Boost cutout vs vacuum cutout
Rather than start a new thread, I re-read this one and and still trying to decide whether to go electric or the other way.
Electric would need what, 3 wires? Trigger, power and ground? Would it need a relay?
I don't quite understand the other option, when folks say vacuum or boost operated it's basically saying the same thing? If it's basically saying the same thing, it just uses a boost/map reference and that's all there is to it?
And who makes the better product, Bandlanz or Loudvalve? I know QTP is still out there too.
Electric would need what, 3 wires? Trigger, power and ground? Would it need a relay?
I don't quite understand the other option, when folks say vacuum or boost operated it's basically saying the same thing? If it's basically saying the same thing, it just uses a boost/map reference and that's all there is to it?
And who makes the better product, Bandlanz or Loudvalve? I know QTP is still out there too.
Elec kits I’ve dealt with did not require a relay. They are pre wired and only need power and ground. Usually a rocker switch that you bump open and bump closed. Badlanze is the best I’ve dealt with.
The boost activated are pneumatic. No electronics required. You plumb them to a boost source or a vacuum source on the motor. You buy them either normally open or normally closed and boost/vacuum closes or opens them.
The pneumatic valves are better IMO as they never wear out and are pre loaded to not rattle and cause issues. Eventually the electric ones will rattle or become loose and need maintennace.
The boost activated are pneumatic. No electronics required. You plumb them to a boost source or a vacuum source on the motor. You buy them either normally open or normally closed and boost/vacuum closes or opens them.
The pneumatic valves are better IMO as they never wear out and are pre loaded to not rattle and cause issues. Eventually the electric ones will rattle or become loose and need maintennace.
Rather than start a new thread, I re-read this one and and still trying to decide whether to go electric or the other way.
Electric would need what, 3 wires? Trigger, power and ground? Would it need a relay?
I don't quite understand the other option, when folks say vacuum or boost operated it's basically saying the same thing? If it's basically saying the same thing, it just uses a boost/map reference and that's all there is to it?
And who makes the better product, Bandlanz or Loudvalve? I know QTP is still out there too.
Electric would need what, 3 wires? Trigger, power and ground? Would it need a relay?
I don't quite understand the other option, when folks say vacuum or boost operated it's basically saying the same thing? If it's basically saying the same thing, it just uses a boost/map reference and that's all there is to it?
And who makes the better product, Bandlanz or Loudvalve? I know QTP is still out there too.
I'm a firm believer that proximity to the turbo plays a big role in longevity, mine was down stream where 007FJ has his and even there they made a huge difference in spool and power production.
I liked the electric because I could open it while idling through the cruise ins and car shows.
You could of course do the same with CO2 like Zach's RX7 which is very cool.
I used the pneumatic valves ones that are normally open, then used vacuum to close them. You can run an inline vac solenoid so you can open/close it anytime you want. I even ran a mini $3 vac pump on one so I could close it before starting car and not wake my kiddo.
Spoke to the Badlanze guy a lot. He said the number one thing that takes out the electric ones it people holding the button too long when closing/opening. It stresses the gears and motor. You are supposed to bump them open and closed.
Spoke to the Badlanze guy a lot. He said the number one thing that takes out the electric ones it people holding the button too long when closing/opening. It stresses the gears and motor. You are supposed to bump them open and closed.
I used the pneumatic valves ones that are normally open, then used vacuum to close them. You can run an inline vac solenoid so you can open/close it anytime you want. I even ran a mini $3 vac pump on one so I could close it before starting car and not wake my kiddo.
Spoke to the Badlanze guy a lot. He said the number one thing that takes out the electric ones it people holding the button too long when closing/opening. It stresses the gears and motor. You are supposed to bump them open and closed.
Spoke to the Badlanze guy a lot. He said the number one thing that takes out the electric ones it people holding the button too long when closing/opening. It stresses the gears and motor. You are supposed to bump them open and closed.
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Verdad Gallardo Both are fine IMO. Though Badlanze offers a 5". I don't know of a pneumatic 5".
DPW also makes one thats spring loaded and electric. Its kinda cool. I had one of those on my sport bike. Worked well and never rattled.
DPW also makes one thats spring loaded and electric. Its kinda cool. I had one of those on my sport bike. Worked well and never rattled.
Looped the hard line off the rear turbo manifold to an aluminum distribution block mounted on the engine. Pressure gauge and feed line to the cutout are also mounted on the block.
Here is the feed line to the boost activated cutout on one of my exhaust tips. This will still send exhaust through the 3.5" magnaflow muffler, but not the longer 3" one.
TECH Resident
Joined: Sep 2013
Posts: 994
Likes: 119
From: Mechanicsburg, PA
Sorry to resurrect this thread from the dead, but thought my problem goes along with this subject. I have a 4” vacuum operated cutout. I used a vacuum switching valve and a $5 Amazon mini vacuum pump from a vacuum food sealer. Makes an easy 15” of vacuum. But I get too much exhaust leakage past the blade. Even if I install a hand pump and apply 20” of vacuum, same thing. Any suggestions?
