OK so I had a single FlowMaster split to two tips. I took it off had dual pips, an H Pipe and two Flows put in its place. Now I think I have no back preasure. With the CAI I had I could give it WOT and I would get a nice punch from behind. Now I get hardly nuttin. Even with the NEW Griffin I installed when I got home after the exhaust change. I feel like I may have spent some $$$ for no reason, whats you opion???

 

well you are automatically going to lose back pressure with true duals over a SI/DO system, but the h pipe should have brought some of that back

 

I was thinking the same thing but I just don't feel the power like I use to.

Does anyone think I should take them back off?

 

I would - If you like duals , go w/ SIDO muffler - An "X" Muffler can help as well. You might want to reduce pipe size after the muffler, not sure if that will matter much. It's all about the tune after that.

It sucks being without torque - It takes allot more effort getting up to 60 mph under normal acceleration.. Very noticeably different.

 

That is true duals..

But yeah true duals takes away slightly from your low rpm, but the high rpm is much better now.

 

Well I don't think the torque feels like its there low or high. It could just be me but I don't know. It felt really strong with just the SIDO Flow and CAI but when I left the muffler shop it felt sluggish. And then the passing gear use to kick hard with and now after the true duals not so much. And like I said earlier after the true duals I installed a PHP Gryphon and it didn't feel like it helped out much to get me back to where I was before the true duals!

Maybe I'm looking for to much!!

 

*sighs*

It has nothing to do with backpressure and all to do with exhaust gas velocity.

What size are your pipes? Tips? Are they mandrel or crush bent? A well made true dual system will outperform any si/do system.

For now I suggest swapping your h-pipe for an x-pipe and your Slowmasters for Dynomax Bullets or short Magnaflow Magnapacks.

 

- I was waiting for someone to say something about that lol.

Back pressure and velocity - one in the same. Exhaust shops still use the term back pressure but they are indeed referring to "velocity" as you mentioned.

Less obstructing straight thru race mufflers are just that "less obstructing"/more "velocity"/less "back pressure". Offset chambered mufflers create the "back pressure" term which in turn slows velocity - It's just slang man, that's all.

Stock PCM's running factory tunes are programmed for "less" velocity, more back pressure than say - true duals or straight thru mufflers provide. The trick is to increase the velocity, better the scavenging, BUT only enough that makes it possible to tune in on the Dyno. You don't want to over due the exhaust if you don't have the motor for it. They won't be able to tune it in if you do. True duals IS over doing it with a stock motor IMO.

 

Less obstructing does mean less backpressure, but not neccessarily more velocity. You can throw on a Magnapack and 3.5" pipe from the cat back. You'll have a lot less backpressure, but also a lot less exhaust gas velocity than stock. Now, bring that pipe down to 3", or even 2.5" and you'll up your exhaust gas velocity while reducing backpressure.

I do agree though. You can definately "out do" the motor with an exhaust (overkill). You just need to give the motor what it needs (most N/A F150's don't need 3" duals or 3.5" single pipes).

 

My pipes are 2.5 from front to back, mandrel bent not crushed, and I'm sorry not flows any more but I put my MAC Flowpaths off my old exhaust set up off the Cobra. The are offset/offset mufflers. I also had my old BBK X pipe and I told the guy I wanted the X in there. He said that the his H would look the same. But it didn't so I guess I'll take it back and get the X put in. I know I don't wanna out do the motor so I stayed with the smaller exhaust.

 

An X pipe will definately create more back pressure than the H. The X forces both sides of your exhaust together and makes them pass through an area that is slightly larger than a single exhaust pipe. The H pipe just equalizes pressure on both sides of your exhaust and from what I can tell does not really create much back pressure at all. I have an X on my truck and an H on my Mustang and IMO the X pipe is the way to go on these trucks.

 

so with 2 14" maggies, 2.5' throughout with 3.5 tips and an X pipe

what should i be looking at less torque? or what

 

I have that set up minus the mufflers and I have not noticed any torque loss at all. It does have more punch up at the high end though. Your set up has been used by several members here and will sound very nice.