Air by pass valve question.

Jaegermeister2k · 10-15-2003, 07:29 PM

Since i'm getting a supercharger,probably a vortech,i was thining about by pass valves.After asking and reading this is what i think i know so far.Superchargers use air by pass valves instead of the blow off valves i was used from turbos.And instead of blowing the air into the atmosphere like a blow off valve does,the by pass valve just reroutes the air into the intake part of the supercharger.Now you would think that you could just put a blow off valve where you would usually put a by pass valve to get the nice sound(call me a ricer but i love it)but you can't.Because i've heard of people having problems idling,and a by pass valve fixes that problem.But i also know that some people have no problems idling without a by pass valve.That's all i know.Any way to make it work somehow?To get that sound i mean.I would go with a turbo but they're just too expensive.

speedytang · 10-16-2003, 03:11 AM

It does not matter if it is a supercharger or turbo you will have the same problem if it is a MAS car and it is not a blow thru design. If you want a true blow off valve just get your MAS calibrated for blow thru just like Procharger does on its supercharged kit and turbo kits. I am going to get my old Ford 70mm meter calibrated for blow thru so that I can solve a lean off full throttle condition.

Jaegermeister2k · 10-16-2003, 05:47 AM

How could i do that?

USMC302 · 10-29-2003, 04:42 PM

Blow thru?!?!

Dave_mustang_50 · 10-29-2003, 05:01 PM

Not only will you get the sound you want but you wont be recirculating the hot air. The ones I priced were around 350 bucks. My Procharger came with a bypass but my speed shop wants to go with a blow off for that reason. So much for my little sleeper.

Jaegermeister2k · 10-29-2003, 05:50 PM

Yeah blow thru.How do i do that?I'm probably gonna buy a novi 1000.

Jaegermeister2k · 10-29-2003, 05:51 PM

Quote:

Originally posted by Dave_mustang_50
Not only will you get the sound you want but you wont be recirculating the hot air. The ones I priced were around 350 bucks. My Procharger came with a bypass but my speed shop wants to go with a blow off for that reason. So much for my little sleeper.

$350 for what?Blow off valve?

speedytang · 10-29-2003, 05:53 PM

The meter is installed between the throttle body and the supercharger instead of betwwen your air cleaner and supercharger.

Jaegermeister2k · 10-29-2003, 06:04 PM

Yeah but how could i program it for blow thru?

speedytang · 10-29-2003, 07:24 PM

Have your meter recalibrated by PRo-M for that purpose. They change the metering rate per cfm of air to allow the car to handle the pressure going across the Hot Wire of the meter.

Jaegermeister2k · 10-29-2003, 07:36 PM

Pro-m?I probably have to send em mine first right?Do they have a website?And how does it work?If i move the MAS then all i would have to do is instead of a by pass valve just put a blow off valve in its place right?

91LX2Bfast · 10-31-2003, 11:08 AM

If you do stick with your pull through MAF, just make sure you route the bypass far enough away from your MAF so that you don't get surge pushing back through the MAF. That'll creat all kinds of driving problems. 8-10" away is usually far enough.

Jaegermeister2k · 10-31-2003, 04:45 PM

Quote:

Originally posted by 91LX2Bfast
If you do stick with your pull through MAF, just make sure you route the bypass far enough away from your MAF so that you don't get surge pushing back through the MAF. That'll creat all kinds of driving problems. 8-10" away is usually far enough.

Aren't the points i can route it to already set on the pipe?Or what do you mean?

91LX2Bfast · 11-12-2003, 06:32 PM

If you get a pre-made setup, then you might not have to worry about it. But if you are rigging up you own bypass, you need to pick a point on the intake tube to re-route the bypassed air back into. Keep that point 8-10" away from the MAF. I'm not sure if that helps or not.
See, if you put it, say 4" from the MAF, what can happen is this: the air coming back into the intake pipe once the TB is closed can push backwards through the MAF causing poor drivablity. You might notice a bucking or surging when you let off the gas.

ArtMan · 11-14-2003, 08:34 AM

A turbo's blow off valve and a s/c by-pass valve are two different valves. They don't do the same thing.