Teching In
Joined: Mar 2025
Posts: 16
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Sorry to resurrect this thread from the dead, but thought my problem goes along with this subject. I have a 4” vacuum operated cutout. I used a vacuum switching valve and a $5 Amazon mini vacuum pump from a vacuum food sealer. Makes an easy 15” of vacuum. But I get too much exhaust leakage past the blade. Even if I install a hand pump and apply 20” of vacuum, same thing. Any suggestions?
TECH Resident
Joined: Sep 2013
Posts: 994
Likes: 119
From: Mechanicsburg, PA
Do you mean it leaks too much past the blade valve when its fully closed? IE exhaust leak? Did you verify it is fully closed and seated? Sounds like you may just have a bad valve if that’s the case.
Mine were all adjustable I preloaded them a bit with the adjustable actuator rod to ensure they pulled closed tightly. I also put a hole in my vac source line as it was getting too much vacuum and also wouldn’t bleed down quickly when I turned the pump off without it.
Mine were all adjustable I preloaded them a bit with the adjustable actuator rod to ensure they pulled closed tightly. I also put a hole in my vac source line as it was getting too much vacuum and also wouldn’t bleed down quickly when I turned the pump off without it.
TECH Resident
Joined: Sep 2013
Posts: 994
Likes: 119
From: Mechanicsburg, PA
Do you mean it leaks too much past the blade valve when its fully closed? IE exhaust leak? Did you verify it is fully closed and seated? Sounds like you may just have a bad valve if that’s the case.
Mine were all adjustable I preloaded them a bit with the adjustable actuator rod to ensure they pulled closed tightly. I also put a hole in my vac source line as it was getting too much vacuum and also wouldn’t bleed down quickly when I turned the pump off without it.
Mine were all adjustable I preloaded them a bit with the adjustable actuator rod to ensure they pulled closed tightly. I also put a hole in my vac source line as it was getting too much vacuum and also wouldn’t bleed down quickly when I turned the pump off without it.
The 3" and 4" Proflow boost activated ones seem to seal pretty well.
Very similar (or the same) to the Chinese/Amazon version. Opening pressure is 7 psi which allows a pretty strong spring to hold everything shut. I can't force it open by hand. Seems to seal pretty well. Had both the 3" and 4" on the car over time. Both seemed to seal pretty well and have held up for several years so far.
Very similar (or the same) to the Chinese/Amazon version. Opening pressure is 7 psi which allows a pretty strong spring to hold everything shut. I can't force it open by hand. Seems to seal pretty well. Had both the 3" and 4" on the car over time. Both seemed to seal pretty well and have held up for several years so far.
Teching In
Joined: Sep 2023
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The 3" and 4" Proflow boost activated ones seem to seal pretty well.
Very similar (or the same) to the Chinese/Amazon version. Opening pressure is 7 psi which allows a pretty strong spring to hold everything shut. I can't force it open by hand. Seems to seal pretty well. Had both the 3" and 4" on the car over time. Both seemed to seal pretty well and have held up for several years so far.
Very similar (or the same) to the Chinese/Amazon version. Opening pressure is 7 psi which allows a pretty strong spring to hold everything shut. I can't force it open by hand. Seems to seal pretty well. Had both the 3" and 4" on the car over time. Both seemed to seal pretty well and have held up for several years so far.
I just ordered this cutout from AES Racing Muffler out of Australia. It’s super beefy and high quality. Come with the whole vacuum pump setup as well for under $400.
Bringing this back up. I ran a boost activated 3" cutout on my turbo LQ4 and loved the automatic function, but it would be nice to be able to open it up at cruise nights idling around (kids love it). I am thinking about adding a solenoid that would dump vacuum and block the line going to the valve when turned on, which would leave it open on command.
Obviously the valve will open once the throttle is opened (zero vacuum, atmospheric), but will going into boost damage the diaphragm? I would imagine the plunger/piston is held against a hard stop via spring force, and going into boost would only add to that.
https://www.aliexpress.us/item/22558...yAdapt=glo2usa
Obviously the valve will open once the throttle is opened (zero vacuum, atmospheric), but will going into boost damage the diaphragm? I would imagine the plunger/piston is held against a hard stop via spring force, and going into boost would only add to that.
https://www.aliexpress.us/item/22558...yAdapt=glo2usa
Last edited by LQ4-E39; Jun 18, 2025 at 10:26 AM.
Bringing this back up. I ran a boost activated 3" cutout on my turbo LQ4 and loved the automatic function, but it would be nice to be able to open it up at cruise nights idling around (kids love it).
Obviously the valve will shut once the throttle is opened (zero vacuum, atmospheric), but will going into boost damage the diaphragm? I would imagine the plunger/piston is held against a hard stop via spring force, and going into boost would only add to that.
Obviously the valve will shut once the throttle is opened (zero vacuum, atmospheric), but will going into boost damage the diaphragm? I would imagine the plunger/piston is held against a hard stop via spring force, and going into boost would only add to that.
