Do all superchargers need a bov
02-04-2005, 01:29 PM
#1
Le Mans Master
Thread Starter
Do all superchargers need a bov
I picked up a supercharger setup for my tpi and it doesnt have a blow off valve,i would assume you would need it when you let off the throttle.And if i do i know ill have to blow it back inline and not to the atmosphere because im running a maf setup.So should i look into getting one ?
02-04-2005, 01:49 PM
#2
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Pat
In the supercharging book I have it calls it an 'idle bypass valve' and states that it enhances the driveability and long term durability of the system during aggressive driving which I assume you will be doing.
I would imagine the higher the pressure you are using the more it would help. What sytem did you pick up?
In the supercharging book I have it calls it an 'idle bypass valve' and states that it enhances the driveability and long term durability of the system during aggressive driving which I assume you will be doing.
I would imagine the higher the pressure you are using the more it would help. What sytem did you pick up?
02-04-2005, 01:53 PM
#3
Le Mans Master
Thread Starter
Chris.its an older paxton sn93 setup ,i picked it up from my brother for $500 for everything also with the xtra new 8 lb pulley.I figuredid run it for awile then upgrade it later on to a newer unit.
02-04-2005, 01:53 PM
#4
Le Mans Master
Have you seen Vette magazine this month ? Big feature
on blowers and superchargers. One that they showed had a
valve built into the manifold that equalized pressure when
letting off the throttle. This probably doesn't help your problem,
but it might be interesting reading.
on blowers and superchargers. One that they showed had a
valve built into the manifold that equalized pressure when
letting off the throttle. This probably doesn't help your problem,
but it might be interesting reading.
02-04-2005, 02:53 PM
#7
the bov on a turbo is there primarily to catch the pressure spike travelling back through the ducting after being bounced off the closed throttle plate to keep it from slowing the compressor (and therefore the turbine) down and keep lag to a minimum (keep it spooled up), the wastegate is too slow to catch it (and to spool the turbo down), however when violent the spike can shatter the compressor wheel, on a supercharger that would be the only reason to install it. There's no chance of it slowing the compressor down since it's belt & gear (inside trans case) driven.
02-04-2005, 03:16 PM
#8
Le Mans Master
Thread Starter
i found this on the c4 section
If I understand it correctly, the by-pass valve returns the extra boost into the supercharger and the blow-off valve vents it too the outside. I believe once you go above 8 lbs, you want to go with a blow-off valve.
Thanks for the reply,
If I understand it correctly, the by-pass valve returns the extra boost into the supercharger and the blow-off valve vents it too the outside. I believe once you go above 8 lbs, you want to go with a blow-off valve.
Thanks for the reply,
02-04-2005, 03:18 PM
#9
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Prolly some hhype involved but makes sense:
http://www.magnusonproducts.com/bypass.htm
Why do you need a bypass valve? The best kept secret in forced induction is the little known bypass valve. This small valve, when properly installed between the supercharger and the air throttle body, allows the supercharger to become extremely efficient in terms of economy and parasitic power loss. Our M90 supercharger uses less than 1/3 of 1 HP at 60 MPH cruising. The bypass is operated by a vacuum actuator control unit that is normally closed. When vacuum is high (idle-cruising) the actuator opens the bypass valve, equalizing the vacuum pressure throughout the system. When boost is required (accelerating) the vacuum is decreased and the bypass valve instantly closes, causing pressure to increase into the cylinders. This equalized vacuum condition virtually eliminates the normal parasitic power loss of a forced induction system
02-04-2005, 03:28 PM
#10
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Vortec:
$252 bucks but I bet you could find or adapt one much cheaper.
Vortech's Mondo Racing By-Pass Valve Assembly for high-output race supercharger applications. The by-pass valve acts as a pressure-release valve that relieves un-needed and potentially hazardous pressures created by the supercharger by recirculating it through the supercharger for later use. The benefits include smoother idling, due to a reduction in blower surge, and protection against damaging head gaskets amongst other engine parts. By-pass kits are highly recommended for all supercharger applications and are required for superchargers with 7psi or higher boost ratings.
02-04-2005, 03:43 PM
#12
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Figure it out and let us know.
I think a supercharger in the vette would be
, and would like to toy with a rear mount turbo in the formula similar to the kits for LS1/6 f-bodies, all will have to wait a year or 2 till I move. 
I think a supercharger in the vette would be
, and would like to toy with a rear mount turbo in the formula similar to the kits for LS1/6 f-bodies, all will have to wait a year or 2 till I move.
02-04-2005, 04:24 PM
#13
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Lets think about this. You are accelerating and producing boost. Everything is all hunky-dory. Then, you suddenly let off the gas and the throttle plates close on the carb, or in your case the throttle body. The supercharger is still creating boost, and you just cut off the flow. The pressure is still there and it will all go somewhere. Typically the joints on your ducting will blow. Long story short, you need a bov.
02-04-2005, 06:40 PM
#14
Le Mans Master
Thread Starter
Then it looks like ill be getting a bov,thanks guys.technically i need a bypass valve because im using a maf setup.i found a ton of them on ebay.
Last edited by patsnitrovette; 02-04-2005 at 09:57 PM.
