Question about exhaust.

[04FX4]

I want to up grade my exhaust. I do not want to loose any hp or tq.I am leaning towards magniflow but what is better. SI/SO or SI/DO? I see bill always saying SI/DO so which one is best?

[Power Hungry]

From my experience, either single in type is fine. The exit is personal preference as to whether you want a single pipe out the passenger side or duals out the back/corners/sides.

Anyone else have any thoughts?

[Jackpine]

From my experience, either single in type is fine. The exit is personal preference as to whether you want a single pipe out the passenger side or duals out the back/corners/sides.

Anyone else have any thoughts?

Back in the bad old days, before most of you were born, :geezer: duals with straight pipes that were tuned properly (you didn't want interfering pressure pulses) were supposed to "scavenge" the cylinders better during the exhaust stroke so that they were "cleaner" for the next intake charge.

I imagine, with the introduction of catalytic converters, EGR valves and the like, that these ideas sort of went the way of the dodo.

You'd need a bigger capacity exhaust system if say, you put a blower on the engine (conservation of mass again), but I doubt there's too much reason for changing it otherwise (beyond looks or sound). Possibly you can get a slight power increase with a less restrictive exhaust system, but I doubt it is going to be a significant change on anything beyond your wallet. My :2cents:

[cleatus12r]

I changed the exhaust on my '73 2wd about a year ago. It's had a few different setups since I started modifying it about 14 years ago.

The one I have now is the one that's staying until it gets turbocharged.

I picked up so much more midrange and top end (as if 4000 RPM is high) that it was scary for the little bit I actually did to it. (dyno proven)

My recipe for success:

Single exhaust. Sure it sounds terrible but it works. The headers never changed....neither did the first 6 feet of 3" dual pipes or the dual dynomax welded mufflers. However, immediately after the mufflers, I joined the two pipes with a "y" (not a "Y") and ran a single 3" pipe out behind the left rear with very little arch over the rear axle.

Instead of losing torque at 3000 RPM, it held absolutely rock steady up until 4000 RPM. For reference, the dyno graph for torque hit 353 ft. lbs. at 1800 RPM and stayed perfectly flat until 3500 RPM. The old setup began dropping torque at about 2600 RPM....even though it SHOULD have had better breathing.

I'm a firm believer in smooth exhaust flow....I've seen it help so many vehicles. For example, a friend's 66 Chevelle with a worn out 327 (45% leakage past the rings on most cylinders) with long tube headers, dual 2.25" pipes and glasspacks dumping in front of the front axle was a complete turd at all RPMs...it was terribly doggy.

Then (against advice from EVERY exhaust shop) he installed 3" pipe from the collectors into *cough* Flowmasters *cough* and did side exits in front of the rear tires. Did he lose any power? No. From idle all the way to redline (nearly 6500 RPM most times) he gained. It sounded terrible due to the Flowmasters, but it ran like a mad chief after the exhaust job.

You DO NOT want backpressure at all. It's a myth. If backpressure was good, stuffing a potato in the tailpipe would make your front wheel drive car do wheelies. You don't want stagnant flow either. Once the flow slows down too much, the engine has to work to push the exhaust out of the pipe.

[kokopellimotorsports]

Cleatus, this is why I am upgrading my exhaust. I will be putting on high flow cats (magnaflow) to a si/do corner exit MBRP exhaust.

To the OP, when you are ready for exhaust let me know, I have access to many manufacturers.

Ty

[Jackpine]

Nice post, Cody! Everyone can ignore my final comment about exhaust mods only changing your wallet! :o

- Jack

[cleatus12r]

Oh, and I wanted to add that YOU DO NEED SOME SORT OF EXHAUST SYSTEM.

Some folks think that open headers are awesome (and sound good :throwup:) but they really hurt performance until the exhaust pulses are often enough (read: high RPM) that there is no atmospheric pressure reversion into the collector or primary tubes.

An exhaust system CAN be too short and it CAN be too free-flowing. Don't get my original post wrong....I re-read it and can see where it might sound like I condone huge pipe that's only six inches long.

Unfortunately, tuning the exhaust is very difficult to do. To do it right, both pipes on a "v" type engine would have to be the exact same length and that's tough when both pipes run down one side of the truck. They should have equal bends (both angle and length) and we know that is impossible. There's always a compromise.