The by-pass valve on a s/c is meant to recirculate blown air during decelaration (when the throttle is closed and the rpms are high). The blow off valve on a turbo releases excess boost when it reaches a predetermined max.

These valves peform two different functions

91LX2Bfast · 11-14-2003, 12:43 PM

Quote:

Originally posted by ArtMan
... The blow off valve on a turbo releases excess boost when it reaches a predetermined max.

You're thinking of a wastegate.

A blow off valve and a bypass valve (or divertor valve) are basically the same thing. Used on MAF equiped cars, the bypass and divertor valves recirculate the air back into the intake track before the compressor but after the MAF. Where as a BOV just releases it to the atmosphere.

ArtMan · 11-14-2003, 04:39 PM

OK, thanks. When he said blow off valve, I thought he meant wastegate.

You can install a bypass valve on a s/c and leave the end open to the atmosphere. And you definetly will get a noise - some say a farting noise.

Jaegermeister2k · 11-14-2003, 05:23 PM

Quote:

Originally posted by ArtMan
OK, thanks. When he said blow off valve, I thought he meant wastegate.

You can install a bypass valve on a s/c and leave the end open to the atmosphere. And you definetly will get a noise - some say a farting noise.

But that's the problem.If you do that some superchargers have problems idling.I've talked to several people claiming that.

91LX2Bfast · 11-15-2003, 04:36 PM

Yup. With a pull through MAF (oem type,) you want to recirculate the air. The bypass/divertor valves still make that "cool" whoosh sound, just not as loud as the bov.
With a blow through MAF, you can install a BOV and vent to the atmosphere.

USMC302 · 12-08-2003, 07:12 AM

ok, let me ask the obvious. Pro-M will only be able to recalibrate Pro-M meters right? Does C&L have this option, anyone know?

10-15-2003, 07:29 PM	#1
Jaegermeister2k Registered Member Join Date: Apr 2003 Location: Brandon,Fl Posts: 163	Air by pass valve question. Since i'm getting a supercharger,probably a vortech,i was thining about by pass valves.After asking and reading this is what i think i know so far.Superchargers use air by pass valves instead of the blow off valves i was used from turbos.And instead of blowing the air into the atmosphere like a blow off valve does,the by pass valve just reroutes the air into the intake part of the supercharger.Now you would think that you could just put a blow off valve where you would usually put a by pass valve to get the nice sound(call me a ricer but i love it)but you can't.Because i've heard of people having problems idling,and a by pass valve fixes that problem.But i also know that some people have no problems idling without a by pass valve.That's all i know.Any way to make it work somehow?To get that sound i mean.I would go with a turbo but they're just too expensive.

10-29-2003, 04:42 PM	#4
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Blow thru?!?! __________________

10-29-2003, 05:01 PM	#5
Dave_mustang_50 Registered Member Join Date: Aug 1999 Location: New Port Richey, Florida Posts: 483	Not only will you get the sound you want but you wont be recirculating the hot air. The ones I priced were around 350 bucks. My Procharger came with a bypass but my speed shop wants to go with a blow off for that reason. So much for my little sleeper. __________________ 1969 Mach 1 351C with a c6(for now) Sold 92 Rag Top GT Procharged & intercooled DSS 331 LC Holley Systemax 2 Intake, Edelbrock RPM Heads,E 303 ,blow thru air meter, race bypass, 42 pph injectors,65mm tb,1.7 rr, Mac long tube headers w/off road H pipe, Force 2 catback, TKO,Pro 5.0, K&N, Alum DS,3 core radiator, subframe connectors,3.73`s, Nitto DR`s and a Heavy Foot.

