[commandeered98GT]

Does having mufflers increase HP? logically, they create resistance and back pressure, which would decrease HP. Currently I only have the stock H-Pipe with straight pipes, no mufflers. I was thinkin about getting some flowmaster 40's, or perhaps even 10's. Would flowmasters help, inhibit, or go unnoticed in the HP department?

[p4ndiamond]

Will sound better but i doubt you will see much power difference on an NPI N/A, but the NPI needs all the power it can gain.

[commandeered98GT]

whats an NPI? non-performance improvement?

[97S281]

Originally Posted by commandeered98GT whats an NPI? non-performance improvement?

Non -Power Improved.

No, mufflers do not add HP.

[flowmann]

Originally Posted by commandeered98GT Does having mufflers increase HP? logically, they create resistance and back pressure, which would decrease HP. Currently I only have the stock H-Pipe with straight pipes, no mufflers. I was thinkin about getting some flowmaster 40's, or perhaps even 10's. Would flowmasters help, inhibit, or go unnoticed in the HP department?

Commandeered98GT – If you’re comparing a stock exhaust system on a 2011 5.0 to a Pro-Series Flowmaster Cat-Back system (for instance)…Yes! You can increase your HP and torque. We don’t release an exhaust system unless it gains power over the stock setup. If you’re asking if switching from a pair of aftermarket brand mufflers to a pair Flowmaster Super 40 mufflers, you may or may not notice a difference in power. You’ll notice a difference in sound and volume. Every exhaust system is different and for optimum power, your muffler needs will differ, so getting the right mufflers will affect the end result. Some mufflers will rob power especially on a street car in the normal operating RPM range. Also consider, if one brand lowers output by 10 hp and another brand lowers output by 5 hp, it’s fairly nominal on a 300+hp car, but which muffler would you want? Or would sound matter more to you?

Most people simply install Flowmaster mufflers for sound and the power concern is secondary.

Flowmaster mufflers are designed to increase velocity in the exhaust system to increase flow, not restrict flow and create back pressure. A perfectly tuned system will have zero back pressure. You don’t want positive back pressure or too little of it. You want zero. It’s not easy to accomplish. Zero back pressure lets the exhaust system use velocity to move the gases from the engine to out the tailpipe fastest. That’s how you create power, or at best…don’t rob power.

[WhiteNoise]

wouldn't straight pipes create the least resistance (nothing holding it back...)?

[commandeered98GT]

Originally Posted by Kodysteeler43 wouldn't straight pipes create the least resistance (nothing holding it back...)?

thats what i woulda figured. But apparently on dirtbikes, a muffler adds HP. and i dont know, er'one is sayin that the difference be it + or - goes unnoticed.