air rushing through the carb. It has more oxygen molecules and it needs more fuel molecules! No wait, that isn't a problem, it's a good thing! The problem is deciding which passages to put the extra fuel through; how much and when. :D

Tomcat:

Thanks for once again taking the time to point me in the right direction. It is certainly a huge help (and a great relief!) to know that the white insulators might not indicate a lean mixture.
This forum certainly benefits immensely from having knowledgeable people like yourself take such an active part in these types of threads.

I agree with you that I need to measure my PVCR's before I guess anymore and I am grateful for the expertise on calculating total metering area. As soon as I have some more info/testing data I will let you know whats up.
Thanks again.:)

Hardcore:

The reason I say I'm not the carb guy is because my knowledge is mostly theoretical. When it comes to the practical application I'm learning too. But you've got practical experience and can apply the theory.

The reason I refer people to Nickerson is pretty simple. Nickerson has a supercooler, so I know that anyone I send his way will get the carb calibration that Nickerson has worked out on the dyno and in the water for his own boat engine. That way I can relax!

There is a good discussion of metering area and changing the ratio of metering area between main jets and PVCRs on page 65 of the S-A Design book "Super Tuning and Modifying Holley Carburetors". They also talk briefly about blowthrough carb jetting on page 71, but they don't go into using the PVCRs.

Thanks. I don't think have that book. I have one by Alex Warlordy that I need to read over again. As far as I can recall he has quite a bit of material on tuning with power valves, but the book is like circa 1980s. (although Holley Carbs haven't really changed that much in the last forty years or so...)

Hey guys,
Man, I knew if I kept hangin around here somebody would tune my Prochargers for me :). I have decided to let my tired 454 mags rest thru the summer and blow them up late fall with the M 3's. I am just now getting my new/old '29 Fountain in the water and changed to Aeromotive pump and reg,built return lines,repositioned hatch lift,bad outdrives,upholstery, etc, planning on having it blown&tuned by now but multiple delays and ignorance and learning has slowed me down to much,,,AND I'm tired,just want to drink a cold beer on my boat,away from the ramp. Don't want to risk it this time of year:( I hate being practical but could not stand being boatless after all the time and $$ I have spent since Jan.
I have to say again the incredible amount of experience combined with a common interest and just plain helpfulness on this site has made what was once almost impossible( getting useful info about high perf boats) a click away. I have decided to join up as a paying member. This is cheap and easy compared to what I have saved and been able to do myself.
Keep tuning HARDCORE. Maybe you can help when I get ready around Oct. Where do you live in the Caymans? We were down there for our honeymoon in '02 and loved it. Georgetown on a cruise stop.
TOMCAT, I'm saving all your "theory" and going to send to a publisher soon. May I just say,,WOW !!!
My wife is getting her PHD in Finance(she can do hypersurface calculus(I can't even spell it)) and she thinks I'm a genius because I can build a mtr or whatever and it usually works. I told her to read a few of these post and she'll see I know nothing compared to you guys,,but I'm learning,and always doing,so maybe I can help some poor sap find his #1 cyl or oil filter and do my part here:)

Hey Cooltoys. Like I had indicated in my earlier post, without the expertise AND willingness to be helpful on the part of Tomcat (and quite a number of others on this site) this forum in particular would be quite useless. I too am going to sign up as a paying member (as soon as I can stop kicking myself in the A$$ for not buying a Supercooler setup!). I feel obliged to say that if this is an indication of the kind of dedication that Tom shows his customers, I wouldn't hesitate for a second to recommend buying his product (even if it didn't make a sh!tload more power, to boot!)
I'm going to find out what this problem is this weekend (or blow my motor trying!)
Sounds like you have a sound understanding of these things yourself. My last boat was a light weight Mirage River Racer w/ a Merc Drag motor (ran 109mph in the 1/4 mile) and before that it had a Nitroused OMC so the whole setup of my boat has been a new experience for me. I basically bought the hull w/out motor and tore it apart and started from scratch. Believe me, without help from this forum and friends like "Cayformula" I wouldn't have known where to start.
As soon as I sign up I'll post some photos of the rig.
BTW: I live in the central part of Grand Cayman and work in George Town (attorney) but I spend most of my weekends in the water (since we are, after all, surrounded by it here). Later.
:D

Hey cooltoys61:

The fact that you're waiting until fall to install the blowers makes you smarter than me. Have a good season!

Hardcore:

I checked my books on the equation for venturis. What it boils down to is the signal or "suction" generated at the fuel nozzle increases in proportion to velocity SQUARED, but that signal only increases in direct proportion to density.

