replacing the stock exhaust
 

I've made a post earlier in here about what I need to do to my stock exhaust in my 93 Eddie Bauer 351ci.

Reason I'm asking in here instead of in the exhaust forum is that I want to know from you Bronco gurus more than a F-350 powerstroke guru :)

Before I do, I just want to see what yall's opinions are, and if I'm not doing something that's caused major grief to one of you before.

My plans are to ditch the entire stock exhaust right before the 1st cat. Since the 1st converter has 2 in and one out, I'm going to have to have the shop weld a Y that brings the 2 into one 3" pipe. From there, I'll go into a 3" high-flow CATCO cat, and then to 3" pipe again. I'm putting a flowmaster 50 SUV series (part#53057), and then just running 3" out to where the stock exhaust is currently at. No boom tips or chromies; just exhaust tubing.

I want a much better sounding exhaust without loosing low end torque.

Anyone see a flaw so far?

BTW, I'm getting the cat and flowmaster for about 140$ and the install job w/labor for around 125$. If this sounds a bit high, lemme know, cause I can't find it cheaper anywhere else.

Thanks in advance!

replacing the stock exhaust
 

if your running a single 3" pipe all the way that will be fine, if you running duals then you should stay at 2 1/2's so you wont loose any low end tork. DW on mine i cut the pipe rite in front of the second converter, (its a 3" pipe) i have a single 40 series 2 camber flow master ( 3" inlet, dual 2 1/2 outlets) it slid right on the pipe and sits up inside the skid plat beside the TC perfectly, put a clamp on it drove it to my muffler shop and had dual 2 1/2 in aluminized pipes run out the back with stainless tips. sound good if i do say so my self! :) DW

replacing the stock exhaust
 

i just had my exhaust built up to three inches. the guy who did it told me that for max horse power to stay with a single magna flow 3 inch exaust and still be street legal. to go to duals means too much unequal length plumbing plus there is a problem going over the left side of the rear axle sppe sensor and brake lines (non metal). looks stock but shure runs good and does not sound bad. i was going for hp not sound. with duals you dont get much hp advantage. i also went to a bbk 56mm throttle body and a k&n fipk. it runs great now much more hp

replacing the stock exhaust
 

UH, the problem with duals is poeple run to big of a pipe and they loose there low end tork, duals are absolutely fine, and increase HP and tork if properly run, as far as geting them over the back axle on the drivers side of a bronco, if your shop cant do it, then i hate to inform you, but he's not that good! both my pipes go over the back axle ther perfectly straight, even, dont touch or rub anything and dont move. DW

replacing the stock exhaust
 

DW

You have any PICs of your exhaust? I am considering a similar plan.

replacing the stock exhaust
 

No i dont right this min. but if i can get a chance, mon or tue i'll slide under it and take a couple and put them in my gallery or on my web site. most people dont like mine cuz i ran them straight out the back, so you cant cruz with the back window down, unless you put a air wing on the back to blow the fumes away. which is my plan. I just personly dont like the side exits. DW
P.S. Go to my gallery and scroll down to pic of my bronco veiw from the back, click on the (2) for the larger image and you can see how they exit. but i'll still get some more from underneath.

replacing the stock exhaust
 

DW

Thanks, that would be great. I am planning to go out the side, rather than fight the exhaust in the cab problems. PICs would still be helpful. Whenever you can get them would be fine.

replacing the stock exhaust
 

NO problem would be glad to do it. I'll e-mail you soon as i get them up. DW

replacing the stock exhaust
 

I got the pics of my exhaust posted in my gallery, for anybody who wants to see them, thers two pic albums, (MY STUFF) and (TECH STUFF) the exhaust pics are in tech stuff. Thnx DW

replacing the stock exhaust
 

my shop would have been glad ($$$) to put twice pipes on my sport for the extra bucks but i do lots of business with them and they gave me the best plan for hp at the best bucks. plus i wanted power not sound. and they are correct about loss of loe end tork.

replacing the stock exhaust
 

I gues theres no point here, you just can teach some people anything there gon a belive what they belive. GEEZ DW

replacing the stock exhaust
 

"plus i wanted power not sound. and they are correct about loss of loe end tork."

With the correctly sized and routed pipes, you can skin the cat either way. Going duals or big singles does not in itself make more torque. Or even a deeper sound for that matter. The engine has no clue how many tailpipes it has. It just knows how much combustion air is sailing out the exhaust ports. Correct pipe diameter, length and smooth bends are what matter. You need a dyno to properly evaluate two custom built systems.

replacing the stock exhaust
 

yea, what he said!! :) DW

replacing the stock exhaust
 

LbbBronco:

FWIW, your plan sounds solid to me. It should net a serious improvement in both sound and exhaust flow over stock. I guess my only question would be why not go with duals while you are at it? But depending on whether you have done (or will do :9) any other performance mods it may be overkill. The price sounds ok.

ckirwan514:

So if all I want is low-end torque, I need to bottle up my exhaust a little more? How does less flow equal more torque?

I thought that the difference between torque and hp is how they are measured: torque being the twisting force created at the shaft at a specific point in time and hp being the amount of work that can be performed over a period of time. So while there is certainly a difference in how you build your engine for low-rpm and high-rpm torque/hp, the basic concepts remain the same.

The objective is to increase volumetric efficiency. Unless the single pipe can increase exhaust gas velocity to the point where it is scavenging not only exhaust but fresh charge, and then send a positive wave (which would require some type of resonator or convergence) back to the cylinder to cram the fresh charge back in after the intake is closed and before the exhaust has closed, I can't possibly see how it helps produce more torque. This would also be a "tuned exhaust" and only help at the specific rpm for which it was designed.

Better system flow (from air inlet to exhaust tip) will help increase volumetric efficiency across the entire rpm range. Now too much of a good thing can be had, but typically that only occurs if there is not enough intake port velocity to properly mix the fresh charge. Most likely not a problem for any of us with cast iron Ford heads (anyone with Boss 302 or 351C 4V heads excluded).

I have no doubt that ckirwan514 has observed a significant improvement over stock with the single 3" exhaust, but I do not think that DW2455 will hurt is "low end torque" by going to duals either. Depending on the rest of his induction/exhaust system DW2455 may or may not notice an improvement over a single 3", but duals certainly will not hurt his low-end torque in any way IMLWO. (the LW=Long-Winded :-blah).

bringing this thread back from the dead
 

was doing a search and also had a question on the exhaust topic...

what are the pros and cons of taking off just 1 or both cats, is it best to leave one in-tach (is it possible to hollow out a cat... in a quality mannor).

and do I need (i think its called) a oxygen emmulator to fool the idiot lights, or is that not needed






'95 351