Using the 2.4 HHR and the Magnaflow catback as an example the tubing is increased to 2 1/2" diameter. It netted 7 HP and 8 lb.-ft. of dyno proven torque:

They increased the diameter of the tube and didn't lose power and torque, it did the exact opposite and I'm sure it doesn't run like a**. By swapping the muffler alone what do you gain? Maybe 2 or 3 HP? Nothing you'll notice or feel! Please have a clue before making comments!

 

I have the same muffler as Kenny and there is a "noticeable" improvement off the line. My HHR "burns out" more than before. the engine "breathes" better too, you can feel that it is more open and less restrictive than stock.

Regarding the MagnaFlow: Sounds like white rice. VERY Loud. Way too ricey for me. Also, we found during testing for the AEM intake that the HHR likes "higher velocity" runners on the intake - I'm betting it likes the same in exhuast. 2-1/4 is MORE than enough for this engine - it's only a 2.4L 4-banger!

I will have official dyno numbers of my HHR with muffler sometime next week - that should clear up the actual figures once and for all. I'm still betting it's 5-7hp gain.

(*Note to cynics: Iv'e been doing this over 20-years and worked as a managing editor for automotive magazines for 18 of those. I've done enough exhaust swaps and seen the dyno results to be able to make a fair judgement call on this.)

 

How are you going to base line your HHR if the exhaust is already on the vehicle? You would have to run it with the stock exhaust on first in order to give the charts any validity. You should know that. Even if you base line another similarly equiped HHR there is still variation in stock engine figures so there is the posibilty that it wouldn't be the same as your HHR.

 

My HHR was already baselined "stock" at AEM before we did any intake testing. Gotcha!

You should know me better Howdy!

 

You got me! I didn't even think about that. All the cold weather and lack of sun is starting to affect my brain.

 

No Prob Howdy - no one's perfect...especially me!

The numbers will tell the tale soon.

 

PLease educate me as to what back pressure exactly is. What qualifies a person as an exhaust specialist? Maybe if I put 3-4 different mufflers on my car then claimed it would make more power than a catback I could be one to. A mandrel bent catback, even if its the same diameter pipe will flow better than stock, period. I'm only an ass after dealing with stupidity, you being a perfect example.

 

Geez guys...are we still in high school (no offense to those that are)? Opinions are just that...everyones got one and you don't have to like it, but at least respect it. Not everyone is born with a chromed Snap-On wrench in their hand and they have to learn some where...at least they want to learn. As far as what works/performs better, no matter what facts (dyno sheets, etc) are presented, past experiences and preferences will usually win out. To each their own...just don't turn this board into I'm better than you, my car's faster than yours, my dad will beat your dad, etc. Let's keep it fun...the way cars are supposed to be.

 

Guilty! I just didn't like the get a clue remark at a statement I made months ago. Especialy when everyone knows a catback is going to net you more HP and torque than just a muffler.

 

Not pointing at anyone specifically Capn. If I have learned anything in my years of being around cars and racing, is that there is always some one who knows more than everyone else. These are usually the ones who can't back-up any so-called claims. I personally (this is me...don't expect all to be the same) take the strong silent type approach and let my time slips do the talking. I may not be the fastest or best at the end of the night, but at least I keep my dignity.