Jack, you're right, most aftermarket exhaust systems or custom exhausts are only for asthetics and sound....let's face it, if it doesn't sound bad-***, it probably isn't. Besides, factory exhaust is not visually pleasing. No disrespect meant to your last comment. :howdy:

On edit:
The most disheartening thing I see when it comes to exhaust is the pipes people will have installed at an "exhaust shop". As a diagnostic rule, the new Chevy trucks are designed FROM THE FACTORY to have a backpressure to not exceed .5 PSI (one half of a PSI) of backpressure at full load redline. That is VERY LOW. It would be hard to beat that with ANY custom job. The factory pipes on the 2500/3500HD trucks with the 6.0L or 8.1L gassers are 3" and they go into a dual inlet/dual outlet muffler then "Y" into a 3.5" tailpipe that has nice, smooth bends over the rear axle. These people have the dual 3" Inlet/Outlet muffler removed and have two 2.5" pipes/mufflers welded in with tight non-mandrel bent pipe twisting all over the rear axle to avoid the spare tire. Under certain conditions, the backpressure in the pipes will actually cause a passive EGR effect (reversion back into the combustion chamber) and set misfire codes. UGH.

The exhaust from reputable companies (that our vendors sell) are good in the flow department and usually sound really good. Power wise.....maybe a little. But they do look nice with a polished stainless tip!

[Jackpine]

Cody, no offense taken at all! I was, as usual, being my normal opinionated self and making a broad, sweeping statement that could not possibly be right in all respects. You pointed out holes in it (in a very diplomatic way, I might add) while at the same time supporting other parts of what I said - you just said them better! :2thumbs:

Exhaust mods were really a big thing back when I was young. And, you had to be careful with them. You run into many of the same problems I was concerned about in intake mods. Airflow engineering, especially in ducts, is a VERY tricky, poorly understood, science!

- Jack

[88Racing]

Two questions you should ask yourself:

1) How much noise am I or everyone in the truck going/willing to put up with?

2) Are you going to pull any trailors?

Fords are supposed to have quiet steel? On a real long trip the sound may get to you. Especially if your married. "I told you it was going to be to loud"

The trailer question is that it depends what type.
Straight out the back are good with flat beds and most of the time with "V" and round noses.
I would not recomend them when pulling flat nose type trailers such as campers. The sound echos back at the cab.

I recomend some system with side discarge then you don't have to worry about the above.

Lars

[88Racing]

Forgot to add this in.

How long are you keeping the truck?

I only ask that because up here up where I live some of the galv steel kits rot out in 3 to 5 years due to road salt. So I went with with stainless did not want to spend the money again. But it is easily justified if the truck needs a new look again.

Lars

[04FX4]

I am married and dont want loud. I also pull a Travel trailer. I think I will get a magniflow SI/SO.

[88Racing]

I have partial hearing loss and even when I put my first Gibson on si/do under the bumper it got to me after 90 miles of travel of a 450 mile trip. I was pulling a uhaul tandom cargo. The good thing the drone put the kids to sleep the bad thing was the ringing in my ears. After that took it off sold it to a buddy. Replaced it with si/do same side 2 outlets in stock location. Was alot better after that, wife was happier too! Noticed after I got married their opinion counts for a whole lot more.

Lars

[Dixie Design]

Before I went true duals I did a swap out for a 14" oval Magnaflow SI/SO. Sounded great, MUCH better than stock. My wife didn't mind it at all. Soon as I cut that Y-pipe out and added another muffler, high-flow cats (now pre-cats only), she doesn't get too excited about riding in my truck.

I think you'd really like a 14" Maggie, don't get discouraged right off if it's not quite loud enough, it'll get louder for 3-6,000 miles.

[coolio4433]

lol, my fiance wanted me to get a louder exhaust.

Her brother has ridiculously loud straight pipes on his truck and she likes that.

I however do not want to announce my presence from 1/2 mile away so I opted for something that included a muffler.

[Sburn]

My smart-azz, redhead wife: "Louder exhaust? Is that so my boyfriend has time to get dressed and out the back door before you pull up?"

Me: "No, that's so you have chance to get my icy-cold beverage poured and into my hand as I walk in the front door."

:hehe:

[88Racing]

My smart-azz, redhead wife: "Louder exhaust? Is that so my boyfriend has time to get dressed and out the back door before you pull up?"

