Hi guys, I have a tendency to never be satisfied with exhaust systems. Since I weld, this makes for many, frequent configuration changes to amuse myself. I have had probably 5 different mufflers on my LeSabre, including an 82-92 dual outlet flowmaster, a Flowtech Afterburner, two different glass packs, and some assorted turbo mufflers (this is all over the course of like 30,000 miles). I finally ditched the stock 2.25" exhaust over Christmas break and replaced it, cat back, with a mandrel bent full 2.5" exhaust pipe from a 92-93 Bonneville/LeSabre. I have a large case (almost stock size) Dynomax Thrush turbo on the car right now (it has 2.25" internal pass tubes). It definitely flows a lot better than a stock GM muffler (the mufflers GM used on the H bodies had a 2" primary pass tube and like a 1.75" final pass tube -- I can't believe any air makes it from one end of these mufflers to the other!) This Thrush is decently quiet, which is what I was going for, with a slightly noticeable outside exhaust tone. Unfortunately, the exhaust tone is really crappy -- it has a very weird, hollow sound, it'* all midrange. The Thrush has the biggest case I could get, 20" long 25" overall, so I guess it does it'* job and takes all the low tone out of the exhaust. I'd like to go with a muffler that has a little more bass to it, still without interior droning or really "Loud" tone. I have run Magnaflows on a 350 Nova and I currently have Dynomax ultraflo'* on a 2.25" dual mandrel bent exhaust behind my fuel injected 327 chevy. This style packed case, straight through muffler makes for surprisingly quiet, drone free cruising, with nice aggressive attack when you open the throttle. I know a 3800 isn't going to sound anywhere near as nice as a V8 (I got to listen to it constantly with the stupid flowmaster on it) but the Thrush hollow tone is annoying me right now.

I actually have a nearly new 2.25" offset/center 14" case Magnaflow kicking around in my friend'* garage. I'm curious whether you guys are running the 2.25 or 2.5" magnaflow/dynomax mufflers, what length case, and what size cross section (4x9, 5x9, etc) . I'd probably go for the big (18") case over the smaller 14" since I do not plan on using a resonator up front (the 92-93 2.5" exhaust does not use a resonator)

I should just put a 3 bolt header-flange type connection before the muffler when I change it, so I can swap mufflers in and out as I please.

I think that willwren has a Magnaflow

We have different applications, even amongst the different years and trim levels of the Bonneville. What you do will ultimately be determined by the current diameters and sizes of your exhaust.

Your car probably came STOCK with 2.25" exhaust. Mine came with 2.5". All my components (magnaflow cat, res, and muffler) were carefully chosen not only for my application, but also so that each union was non-restrictive. In fact, the flanges were cut off my resonator in order to slip my existing intermediate pipe inside the res for less restriction (this also helped as I was constrained for space to install the long sucker). The inside of the resonator is actually 3" ID.

Willwren, I did have a 2.25" exhaust, with resonator, stock. It is now a 92-93 2.5" exhaust, transplanted by me. I have the same pipe, minus the resonator, that you do. I can't understand why GM used the big 2.5" mandrel bent exhaust on the low hp series I'* (the N/a 170 hp cars had the 2.5" too, I took my pipe off a 92 n/a car) but it made for a huge flow gain for 10 bucks.

Here'* pics from my resonator install at WCBF '04 Tech Day:

http://www.bonnevilleclub.com/forum/...onator+install

You can see how the flanges were cut off to allow me to slip my intermediate pipe inside the edge.

Adding a resonator to a 92/93 exhaust mellows it out very well. Still a nice grumble, but not annoying.

Magnaflow now sells a combination unit incorporating a hi-flow cat and resonator into the same part. It takes less space in the intermediate pipe for install, and should work very well. I would have done it, but my hi-flow cat was only one year old when I had my resonator installed.

CarSound 94009 Cat, 2.5" Resonator and F-Body Dynomax Super Turbo crossflow w/dual 2.25" outlets...hate it :P but then I'm old too

Cheers,

Hey there Foghorn. Are you still using the 2.25" stock exhaust pipe that the 97s came with? The 2.5" has so much more volume than my old 2.25" pipe that it changed the tone significantly. What 2.5" resonator are you running, where did you get it, and what did it cost? I really wouldn't mind getting a high flow resonator to cancel out the 3800s characteristic 2000 rpm blasting drone, and then using an overall louder muffler, as opposed to my having no resonator and a quiet muffler that only makes a tone at all in the "drone zone". This high flow cat/resonator also doesn't sound like a bad idea, although a resonator needs to be pretty big to be tuned properly for the rpm range we need it. If the resonator chamber is really compact = convenient, but it won't be anywhere near as effective as the correct (stock) size chamber. I wish I could find a stock application 3800 resonator with a 2.5" in 2.5" out, instead of the 2.5" in 2.25" out that I took off the car with the old smaller exhaust. I will definitely not be running one of those fake duals cross flow mufflers, as the LeSabre does not have cutouts for it. I ran dual 2.5'* out of a flowmaster 80 series when I was in high school, but the pipes had to exit below the bumper cover, which looked pretty stupid, seeing as one side did have a cutout (I probably have pictures somewheres)

Oh I just read your resonator install post Willwren. That magnaflow res. is beautiful! That looks like the ticket for what I'm trying to do -- it'* a huge case, so it will be providing maximum cancellation down low in the revs where the 3800s drone. What did that cost?

the SSEi has the 2.5

Ahaaaaaaa. Did a 1997 SSei have a resonator stock? If so, there'* my factory 2.5" in/out 3800 resonator application that I can call some junkyards up for. The magnaflow would be better than nothing, but a factory resonator will be perfectly acoustically tuned for this car.

yes everything from 94+ has a resonator at least on the bonne