Hi, all, I am new to the exhaust upgrades so I have a few questions that have not been answered from searching this site.
I am thinking of putting a magnaglow muffler on to replace the stock one, but keeping the stock pipes. I have not been out the measure them, but I am pretty sure they are less than the 3 inches from the kit. First of all is this even possible, and second of all will I see the same performance increase as going with the kit. From what I understand, it is the muffler that helps with power and not so much the pipes. I have a '97 4.6L, and from what I understand a dual out will make me lose torque. I am not so much interested in getting flashy pipes as I am the performance increases.

Thanks to all who reply!

P.S. allready have the Microtuner and Airforce 1

 

For performance increase on a budget, cut off the stock y-pipe, run the 2.5" pipes to a dual 2.5" in and single 3" out Magnaflow muffler, then a reducer to 2.5" to keep the stock tail pipe.

 

Here is my experience.
First I put on a Gibson sweptside si/so 3" system. Result's:Not bad but really did'nt notice a perf. gain at low end. Slightly at high end. Not enough to do it again though.

Second, I put a set of Flowmaster's on si/do with a delta flow 50 series muffler dual out the back 2.5" pipes. Result's: It really dogged the truck out , lost alot of low end and the in cab constant drone sucked to the point that I took it off in about 2 week's & put the Gibson back on .

Third I talked to alot of gear head's about exhaust's & stopped by alot of shop's & talked to them & everyone told me that doing the whole exhaust was pretty much a waste & gain's will be minimal at best when on a stock or near stock engine. They told me to get the best gain's from my truck exhaust (excluding headers) would be to swap out just the muffler for a free flow design and leave the 2.5" stock pipe on it and put a nice tip on the end if you want. The biggest restriction is the stock muffler.(beside's cat's too) I have yet to try this but if I do anything to my exhaust on my new truck it will just be a muffler swap. Probably to a Magnaflow.

This is'nt the exhaust bible,just the info I have heard. Don't know if right or wrong. But next time I will give it a try. They also told me opening an stock engine's ehaust will probably loose you loe end power .

 

APT -

I've noticed you've posted in a couple different places your suggestion to cut the y-pipe and use the Magnaflow SI/DO backwards (though they are bi-directional).

I am considering the same thing - to cut the y-pipe, run duals to a Magnaflow 5x11, D/S 2.5"/3.0" (12588), and then out the back with the 3" Magnaflow tail pipe (15004).

From your experience, what can I expect power wise across the rpm range? How is the sound? Also how is the fit and finish of the Magnaflow parts?

Appreciate your advice!

FYI to everyone else – found this stuff on bigexhaust.com
$87.67 for the 5x11 S/D 2.5”/3.0” muffler, pn12588
$43.00 for the 3” tail for a 97-02 F150, pn15004

 

Here's my spilling of guts on exhausts for the F-150 from all the gathering of data I have gotten.

I personally have not done it. I have the stock system still on my 5.4L. I'm getting closer, maybe this Spring. A few people have cut the Y-pipe and replaced it with a Flowmaster Y-pipe (dual 2.5" in, 3" out) to a 3" in/out muffler of choice. Some use a 3" tail pipe, others the stock 2.5". Magnaflow does both in one unit for less total money. In one thread that had a lengthy discussion on the Y-pipe cutting, one or two used the Magnaflow and loved the results over stock. Not sure if they had 4.6 or 5.4 or 2.5" or 3" tail pipe.

I have noticed is that most people that use a Flowmaster muffler-back setup don't notice any power differences, or at least for the better. The people that replace the factory y-pipe and use a flowmaster muffler seem to get more low and high end. Makes me think the y-pipe was a restriction because I think the Flowmaster y-pipe is a very good design (so is Magnaflow). But, many people have repalced the muffler-back with a straight through design (there are others besides Magnaflow), but keep the stock y-pipe and get great results throughout the powerband, such as WLF. So the muffler is a restriction too.

Based on everything I have read and my own reasoning, what you describe is ideal for stock to near-stock motors. I'm not sure the difference between using the a single 2.5" tail piple vs. a 3" one would be. My speculation is the OEM 2.5" tail pipe (which is a great design and stainless steel) would work best for the 4.6L V8 and the 3" may be better for the 5.4L. But I haven't seen many people try it so I can't make any conclusions. If I had the time/money/inclination, I'd love to experiment with a 4.6L and this setup, swapping the tail pipe and trying to notice any differences. Same with the 5.4L. But I'll probably only use the stock pipe and save some money and it is stainless which is important for my truck which gets driven in the salty Michigan winters.

