Powervalves - Moparts Forums

Powervalves

Posted By: moparniac

Powervalves - 01/18/09 07:12 PM

i dont have one in my Dominator carb but If I do run one what about jetting.... I read my holley book but its a book. rather hear what you guys have done...

90's squared
pri shooter .035
sec shooter .035
idle feeds .035
bleeds .045 idle / .075 mid / .035 main

street car 3800lbs
changes were 3.91 28" tire to 4.10's 30" tire
11" converter to 9" custom converter
Eddy rpm's stage 3 to Indy CNC's 295's
8 3/4 to Dana 60
TM7 with 4500 adapter to Indy 440-3

SS springs to caltracs
CE stuff to Ranchos / front calvert shocks

93 pump gas car

I listed this stuff so someone wouldnt ask

Posted By: Thumperdart

Re: Powervalves - 01/18/09 07:17 PM

I ended up w/90`s in the ft. w/a 3.5 pv and 99`s in the rear on my hp 1050 8082-3 dommy and it was chassis dynoed and has gone faster than ever this way. I usually jet down 8-10 sizes when using a pv.

Posted By: moparniac

Re: Powervalves - 01/18/09 07:21 PM

also where do you guys hook up your vacuum guage to? got any pics also?

thx

Posted By: dartman366

Re: Powervalves - 01/18/09 07:37 PM

A lot depend's on what your power valve channel restricter is in your metering block, mine were .082 and I ended up jetting way down in the front, because when the PV opens the jet size and PVCR are added together to give you the fuel that the motor see's, seem's like I jetted down about 13 size's in the front when I put the PV in,,,B1KEN had a chart that showed the fuel flow of the jet's and a formula that did the same for the PVCR,I have stuck to that info and it has worked good for me,,,,as far as a vac gauge I drilled and tapped a hole and added a fitting to the spacer under my carb.

Posted By: Thumperdart

Re: Powervalves - 01/18/09 07:55 PM

I have a port on my adapter/spacer that I hook a gauge up to although w/ big cams, a 2.5-3.5 gets the job done.

Posted By: dartman366

Re: Powervalves - 01/18/09 09:09 PM

Quote:

I have a port on my adapter/spacer that I hook a gauge up to although w/ big cams, a 2.5-3.5 gets the job done.

That's where I ended up with my PV,,,3.5

Posted By: moparniac

Re: Powervalves - 01/18/09 09:15 PM

Quote:

Quote:

I have a port on my adapter/spacer that I hook a gauge up to although w/ big cams, a 2.5-3.5 gets the job done.

That's where I ended up with my PV,,,3.5

my current cam is 248/254 @ 50 solid roller....

Posted By: The Avg. Valiant

Re: Powervalves - 01/18/09 09:28 PM

I just took my intake vacuum, divided by 2 and there was my PV number. This is what I was told to do by 2 old time guys, not sure if its true but its worked so far.

Posted By: Quicktree

Re: Powervalves - 01/18/09 09:28 PM

Quote:

I ended up w/90`s in the ft. w/a 3.5 pv and 99`s in the rear on my hp 1050 8082-3 dommy and it was chassis dynoed and has gone faster than ever this way. I usually jet down 8-10 sizes when using a pv.

how muc vac do you have at idle in gear?

Posted By: Quicktree

Re: Powervalves - 01/18/09 09:29 PM

Quote:

I just took my intake vacuum, divided by 2 and there was my PV number. This is what I was told to do by 2 old time guys, not sure if its true but its worked so far.

thats not the way you do it

Posted By: moparniac

Re: Powervalves - 01/18/09 11:20 PM

Posted By: Thumperdart

Re: Powervalves - 01/19/09 12:41 AM

Quicktree, I have about 5 1/2-6"`s at idle and bet 10-11 cruising.

