exhaust questions

dodgedifferent2

dodgedifferent2

hung like a stud field mouse and
My brain is in overdrive the last few days since i have not been able to wrench on the dart in a month. So i am doing research digging.

So with the 340 i have headers installed and with the .484 purple cam and the six pack intake.

Now should i run 2.5" exhaust pipe or would i gain/lose with a 3" pipe?

Also looking at X pipe style

Thinking i like the Dynomax Ultra flo welded mufflers

Trying to decide between a full stainless pypes http://www.summitracing.com/parts/pye-sma10

or pay the price at TTI exhaust?

What are the nut thoughts on this?
 
You will lose considerable lower-end torque with 3" pipes on such a mild engine, something 340s never had much of in the first place and even less of with the .484" cam. You'll be much happier with 2.5" or even 2.25" pipes. A lot of people simply put way too much pipe diameter on an engine that doesn't need it. A stock 340 Six Pack only had 2" pipes and ran just fine, Hemis were only 2.25" pipes into the muffler. Hell, a factory 340 A-body bright exhaust tip measures a whopping 1.5" inlet diameter (I just measured an original pair).

The Ultra-Flo mufflers are well-built units, but be warned: they drone like crazy on the highway. They make your eardrums resonate and it's extremely unpleasant. They have that blatty, farty sound outside the car like a glasspack, which some people like, but when the RPM levels out the droning is mind-numbing. Much is made about exhaust technology and flow, but in most cases the muffler will outflow the engine anyhow. I like the sound of a chambered muffler (Flowmaster, Hooker Aero Chamber, Thrush Welded) but again, they drone like crazy. I prefer a reverse-flow muffler such as a Walker DynoMax Super Turbo or even factory-replacement Hemi mufflers. Plenty of flow and nothing obnoxious about them at any RPM while delivering a deep, throaty sound rather than sounding like a kazoo.

If you want the Ultra-Flo, look into AP/Goerlich/whatever they're called this week's X-Celerator line (AP, last I knew). They're essentially the same exact muffler for quite a bit less money. A lot of chains carry the brand for replacement pipes and mufflers, so they should be able to get them. A lot of exhaust shops carry the brand as well. It might save you a considerable amount of money.

For you truck lovers, AP also makes very nice mandrel-bent dual tailpipes to work as a cat-back system with their 1-into-2 X-Celerator muffler. That setup doesn't drone as badly as the flow splits and the muffler is behind the cab. The pipes are a lot less expensive than "name brand" systems with the same quality. I used to sell the heck out of them, considering the aluminized ones were around $80-$100 per pair with stainless not much more.
 
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I had flowmaster 40s on my dakota for awhile and the drone started to annoy me. Now i have the gibson chambered and they are worse then the Flowmaster. I cant hear my daughter in the back seat.

I am trying to avoid the highway drone, but also want to know that something is there.

I did look at the Hooker Aero Chamber but i heard drone was horrible at highway speeds.

The glasspacks that everyone seems to run around here sounds horrible.

I do like the chambered mufflers, but the drone is rough ...
 
I will recommend the Dynomax super turbos. I have 2.5" duals with those mufflers on the wagon. We have vacationed many times...wife and two daughters...and never had any complaints about drone....and we have put several thousand miles on doing so. I have even specifically asked and they say it doesn't bother them. The 440 has a nice deep rumble at idle, and a nice hum while cruising...but they do make some racket when you stand on it...as they should. ;)

My neighbour with his 63 Impala got the same set-up on his SBC/4spd combo because he liked the sound of my wagon so much.
 
That's why I like the DynoMax Super Turbos. Turbo mufflers don't drone, but just about every other design does. As turbos go, the DynoMax are the highest-flowing. They're deep and mellow at idle, with plenty of bellow when you stand on it. Don't forget, headers alone make a vehicle considerably louder at the tailpipes without changing anything else in the system. Stretch's car sounds great with headers and repro Hemi mufflers, but has no drone whatsoever... and you "know something's there" whether at idle or cruising comfortably down the highway. The DynoMax units are a little louder without being obnoxious.
 
I had 3" flowmaster 40's on my last Dart... Loud as hell and not enough back pressure
Now I'm using 2.5" flowmaster 40's on this Dart and the sound is perfect. Nice rumble but not overly loud, til you open it up then its extremely loud
If you don't want to hear drone then put down some sound barrier under the carpet, no more drone
 
Not enough back pressure? What purpose does back pressure serve other than to spool a turbo?
 
Ok, and what does that have to do with back pressure? I agree, running an engine with open exhaust ports might cause problems with the valves, since cool ambient air would have access to them. But, what possible damage could running an efficient exhaust system that just happens to produce practically no back pressure do?
 
My brother and I ran an old ford pick up truck with just the exhaust manifolds. It was an old 352...you could see the back exhaust valves moving. Drove it on the street that way for several weeks....firewall got a little cooked though...but never seemed to have any valve issues. We had heard that you could warp/bend a valve by doing this, so we wanted to try. :)

I think with a full exhaust..regardless of diameter..you won't get cool ambient air moving up the system to effect the valves.
 
Running without even manifolds supposedly will cause trouble. I've never tried it, but I can see how it might.
 
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