Chevy & GMC Vans

okay i need to know what size muffler for the inlet and outlet size for my 1992 astro cause i am gonna to buy a flowmaster 40seires muffler i am not going bigger.!! it will be single in and single out. and dump under the van

I don't know the size of your 92 buy the 96+ are 3" in and 2.5" out. If you dump the 40 series under the van it will be extremely LOUD! I know...I did that with my 40 series 3" in dual 2.5" out.

i am gonna keep it the stock pipe size coming from the y-pipe and my plan is to get the cat and stock muffler cut off and get the flowmaster welded in!! i want it very loud i am 18 i like that stuff i live in oklahoma sooo NO emission testing!!!

If you've got a big pipe wrench - call them a monkey wrench down here, you can turn that down until it contacts the pipe then measure the gap in the wrench.
If you don't have a wrench that big, wrap a piece of string around the pipe, make a mark on the string and measure from the end of the string to the mark, then divide by pi (3.14159) It will be close enough so you can tell if you have 2 1/4, 2 1/2 or 3" pipes. measure behind where the pipe and muffler are fitted together.
My '89 had 2 1/4" pipes in and out of the original muffler.

Dean's right about the noise, it's going to sound louder inside than it does outside, resonates right through the floor pan.

When you have an exhaust exit underneath the van, it is possible to have exhaust fumes enter the interior. I would recommend a side or rear exit and with a 40 series Flowmaster, don`t worry it will be loud enough.

okay i got my exhaust done i decided to go with Wicked flow which is suppose to be a magnaflow knockoff it was 50 bucks less i kepted the cat. and the new muffer is single in and dual outlet and is dumped before the rear axle it is very loud but it sounds good it is deep not what i was expecting for a v-6.!!! it cost me 150 bucks.

here is the issue okay my exhasut set up sounds nice and loud but it drones into the passenger compartment too much so if i put turn downs will it lessen the drone and still be nice and loud outside??

LiftedAWDAstro wrote:If you dump the 40 series under the van it will be extremely LOUD! I know...I did that with my 40 series 3" in dual 2.5" out.

Seems like I already answered your question as the 1st reply to this thread. You really need to read the responses!

i know!!! but i still want it loud outside just not inside and the muffler that i got was a wickedflow it is a magnaflow knock off what do you think. and it is single in and dual outlet!!

If you want it quiet inside, put the stock one back on. It will get a little quieter inside with exiting the exhaust out the rear or out behind the rear tires. Plus you won't have to worry about carbon monoxide in the cabin like you will with the dumps at the rear axle.

do you think it would sound better or louder with turn downs or echotubes?? how would it sound with turn downs???

With turn downs it will not sound any different. You MUST exit the tubes out the rear someplace to quiet the interior droning down.

id go to rockauto and order 2 tailpipe sections and run dual pipes out the stock location or turn them out the side like a ford lightning.

i went too mills fleet farm and picked up a cherrybomb turbo muffler 2.5"id 2.5"id for 20$ and mounted it myself. i regret not getting the glasspack, there louder and 5$ more than the turbo. it sounds good.