Then he wakes up.

 

What? About a$$? Figures, rainbow boy.

 

On the 5.4, according to Mag, it's only good for 9hp and 11fp over STOCK (they have dyno sheets on their site)! The Flow is worth _at least_ that. And that's not anywhere near enough of a performance increase to feel under your foot. I once read a testimonial from a Mag customer who said he couldn't even chirp his tires, but after the mag cat-back, he could lay down 30-40 feet of burnt rubber. That's utter horse s^^t. It's a f^^king muffler for crying out loud! It's not a damn blower or something!

I would be talking out of my a$$ if I told you that Flow was better. Equally so are those who would beat you to death for buying a Flow instead of a Mag. Truth be told, neither of them flow worth a ****. If you were buying a muffler just on its shear performance alone, you wouldn't buy either, you would go with a DynoMax Ultra Flow which flows better than 4 Mags or Flows put together. DynoMax doesn't sound worth a crap, but they are far better performers.

99% of the time, with aftermarket mufflers, people who go to any muffler after a Flowmaster will say their new muffler performs better. It's not that they are full of it, or their trying to fill you full of it, it really boils down to the Flowmaster itself. See, Flows have a much sharper, tinny, and higher pitched exhaust note. Because of that higher note, the engine sounds like it's working a lot harder than it really is. If you heard two engines running side by side, at the exact same RPM, one running a Flow, and the other a Mag, the Flow would sound like it's turning a lot more RPM, even though it's the exact same. Where that misleads people is when they go with a lower toned muffler like a Mag or Borla after they part with their Flow. They feel like their vehicle is faster, or has more power. In truth, it doesn't. If you put them both on a dyno, or timed them on a track, they would run pretty much the same. See, the Flow makes the engine sound like it's working harder, and spinning faster, to accelerate the same, or pull just as hard. The lower tone muffler makes it sound like the engine isn't spinning nearly as fast or working as hard, even though it's the exact same! In truth, it's all in your head. You probably noticed this BIG TIME when you went from stock to Flow. With your stock muffler, 3,000RPM didn't sound like the motor was working hard at all! But with the Flow, at 3,000, it sounds like it's REALLY starting to wind up! That's about the time you start looking around for cops because you are afraid they might think you're racing. But with your stock muffler, at 3,000 you wouldn't have given it a second thought. This is also THE EXACT reason people think Flow's rob torque. BUT BUT BUT, as soon as they go to a different muffler that has a deeper tone, they think that torque is back! It's NOT back! It never left! You're giving it the same amount of pedal you did with the Flow! The ONLY difference is that it sounds like the motor isn't working as hard, even though the throttle and RPM's are the SAME. That's EXACTLY why people who have dropped their Flows for a different muffler think that they had to "wind up" their motor to get anything done when they were running the Flow!

With mufflers, especially on a basically stock engine, whether you go with Flowmaster, Magnaflow, DynoMax, Borla, or even a $20 turbo muffler, they are all going to perform pretty much the exact same. The only thing that matters about which muffler you choose is which SOUNDS best TO YOU.

Header info in next post. Waaaay too long for one post.

 

I thought Jbrew seemed a little too rooty tooty fresh and fruity

if ya catch my drift.

o well, i shall cease my flatulent winds of flatulence.

 

Headers.....

In order for long-tubes to do their job and scavenge the cylinders properly, the whole exhaust system needs to be as free-flowing as possible. This is not the same as with shorty headers which will cost you torque if you have to little back-pressure. Think of long-tubes as a supercharger in reverse. As the pressure wave exits the head and travels down the tube, it gains momentum, then the exhaust valve shuts. The momentum of the gas moving down the tube creates low pressure at the exhaust valve so that when it opens again, this low pressure will actually SUCK the exhaust from the cylinder. Not only does this keep the motor from pushing the exhaust out, but the cylinder will have a much lower pressure when the intake valve opens which helps SUCK in more fuel and air. That's how long-tubes provide sooo much more power than factory manifolds or their shorty counterparts which only provide gains by decreasing restriction. (There's a little more to it, there are pulses bouncing back from the collector, better scavenging at certain RPM's, etc. but I am keeping it simple as this is already goig to be another long *** post!) Shorty headers could do the same thing too, but because they are so short, the engine would have to be at an unreal RPM for that to happen. Faaaaar higher than the engine will ever reach and live to tell about it. In order for the pressure wave to move quickly down the tube, it must have somewhere to go! Keeping the exhaust flowing as freely as possible gives that wave somewhere to go with as little resistance as possible so it can provide the greatest affect!

You can't go to long tubes and not change out the pipes. They are much longer than the factory manifolds and the factory y-pipe will not work. Thusly, you will have to either buy one, or have an exhaust shop make you one. Now, this is something you need to keep in mind when you buy your muffler.... Any exhaust shop can neck a muffler down to use it with your small factory pipes. Getting a 4" muffler now, and having them neck it down when you have it put on, means that later you can go to 4" by just having them whack off the adapter. With a Flow, they are all the same inside, they can just cut back the inlet to make it bigger.

The magic number on a small v8's exhaust is dual 2.5". Since two 2.5" pipes have almost the exact same volume as a single 3.5", you could either go with dual 2.5" (go ahead and go 3" if you plan on a blower at some point) all the way back, or have a 2.5" y-pipe made with a 3.5" pipe back to your muffler. If they don't have 3.5", go ahead and go 4", but don't go less than 2.5" on the y-pipe. You will also need a pair of cats for the new y-pipe. Get hi-flows in the diameter you choose for the y.

You owe me a beer for having to spend an hour and write all of this s^^t out. Why don't you guys ever ask questions I can answer without a thesis!?


You got your cab back!!! Sweet!!! No more bugs in your teeth!

 

doesnt back pressure increase engine braking? make the engine drop rpms quickly after you pipe it?

 

thats a lot a readin. thanks.

that explains alot. thats most likely going to be my next major mod is a full exhuast system replacement.

i cant remember exactly but i BELIEVE the stock piping is 2.25 and the exhuast shop put on 2.5'' from the Y pipe back.

that stock muffler was unfreakin believably HUGE

thanks for the info im gonna have to read that a couple times

 

No.

There is almost 0 flow from the heads when you come off the throttle and let it fall to idle. Flow doesn't start again until the RPM is near idle. Regardless of the RPM (even 9,000 RPM), the amount of air moving through the exhaust when you completely cut the throttle is the same as if it were at idle. If it's winding down from a high RPM, it's actually a little less than at idle because all the fires are out so the gasses aren't expanding from combustion. It's vacuum and mechanical drag alone that is responsible for engine breaking. Surprisingly, compression actually has nothing to do with it unless the RPM's are very low or near idle.

When you come off the throttle, the pistons are pulling against a vacuum in the intake with the closed throttle. The cylinder takes a big gulp of nothing because all of the air has been evacuated from the intake because all 8 cylinders are pulling a huge amount of air that just isn't there. They have to pull down HARD because the crank is forcing the piston down (RPM, inertia) on the intake stroke, so it's pulling vacuum against a vacuum. There's almost 15 psi against the BACK of the piston (facing the crank) from atmospheric pressure which is trying to push the piston UP the bore to fill the vacuum. And since they are sucking in nothing, there is nothing to compress. Likewise, when the exhaust valve opens, there's nothing there to expel. When the exhaust valve opens, air actually rushes INTO the cylinder instead of out (to satisfy the vacuum), then as the piston travels up through the exhaust stroke, it blows the air it just sucked in, right back out. So instead of pushing exhaust down the system and out the tail pipe, it just slams back and forth from the cylinder to the exhaust manifold (or header tube) and back into the cylinder again really quickly. That's why engines sound odd when you rev them with an open exhaust (no mufflers). Kind of a vrooom....blaaah. What you hear when it's winding down is just the air moving back and forth in the headers/manifold really fast but not actually going anywhere. Ever notice how engines with blown rings smoke a lot worse after a rev when they are winding down? That's because the vacuum the pistons are working against is actually sucking oil up into the cylinder from around the bad rings and splattering it all over the insides of the cylinders and into the manifold. It is literally blow-by in reverse.

In fact, if you hold your had over the exhaust pipe and rev it, you will feel it blow your hand away as the RPM's climb, and then when they fall, it will suck your hand back to the pipe and blow it out again VERY VERY VERY fast like your hand is chattering or rattling against the pipe. If you try this, make sure the motor and exhaust are cold, don't burn yourself! LOL!

 

stop with the long posts!! i dont wanna have to read all those

 

You don't have to cuz there ain't nobody talkin to you!

Complicated questions have long answers, duhh!

 

triton - I had a chance to buy a motor and trans last year , but didn't because I didn't come with the computer.

Hows Klitch going to get it to work.??

Freakin kicking myself now!! It had low miles and I really could of used that trans now..

 

What do you have to have from the donner?

 

Well, Yeah!! Don't you know how it works?

You charge $10 for the Coil and $680 for shipping.

 

Motor and trans? What, the 32v?

 

EBAY!!! lol

anyways, my route was to keep the 4.6 ignition and go bug mike for a custom burn.