Me: "No, that's so you have chance to get my icy-cold beverage poured and into my hand as I walk in the front door."

:hehe:

Wish I could post a smilie right now!
Lol's

Lars

[Power Hungry]

My smart-azz, redhead wife: "Louder exhaust? Is that so my boyfriend has time to get dressed and out the back door before you pull up?"

Me: "No, that's so you have chance to get my icy-cold beverage poured and into my hand as I walk in the front door."

:hehe:

That $hit is FUNNY, right there. I don't care who you are! :giggle: :smiley_roll1:

[BlackSTX]

I installed the Maggie SI/DO the rear, and I'm quite happy with the noise; wife can tolerate it too, but she is also deaf in one ear and hard of hearing in the other. I guess that doesn't make for a glowing endorsement though....
However, light throttle, it's not bad at all; under full throttle, you know it's there!
I agree you probably do not want rear exit if you pull a trailer. However, a nice thing is that you can go to manufacturers web sites and hear audio clips of their systems. While it's not the best representation of how it will sound on your truck, it will give you an idea. You Tube may also be of some help too.

[88Racing]

I installed the Maggie SI/DO the rear, and I'm quite happy with the noise; wife can tolerate it too, but she is also deaf in one ear and hard of hearing in the other. I guess that doesn't make for a glowing endorsement though....
However, light throttle, it's not bad at all; under full throttle, you know it's there!
I agree you probably do not want rear exit if you pull a trailer. However, a nice thing is that you can go to manufacturers web sites and hear audio clips of their systems. While it's not the best representation of how it will sound on your truck, it will give you an idea. You Tube may also be of some help too.

You tube is a great resource to hear any and all exhaust systems, aftermarket or custom.

Lars:2thumbs:

[99350]

Sorry to chime in late here but I have a couple of tidbits you might want to take into account for your exhaust purchase.

1) the scavaging of the exhaust happens in the manifolds/headers and then the rest of the exhaust helps keep that flow going.

2) if you go with true duals an H-pipe or X-pipe in the middle will help equalize the pressures b/t the 2 sides and help with the scavaging effect (due to the firing order)

3) Your pipe diameter is also important if it is too big then there is not enough backpressure and you will actually loose power and for single exhaust you want the pipe diameter about 1.5-1.75X the size of duals (most aftermarket exhaust companies already done the calculations to find the right diameter for you application)

I would look for a quieter system by law they are required to meet a maximum 95db level to be street legal otherwise it will be for offroad use only. I like the sound of flowmasters quite series mufflers when at WOT or part throttle you can hear it pretty good outside the truck it sounds good plus at cruise speeds it sounds almost stock no annoying drone or excess noise.

My $.02

[88Racing]

Sorry to chime in late here but I have a couple of tidbits you might want to take into account for your exhaust purchase.

1) the scavaging of the exhaust happens in the manifolds/headers and then the rest of the exhaust helps keep that flow going.

2) if you go with true duals an H-pipe or X-pipe in the middle will help equalize the pressures b/t the 2 sides and help with the scavaging effect (due to the firing order)

3) Your pipe diameter is also important if it is too big then there is not enough backpressure and you will actually loose power and for single exhaust you want the pipe diameter about 1.5-1.75X the size of duals (most aftermarket exhaust companies already done the calculations to find the right diameter for you application)

I would look for a quieter system by law they are required to meet a maximum 95db level to be street legal otherwise it will be for offroad use only. I like the sound of flowmasters quite series mufflers when at WOT or part throttle you can hear it pretty good outside the truck it sounds good plus at cruise speeds it sounds almost stock no annoying drone or excess noise.

My $.02
Some very good points.
The other thing I like to add is the flowmaster is not a straight through design which can change things also.
Also a straight through cat back 3" si/so muffler is the max best you can do to the vehicle before changing cats headers and the "y". All those need custom tune support.

Lars

[99350]

Yes and no to the needing custom tunes for the extra exhaust you do not have to have it but you will be able to take full advantage with a tune.

All newer and older carbed vehicles are like this some manufacturers will see the extra power and detune to make the factory power after adding bolt-ons (Subaru is the worse)

Oh some food for thought if anyone is looking at making some big power #'s later on testing different collector lengths primary lengths etc can help get the last little bit f power out of the motor. (NASCAR guys are playing with them)

[88Racing]

Yes and no to the needing custom tunes for the extra exhaust you do not have to have it but you will be able to take full advantage with a tune.

