power valve??

2838 Views 30 Replies 13 Participants Last post by Shaun, Jul 12, 2009

1975sleekcraft

Discussion Starter · Jul 8, 2009

if i am running 64 jets with a 85 power valve on primes and 85 jets with a 65 power valve on seconds then what am i pullin with the power valves open??????????????

someone on the boards is helping me out, i am just askin for a census..

just for my knowledge???

thinking of plugging power valves????????????

1 - 20 of 31 Posts

gregb

· #2 · Jul 8, 2009

What carb? Size, list number before anyone makes a recommendation.

Sleeper CP

· #3 · Jul 8, 2009

PV is worth 6-8 jet sizes... if that's what you're asking.

S CP

1975sleekcraft

Discussion Starter · #4 · Jul 9, 2009

Sleeper CP said:
PV is worth 6-8 jet sizes... if that's what you're asking.

S CP

yeh that is what i am looking for thanx

1975sleekcraft

Discussion Starter · #5 · Jul 9, 2009

list 6213

1975sleekcraft said:
if i am running 64 jets with a 85 power valve on primes and 85 jets with a 65 power valve on seconds then what am i pullin with the power valves open??????????????

someone on the boards is helping me out, i am just askin for a census..

just for my knowledge???

thinking of plugging power valves????????????

4165 series
holley list 6213

Sleeper CP

· #6 · Jul 9, 2009

1975sleekcraft said:
yeh that is what i am looking for thanx

You're welcome. If you're going to plug the power valves that thing will more than likey suck gas like crazy. Power valve = economy valve. What's the engine and how high do you rev it ? and what the reasoning to wanting to plug the PV ?

S CP

2FORCEFULL

· #7 · Jul 9, 2009

Sleeper CP said:
You're welcome. If you're going to plug the power valves that thing will more than likey suck gas like crazy. Power valve = economy valve. What's the engine and how high do you rev it ? and what the reasoning to wanting to plug the PV ?

S CP

i would check the vacume.....8.5 is alot

sleekcrafter

· #8 · Jul 9, 2009

PV on the secondary make no sense on a jet boat, should be plugged and jump up the secondary jets, imo.

Jetaholic

· #9 · Jul 9, 2009

sleekcrafter said:
PV on the secondary make no sense on a jet boat, should be plugged and jump up the secondary jets, imo.

X2!!! The only time you're in the secondaries on a jet is when it's dumped to the floor.

However, if this boat is a cruiser and not a boat that runs at WOT at all times leave the primary power valve in. This will give you an "economy" setting for cruise.

Sleeper CP

· #10 · Jul 9, 2009

sleekcrafter said:
PV on the secondary make no sense on a jet boat, should be plugged and jump up the secondary jets, imo.

Very true on the secondaries and I would think a 6.5 would be a better place to start on the primaries. RPM of engine and intake manifold type ? The 85's might be enough in the secondaries.

I should add that the secondaries are dependant on the progressive linkage of the carb. Do the secondaries open at 1/2 throttle or before?

S CP

turbo wog

· #11 · Jul 9, 2009

i am running two power valves. i guess if you were cruizing maybey @ 3500-4k and the ower valves may close for good mpg,but if you were exelerating they would fatten it up for ya. the primary opens first so the motor can start drinking the fuel then a little more rpm & the second one kicks in.if it runs good like that keep 'em.. its a finer tune

turbo wog

· #12 · Jul 9, 2009

i believe you take a vacuum reading at cruise then use a pv that is 2 less on the vacuum

Performance Jet

· #13 · Jul 9, 2009

Jetaholic said:
X2!!! The only time you're in the secondaries on a jet is when it's dumped to the floor.

However, if this boat is a cruiser and not a boat that runs at WOT at all times leave the primary power valve in. This will give you an "economy" setting for cruise.

An economy setting at cruise? Your kidding , right.. Keep the power valves in and set the carb up right, you will be fine. Jim :|err

Sleeper CP

· #14 · Jul 9, 2009

Performance Jet said:
An economy setting at cruise? Your kidding , right.. Keep the power valves in and set the carb up right, you will be fine. Jim :|err

I guess someone should define "cruise"

bulb

I know what he's saying and agree with the comment.

S CP

1975sleekcraft

Discussion Starter · #15 · Jul 9, 2009

Sleeper CP said:
You're welcome. If you're going to plug the power valves that thing will more than likey suck gas like crazy. Power valve = economy valve. What's the engine and how high do you rev it ? and what the reasoning to wanting to plug the PV ?

S CP

it is a 455 olds with 10-1 compression, 280 comp cam, edlebrock performer intake, and a fresh set of "g" heads with a three way grind on them.

the highest it has ever spun is 5300, last time i was out i was only getting 4900. being an olds and building it the way i did, i have been told not to exceed 5300. so that has been my threshold !!

cruise has always been around 4000 rpms without touching the secondaries!! i hit WOT alot, but not for any lenght of time.

after all that has been said, trying to build my 800 cfm holley to work the best with my application.

so it would be safe to say that the over all censous on this thread is, remove the pv on my secondaries, but continue to run one on my primes???????

Malcolm

· #16 · Jul 9, 2009

1975sleekcraft said:
so it would be safe to say that the over all censous on this thread is, remove the pv on my secondaries, but continue to run one on my primes???????

I would agree with that statement.

To change the subject a little bit, when are we going to see you on the Snohomish river???

hand

jetboatperformance

· #17 · Jul 9, 2009

Performance Jet said:
An economy setting at cruise? Your kidding , right.. Keep the power valves in and set the carb up right, you will be fine. Jim :|err

Good info here IMO !

Sleeper CP

· #18 · Jul 9, 2009 (Edited)

1975sleekcraft said:
cruise has always been around 4000 rpms without touching the secondaries!! i hit WOT alot, but not for any lenght of time.

so it would be safe to say that the over all censous on this thread is, remove the pv on my secondaries, but continue to run one on my primes???????

That's what I was getting at. Our boat "cruises" at 3,900-4,000 out of the secondaries approx 50 mph. ( At least with the old 1,050 #9375 the new 1,200 carb might not be the same) Primary PV no secondary PV. Have pulled the PV out and up jetted and the thing sucked gas like I couldn't believe. Secondary PV's for anything that accelerates hard is questionable. Rear PV's un-load under hard acceleration and they don't make PV extensions but they do make jet extensions. Since your secondaries are only opening past 4,000 and it only rev's to 5,000 I'd pull the secondary PV out and see what happens.

I would check the Vac at cruise to see about the 8.5 PV in the primaries.

I guess you can say I have an economy setting at cruise at 4,000 rpm. If I put a PV in the rear it might save more fuel but for the most part when the secondaries are open it's under hard accelleration and I don't want to un-load the PV. Your boat may not accellerate as had so maybe it's not a problem you need to worry about.

bulb

Just my .02

S CP

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1975sleekcraft

Discussion Starter · #19 · Jul 9, 2009

Malcolm said:
To change the subject a little bit, when are we going to see you on the Snohomish river??? hand

i have been slacking on putting the boat back together. trying not to melt down my heads again!! putting the final touches on it today, and taking it out for plug tests tomorrow!!

thanx for all input, and any more to come!!!!!!!!!!

Malcolm

· #20 · Jul 10, 2009

Looks like Saturday is gonna be a good one to go out and do some testing.

I'm looking forward to doing some tuning on my new engine (same as yours 'cept for intake and carb).

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