Exhaust Adaptive Valve

[Jon A]

EGR valves didn't protrude into the exhaust stream, blocking the flow if they got stuck. They were usually located at the intake manifold and connected to the exhaust manifold with a steel tube. The exhaust had an open path.

[Badass69]

EGR valves didn't protrude into the exhaust stream, blocking the flow if they got stuck. They were usually located at the intake manifold and connected to the exhaust manifold with a steel tube. The exhaust had an open path.

No egr valves did not. However a thermally operated flapper valve to force exhaust from one side of the engine to the other through the exhaust crossover in the heads and intake did. That said it still allowed the engine to run and gave the exhaust a path to follow.

 

If you live in a place where it never freezes they won't care about the old flapper in the pipe lol.

 

 

Sent from the Great White North

[SLESierra]

Lot less of an issue when it was designed to be closed on cold start to force exhaust through the crossover under the carb... and being right at the engine on the exhaust manifold even if it froze within a few seconds it would be free.... not the same deal when its halfway to the back of the truck and plugs the whole exhaust system off.

 

 

Sent from the Great White North

I agree but had a few of those that would weld shut when you had a carb go lean - I hated those as well too lol.

[Badass69]

Oh I'm not saying they didn't. But they didn't cause an issue the first day when the vehicle was brand new either. Especially based on the ambient temperature

 

 

Sent from the Great White North

Edited January 2, 2014 by Badass69

[mzodarg]

Had mine removed along with the resonator. No more clanking noise on start up. With the Maganaflow 18", it actually sounds like a truck.

 

Mike

[Sir Dan]

Just curious...What are the symptoms if this flapper freezes shut? Does the engine start at all?

[bogeypro]

What... moisture in exhaust..... really????? Hydrocarbon combustion creates H2O..... no..... never.

 

That must be GM's standpoint anyway. Grandpas old tractor muffler flapper seemed like a great idea..... except grandpa had it to keep wildlife and water out of the muffler and manifold/ engine when it stood straight up in the air. Not to attempt to dampen sound during 1/2 cylinder time.... Its not the end of the world but for us cold climate types its something else to get rid of.

 

 

Sent from the Great White North

 

Dude, its called condensation....That isn't GM's fault, that is mother nature. Now, the flapper thingy is GM's fault. LOL

[MotoMedic]

Just curious...What are the symptoms if this flapper freezes shut? Does the engine start at all?

Possibly would start but then die shortly after.

(As I type this, I'm picturing Eddie Murphy in Beverly Hills Cop stuffing bananas in the tailpipe. ha)

[loganbent]

Possibly would start but then die shortly after.

(As I type this, I'm picturing Eddie Murphy in Beverly Hills Cop stuffing bananas in the tailpipe. ha)

 

LOL, I was talking about this exact problem with my Dad last week and I think he described it as we all got the "Banana Tailpipe Package" as an added bonus and didn't know it

[CorvetteOJ]

Possibly would start but then die shortly after.

(As I type this, I'm picturing Eddie Murphy in Beverly Hills Cop stuffing bananas in the tailpipe. ha)

Hey Medic, when I read your post, I immeidately remembered when I was a kid, (teenager) guys would stick raw potatoes on the end of someone's exhaust pipe, and in most cases, would get the same effect. The car would start, but then die. This worked on most cars, however, I saw a guy in a '63 409 Impala SS crank his engine one night at the local burger joint after a couple guys (practical jokers) put potatoes on both tail pipes. He "goosed it (hit the gas pretty hard a couple times) and blew those potatoes straight back like rockets. That was one exception. Most of the time the vehicle would die and the driver would have a time trying to figure out what the problem was. That vision came back to me crystal clear when I read your line about Eddie Murphy and the bananas. Sometimes it's fun to remember the "old days."

 

[CorvetteOJ]

In the for what it's worth department...within 24 hours after taking delivery of my Denali, I was at my local performance exhaust shop having my exhaust customized. this was the 8th of November. I had the entire factory system cut off just behind the 3rd cat and replaced with a 22" Magnaflow and custom pipes running straight out the back. (I'm still old corp.) This means my flapper valve and resonator went in the trash along with the factory muffler. My exhaust guy said he had modified numerous exhaust sytems, especially on the new Camaros because of the flapper valve making a noise. He said after about a year most of them get loose and start clanging like a dozen marbles in an empty coffee can. He had replaced them for the noice they create, not for freezing up, as we are in Montgomery, Alabama. Very seldom does water freeze here, much less exhaust valves. I just in a friend's 2012 Camaro last week. He wanted me to hear a strange noise he had in it. I told him it was the flapper valve. He had it cut out on Christmas eve and called me to tell me he owed me one. I guess I share this story so everyone will know that "flapper valve" sucks, regardless of what part of the country or climate you live in.

[DRS 95 Silverado]

In another thread a few of us talked about a humming sound, in my case kind of comes and goes as your driving along. Any chance it's this flapper valve I'm hearing fluttering under just the right back pressure?

[Bigluke]

So I have a 2014 silverado and wanting to put a flowmaster 40 dumped if I cut the muffler off including the valve and resonator off it won't mess up my truck or make any check engine lights come on will it

[TJay74]

Yes you will be fine, but skip the flowmaster unless you are ok with losing power just to get some sound.

[Bigluke]

Would magnaflow be better or just dnt dump it