Boost Waste Valve
Member
Joined: Jul 2001
Posts: 70
Likes: 0
From: Iowa
99WhiteBeast:
In the old days when we put a 6-71 on say a 302 you had to provide a way to bleed off the boost when you have to slam the throttle shut. Otherwise you could bang the blower and or manifold. And I did my share. When we made our manifolds (couldn’t buy one for small block Fords back then) we put a pressure relief valve in to handle it. To make a blower setup we usually milled off the bottom of a dual four-barrel tunnel ram manifold down enough to have clean bosses for bolts and put an aluminum plate on to accept the 6-71. In the middle of the plate between the two milled castings we cut a square hole and covered it on the bottom with a larger price of aluminum ( with gasket ) held on with two bolts and springs set to go off at 30lbs. We usually ran the pulley ratio at 9% under on 302in motor to yield 16lb of boost. If you slammed the throttle shut under WOT around 6500rpm you could sometimes hear it blow open.
Now days they call them burst panels. They only work once and are required by NHRA in the appropriate classes. You also have to change them when they get stretched or fatigued. Otherwise you can find yourself at half-track and no boost…
Having said that, I believe the following excerpt from the Ford Factory Service Shop CD is on point..
"Supercharger Bypass Vacuum Solenoid and Actuator:
The Supercharger Bypass Vacuum Solenoid will bleed off boost during sudden throttle closing. This prevents damage that can occur if the throttle is quickly closed while the engine is still under heavy boost. The solenoid is located on the upper LH side of the engine. The solenoid uses engine vacuum to operate a actuator and linkage that connects to the pressure bleed off valve. The actuator is located near the solenoid and is connected to it by a vacuum line."
"At partial-throttle opening or when vacuum is present in the intake system, a vacuum-controlled bypass valve reroutes some discharged air from the supercharger back through the intake plenum. This prevents the supercharger from cavitating, causing reduced performance, increased temperatures, and poor economy."
You may want to enlighten your ace mechanic before he misleads someone in to potentially damaging his or her beloved L
Just my .02
David
In the old days when we put a 6-71 on say a 302 you had to provide a way to bleed off the boost when you have to slam the throttle shut. Otherwise you could bang the blower and or manifold. And I did my share. When we made our manifolds (couldn’t buy one for small block Fords back then) we put a pressure relief valve in to handle it. To make a blower setup we usually milled off the bottom of a dual four-barrel tunnel ram manifold down enough to have clean bosses for bolts and put an aluminum plate on to accept the 6-71. In the middle of the plate between the two milled castings we cut a square hole and covered it on the bottom with a larger price of aluminum ( with gasket ) held on with two bolts and springs set to go off at 30lbs. We usually ran the pulley ratio at 9% under on 302in motor to yield 16lb of boost. If you slammed the throttle shut under WOT around 6500rpm you could sometimes hear it blow open.
Now days they call them burst panels. They only work once and are required by NHRA in the appropriate classes. You also have to change them when they get stretched or fatigued. Otherwise you can find yourself at half-track and no boost…
Having said that, I believe the following excerpt from the Ford Factory Service Shop CD is on point..
"Supercharger Bypass Vacuum Solenoid and Actuator:
The Supercharger Bypass Vacuum Solenoid will bleed off boost during sudden throttle closing. This prevents damage that can occur if the throttle is quickly closed while the engine is still under heavy boost. The solenoid is located on the upper LH side of the engine. The solenoid uses engine vacuum to operate a actuator and linkage that connects to the pressure bleed off valve. The actuator is located near the solenoid and is connected to it by a vacuum line."
"At partial-throttle opening or when vacuum is present in the intake system, a vacuum-controlled bypass valve reroutes some discharged air from the supercharger back through the intake plenum. This prevents the supercharger from cavitating, causing reduced performance, increased temperatures, and poor economy."
You may want to enlighten your ace mechanic before he misleads someone in to potentially damaging his or her beloved L
Just my .02
David
Senior Member
Joined: Feb 2003
Posts: 1,294
Likes: 0
From: Colorado,
I still remeber my first WOT drive!
I feel sorry for those that don't!
I don't drive my truck all week and then on the weekend I have a big
on my face as I pull my dirt bike out to the trailhead. That is the toy that I thrash and abuse and experiment on. Then when I have had my fill I crawl back in my stock lightning ( fastest stock production truck in the world) and enjoy the ride home.
Greg
Senior Member
Joined: Feb 2000
Posts: 2,297
Likes: 0
From: New Hampshire
Re: Do Tell!
[QUOTE]Originally posted by Silver-Y2K-SVT
[B]'Beast:
This sounds credible to me. My buddy Eddie told me that his buddy T-Money heard some mechanic guy or something say that there was a good 100 HP "locked up in these things" by emissions and other little doo-dads and such. The dude said that Ford totally choked the things for insurance reasons and so that the cops could chase them better and whatnot. I checked with anther guy I know (Tim Dog) who has like a 450 HP Trans Am and Tim Dog said the he heard that all you have to do is cut like one wire or something in the computer and these thing would run 12's, easy.
You are right .....................kinda.The TUNERS do get about 100 hp with a chip/pully.So Ford did hide hp.The tuners find it
[B]'Beast:
This sounds credible to me. My buddy Eddie told me that his buddy T-Money heard some mechanic guy or something say that there was a good 100 HP "locked up in these things" by emissions and other little doo-dads and such. The dude said that Ford totally choked the things for insurance reasons and so that the cops could chase them better and whatnot. I checked with anther guy I know (Tim Dog) who has like a 450 HP Trans Am and Tim Dog said the he heard that all you have to do is cut like one wire or something in the computer and these thing would run 12's, easy.
You are right .....................kinda.The TUNERS do get about 100 hp with a chip/pully.So Ford did hide hp.The tuners find it