Attached picture 4957209-domtrack.jpg

Posted By: The Avg. Valiant

Re: Powervalves - 01/19/09 01:06 AM

Quote:

Quote:

I just took my intake vacuum, divided by 2 and there was my PV number. This is what I was told to do by 2 old time guys, not sure if its true but its worked so far.

thats not the way you do it

Im all ears(im just running a 750 with vacuum secondaries, so I to am interested in how to set this as I dont have a DOM)

Posted By: Thumperdart

Re: Powervalves - 01/19/09 01:54 AM

I`ve heard about the divide your total vac in half theory also and who knows. For the longest time I ran a 2.5 but was told they can actually shudder off and on(open and closed)so I installed the 3.5 but can`t say for sure if it helped or not. If it`s a race deal and lets say you have 6" in gear I would run a 3.5 or a 4.5 myself. Then there`s the economy tuning but who needs that.

Posted By: moparniac

Re: Powervalves - 01/19/09 02:12 AM

Quote:

Quicktree, I have about 5 1/2-6"`s at idle and bet 10-11 cruising.

what do you have at WOT ....

Posted By: moparniac

Re: Powervalves - 01/19/09 02:15 AM

Quote:

Quote:

Quicktree, I have about 5 1/2-6"`s at idle and bet 10-11 cruising.

what do you have at WOT ....

isnt idle supposed to be around 20 ???

Posted By: moparniac

Re: Powervalves - 01/19/09 02:21 AM

this video says divide by 2 ???

http://www.youtube.com/watch?v=6vKlAnKdcB4

Posted By: Quicktree

Re: Powervalves - 01/19/09 02:58 AM

Quote:

Quicktree, I have about 5 1/2-6"`s at idle and bet 10-11 cruising.

then your PV should a 41/2 to 5

Posted By: AndyF

Re: Powervalves - 01/19/09 03:41 AM

Intake vacuum divided by 2 should work fine. If the idle vacuum is higher than 12 inches then use a 6.5.

Posted By: Blown61

Re: Powervalves - 01/19/09 03:44 AM

Why not put a vac gauge on it and map where it is during cruise and wot then you can put in a pv with a lit lower rate to stay shut until you need it?

Posted By: moparniac

Re: Powervalves - 01/19/09 10:29 AM

Quote:

Why not put a vac gauge on it and map where it is during cruise and wot then you can put in a pv with a lit lower rate to stay shut until you need it?

makes sense to me but i am a racer in training.... soooooooooo

Posted By: Quicktree

Re: Powervalves - 01/19/09 11:30 AM

Quote:

Intake vacuum divided by 2 should work fine. If the idle vacuum is higher than 12 inches then use a 6.5.

it may work if you compensate for the fuel loss at tip in some other way. 2 less than the vac at idle in gear is the way to set PV'S.

Posted By: Thumperdart

Re: Powervalves - 01/19/09 06:50 PM

At wot the vaccum goes to zero or close to zero. As far as 20"s at idle, camshaft duration, overlap etc. play a big role in the amount of vaccum a motor produces so the bigger the cam, the less vacuum. This is a basic version and I`m sure someone can better explain it.

Attached picture 4958655-domtrack.jpg

Posted By: Bigcube

Re: Powervalves - 01/19/09 07:30 PM

I run a 6.5 PV in the front. The PV will NOT see vacuum at idle if the carb is on the idle circuit therefor dividing idle vacuum makes no sense. In my 1150 dominator I ran 93 sq jetting with the PV's blocked and don't recall exactly where I ended up with the PV in the front but I think it was around 98 in the back and 85 the front with the PV.

Posted By: Quicktree

Re: Powervalves - 01/19/09 07:32 PM

Quote:

I run a 6.5 PV in the front. The PV will NOT see vacuum at idle if the carb is on the idle circuit therefor dividing idle vacuum makes no sense. In my 1150 dominator I ran 93 sq jetting with the PV's blocked and don't recall exactly where I ended up with the PV in the front but I think it was around 98 in the back and 85 the front with the PV.

Posted By: 67HEMI

Re: Powervalves - 01/25/09 07:59 PM

Why on earth would you want to run a powervalve in a dominator?

Mine has zero issues with idle and has a 268/276@ .050 roller.

