Two mufflers!!

[brun064]

My parents recently just bought two new Intrepids with the 2.7L engine and i looked under the back bumper and noticed that there are two mufflers, or one muffler and one resonator. I got to wondering if the other engine sizes has this setup. Does the 3.2L and the 3.5L? My '94 Concorde with the old 3.5L has a resonator but does the new one. Why does chrysler put the muffler and resonator on instead of just putting a better muffler on without a resonator in the first place? I'm suprised there isn't an aftermarket performance exhuast system for the LHs since it would definetly improve power.

[Fluid]

Exhaust system design is more complex than just slapping on a 'hollywood' muffler and big pipe. Few buyers want to hear much exhaust noise at all, and tuning out various resonance frequencies can be time consuming and expensive. Likely the DC engineers found that with a single muffler there was a resonance at some normal engine speed - perhaps near the 2000 rpm 'cruise' engine speed which is seen most while driving. The only way to remove the unwanted noise is to add a resonator tuned to remove that frequency. If one muffler would do it, that's the way DC would have gone - parts left off cost nothing.

[brun064]

but the resonator/muffler setup is a huge power sapper. Why hasn't any company made a Cat-back system for the LHs. It would increase power so much it would make major bucks. (Hint to Borla, Flowmaster and others)

[Fluid]

brun064 - please don't get the idea that I am arguing with you! I just am trying to point out some of the things I have learned. There is no data ( as far as I know ) to prove that the front resonator is a power robber at all. Who has done a test to find out? Some owners have replaced the entire exhaust system, but that proves nothing about the resonator - the mufflers or the long, small diameter exhaust pipe may have been the culprit. Some back pressure must be present to preserve low rpm power, and the resonator may produce very little by itself.

A cat-back system would be a good idea, but on the newer LH cars it would be rather expensive, because the two cats are in the engine compartment!

[brun064]

Of course there is no data, but we all know that when an automaker puts a muffler on the car, it's main purpose is to cut down sound. And when they put a resonator on the car its purpose is to cut down even more noise. Now DC, like all car makers are going to go for the "not so expensive" exhaust system. They are not made for performance, but to pass EPA standards and all other government BS. Anyways the pipes are usually 2.25 to 2.5 which isn't that small. I understand your not trying to argue with me but a new aftermarket muffler will always be better than the factory one.

[Fluid]

Hi brun064 - sorry, but the facts don't support the claim that aftermarket mufflers are 'always' better. I'm a member of the DakotaRT e-group ( 75+ members ), and a lot of members changed out their stock mufflers for Flowmasters, Dynomaxes, etc. Some of them swore that their trucks were faster, but on the drag strip there was no time or mph difference before and after. Several even gutted their cats, only to find no reduction in 1/4 mile times - but an increase in noise.
The factory systems are not always 'cheap' either - that's why they use stainless steel, for better quality and performance in spite of the higher cost. Before we make absolute claims about performance increases, it would be a good idea to find out the facts first. Common sense is often wrong.

Lots of times the increased sound level makes us think we have better performance, but on the dyno or on the track the difference is often nil. This doesn't mean that replacing the resonator ( which is often nothing more than a glasspack anyway ) won't give more power, but it is a potential waste of money to do it without evidence that it works.

If it were me, on my ES with dual cats I'd replace the muffler and rear resonator with larger diameter ones, and use larger pipe. [ The front resonator acts as a y-pipe and is large enough to cause little if any meaningful restriction. ] I just might do it too!

[aspense]

Fluid - how about going with an R/T-issue rear-section exhaust for the ES? I was informed by another Moparchat member that his Dodge dealer told him it would cost $246. I'm assuming for the rear muffler and resonator.

[Marlin]

Don't know how relevant this is, maybe it is. I have tried the stock setup on my '95 ES, a free-flowing exhaust (aka straightpipe from the cat back) and now have a Thrush California Boss Turbo muffler and albeit I have no stats, the car has more low-end push and feels stronger overall than it did with just the cat and some straightpipe...it's quieter than the stock setup too, for only $17.

[Fluid]

aspense: I had thought about using the R/T rear section but forgot about it - maybe it will work! I don't know if the cat-back pipe diameter is larger on the R/T vs the ES, but the R/T rear section should at least give the car that great sound, and it should fit too. That's a great tip - I'll contact my dealer after the holiday...thanks!

Jay T

[Fluid]

Oops....checking the FSM indicates that the exhaust system on the LH cars comes in two pieces - the long front section with the dual-in resonator and muffler, and the rear section with the resonator. I suspect, but will have to confirm, that the $246 couldn't be for the entire system, so is probably just the rear resonator and shiny tip. I'd bet that this change would improve the exhaust note, but would it then be the same restriction and sound of the true R/T? Don't know.