What if you put a freer flowing muffler, like a full bore or flowmaster or magnaflow/xlenator and put a single SMALLER diameter pipe (2.25 or 2.) from the cat. to the muffler to the exit? Would this increase low end torque?

I was already to get an aftermarket catback system with a single 3 inch pipe. After too much research, I left the stock pipe and added a fullboar muffler (not much louder than stock). It "feels" like I have a slight increase in low end torque. Now, I am thinking of actually REDUCING the stock single 2.5 pipe to a smaller size to see if that increases torque more.

 

Well, in my case the whole reason for an exhaust is that of course my 97 dumped in front of the wheel whic hcaused some tarnish on my AR Baja's. So mine dumps before the axle, sounds crappy, and can sometimes smell the fumes.
I have found I can get a Flowmaster setup for around 150 (friend) or I can buy some Dynomax mufflers at 20% off at work. I haven;t made my mind up yet on what type or brands I will use but I do want to keep or gain low end, I want duals, I want a good deep, sort of loud system and I know to use 2.50 pipe or smaller.

A vacuum or even better P-ferlows RPM activated setup would be really nice. I might go dual setup and have restictor plates made like Flatsman has.

 

Sounds good KYFordFreak.

Ironhorse: I don't think I'd go smaller than 2.5 on the intermediate pipe or tailpipe though. The Ford engineers were probably looking to maximize torque with the OE setup while keeping the horsepower. I'm just guessing though. And if you ever slap a Magnacharger on there you'll have to ditch the 2.5 inch for a 3inch or the top end will suffer.

...not that I could ever afford a Magnacharger but one can always hope.

I'm going to finish mine before my b.day end of June and I'm pretty much set on the flowmaster y-pipe going into a 3inch, into the 3" SI/SO Ultraflo muffler (I bought used) and out the 2.5 OE tailpipe. See how it goes.

 

The Magnaflow muffler is now in. I had the outlets further reduced to 2". I disconnected the battery, so this won't take long. It seems like there is more low-end torque and it is MUCH quieter. Time will tell.

 

1 week later, jury still out. Seems like more low-end torque. Pereformance still not up to snuff. Gonna put new plugs in & gap em at .065 & de-carb the engine. Stay tuned.

 

Thanks for the update!

 

Earlier I posted a link to a cable operated butterfly valve that dumps the exhaust and might be used in an attempt to regulate backpresure throughout the RPM range.

I found something else that's pretty interesting. Seems like a good idea but I'm wondering if the best location for it is at the tailpipe. Would it be better to have a device like that closer to the cats?

The following comes from the Dynomax tech page:

Balance Tubes

Balance Tubes (or ‘H’ pipes) help to even out the pulses in the exhaust gases and balance the backpressure between both banks of your engine. They not only help improve horsepower, but sound as well.

To find the right location to install your balance tube, apply a strip of paint down the front portion of the exhaust pipes. The balance tube should be placed where the paint burns off (bubbles) on the exhaust pipes. Generally, put the balance tubes as close to the headers as possible. The balance tube diameter should be at least 75% of the diameter of the pipes with which it connects.

Should this apply to devices that modify packpressure as well??
Wonder how it would sound ??

I'm looking forward to all your responses, Thanx.

 

Now that's pretty neat. I wonder how much something like that costs. If it's made of stainless steel like it says it is I would say it's not cheap. Also, that website is just talking about selling to reseller's ( ie: garages, shops).
Also, I noticed that they sell a inline bullet in almost any size you would want.

On another note I saw in Jegs last night that Hooker Header's offer a "adjustable flow" tip (actually they call it a muffler). Says sound and flow can be adjusted up to 40% without disassembly. Features a rotating stainless steel barrel with polished billet retainer and crome plated housing. 2.5 ID inlet. 15x4 straight cut or 15.5x4 slash cut either one 115.99.

For me that would mean around $150 for pipes, muffler (cheap one), and labor. Then if I used these tips another $232, so now I'm at 382, then I noticed my cats seem to smell just a little so add another for twin high flow cats. So then I would have a $600 exhaust that is not even stainless in parts. This is getting to be way too much. My wants and dreams always seem to exceed my pocketbook.

 

That adjustable tailpipe piece sounds like a rip-off on the supertrapp system which can be adjusted by adding or subracting discs on the end.

H-pipes aren't really useful on our trucks because they don't have dual exhaust systems that run down the centerline of the vehicle like the Mustang V-8's.

Something that would make more sense would be an exhaust pipe setup that hooks in between the cats and the muffler inlet and has pipes that are equal length from the cats and merge into one, then pipe over to the muffler inlet. This gives you equal distance to the merge from either exhaust bank and will aid in exhaust gas scavenging.

Have you seen Ford is giving the SVT Mustang 390hp for 2003? Start saving.

Next week I'm picking up the flowmaster 2.5 dual in 3 inch out y-pipe. That's the last piece I need before I start welding. Going to leave the stock tailpipe for torque.

 

I really like the idea of these and hope they work good. Flatsman did his x-pipe system and lsot 17RWHP but when he added restrictor plates to his tips he gained it back. I agree inline might help more but help any where is a good thing. I agree with the fact that a h-pipe needs to be in an equal length system but I would not think it to be totally useless in a unequal length system also. It all comes down to opinion and the individual truck and what the owner wants it to do and sound like.
I have emailed them requesting tech info, distribitors and prices. Let you know if I hear anything.

