I was just wandering what it was that gave Z-71's that loud rattling sound when they have duals. I have a few friends that have trucks like that and it annoys the hell out of me, what causes it?

Thanks,
Steve

 

i dunno, my dad has a 95 z71 and it doesnt have a rattle???

 

rattling??? when? when they let off the gas? if so it could be a glass pack called a cherry bomb. i think what happens is when you let off the gas, there gets some unburnt fuel in the exhaust. when it reaches these particular mufflers, it ignites the unburnt fuel.

just my .02

 

On trucks, the muffler is in the "middle" of the exhaust pipes, not at the tail end like in Camaros. Maybe that is why?

 

also, can the pipes after the mufflers be straight?

 

It's a whole different exhaust routing, thats why they sound different.

Their trucks use "straight through" mufflers while our 3rd gens use "crossflow" mufflers. Very different arrangement.

 

Ok, it's not really a rattling type sound its hard to describe kinda like a loud crispy sound. I dunno, could be because the straight through mufflers? I notice it on Silvarado's, Suburbans, Tahoes, and pretty much any other GM with a V-8 built for towing. Z-71's seem to be the worst, around here they will remove cats and mufflers then get the 3in exhaust pipes on the sides of the tow hitch in the back. Pretty much all of them that have there exhaust like this sound like crap. And they seem to be proud of it. Maybe the motor is starved for air or backpressure. I dunno, its just wierd how they all sound this way. Listen to the sound I enclosed you can notice it a little in this one.

Paste this url in your browser since geosites doesnt allow linking.

http://www.geocities.com/stephen_36695/z714x4to.wav

 

One... are they stock exhaust ??? if so the cat on chevy trucks has 2 inlet (one from each side), and 1 outlet... which travels the ENTIRE LENGTH OF THE BED (or back) OF THE TRUCK through a muffler... It's a combination of the vibration of the pipe (after the cat) since it's 6-9 feet long, and the way that the air has to go through the cat...

 

your pretty off, im not sure about stock routing, but on the exhuast me and my dad put on his, it has the y pipe into a 2 1/2" pipe for 1 foot, then there the cat, single in single out, then 1 1/2 feet of 3" piping, then goes into a single inlet dual outlet muffler, which then the pipes are ran to 4 or 5 feet from the rear of the truck then the left goes off to the left and over the rear end, the right stays where it it and keeps going to straight out the back, i just drove his a few minutes ago and reved to see about that sound and i dont hear it...im puzzled

 

Ok,.. .i just replaced the STOCK converter on my mom's '97 tahoe... each side of the engine has a pipe that comes into the cat... DUAL INLET... and one pipe that comes out... goes about 4 feet into a STOCK muffler, and about 2 feet of pipe to the rear behind the wheel, WHAT YEAR IS YOUR DADS TRUCK... they made different types of exhaust for v-6 , v-8, vortec, AND Z71...

 

95 silverado z71, i dont remember what his has stock, might be differant because your mom has a tahoe, im not sure, but ive never heard of a dual inlet cat converter?

 

90's GM 350's seem to have a gurgling sound with glasspacks, or no exhaust at all... to me anyway.

 

has anyone thought of the heads and cam that those things have? they are not going to give the same type of sound open exhaust on a stock f-body gives because of the lift/duration of the cam as well as the way the heads flow.

 

Thats pretty much what I notice on Z-71's that have open exhaust (nothing but pipe to the back) they do it very badly, ones with performance exhaust do it, but only to a certain extent. I really wish I knew exactly what it was. One day I will figure it out.

 

I just bought a new 03 Z71 and havent noticed any gurgling. not sure about the cat deal though, i will check it out tomorrow

 

Might it be that these engines in the Z71 trucks are built for torque? Maybe they have different heads or something.

Yall got me wondering about this to! haha!