10-31-2003, 11:08 AM	#12
91LX2Bfast Registered Member Join Date: Dec 1999 Location: Warrington, PA Posts: 694	If you do stick with your pull through MAF, just make sure you route the bypass far enough away from your MAF so that you don't get surge pushing back through the MAF. That'll creat all kinds of driving problems. 8-10" away is usually far enough. __________________ '97 T-bird LX 4.6L 2V, auto SVO heads/intake, Vortech T-trim, front mounted intercooler, blower cams, Cobra crank, Manley H-beam rods, JE pistons, Aeromotive fuel system w/ 42# injectors, and much more No times yet

11-14-2003, 08:34 AM	#15
ArtMan Registered Member Join Date: Dec 1998 Location: Scarsdale, NY Posts: 45	Am I missing something? A turbo's blow off valve and a s/c by-pass valve are two different valves. They don't do the same thing. The by-pass valve on a s/c is meant to recirculate blown air during decelaration (when the throttle is closed and the rpms are high). The blow off valve on a turbo releases excess boost when it reaches a predetermined max. These valves peform two different functions

10-16-2003, 03:11 AM	#2
speedytang Registered Member Join Date: Oct 1999 Location: Marengo, Ohio.USA Posts: 135	It does not matter if it is a supercharger or turbo you will have the same problem if it is a MAS car and it is not a blow thru design. If you want a true blow off valve just get your MAS calibrated for blow thru just like Procharger does on its supercharged kit and turbo kits. I am going to get my old Ford 70mm meter calibrated for blow thru so that I can solve a lean off full throttle condition.

10-16-2003, 05:47 AM	#3
Jaegermeister2k Registered Member Join Date: Apr 2003 Location: Brandon,Fl Posts: 163	How could i do that?

10-29-2003, 05:50 PM	#6
Jaegermeister2k Registered Member Join Date: Apr 2003 Location: Brandon,Fl Posts: 163	Yeah blow thru.How do i do that?I'm probably gonna buy a novi 1000.

10-29-2003, 05:53 PM	#8
speedytang Registered Member Join Date: Oct 1999 Location: Marengo, Ohio.USA Posts: 135	The meter is installed between the throttle body and the supercharger instead of betwwen your air cleaner and supercharger.

10-29-2003, 06:04 PM	#9
Jaegermeister2k Registered Member Join Date: Apr 2003 Location: Brandon,Fl Posts: 163	Yeah but how could i program it for blow thru?

10-29-2003, 07:24 PM	#10
speedytang Registered Member Join Date: Oct 1999 Location: Marengo, Ohio.USA Posts: 135	Have your meter recalibrated by PRo-M for that purpose. They change the metering rate per cfm of air to allow the car to handle the pressure going across the Hot Wire of the meter.

10-29-2003, 07:36 PM	#11
Jaegermeister2k Registered Member Join Date: Apr 2003 Location: Brandon,Fl Posts: 163	Pro-m?I probably have to send em mine first right?Do they have a website?And how does it work?If i move the MAS then all i would have to do is instead of a by pass valve just put a blow off valve in its place right?

11-12-2003, 06:32 PM	#14
91LX2Bfast Registered Member Join Date: Dec 1999 Location: Warrington, PA Posts: 694	If you get a pre-made setup, then you might not have to worry about it. But if you are rigging up you own bypass, you need to pick a point on the intake tube to re-route the bypassed air back into. Keep that point 8-10" away from the MAF. I'm not sure if that helps or not. See, if you put it, say 4" from the MAF, what can happen is this: the air coming back into the intake pipe once the TB is closed can push backwards through the MAF causing poor drivablity. You might notice a bucking or surging when you let off the gas.

11-14-2003, 04:39 PM	#17
ArtMan Registered Member Join Date: Dec 1998 Location: Scarsdale, NY Posts: 45	Thanks OK, thanks. When he said blow off valve, I thought he meant wastegate. You can install a bypass valve on a s/c and leave the end open to the atmosphere. And you definetly will get a noise - some say a farting noise.

11-15-2003, 04:36 PM	#19
91LX2Bfast Registered Member Join Date: Dec 1999 Location: Warrington, PA Posts: 694	Yup. With a pull through MAF (oem type,) you want to recirculate the air. The bypass/divertor valves still make that "cool" whoosh sound, just not as loud as the bov. With a blow through MAF, you can install a BOV and vent to the atmosphere.

12-08-2003, 07:12 AM	#20
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	ok, let me ask the obvious. Pro-M will only be able to recalibrate Pro-M meters right? Does C&L have this option, anyone know? __________________

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