Hey Guys,

I have a question about what type of exhaust system I should install for my truck!

I am debating wether I should go with a true dual exhaust ( duals from collectors to tips), or if I should just install a SI/DO hi flow muffler with dual tail pipes.

I am concerned that if I do the SI/DO, my truck will suffer later after I install other mods such as Cold Air Induc., Tuner Chips, etc..

Would a true dual exhaust be beneficial, or is it a waste of money?

I posted this same question in the Aftermarket/Exhaust , but haven't recieved any input. Hope this is ok

Thanks

 

True duals perform no better than a "PROPERLY SIZED AND DESIGNED" single exhaust system on a mildly modified, street F-150. True dual's advantage would be if your truck lived on a race track and it's normal driving conditions were WOT, top-end, or top-speed runs.

 

Thanks Max, I appreciate the info.

 

You're Welcome !

 

I'll post a counterpoint and say I noticed quite a difference going from a SI/DO to a true dual setup. Granted, I put in high-flow cats and an X-pipe at the time of install, but the gain was not unsubstantial.

-Flea

 

Thanks for the additional input, Fleas!!

It seems like everyone has their own opinion of what is best. I am a perfectionist, and like to know what IS the best. Sometimes it's hard to find that out! So, I like all the input I can get, before making my decisions.

I would be interested in finding a chart that shows what size pipe you should use for each application....SI/SO, SI/DO, and Duals.

I guess that is why we have muffler shops though, huh?

 

General rule of thumb:

4.6:
SI/SO - 2.5"/2.5"
SI/DO - 2.5"/2.25"
DI/DO - 2.25"/2.25"

5.4:
SI/SO - 3"/3"
SI/DO - 3"/2.5"
DI/DO - 2.5"/2.5"

-Flea

 

Here is a pipe sizing chart:

www.dynomax.com/techsupport.stm

 

Thanks guys, both posts were a big help. One last question....

My local muffler shop said he could do a dual system, from cats all the way back, using two seperate magnaflows, using 2.25" pipe.

According to the the chart that would leave me in the 250hp range. Should I tell him to run the 2.5" pipe?

Because after I add a cold air intake, and tuner I will be getting close to that 300hp mark.

The reason he wanted to run the 2.25" pipe is because he was afraid I would loose my low end torque.

Thanks,

 

He's right. Ford has used 2" or 2.25" duals on their 300-400HP muscle for almost half a century. Examples: 2004 Mustang Cobra, 390 supercharged HP uses dual 2.25". 1970 Torino Cobra, 429SCJ with a drag pack option, underrated at 375HP uses dual 2.25". If you would like to know the "ACTUAL" physics behind the flow characteristics of single vs dual pipe, you can find the formulas here:

http://www.rit.edu/~rfaite/courses/t.../pipe/pipe.htm

 

Glad to hear that! He seemed like he knew what he was talking about, but you just never know. It's nice to hear somebody that knows what they are talking about, back up the guy that is going to work my rig.

Im always a little paranoid about people working on my vehicles. After talking with him, and you all on here....I think he will do me right.

Thanks a bunch for the information and help. I can't wait to get her back from the shop tomorrow and turn that key over for the first time with new exhaust.

I feel pretty confident in the Magnaflow decision, from all my research and input from all you guys on here.

Thanks Max, Fleas, and F150ONLINE!!

 

Good luck with your installation.

 

Hey Gang,

I got the truck back yesterday and let me just say...PERFECT!!! Magnaflow has me sold from here on out.

The sound was exactly what I was wanting, and the performance increase is noticeable.

The installer did an excellent job, and I am very pleased. Local install is the way to go.

Thanks for all your help and suggestions, I really appreciate them. I was better informed and therefor I think in the end, it resulted in 100% sattisfaction at the shop.

I went with a custom dual pipe setup with magnaflow mufflers (p/n 12225.) That is a 2.25" SI/SO muffler with offset input/center ouput. Aluminized 2.25" pipe, and of course 2 Chrome slant cut tips.

PICS in the My Gallery.

Thanks Again!!!

 

That sounds and looks like a good deal all around. Congratulations.

 

Lookin' good man! Betcha love the sound!