i dont know about the rest of ya guys but...
he sais he has a 4" duell silverline exhaust...
I may be wrong but thats for a diesel and i know that that exhaust for the diesel isnt good on the botton end/low end of the power band.
so a 4" inlet.duell4" outlet exhaust system on a 5.4L is going to be probely worse than the stock sized exhaust...
the chip, right sized exhaust(3"inlet/duell 2.5sor 3"singal outlet)maybee headers and cold air intake will do the best..but remember its a truck not a race car..then buy a blower/suppercharger if you want it to be a racer

 

No offense but you have some spelling errors in that post. I have a CAT-BACK Silverline exhaust with 4" dual pipes. It sounds great. I bought the truck last year and it was already on the truck. It's all welded so I'm not about to replace it but I'm planning on getting a set of headers also. It's illeagal to change the CAT if it's still functioning but who will know.

 

Low end torque is based on flow velocity, not the volume. I'll qualify that by saying you still need to get rid of the exhaust gases, but you want a system that assists in scavenging. By keeping at least one large component in the system near the head, you should keep roughly the same flow velocity, based on that component's set restriction.

What are the components most likely to be kept? In the 4.6/5.4 case, the intake manifold is a given... not too many aftermarket intake manifolds that don't involve either a blower or custom fab. On the exhaust side the cats and their related pipes due to the Feds. I can see that adding shorty headers may improve the velocity... especially those that are either tuned or nearly so.

The larger exhaust diameter allows for more volume which, in theory, detracts from the power gains we look for. It essentially moves the power bands to higher RPMs. If you keep the components I've listed, the shift to these higher bands won't be so dramatic. Many of the aftermarket exhaust systems are designed to work with this set up... that's where gains in power come from, by getting those numbers higher in the bands.

When you reach a certain size exhaust outlet after the cats it doesn't do any more good than lopping the pipes off at the 'y' unless you have plans to shortly install a unit to use that large exhaust.

My purpose of going with a true dual exit is to make the truck ready for the next phase in my build up... the supercharger.

Keep your ultimate goal in mind or be able to justify your reasons for modifying... outside of the simple " 'cause it's cool." You won't seem like such a goon to those that know.

-Kerry

 

Very well said, Kerry

 

I'm having the same trouble, my f250 is rather sluggish with my 315's and 3.73 gears. My mod list so far is gibson single out, KN Gen2, Gibson shorties, and an ever evolving custom tune. The cold air made the biggest difference, next would be my program. I am running a lot of advance on the low rpms. Currently, if I can get a jump off the line, I can keep up with the Diesels. Next mods will be a full shift kit, stallion torque converter,and 4.10 gears.

If you find a magik pill, please inform me.

 

4:10 gears are lower. takes more rpm to turn the drive wheels.

 

The 4.10s are lower, the point of using them is they make getting to the power band of the truck, quicker... the truck seems to have more power. In reality, the useful torque is seen sooner. Drawback is the top end, passing power (w/out downshifting), and highway mileage start heading down hill.

ReAx - If your drag racing diesels as a daily hobby, part of your issue is the tires. Your larger tires' rolling weight and added resistance detract from your power gains. Keeping an extra 50-100 pounds takes torque and power away that could give you a tenth. The 4.10s will help your launch, but they'll kill your top end.

-Kerry

 

Exhaust, Cold Air Intake, Chip, Tuner and E-Fans all combined should show some good power increase. Of course high flow cats and headers never hurt either.

 

It's not a hobby, but nice to know I can do it if I feel like it. The 4.10 should bring my final drive ratio back up close to stock with my tire changes. I know I am our of the power band with what I have, under 3000 rpm, the truck is lazy. I also think it will improve my milage a bit, by reducing the load on the engine at cruising speeds caused by my tires.

I will agree with everything but the Cats. I did electric fans on my 89, and it made a seat of the pants difference. Catalytic Converters have been around for 30+ years, After about 1999, Factories used decent cats. Myself, I would not bother with them until I supercharged the motor, then I would delete them.