I installed the Magnaflow 12468 about a month ago on my 99L. for some reason the truck is not as quick as it was before. At cruise when i gradually give it more gas it hesitates before building speed. You know normally when you just barely give the L a little gas to pass someone it responds quickly. Mines slowly builds speed . When they installed the muffler, it sits at an angle so the inlet will match up with the pipe lines. Also they changed the lines to fit on the muffler. I noticed that there are crinched points at the bends on the pipes. I'm wondering if thats resticting the flow robbing me of my power. I didn't get the chance to notice if the factory Pipes had those same crinched points..I seriously doubt it being the exhaust was SVT tuned. Maybe i'm just being picky or use to the power. Also i just turned over to 40,000 miles..I heard that L lose power around that point in the milage.. If anyone has a clue please give your opinions. I have an airaid enclosed filtercharger.

Thanks!

 

The stock pipes are mandrel bent,your new ones arent.Should not make any real difference though.I have a 14468.They bent new pipe for mine too.I didn't see any gain or loss in power though.Just more sound.

 

If you are running stock boost you could be loosing alittle boost due to less back pressure, I really doubt it though. Maybe your not hearing the Supercharger like before and now you hear the exhaust?

 

Find someone with a mandrel bender and have it redone! I had dual Flowmasters and the bends were crimped like yours. My back pressure was so high that I burned the mufflers up in less than 2000 miles. On the dyno with a chip, K&N drop in filter, and the dual Flowmaster set-up, I only made 336 rwhp, which is less than most '01s make stock. My torque however, was measured at 450 lbs.-ft. at 3650 rpm which is where the guy set the machine to start measuring performance. Since these engines make even more torque at lower rpms, I'd say I was making closer to 500 lower in the 2500-3000 range. Just guessing since I don't have the numbers.

The place that did my install admitted fault and gave me $280.00 credit that I've been using toward labor for other mods and for the installation of my Borla cat-back system.

Roger

 

Roger,are you sure it it wasnt because of the Flowmasters?I've heard a lot of negative about them from muffler guys.

 

No, I'm positive that the bends in the pipe were the culprit in my case. The stock system is supposed to be tuned to the motor on our trucks. By closing off the flow at the bends, you restrict the flow of the exhaust. The flowmaster probably made my problem a little more extreme than "99Zeus rtrns" problem, but I think it's the same thing, aside from the brand of mufflers used.

Here's a copy of the Dyno sheet:

 

Damn,I guess i'll have to find a shop in Florida with a mandrel machine.They are huge money.Not many shops have true mandrel machines.

Anyone in Florida know a shop?

 

That's why I went ahead and spent the money for a cat back system. I wanted to run Dynomax mufflers; but, I couldn't find a place local that had a machine.

 

Thanks for the advice man.Now I gotta right a wrong.Will just need to redo the bends just before the tips.Just need a freakin machine.

 

Try this web page. It has a list of places that have mandrel bending. Some of them are in FL.

http://www.dsm.org/vendors.epl

 

Thanks man.

 

One alternative is to use (not the prettiest but effective IMHO) is to use a dual out kit for a 97+ F150. Dont have the part number, sorry. The tech that installed my 12468 used this kit but had to work (not BEND) the pipes a bit. Much cheaper than mandrel bent pipes also.

I have images in my gallery linked below but that part of the website is way busy/inaccessible at the present time.

 

Well thats another option.Thanks Bob.

 

Im confused. I am planning on getting some Maganapck 14416's installed along with and x-pipe after the mufflers just like ****** did. Am I goin to have to get new pipes bent or can they just take out the mufflers i have now and put the new ones in with the x-pipe and use the same pipes??

 

I don't think ANYONE makes a direct replacement muffler for the L. Any muffler by itself will need SOME manipulating to get in properly.