I recently removed my stock muffler on my 2002 Excursion PSD.
I love how the turbo makes tons of noice now-and can be heard for blocks.What i dont like is how the exhaust seems to "flutter" as i drive.It is only magnified when another car is next to me.My question is why this is happening? Another question is how a straightpipe affects the performance of the truck ? I feel as if i lost some low-end toqure but gained some high end HP but i would like to hear what other people who have done this to their trucks have to say.

:-X23

 

I am also in search of the biggest-loudest exhaust for my PSD Excursion - Any info would be a great help !!

 

>I love how the turbo makes tons of noice now-and can be
>heard for blocks.What i dont like is how the exhaust seems
>to "flutter" as i drive.It is only magnified when another
>car is next to me.My question is why this is happening?

My guess is that you are now hearing each powerstroke, or exhaust stroke, from the cylinders more pronounced than before because the "noise" doesn't have anything to reverberate in anymore.

>Another question is how a straightpipe affects the
>performance of the truck ? I feel as if i lost some low-end toqure but gained some high end HP but i would like to hear what other people who have done this to their trucks have to say.

You don't really need the advice of a truck owner. This is
common hot-rodding. I've been doing this to my motorcycles for years. Letting as much air in and out is important for HIGH rpm power but sucks for low-end. You see everybody wants a straight through exhaust for sound or cause they think it'll give a lot more power but don't realize that to produce good low-end / mid-range torque you NEED some back-pressure. So of course you lost low-end power and gained it up high. The engine can breath a bit easier up high. But is that where you really need it? Too many folks make modifications in the sarch for more power but don't realize that they are not manking any more they just moved it around within the operating RPM range.

I found that this is more pronounced in intake and exhaust modification in diesels than in gassers for some reason. There are some good (cheap) mufflers that will not reduce low-end so bad but will amplify your truck!! Ask around and listen to other trucks to see what you like. Good luck on your quest for Loudness and Pronounced Turbo Whine!!

 

MONSTA hit the nail on the head. I have read reports on another web site of a muffler called the "Walker Big Truck Muffler" that is very efficient.
I have a Magnaflow turbo back exhaust system (3.5" DP and 4" Tail pipe)that includes a straight thru muffler. Very little more noise as opposed to stock. The flutter you hear is the turbocharger not the exhaust. Retrictive exhaust systems (such as the factory one) lessens this by way of greater backpressure. The use of a muffler such as the two I have mentioned can help reduce this flutter and reduce EGT's.





01 F350 4x2 DRW CC Lariat PSD AUTO, 11,500# GVWR, 3.73, Tranny cooler w/remote fan, magnaflow turbo back exhaust,EGT & Tranny pillar gauges,
RS9000's,K&N air filter, Fleetguard Stratapore oil filter. Pulling 37'
10,500# 5er.
NRA endowment member, NRA-ILA

 

A week after I got my 99 I put a 4" straight on it. A week later I put a 4" straight muffler on it. You will loose a little bit of bark but the flutter is a lot better. I notist a little bit of low end power but not a nuff to bother me. I pull a 20' gooseneck stock trailer that quite easily brings the gross to 20 grand and it pulls it a hell of a lot better than anything else I have drove.

Ben

 

My plan at the momment is i am going to put a 4''Flowmaster
muffler on my truck that i have lyin around from my 1972 Nova.
That should take some of the flutter away untill i get my
huge exhaust which i am still looking for.
I heard Banks sells a 5'' exhaust for the Excursion , but is it loud ???

 

Folks-

A few misconceptions I'll point out, and trust me that I am not trying to start an arguement. I love this board and its members.


1. Back pressure is NOT a good thing. You don't really NEED backpressure. The reason some engines run poorly, or not as well as expected is because the backpressure was removed, but the fuel, timing, valve overlap, and the rest of the engine has not been modified to take advantage of the flow gains. A very carefully designed exhaust system may take advantage of the exhaust pulses and timing to create a situation of entrainment that helps scavange or pull exhaust from the cylinders at certain engine speeds. This is done with specially selected pipe diameters, which join at the collector to create the pulse train. Unfortunately this isn't effective at all engine operating speeds. The idea is to create no restriction downstream, so that the pipe diameters always increase as you move away from the exhaust ports. However, just adding the hugest pipe is not the solution, because as gas expands it cools, and moves slower.

So the best bet is to keep the heat in, the gas velocity high, the length of travel short, and make bends and kinks as smooth as possible. Open headers are the ultimate, as long as the rest of the engine is set up for it and you don't live where there are police.


2. None of that really matters when the engine is turbocharged. The turbocharger itself is the largest restriction and source of backpressure. The best exhaust on a turbocharged engine, after the turbo, is nothing at all. Some sort of pipe(s) may be necessary to pull heat away from the turbo housing, but this is a comprimise to save the turbo, not to increase power or exhaust removal.

I certainly believe that the stock Ford system was an effort to reduce noise, and that aftermarket free-flow systems or straight pipes will have great effects on power and torque. But no matter how carefully designed or expensive, ANY exhaust after the turbo is a comprismise in noise abatement and neighbor control, and NEVER better than an open turbo exhaust scroll.

What we really all need is an open 6" diameter 321 stainless J pipe poking up through the cowl on our PSDs. And maybe some foam earplugs.

-steve

 

[updated:LAST EDITED ON 01-Feb-02 AT 12:22 PM (EST)] As I kick myself for such a such a simplistic answer, I also realize that my statements were true BUT for a NON-TURBO engine. You see, I regretfully omitted, while drafting my response, the taking into consideration that the PSD is turbo-charged. Duh, on me.

Whilst naturally aspirated engines can indeed benefit from a bit of back-pressure in the lower RPMs to help scavenging and keeping the exhaust velocities high, the exact opposite is true for turbo charged engines as you so eloquently stated. My hats off to you. EXCELLENT reply!!

 

Thanks guys for all the input.

 

Im on my 6th exhaust in 1 year
first was the stock muffler
2nd was the stock pipes with no muffler , too much fluttetr and noise'
3rd was a dmax race muffler in the stock pipe
4th was a 3.5 striaght out in front of the tire , too loud and lost bottom end But the egts were low then when I added the chip I got the power back
5th was back to the 3.5 with a muffler
6th is 4" from down pipe to the end without a muffler using a walker over the axle pipe.
sounds good and the egts are good
this one will stay for a while

y2k PSD just a little more than stock 300rwhp +

 

Damm here I am allways trying to make my trucks and equipment quieter,,,,I guess it's time to go resurect that old Autocar with the 318 Detroit I have laying out back