So if you increase the amount of air entering a naturally aspirated engine, by using better heads and more RPM, such that the air velocity in the venturis goes up by 1.5, the signal on the fuel nozzle goes up by 2.25. Due to similiar laws of physics, you need this 2.25 increase in signal to get the fuel passage to flow 1.5 times more fuel. So carbs can do a good job of metering fuel flow according to air flow, as long as density doesn't change.

But if you increase the amount of air entering the engine by supercharging to get a 1.5 increase in air density, and actual CFM and therefore velocity don't change, the signal on the fuel nozzle only goes up by 1.5. This is only enough signal to pull 1.225 times more fuel. So you need to add more metering area to bring the total fuel flow up to 1.5 times more fuel.

In the calculations of total metering area a few posts ago, I ignored the fact that density increases do increase the signal somewhat. I thought that this was a conservative approach, and might result in an overly rich, but safe mixture which could then be tuned down. But there is another factor to consider.

Whereas naturally aspirated engines are often tuned for a BSFC of 0.45 - 0.5, supercharged engines seem happier at 0.6 - 0.7. The exact numbers depend on lots of things but if we just consider this ratio, it means we need not 1.5 times more fuel, but

1.5 X 0.6/0.5 = 1.8 times more fuel

Based on this I feel a rule of thumb coming along. If the increase in air density is 50%, add 50% more metering area and rely on the response of the venturi to density to provide the rest. Using the numbers from above, the new fuel flow based on both metering area changes and signal increase due to density would be:

1.5 X 1.225 = 1.84 times more fuel

Once again this is theory, but it's good to know. ;)

Re: Jetting/tuning For Procharger setup
 

Hey Tom. Thanks again for the guidance. I found out that I had stupidly installed #84 jets instead of #90s!!! How it happened was simple. I took them out of the Holley box that I have them stored in and simply looked at the guide on the lid of the box. #84 is right above #90 and so I simply took them out of the wrong compartment! (If that don't get the stupid mistake of the year, I don't know what will!)Anyways, not to fear. The ENGINE is OK. The drive - well, we'll get to that.
I measured the PVCR's and found that they are in fact .080" (apparently, I can read minute measurements better than I can read writing! So, it seems that I did have adequate fuel augmentation from the P/Vs so no meltdown (WheW!)
I installed #88's in front and #90's in the rear and installed the .150" inlets. I quickly removed the inlets though because the floats just can't produce enough leverage to keep them closed once they are at higher pressure under boost. (or so I was thinking at the time)
The lugging is now more like a speed limiter, like the power just flattens out up top. Felt like it was just going way rich up top. Also, I'm now getting a lot of slip according to the speed versus RPM's (can you guess where this is going?)
After a couple of runs, I really started studying the fuel pressure and noticed that it would fluctuate and that when the problem occurred the pressure was spiking - like 17+ psi! WTF? It was obvious that something was causing a pressure spike (NOT a pressure drop).
So, pulled down the regulator. Found that the nipple for the boost reference was screwed into the body so far that it was hooking on the spring, which would obviously cause a problem and I'm thinking that at higher RPM's, when there is less flow through the bypass (more fuel being consumed by the engine) so that the diaphragm sits lower and simultaneously the boost pushed the diaphragm and spring down more into the well of the regulator, the spring would hook on the nipple and keep the bypass closed (or nearly) and consequently, increase the pressure. Quite a complex little problem isn't it?
Well I'm happy now, so I launch the boat yesterday, reversed off the trailer and WTF? No forward gear! Apparently my cone clutch has given up the ghost and gone to the big boat-boneyard in the sky! Oh well, as soon as I can cornswabble a drive off someone I'll report back with my findings on the "regulatory issues".
Thanks once again for all of your assistance.
to be continued...

Re: Jetting/tuning For Procharger setup
 

Hardcore I have been following your thread and have learned from you as well as the other intelligent post on this thread, as stated earlier several of us have faced this issue with the Prochargers and eventually gave up to buying fuel injection systems. two things I'll mention, I have a twin carb box that I'm no longer using and would love to sell- intake carbs polished box. I will give you a smoking deal on all of it, for I no longer have a need for it, but it is all excellent condition and ready to use. second after making it this far and reading admiring your mechanical ability thus far, I would encourage you to tear in to that drive and fix it yourself, I did and was amazed how easy Bravos are to work on. So amazed that I find it hard to believe that with all the mechanical ability that most of the backyard mechanics on this board exhibit that we aren't all Bravo experts by now. I will give you step by step instruction from memory and serve as a moderator to assist in taking apart or putting back together. The con clutch is a snap to fix. Good luck and let me know on either circumstance if I may be of assistance.

Re: Jetting/tuning For Procharger setup
 

Iwas reading Hardcores post and wondering if you still had that carb box and carbs for sale? How much and what else do I need to make it work ? Greg