Performance expectations should you decide on this setup: Certainly noticable increase of power at the high engine speed range because of the minimized restrictions. Depending on your motor, the low end may increase or decrease. I find it hard to believe 4.6L of displacement can breath enough through a single 2" pipe for example. Is 2.5" just right or 3"? I don't know. With a 4.6L, I'd feel safer useing the stock 2.5" pipe. I'm not certain what I'll decide when I do mine in similar way, 3" or 2.5". If I go with 3", I'm keeping the 2.5" in my garage so I can go back if I ever want to.

Quality wise, I'd be willing to say Magnaflow craftmanship is the best you have seen. I have seen a bunch of aftermarket exhaust systems and components in the Detroit area, although not specifically for F-150s, and the average ones I don't think will last too long. I'm not too old, but I had a Grand Am in college with the Quad 4 with a Flowmaster 40 series. Of course, I thought it was cool at the time. Anyway, it wasn't the best piece. I have seen a bunch of Magnaflow on other cars as I know a local distributer. All the parts are very solid, heavy, and the welds are small, but strong. Borla is another that I think is very good, although IMO overpriced.

Well, did I bore you yet?

The only other thing I recommend is to get the stainless steel muffler (#14588) instead of the aluminized one. I didn't check where you live, but the stainless will last forever in almost all climates. The aluminized one would last 3 years on my truck.

Aaron

 

Boring? Heck no! That's good stuff.

Also I did not realize that the factory pipes were all stainless steel - that makes me think twice about replacing the tail, although, I do like the idea of 3" all the way out. I also think I would want to stick with stainless for the muffle (as you pointed out) and for the additional pipe needed from the old y back to the muffler. That means more money. mmmm...

Anyway - thanks for the treatise.

 

Originally posted by FALLSCREW
... the best gain's from my truck exhaust (excluding headers) would be to swap out just the muffler for a free flow design and leave the 2.5" stock pipe on it and put a nice tip on the end if you want...

That sounds about right. I did that on my ride with the exact look/sound I wanted. Slight increase of low end and noticeable increase of high end. Even if there wasn't, who care, looks a lot better than before. Stainless steel baby!

 

I agree. If you had the 5.4L I would say go with a 3" tailpipe. I did and gained a fair amount of torque. Not sure what would happen with a 4.6L though. I would probably keep the 2.5" tailpipe just to be on the safe side and plus it will keep your cost down so you can spend the money you saved on something else.

Jake

 

I had a Magnaflow 2.5" si/so installed in May with the stock pipes. I noticed a little more low end torque as well as a little more on the top end. It was a little quiet at first, but now it sounds great. It took about 4,000 miles before it really started sounding good.

I do not think changing the tail pipe to 3" will add any noticable performance unless you change the Y pipe as well. The outlet on the Y pipe is 2.5 " so going to a 3" tail pipe won't help because you still have the 2.5 " restriction at the Y pipe.

 

Well I decided to go with the stock tail pipe and added a Magnaflow si/so muffler, with a stainless steel 3.5" tip. So far I love it. I noticed performance gains right away, how much exactly I don't know, but it compliments the other mods I have done nicely.

I am also very pleased with the craftsmanship of Magnaflow.....and I love the new sound!

Thanks for the advice

 

Silver Sport and Wings 023 , I am wanting to do the same as you both have done yes duals are cool , But I would just as soon for now upgrade to Magnaflow exhuast, and use the stock pipes on my 2001 5.4 lariat , (I didn't know these were stainles steel is that true ?) anyway my questin to both of you is do you know what Part # for the muffler you got? and how much$ is it the really cool round type like you se Mario Andretti holding on the web page for magna flow? thanks in advance for the help , I have done the chip and K&n next is new muffler~ , then I am thinking of all synthetics...? any thoughts there , as always thanks for the info. Skully in Colorado Springs CO

 

I would also like to know what model# muffler you used.

Thanks - Scrib

 

I did exactly what you talk about here. By that I mean SS Magnaflow si/so on stock exhaust with chrome tip. I feel I lost some lowend torque. I noticed it right away, as I left the muffler shop. I feel I gained HP at higher RPMs though. I also like the sound of my truck better now. I paid around $175. installed which is less than half of the whole catback setup. I have mixed feelings and may eventually get the whole magnaflow cat back system any how. I keep trying to tell myself that I don't notice any torque loss, but I feel I have.

 

Is that SOTP dyno that you are telling by ?

You might confuse the fact the feeling of the restrictive muffler, with that of TQ.

I have seen this posted quite a many times, and it all seems to be from SOTP dyno, not a dyno machine.

As my saying goes :
Last time I had my butt callibrated, it showed a 26% margin of error, and I went back to using it for what it was intended for, sitting on.

If you do a dyno, you might be shocked to see that you gained TQ and HP on the truck.

 

Originally posted by SSCULLY
... Last time I had my butt callibrated, it showed a 26% margin of error...

My g/f calibrates my butt daily. Consitent 69% error everytime!