8T9 BANDIT

the B.O.V. that came with my p-1sc procharger kit. is either bent outta shape or factory defective. when i took it out to look at the butterfly, it would not seal 100% it leaves a small creavis at the bottom. And i and my mechanic could not adjust it to close all the way. Were now debating weather or not to just get a bosch style simple one for 60bucks there good to 12psi thats the most i want to make for now anyway. and as is im only hitting a max of about 7psi with the bov problem. Anyone else have a similar experiance? and reccomendations?

THIS IS THE ONE I HAVE NOW- http://www.procharger.com/store/inde...d&productId=20

THIS IS THE BOSCH STYLE ONE- http://www.procharger.com/store/inde...d&productId=19

KS91Z28

Is it not closing at all, or just not closing all the way?

8T9 BANDIT

just not all the way. And i have to rev out the car to get 7+pd's outta it.
I thought the p1-sc has a more linear curve to it. So really, until my foots on the floor, i make no boost.

Street Lethal

iTrader: (16)

^ Did you adjust the spring pre-load in the blow off valve, or better yet, how is it adjusted, and is the vacuum hose properly connected....?

Edit: I can't see the picture of your current BOV, can you link the image directly?

8T9 BANDIT

street the link should be working(i just tried it)
ill ask my mechanic about those 2 things. he was messing with it.

Street Lethal

iTrader: (16)

^ Yeah, the link isn't working for me. Is it this one though.....?

8T9 BANDIT

that be the one.

KS91Z28

The only adjustment on that valve is to keep the butterfly from going past center. It isn't meant to seal 100%. They take that into account when they spec the pulley for your setup. If you want one that seals 100%, call ATI and get the Race Bypass Valve. I wouldn't even bother with the tiny litlle Bosch bypass valve.

8T9 BANDIT

so why am i not making boost until WOT?

KS91Z28

That's how a centrifugal blower works. You probably start seeing 1-2 psi around 3,000 RPM and it build to 7 psi at your shift point. Am I correct?

Street Lethal

iTrader: (16)

You should be making boost instantaneously. If you aren't, either the BOV is the culprit, or you have a leak elsewhere in your setup. Pull the BOV off, run the car, and see where your boost gauge is at part throttle....

8T9 BANDIT

sounds about right. so the BOV is not supposed to close all the way?
i will take the car for a spin 2nite. I think ill have to buy a smaller pulley.
so when should i be seeing boost?

Street Lethal

iTrader: (16)

You putz lol, you had me thinking you were at 0-psi until WOT. If your experiencing what KS91Z28 has descibed, then that is linear....

8T9 BANDIT

not really. i still have to floor it, to start seeing boost. on the way up from 4k-red line it will make 2-3 then jump to 7+_ Like i said, i have to floor it for ANY boost at all.
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street dont you do alot of tunning? I may need youre help.

AC

iTrader: (3)

I had something similiar to me "wouldn't close". I had it on backwards!! I had a WELL built 383 and only saw 5lbs. ****er was on backwards.

8T9 BANDIT

my question is, under normal driving and 25% and ^ throttle. Should i be seeing any boost at all?

Street Lethal

iTrader: (16)

It's really hard to tell from the video, but at idle you'll still be pulling vacuum, and if you listen closely to part throttle you'll see the boost immediately hit 5-psi, then work it's way up at WOT, Click Here....

KS91Z28

You won't see any boost at part throttle and normal driving conditions. The boost builds based on load AND engine RPM.

Street Lethal

iTrader: (16)

This part I kind of disagree with, as load and RPM is prevalent even in part throttle conditions, even moreso from a dig, not to mention the size of the pulley utilized also being part of the equation. I'll try to get a short clip of my cousin's Corvette at half, and/or part throttle. The needle obviously isn't pegged anywhere near 10-psi, but it's definitely passed 0-inches....

Charged350

iTrader: (1)

dave, whats the spring rated for in the bov

Damon

You're not going to see boost at only 25% throttle with any blower setup. My roots blower doesn't go into positive boost until about 75% throttle. The few centrifugal setups I've worked with are similar (although boost builds with RPM, even wide open).

The blower has to outrun what the engine is natrually capable of swallowing before the air starts to back up in the intake manifold (which what boost is- a by-product of excess airflow).

Street Lethal

iTrader: (16)

Oh really, then explain the buildup of boost being released by the blow off valve with just the blip of the throttle while idling in Park, Click Here....

Street Lethal

iTrader: (16)

^ Courtesy of KenneBell.net....;

"Having 5-psi at part throttle makes for a seriously fun car to drive. Those 5-psi part throttle stabs will be used 100 times more than the full throttle rips up to redline, especially on a serious motor"....

- Muscle Mustangs & Fast Fords

http://www.kennebell.net/techinfo/ge...erchargers.pdf

Damon

No boost IN THE INTAKE MANIFOLD, chief. That's where you measure boost becuase that's what the motor sees. Hard to make any boost on the far side of a closed throttle plate.