Posted By: AndyF

Re: Powervalves - 01/25/09 08:17 PM

I'd almost always recommend a powervalve on the primary side of a Dominator, even for a drag race car. I don't see any reason to get rid of a fuel circuit when it is there for the taking.

Posted By: moparniac

Re: Powervalves - 01/25/09 08:48 PM

I had a customer BIGS dominator made and it dont have a powervalve.... 90 squared...... seems like most recommend one

Now when i had the carb made I had a 11" converter then and a custom 9" now... and MCH MW indy eZ's coming next week as opposed to the full port eddy rpm's..

3800lb e body street car....

Posted By: 602heavy

Re: Powervalves - 01/25/09 09:12 PM

Always run a PV in the primaries especialy on a street/strip motor , powervalves are also common in the secondaries , there's a limit on jet size.

Posted By: Cab_Burge

Re: Powervalves - 01/25/09 11:44 PM

I have heard on hear about the power valves not opening while idling in gear but I have cured loading up on cars that had 6.5 power valeves in the carbs and idle at 5 to 5.5 inche of vacume in gear

I now use one to two inches less power valve rating than the motor has idleing in gear

works good, last a long time. I like using power valves in all Holley type carbs to keep the idle and part throttle cruise circuits lean enough to help keep the plugs clean

The last post also brought out a good point about the power valves doing exactly what there designed to do, help add fuel at wide open throttle as needed

Posted By: 602heavy

Re: Powervalves - 01/26/09 12:12 AM

If the throttle blades are correctly set @ idle the boosters should'nt see any signal even though the vac @ idle could well be below PV rating.

As said , the PV is a fuel enrichment device , if the power valve is flowing fuel @ idle it would indicate a loose or ruptured PV diaphram.

Posted By: Quicktree

Re: Powervalves - 01/26/09 12:18 AM

Quote:

If the throttle blades are correctly set @ idle the boosters should'nt see any signal even though the vac @ idle could well be below PV rating.

As said , the PV is a fuel enrichment device , if the power valve is flowing fuel @ idle it would indicate a loose or ruptured PV diaphram.

you are wasting your time trying to explain it.

Posted By: 602heavy

Re: Powervalves - 01/26/09 12:22 AM

Okey Dokey , not exactly rocket science.

Posted By: Quicktree

Re: Powervalves - 01/26/09 12:24 AM

Quote:

Okey Dokey , not exactly rocket science.

yup

with you

we just have a bunch of hard headed old geezers on here.

Posted By: MR_P_BODY

Re: Powervalves - 01/26/09 12:25 AM

Lets see here, with a power valve that breaks, I
dont get the enrichment.... no thanks I dont need
anything else that can break.... I'll jet it up
and be happy(plus my dom idles fine and it doesnt
load up)

Posted By: Blown61

Re: Powervalves - 01/26/09 12:28 AM

http://www.holley.com/data/TechService/Technical/power_valves.pdf

Posted By: 602heavy

Re: Powervalves - 01/26/09 12:30 AM

I use a PV cos the motor is street driven , if it were purely for the strip i would remove it , can't say i would'nt use a PV in the secs though , got a bigger motor for this year so a PV in the secs might be on the cards.

Posted By: MR_P_BODY

Re: Powervalves - 01/26/09 12:40 AM

I hope you didnt post that link for my behalf, I
dont run one due to if it breaks I loose a engine,
when I can get away without it and jet up a few jets.....
but thanks for the link anyways but I have it in my
favorites already

Posted By: moparniac

Re: Powervalves - 01/26/09 12:43 AM

is there powervalve blowout protection for dominators...

Posted By: moparniac

Re: Powervalves - 01/26/09 12:44 AM

just read the holley link.. it says a powervalve cant go bad on engine backfire.... impossible it says.....

Posted By: 602heavy

Re: Powervalves - 01/26/09 12:49 AM

What happens when that little ole ball gets gummed up.

Posted By: Cab_Burge

Re: Powervalves - 01/26/09 07:10 AM

Quote:

just read the holley link.. it says a powervalve cant go bad on engine backfire.... impossible it says.....

Yeah, right

where talking about carburetors made after 1992 also so,IMO, never say never