Slow after Dynomax install

[fastrev]

I replaced my Flowmaster mufflers (don't know the model) with Dynomax Super Turbos. The Flowmasters were so loud inside I couldn't hear my stereo. I have a noticable loss of power. My car used to put you back in the seat before the install, now it's very slight. I thought they had a good flow rate. Did I miss something? I have an H pipe. I'm bummed!


I welcome any suggestions!

 

[DMAN302]

Muffler will NOT affect your performance...I think you are being fooled by the exhaust note change. Mufflers add NOTHING to a stocker except sound.

 

[mustangsquared]

I disagree...muffs and cats create back pressure...you need some for torque...put a 3 inch exhaust on a stocker and it will feel sluggish from the lack of back pressure/torque. I doubt that the muff change created a HUGE change, but it may have created a small one. I lost torque when I punched my cats out.

 

[DMAN302]

I will never believe anyone who says a stocker gained any advantage from changing muffler A to B when both are good quality mufflers..I have gone from stock to 2-1/2" LT's with an H to flowmasters an yes the car sounds bad ass but SOTP was negligable. If you are going to tell me that this person has experienced net HP + or - of 2% with a muffler change only then you need to shake your head. Yes backpressure is a factor, and yes 3" exhaust is excessive and will affect you BUT Flowmasters to Dynomax swap alone will NOT affect anything but sound period, and that is ALL he has indicated he has changed..not pipe diameter nor header style.

 

[stangbear427]

I'm with both of you on this one- it logically follows to me that especially if it was a stocker, going to a quieter muff would increase power since it's putting some of that necessary backpressure back into the loop. It isn't always the case, but usually louder= less backpressure. ON that note, if this is a 347 with 12psi of vortech on top, than it only makes sense that the quieter Dynomax's cut down the umph a bit. Brand to brand differences on a stocker are mostly in the imagination. However, he never said the car was stock, did he? I think we need more clarification of the combo here before jumping down each others throats for saying the same thing two different ways... just my $.02

 

[89MustangGX]

The DynoMax's usually make more power than Flows -- it's just the nature of the muffler. What you are experiencing is probably all in your head.

 

[fastrev]

It wasn't in my head!

Well it wasn't in my head, it was in my gas tank!
Just after I installed the mufflers I filled up at a different gas station than usual. I realized this today and filled up at my usually station this morning. She's running good again!

And you all thought I was loosing it

 

[DMAN302]

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