Tony89GTA

iTrader: (7)

You probably won't see any boost or very little under normal driving conditions. To have boost like that out of a supercharger you need to be running a screw or roots type.

BTW what size pulleys are you running on your setup?

8T9 BANDIT

not sure on the pulley, i have to get the serial numbers again and call procharger. I wrote it down but lost it. My whole system was bought used (brand new unopened in box) so i didnt order it. i think it has the 4.** pulley right now. and alex, I have no idea what the spring rate is.

Street Lethal

iTrader: (16)

That's not what you initially said, you said "you're not going to see boost at only 25% throttle with any blower setup". Now, considering the fact that boost gauges are meant to read vacuum/boost from a full intake manifold vacuum port, where else would the guys over at Muscle Mustangs & Fast Fords be reading 5-psi at part throttle on a constant basis? If it wasn't making 5-psi in the intake manifold, they wouldn't get a 5-psi reading on the gauge. As for the video clip, that's just to show that unlike a turbocharger, boost is instantaneous with a supercharger, as it's not so easy to get the BOV to vent in Park with a turbo....

8T9 BANDIT

a freind of mine had a t-bird sc. it made instant boost thrue the rpm range.

fast82z

iTrader: (1)

Granted I'm running a D-1SC, but here's a datalog of one of my 1/4-mile passes. Pretty clear to see that it makes more boost with more rpm and load.
http://i50.photobucket.com/albums/f3...2z/DataLog.jpg

Street Lethal

iTrader: (16)

^ Exactly, unlike turbo chargers which rely heavily on engine load, supercharger's really don't care if there is a load per se, as they increase with RPM either way because they are belt driven, and are constant....

86rsproject

I don't know much about chargers, turbos, etc. But in the picture you posted that was of a surge valve. I thougth those were to release excess pressure in the system and not act like a blow off valve where those release pressure upon shifting. Just my thought... Only 7psi? That seems low most people i hear of try to run at least 12psi.

Street Lethal

iTrader: (16)

The bypass valve and blow off valve are the same in principle, only the blow off valve vents the excess air to the atmosphere, while the bypass valve keeps the calculated excess air in the stream....

8T9 BANDIT

so would the bosch valve give me better boost through the curve?

Street Lethal

iTrader: (16)

^ Forget the Bosch, and get a nice sounding atmospheric BOV valve. The rumor of running excessively rich with a MAF sensor is really a non-issue. The ECM sees when the throttle is closed, and if still over a certain RPM, the injectors shut off anyway until dropped below the targeted RPM....

8T9 BANDIT

any reccomendations? what would the overall diff be?

Street Lethal

iTrader: (16)

^ There are so many to choose from, it's really a matter of preference....

Charged350

iTrader: (1)

call procharger an ask

91z 2 8

IF your not making boost instantly with a supercharger u most def have a big leak, like the one guy stated up a bit. those arent thecnicly BOV their deiverter valves. now i feel like talking and to my bro has fininaly paid off lol he had a deiverter valve on his one elcipse and it never boosted right

KS91Z28

Do yourself a favor and call ProCharger. (913) 338-2886

Charged350

iTrader: (1)

could be a 7 psi spring in the bov ...jus call procharger and ask them dave ...they will know..

86Z

iTrader: (4)

the valve should be fine, i run the same on my car, i can cruise around part throttle and build about 2 psi of boost, i can make 5-6 psi at around 2000-2500 in 4th gear, with a 383 that 4.x pulley is not going to make much more then 7psi, i'm running a 4.0 pulley on a 305 and make a max of 14psi

KS91Z28

It's a bypass valve not a wastgate or a BOV. It doesn't have a "7 psi spring" in it. When it sees vacuum, it opens. When it sees boost, it shuts. Simple as that.

8T9 BANDIT

you make 5-6psi at 2-2500 rpm's?? so then how are you saying mines fine. Like i said, i have to floor it to see any boost at all.

8T9 BANDIT

just called procharger, they said with the p1 thats how it works. i shouldnt see boost till WOT. if i had a d1 it makes boost quiker and longer. But he then went on to say. d1 and stock bottom ends dont work for very long. so for now, im going to go see exacly how much boost im making and maybe order a smaller pulley for a couple more pds. Then in the future if i ever rebuild or get a new motor, i may upgrade to the d1. thanx for all your help guys, i do apperciate it. I will also post my results after the boost test. dave....
oh yeah, he also said the BOV was not supposed to close all the way, he said there should be a hairline of space at the bottom, but then again, the guy didnt seem to sure of anything we were talking about.

Street Lethal

iTrader: (16)

He meant to say that the bypass valve will remain slightly open, not a BOV....

383backinblack

get the open race valve and be done with it.