All newer and older carbed vehicles are like this some manufacturers will see the extra power and detune to make the factory power after adding bolt-ons (Subaru is the worse)

Oh some food for thought if anyone is looking at making some big power #'s later on testing different collector lengths primary lengths etc can help get the last little bit f power out of the motor. (NASCAR guys are playing with them)

That's probably why the easily exchanged shorty header, a simple exchange for the stock header, doesn't see any gains.
But the long tube header that needs some cutting and fabbing to get in requires the additional need for a custom tune. This is probably due to the increased collector length. Like you posted.
Then you throw in some high flow cats and your motor is really pushing the air out.

Lars:2thumbs:

[99350]

That's probably why the easily exchanged shorty header, a simple exchange for the stock header, doesn't see any gains.
But the long tube header that needs some cutting and fabbing to get in requires the additional need for a custom tune. This is probably due to the increased collector length. Like you posted.
Then you throw in some high flow cats and your motor is really pushing the air out.

Lars:2thumbs:


Shorty's will give you some gains just not the best.

There is a lot more to getting air out than the exhaust but that is good for another thread.

[88Racing]

Probably the best setup on the marker right now for the longtube headers.
Dynatech Header System for 2004 & up F-150 with 5.4 3V
122-622100s
Dynatech Longtube Header System including complete High-Flow Catalytic Converters & Y-pipe Assembly.

These beautiful Longtube headers are the only TRUE BOLT-ON setup available for your 2004 & up F-150 5.4 3V!!

This is a true bolt-on setup that will mate right up to any existing cat-back exhaust system, from the stock factory setup to Magnaflow, etc., cat-back exhaust systems.

Power gains will vary based upon boost level, but typically run in the area of 30 RWHP in supercharged applications running lower boost levels, a bit less in normally aspirated applications.

Far more important is what happens to the torque curve - it is extended everywhere, instead of hitting it's peak and falling off quickly, it is extended out significantly, and this aids mid-range power for anything from towing to performance applications, or even normal everyday driving situations.

No "shorty" type of header system can begin to compare to the results, effects and sound of this system, yet there is no "droning" inside the cabin. This extension of the torque curve is critically important in aiding torque & acceleration when driving hard, but also even fuel economy during normal cruising. For example, on our own 2004 5.4 3V F-150, we have averaged a gain in MPG of right at 1.0 MPG overall with or driving conditions, a result we were amazed at in our 6000 lb supercharged 5.4 3V truck!

These headers feature laser-cut flanges & mandrel bends, and are made of T304 Stainless Steel (including hardware!), use 1 5/8" tubes, Magnaflow high-flow cats, and already have both the upstream AND downstream O2 sensor bungs welded in! So all you need to do is to simply screw in all of your factory O2 sensors once you install this system, and it is very easy to install. Your OBD-II system will work as designed from the factory, no more having to run illegally by having your tuner turn off the rear O2 sensors, etc.

No ceramic coating is required due to the heat-retention characteristics of these stainless steel headers and everything fitting to the factory heat shields, etc.



No tuning changes are required from using these longtube headers in 99% of the trucks we have installed them on, unlike some other longtubes.

There is no better quality header than Dynatech - forget trying to go the cheap route with Pacesetter, etc., it's just not worth it when you can get aircraft-grade T304 S/S quality like this that will last a lifetime without cracking, etc. It's just not worth saving a few dollars at time of purchase - if you are going to install headers, do it right - do it ONCE - with Dynatech, just like we do in our own vehicles here at Troyer Performance.

Installation time generally runs about 6 hours, and some of our customers have reported getting them done in as little as 4 hours - no more 8-12 hour jobs fighting the engine height, etc., as with so many other headers for these trucks!

These Dynatech Longtube headers come with ALL hardware needed and it's of the best quality, too. You will also receive the finest quality multi-layer exhaust gaskets money can buy, the highest quality O2 sensor harness extensions and excellent step-by step instructions with plenty of photographs. You will never find an easier to install set of headers!

Dynatech - the best true longtube header system money can buy, in an easy to install bolt-on design - get yours today!

Price:* $1395.00

From Troyer Performance.
Lars:2thumbs: