5.0 Exhaust Thread

[nonhog]

That idea was good, except for the sizing. A V8 needs at least dual 2.5" pipes, and dual 3" pipes will not hurt. The worst that can happen is to need more fuel(PCM programming), due to running leaner from the extra air flow.

These are air pumps, the goal is to get the exhaust out without restrictions.

I'm going to tune my truck, test it, then install dual 3" everything, and follow it with PCM tuning, and testing, likely with dyno testing as well.

Make it bigger, much much bigger, more power.

Won't it only make more power if it needs more flow? (as in restricted)
If an engine cannot accept more fuel (its the pump) how will larger exhaust
(and tuning) make more power?
Velocity is important for scavenging right?

Time frame for your dyno testing? Not saying your wrong but all the text I've read says larger is not needed. Love to see your test results.
Please take my post as non combative. I don't have answers so much, just questions.

 

[nonhog]

Im running 2 borla xr mufflers 2" all the way out the back both dumped on the same side. True duals on mine just small piping. I figured 2 2" pipes is bigger then one 3" outlet.

At a glance (2) 2" seems larger than (1) 3" but its not.

2" pipe has an inside square inch of 3.1 X2 = 6.2
3" has 7.1 inside square inch.

Just a friendly FWIW.

 

[CDW6212R]

Scavenging is a concept/result of parts inside the engine, and the headers, to the collectors. Beyond the collectors, there is no possible scavenging, it cannot be done. That would mean creating a vacuum sufficient to suck air from the collectors, faster than it is being pushed out. Normal(passive) exhaust parts cannot achieve a vacuum like that.

The real debate is whether the engine does really flow(pump) more air than the exhaust will allow to flow out. I keep mentioning the millions of examples of actual 302 Mustangs, to explain that the Explorer exhaust is way too small.

Ford does not overdo things, make too much power, or as much as possible etc. They also do not create the ideal exhaust size, big enough or too big. Ford is always on the small side with exhaust parts, from the actual engine heads(valves, ports, size and shape(poor)), to the headers, and the whole exhaust.

So Ford didn't put the ideal exhaust on 302 Mustangs. Now what are those 302 Mustangs again? They all have 2.25" dual exhausts, true twin 2.25" pipes from the collectors to the tips, two of everything 2.25" in size. By obvious example, the 302 Explorer should have at least true dual 2.25" pipes, and more than that as an equivalent area of pipes.

For a bone stock 302, fine go with a dual 2.25" exhaust. But never go smaller than that, not even for stock. The stock exhaust is a single 2.25" system from the center on back, that is half of a stock Mustang exhaust.

I'm way behind here still. I have a lot of house work to do, then my Lincoln project, swap in the 347 etc. Then I'll get that of to be painted, and I can begin the Mercury project. I am slow, I'm sorry about that.

 

[TekMan05]

I'm thinkin about going true duals in my setup with super delta 44's and installing an x/h pipe. Anyone know of any crossover pipes that'll work in that tight space down there? I already know if I do dual flows I'll have to have them sideways(sides turned vertical) but I want the true mustang style of exhaust plus the 44's flow better than my original dual in/out 40 series.

 

[willzilla]

I'm thinkin about going true duals in my setup with super delta 44's and installing an x/h pipe. Anyone know of any crossover pipes that'll work in that tight space down there? I already know if I do dual flows I'll have to have them sideways(sides turned vertical) but I want the true mustang style of exhaust plus the 44's flow better than my original dual in/out 40 series.

I am running full dual exhaust in my 2000 5.0 Xploder... I ran mine with no cats and a single X style dual in/dual out muffler. I went straight off the TMH's into the dual in dual out muffler and then straight out the back. The muffler acted as the crossover and fit perfectly under the car. I have no spare tire though. Currently it is 2.5" duals front to back... Going to change it to 2.5" off the headers into the dual in/dual out muffler and then 3" duals out the muffler and out back.

I used a FULL BOAR MUFFLER and the exhaust sounds awesome (IMO, lol).

Muffler:

Exhaust currently before it was tweaked a little (added bung to fit A/F gauge sensor)... Going to adjust this again by moving A/F sensor up closer to the headers (into second o2 sensor bung) and swapping to 3" pipes after the muffler can be seen in my build thread for some ideas HERE.

 

[MercuryMullet]

I have rear cats removed, dual in /dual out muffler and 2.5 tail pipes. Mustang cam and torque monster headers.

 

[delexploder]

I have some good pics of my exhaust setup in my album not sure how to move them here

 

[delexploder]

If anyone can move them here I would appreciate it. I just spent over an hour trying and im pretty close to smashing my Droid pad tablet giant pos thing!

 

[Swervedriver]

I got my TM headers installed, took me 12 hours but got 'er done last weekend. I've read this whole thread, other threads on same, and lots of stuff on the web regarding 4 stroke v8 exhaust theory and ford trucks. I've got lots of experience tuning 2 strokes, I understand port timing, reverse pulse charging, scavenging, etc very well on those. The 4 stroke is very different, I'm new to computer controlled car engine tuning and can't really apply what I know very much from 2 strokes.

After all the reading I've done, technical articles say "backpressure" (I think what people are referring to is restriction?) is bad. Yet I see in real world experience reports, NOT ENOUGH "backpressure" is bad in our trucks for low end torque. I don't understand how restriction could be a good thing whether it's created by the low velocity of overly large exhaust tubing affecting velocity, or too small of exhaust tubing creating choke.

I want to follow real world recommendations, but I read things like "backpressure is good" and "use a free flowing exhaust" in the same paragraph and sentence. Doesn't make sense to me.

Without asking for a long treatise on why/what works, I'm asking if anyone knows that if I (by pure chance) discovered the hypothetical "perfectly tuned/perfect velocity/least restrictive" exhaust path possible, can a new computer tune compensate for lost low-end torque I read about on these 302 trucks, explorers, and broncos? This is the question I can't find a real world experience answer for. Most agree dual exhaust reduces low end torque.

But Why??? To lean? Won't additional fuel correct this???

Here's the deal, I have a mac intake, TM headers, and is otherwise stock. I want to remove 2nd cats and install a DI/DO magnaflow 18" bodied muffler with 2 tips exiting rear using 2.25" pipe the whole way. I figure two 2.25" is double the stocker's one 2.25" tail pipe, should be good to go, yes? I thought about 2.5" but would be more expensive, and not sure of any gain?

I really appreciate your input CDW6212R as logic follows your reasoning, but real world experience with these trucks and 302s I've read many times says otherwise and, if scavenging is increased and a resulting lean condition is corrected, I don't understand why the torque loss occurs.

I have a huge thanks here for any help with this question from actual experience ------->

Will a new tune (Henson?) fix the loss of low end torque commonly reported due to decreasing the "backpressure" after installing full dual exhaust in a 5.0 explorer? Increasing fuel pressure/injector size if necessary?

THANKS IN ADVANCE!

Sorry for long post [/rant]

 

[delexploder]

What I did

 

[CDW6212R]

I have some good pics of my exhaust setup in my album not sure how to move them here

Those are great pictures, I love that the perspective is while on your back. That is very good for any stock or mild engine.

 

[delexploder]

I think with a set of the tmh's it will handle 400hp aprox, I have plans if I can get back on it. And i have a ton of parts mostly various stock ford parts. Give me another year or two.

 

[CDW6212R]

...

... can a new computer tune compensate for lost low-end torque I read about on these 302 trucks, explorers, and broncos? This is the question I can't find a real world experience answer for. Most agree dual exhaust reduces low end torque.

But Why??? To lean? Won't additional fuel correct this???


...



Will a new tune (Henson?) fix the loss of low end torque commonly reported due to decreasing the "backpressure" after installing full dual exhaust in a 5.0 explorer? Increasing fuel pressure/injector size if necessary?...

Yes to both questions, a PCM tune will correct the A/F ratios from altering the airflow. It isn't much of a change and the stock injectors are plenty.



"Most agree dual exhaust reduces low end torque."
"Most people" are wrong saying that a bigger exhaust reduces low end torque. They are misunderstanding what happens. The better exhaust makes the engine run lean, assuming it was already close to optimum before the better exhaust.

The PCM cannot fully adjust to big exhaust flow changes, as proven by the countless examples of people saying that they lost torque. Every such example is proof that their engine is running lean, and that they did not adjust the PCM tune, thus it's their fault, not the bigger exhaust.

If the computer could handle these changes, then there would be no loss of low end torque, but instead a gain. If the A/F ratio was corrected automatically, then the higher airflow would result in more power at low rpm too. It doesn't, so the engine is lean, and the tune needs to change.

The 302 Explorer exhaust is the worst ever made, the most restrictive for the given engine. It has less than half the flow potential of any 302 Mustang. So any improvement should be noticeable, and the PCM definitely needs help with the A/F ratio.

I have a Mark VII, and those have tiny tail pipes(2.0" and 1.875" to be exact). Due to the restrictive tailpipes, it is well known that opening up the exhaust of those to 2.5" will create lean conditions, given the speed density PCM made for that small exhaust.

The computers can be tuned for almost anything you want to do with the vehicle, but it has to be tuned for the new combination.

 

[delexploder]

Yea I agree, see when I started my swap ( its in a sport) I had to buy new cats so I figured I would go ahead and get the exhaust setup how I wanted it as it was a big expense and i dont want to mess with it again,I hate exhaust work. I have heads ,pistons,rods,valvetrain, and im looking at a few cams. I haven't acquired the tmh's yet .wife's gonna be pissed when that happens. And then I'll get the tune and that will probably cost me my life . I have a plan just need time and money. Oh and btw case anyone was wondering it sounds pretty good considering the rest is stock.

 

[Swervedriver]

Your exhaust looks good delexploder! The duals just look mean, I'm going dual exhaust regardless of it's effect on torque. How do you like that Boar muffler? My exhaust man says he'll do a rear cat delete, dido magnaflow, and duals with tips for $350, I thought that was a fair price.

Don, I was hoping a tune would fix the torque loss problem, my concern was it was not only a lean condition that needed to be retuned, but somehow the the powerband curve changed due to a exhaust pulse timing change. I can't help but think like a 2 stroke tuner, that's what I know. Changing negative exhaust pulse timing dramatically affects the powerband rpm range on 2 strokes. I thought maybe freeing up the exhaust raised the rpm torque curve, in other words, maybe peak torque gets moved from 2000 rpm to 3000 rpm just for example. This might not be tunable from the computer, but from a change in port duration/timing via cam?

 

[delexploder]

Yea I wish we could get away with out the second set of cats but that will get you in hot water here so I went with the magnaflow direct fit hi-flow 2.5" cats ( I think you can get them in 3" ) but yea the secret to a sbf is the heads and valvetrain. I just put my exhaust together this way because I needed an exhaust and had nothing stock to start with and I knew what I wanted. As for the risk im not running a spare and my tails are inside the frame rails but when it was a sohc I had duals that ended outside the rails with the spare and a hitch in the way and it didn't go under the tank or get close to anything it could burn.

 

[CDW6212R]

Yea I agree, see when I started my swap ( its in a sport) I had to buy new cats so I figured I would go ahead and get the exhaust setup how I wanted it as it was a big expense and i dont want to mess with it again,I hate exhaust work. I have heads ,pistons,rods,valvetrain, and im looking at a few cams. I haven't acquired the tmh's yet .wife's gonna be pissed when that happens. And then I'll get the tune and that will probably cost me my life . I have a plan just need time and money. Oh and btw case anyone was wondering it sounds pretty good considering the rest is stock.

Hold out for the possible member-here made headers, Pufferfish I think. He has a thread about them, he got to a point that it looked like a $22k+ initial cost for a batch. I think he was about to begin asking for interest numbers, who would like a set.

 

[CDW6212R]

Your exhaust looks good delexploder! The duals just look mean, I'm going dual exhaust regardless of it's effect on torque. How do you like that Boar muffler? My exhaust man says he'll do a rear cat delete, dido magnaflow, and duals with tips for $350, I thought that was a fair price.

Don, I was hoping a tune would fix the torque loss problem, my concern was it was not only a lean condition that needed to be retuned, but somehow the the powerband curve changed due to a exhaust pulse timing change. I can't help but think like a 2 stroke tuner, that's what I know. Changing negative exhaust pulse timing dramatically affects the powerband rpm range on 2 strokes. I thought maybe freeing up the exhaust raised the rpm torque curve, in other words, maybe peak torque gets moved from 2000 rpm to 3000 rpm just for example. This might not be tunable from the computer, but from a change in port duration/timing via cam?

The exhaust on these 302's is horrendous, the back pressure is literally massive. Any improvement will help at all rpm's. I doubt that given the awful/small header choices, you could possibly lose any power at any rpm, with any size of exhaust. The headers(TM included) do not allow enough airflow at anything but just above idle speeds.

The entire rpm band is power suppressed, and the TM headers do not achieve maximum power for a 302, at any rpm point. I'd bet anything that if the exhaust was opened up properly, the power will be higher at every rpm with even the TM headers. If a person could really get better headers into these 302 trucks, then it may be possible to get the exhaust big enough to make an imperceptible dip in the low end. There are less than a few bigger header Explorers in existence, so that isn't an issue really. I hope to get there one day.

 

[JackDeath]

hope i'm not stepping out of bounds here, but does anyone have the phone number for Torque Monster Headers place, i think it's al's? thanks

 

[98 mountaineer]

would u have to re-flash the ecu if swapping out factory cats for magnaflow cats??

Would the ecu have to be reprogrammed if swappin out old cats for magnaflow hi performance??