save yourself a lot of trouble just call or email pro systems with carb numbers and he will take care of you .

^^^stated in the first reply to this thread by a Pro Systems dealer.

quote:

Originally posted by SmokinChicken:
I recently purchased 2 Pro System Carburetors (Used)and both of them have power valves. Both are 1150's. Can anyone advise why they run power valves in them? Should I remove them?

quote:

Originally posted by 1320racer:
I doubt they were built with power valves unless they were built for a street/strip car. Get the build # off of each carb and call Pro Systems to get the build sheets.

Did you call Pro Systems with your build #?

I just rebuilt my Pro Systems 1250 with a rebuild kit I purchased from them. Again no power valve.

Patrick is a smart guy, easy to talk to, and knows is stuff

I do wonder why he is running a power valve on strip applications that use transbrakes? Wonder what the thought process is? He could forget More in a day than I will ever know, so I am curious as to the reason, not saying the reason isn't smart.

The APD Maxspeed throttle stop carburetor also uses a power valve and pretty much every Super Class car out there is using a transbrake.

just got a carb from him for race only and i run a trans brake. carb has power valve and he said his carb have a very stong signal that they work better with one and are cleaner when driving.i will see how it works soon

quote:

Originally posted by Cashflow:
The APD Maxspeed throttle stop carburetor also uses a power valve and pretty much every Super Class car out there is using a transbrake.

Vern, the maxspeed uses a PV by design whereas their regular dominators that many of my friends and competitors run typically do not.

Ed,

I get that but it appears that Patrick is using them (power valves) more these days?

I'm currently running a DaVinci and no power valve in mine either. I swear I'm going to switch back to my injection though. I've learned some things and want to try them in S/C.

As an added note, the Mark Whitener alky carb I ran for awhile was without a doubt the most trouble free bolt on carb I've ever used. If I weren't running S/C and were strictly bracket racing I would seriously consider putting it back on.

Vern, all I can tell you is my Pro Systems 1250 Dominator was built in 2013 and it has no power valves as delivered, no different than the Pro Systems dominators I have sold for similar applications(I'm a Pro Systems dealer), no different than the majority of custom built dominator carbs for the same application by nearly every professional carb builder being used for bracket/throttle stop applications.

My dragster is not only deadly consistent in both bracket and throttle stop mode but it's also one of the fastest MPH SC cars in the division.

BTW, my Pro Systems 4150/1000HP atop my 522 in my footbrake launched car has a PV.

quote:

Originally posted by 1320racer:
(I'm a Pro Systems dealer),

Now that this has been disclosed it helps put in perspective all of the negative, defamatory accusations made against competitor builder's products and service...

Not exactly what most reputable business would desire as a company representitive...

Whatta Schmuck...


Dan

^^^says a moron, another clueless nobody.

What is all this PV talk about!!!!!!!

Look, when driving in the pits, PV or not, it doesn't matter because the main system is not flowing fuel unless your drive like a bat out of hell in the pits! So those who state that their carb is clean idling around the pits with a PV,, I have news for you, its clean for a reason other than the PV!

For stop racing, part throttle fuel curves are important,,,, so some choose to work the part throttle fuel curve with a PV and some don't. Both work.

For full throttle racing, a PV is just another part not need that can fail and add cost not to mention more likely to become uncovered by fuel in the bowls. However, I am not saying have a PV in a carb in this application won't work!

EXACTLY!

quote:

Originally posted by TOP38:
What is all this PV talk about!!!!!!!

Look, when driving in the pits, PV or not, it doesn't matter because the main system is not flowing fuel unless your drive like a bat out of hell in the pits! So those who state that their carb is clean idling around the pits with a PV,, I have news for you, its clean for a reason other than the PV!

For stop racing, part throttle fuel curves are important,,,, so some choose to work the part throttle fuel curve with a PV and some don't. Both work.

For full throttle racing, a PV is just another part not need that can fail and add cost not to mention more likely to become uncovered by fuel in the bowls. However, I am not saying have a PV in a carb in this application won't work!

My understanding through the years is you can run the carb slightly leaner because the PV will only open under no vacuum/full throttle conditions.
Obviously running somewhat leaner (unless at wide open) will let the motor see less fuel in theory be more "driveable"
One mistake people do is run the absolute lightest spring PV which I believe is a 35. Meaning it takes 3.5" of vacuum to hold shut. Some combinations can actually start building vacuum again towards the finish line. If it gets as high as 3.5" it can start pulling the PV shut and about the last thing you'd want is to lean out at full full throttle going through the lights.

Dave

Not exactly sure of your first statement so, with regards to WOT, PV or no, the engine needs the same amount of fuel, you can't run it leaner under this condition without loosing power! So a PV has no real purpose under this condition.

Under part throttle/light engine loads, you can run the motor leaner which is why PV's where used in carbs for street cars! So as I mentioned with throttle stop combo's, PV's have some purpose not that they are required for this combo either. But they have no place on the secondary side of the carb (single carb application)

Driving around in the pits, PV's do nothing unless you are basically speeding, Under this condition the motor is running on the idle fuel circuit only so the PV does nothing with regards to leaning the motor/AFR. If your saying you can run the idle circuit leaner because the carb has a PV, you are incorrect.

As for the rating of the PV, first the highest manifold vacuum occurs at the top of each gear/highest rpm and not just at the end of a run. Second, if you have a combo that develops 3.5" of manifold vacuum, your pretty much running a two barrel carb which is badly restricting the motor! A properly sized 4 barrel carb should only develop 1.5" MAX in a single carb application.

So are you saying that my Pro systems carburetor that they just built me with a power valve in front is not necessary? I thought I would run it like that see how it responds. This is a full drag car 8500 RPM

quote:

Originally posted by 1320racer:
EXACTLY!

Ed instead of this^^^ since you are a reseller of ProSystems carbs and so many have posted that the carbs they received from Patrick have a power valve why don't you explain why he puts them in drag carbs? Especially the one that I posted about being an alcohol carb. I know you have posted about yours not having one and running fine but you tout his expertise often so here is your soapbox.

That said I am going to have my friend as a test square the jets and remove the power valve to see what happens. Then I am going to have him block off the vacuum to the reference regulator and see how that goes. I will try to remember and post any differences we might find because I certainly don't believe this carb needs a power valve.

Curtis

you're making a blanket statement, he does NOT put PVs in all "drag cars" and specifically not in all bracket cars running a dominator and not in all throttle stopped cars.

That said, I have yet to find one custom carb builder who's carb outperforms Pro Systems comparing same size carbs.

quote:

Originally posted by mopar man:
So are you saying that my Pro systems carburetor that they just built me with a power valve in front is not necessary? I thought I would run it like that see how it responds. This is a full drag car 8500 RPM

Are you asking me??? If so, I was pretty clear in my post above.

However I will add this, for foot brake folks, when staging, if they are only lightly loading the converter,,, keeping the manifold vac high, a power valve could actually help but that not to say a carb cannot be built to work cleanly without a PV.

A power valve will only provide a leaner AFR under light engine loads (high vac conditions) when the main circuit is flowing fuel. Once load increases enough to drop manifold vac enough to open the valve, its just there for the ride.

As for a drag car, fuel slosh in the float bowls can under either the PV and or jets, and since the PV is higher than the jets, its more likely to get uncovered during a run vs the jets. Give this fact and that fuel slosh is not a constant! from run to run, why add more potential issues that could cause inconsistencies? That's my two cents.