 

KYFordFreak:
The way our truck OE systems are designed where would one mount an h-pipe? Possibly between upper and lower cats? Otherwise there's really no other place to mount it because the exhaust crosses over and goes into the OE T-fitting after the cats.

I was measuring under my truck last night. I had previously bought a 90deg 2.5inch mandrel bend pipe and a 45deg 2.5inch mandrel bend pipe. From the crossover pipe where the exhaust comes from the driver's side on my 98 S/C 4x4 it needs about 6inches lift vertical and 19 inches or more horizontal length. Then both pipes will be beside each other with the new driver's side pipe on the inside. I'm going to have to cut the 45 & the 90 to achieve this but it's possible. Then merge into the flowmaster y-pipe. I'm going to rent a welder and have my buddy do it for me.

You have to fit the pipe above the frame support where the torsion bars mount.

 

Sounds like you've planned out what you want to do pretty good. I really need to get the ball rolling on what I want. I noticed the other day when accelerating on to the interstate with the slider open I could smell exhaust pretty bad. At first I thought it was from a car ahead of me but the closet car was a good 250 feet away. It had a touch of a foul smell like a clogged cat but overall just smelled of exhaust fumes. My truck has the stock exhaust that use to exit in front of the tire. Due to it discoloring my wheels I cut off the bend to have it dump in front of the axle. So now I'm left wondering if I'm just smelling exhaust where it's cutoff or if my cats are starting to get plugged up. If they get bad I should notcie more smell, gas mileage drop, and finally a check engine light when NOX levels drop below O2 sensor thresholds. I guess I could go ahed with a exhaust sytem then if still noticed or if it does get worse replace the cats with 2 hi-flow units and new O2's. I almost have it in my mind to go ahead and rip it all out and spend the 600-800 and replace it all but, then the other side of me thinks theres no need to replace what isn't broken.
I have a friend that works at a dealership that does custom exhaust work that might help me out. I would still pay regular shop fees but I know he would try to do quality work, take me serious, and I could probably even help so the finished product would suit my needs. The other option is to try a cheaper shop I know to save money. The guy there has a lot of exhaust experiance but professionalism is down and quality is unknown.
Good luck with your exhuast.

 

Ahhh... I'd do what I'm doing. Replace the y-pipe with a good one. Chances are your cat's are ok. Exhaust dumping under your truck is bad. If cat's were plugged I don't think there would be an exhaust leak from them, just a serious loss of power.

Get your exhaust dumping on the side behind the rear tire like 98' and up. I've never smelled exhaust while driving my 98'.

Someone here mentioned that exhaust gas is corrosive and will REALLY help rust the underside of your car/truck with a typical turn-down tip halfway under. If you won't be fixing it soon I'd tack weld a turn down on it to at least push it more towards the ground than right onto your rear axle.

I haven't quite decided about keeping the oe tailpipe. We'll see.

If I were in your shoes I definitely wouldn't blow money on new cats. I don't think the OE cats are that restrictive. If they were we wouldn't lose low rpm torque with a large diameter cat-back system.

I always think "KISS"....keep-it-simple-stupid (as a figure of speech - not directed at you of course). Use what you need to get the job done with relatively low-cost and light weight. True duals are heavy. I always LOL when I see those Acura's with the V-6 and dual mufflers when you can see the bad y-pipe by the rear axle coming from the single front pipe. What a waste of a second perfectly good muffler. Plus the weight savings and the lower flow velocity at the Y.

I'm going to pickup that y-pipe this week.

When I finish it I'll post audio and/or video with audio to my personal website with OE "before", aftermarket "after" so people can listen and compare.

 

I have already received an email lfrom Ultralfit Exhaust systems ( the something intersting in Le Pew's post). I emailed at 1am on Sunday and got an email today the 7th from the VP of sales and marketing. He did day it would help with low end torque and he fowarded (is that a word) the rest of my questions to a tech. I have contact info if anyone needs it.

p_ferlow
You never cease to bing up points that I haven't thought about and I always think I have thought of everything. I learned to "KISS" along time ago but I always have this problem with trying to overdue things and make them perfect.
You did bring up some good points about the OE converotrs. The OE convertors may not be as restrictive as most but two high flow's have to flow better than 4 OE types. You might be right (and I hope you are) about the exhaust dumping so soon and me smelling just fumes. Trouble is that it has that slight foul smell to it that you get when they do clog. Right now I do not notice a huge power loss but it's not the power it used to have (with 137K how could it?). To give you all the details I only smell it when I am on the gas hard at about 3000 RPM. It has been warmer around here lately so I have been opening my windows and rear slider and that is when I noticed this problem. I hope it's just that the warmer air allowing me to open my windows combined with the short exhaust that is the problem. I will be keeping my eyes out on how much convertors would cost me. If I do have to purchase it will be aftermarket OE reproductions or aftermarket hi-po just for price reasons. I suspect I would be looking at around 100 per convertor.

 

Just to add my thoughts on why you are smelling exhaust. I'm sure you already know it's because it's dumping under the bed before the axle.

There really is not too much air flow under the truck. Since you are moving thru the air, the cab is creating a sort of vaccum directly behind the rear window as the air flows over and into the bed. I don't recall if you have a tonneau or not, but you'd still get some vaccum at any rate, right behind the window. So you're just sucking the fumes from under the truck between the cab and the bed and into the interior.

I'd say you are correct in the fact that you maybe losing a cat or two or four....... Especially, if you are smelling something besides exhaust.

Get that pipe going out the side (behind the tire) or out the back. You can always deal with the cats later on. I'd think you'll get a CEL at some point if they are going out.