gio89kid

But I thought you used the hp2 shorty on a turbo car?

and yes, I did do this kind of post in the past but then the VT muffler worked out pretty great. The only thing that has changed now is I work at a different job now so it's no longer one hill to deal with, it's constant up and down hills which mean under a load at the perfect drone range the entire time now.

It's low drone but it still rises above the radio during those times.

ok, i see what you mean about the stock muffler, but I was really going for that quiet inside with some roar outside just a little more than stock, which is why I started with the dynomax superturbo which is normally the quietest performance muffler you can buy.

Can you provide an amazon link to the hp2 shorty you used? (If it will work on my non turbo car)

Oldblue

Here's a link

Flowmaster Super HP-2 Series Mufflers | JEGS

An 18 inch resonator


http://m.ebay.com/itm/201368429949?_mwBanner=1

gio89kid

This is looking more promising, if i use the flowmaster to replace the VT it might work great, but if not, its small enough to be used as another resonator, or to replace a resonator, just way more restrictive. But still flowing enough to not make a difference on my HHR, and I assume still more flowing than the stock design since its still technically straight through.

Well, now my question is... Anyone used this on a non turbo HHR?

donbrew

Just a point. You do know that the reason for the resonator is to restrict the flow? The engineers work hard to get exactly the optimum backpressure.

Free flow is not necessarily perfect.

gio89kid

Really, hmm it doesn't look like it would be much. I thought they were just there to remove some of the unwanted noise before the muffler took care of the rest.

So what are you saying for my case then? Two resonators and a HP2 flowmaster still fine?

and since the borla gm upgrade technically was straight though except for a gap in the middle of the muffler, I'm assume it will be fine with that set up? It seems to operate properly now.

donbrew

What I'm saying is that GM engineers engineered the exhaust system for optimal performance. I am betting they know more about it than me or you.

The stock muffler is basically straight through with a gap in the middle of the housing. The difference is the sound baffles.

I think you are confusing exhaust gasses and sound waves. The gasses go straight through a muffler without obstruction. The gasses are restricted by a resonator.

See especially page 2 of this link: How Mufflers Work | HowStuffWorks
Here is more:Performance Muffler Theory of Operation and Selection Suggestions
And my search results: https://www.google.com/search?q=car+...&bih=954&dpr=1

Oldblue

This V-8 has mufflers first , then the resonators



This is similar to our Sunfire GT exhaust, but the mufflers have dual outlets, very nice!



Another member asked Y we answered why not!



This is the Walker resonator I have on my 2.2 HHR, it's longer then the puny 2.2, it's for the 2.4

gio89kid

Touring is what I am trying to achieve.
I read through your links thank you for that.

From what I understand is the exhaust gasses will have a much easier time flowing through a straight through muffler with packing. The packing is the most efficient way of quieting the noise that is generated by the gasses. But reflection due to baffling or chambers work great to reflect sound waves upon themselves to cancel out the unwanted exhaust noise, yet they are not as good at flowing. Straight through can be loud and quiet depending on the application, the alternative will be quieter but both can still be too loud. It's all in the design.

That being said, the stock GM muffler may work great, a performance muffler will allow for more performance gains, especially if intake modification was done like the K&N I have. More air entering a heat engine will want more air to exit with an exhaust. Which is what I have noticed with my current set up, RPMs ramp up right away and the car overall can achieve faster speeds more quickly, but you go through more gas during those times. lol But save gas when not doing that because of the added efficiency of the air fuel mixture. I have noticed some hesitation though every now and then when smashing the pedal at a stop or rolling speed, this may be do to the lack of needed back pressure for low end torque??? Or it could be a malfunction in my pedal cause at a stop it will ramp up the rpms a little at random???

Either way, I have always been a fan of quiet exhaust systems, but not stock exhaust systems, quiet as in you can never hear it disrupting a low volume radio, or when sleeping on a long trip. But outside you can tell there is a little umph added to the car. Now some stock cars sound like this, so maybe that will tell you what kind of levels I am looking at.

And with every car I have owned, I am able to achieve this with a super turbo muffler. A super turbo muffler is much like the stock exhaust or the info you provided above where there are three tubes like the walker tri-flow but there are channeled flow directors that curve the gasses to whip right through each tube. This provides excellent flow with slight back pressure for the best all around upgrade to any car.

Then comes the HHR! Dum dum dum. The HHR breaks this rule and all the sound resonated into the cab. Luckily the stock exhaust is very quiet, but too quiet, I am looking for something more, but not much. And the VT has been able to provide that until now, mind you it was never my plan to have a VT, I was looking for an exhaust similar in restriction to stock, just a little more flowing to complement the intake and just a little more rumble to sound a little meaner.

So! and the big SO! should I attempt this SP2 muffler in hopes it will be very quiet with the car now having two resonators and the SP2 being more restrictive then usual, or am I wasting my time and hearing by having it be too loud for my liking? According to my decibel meter Its only around 77db now, so I think my hearing has been safe this whole time, plus its only that level under a load, but I don't like it.

Sorry for the long post but I enjoy this car and I feel like it will be one of those cool classic cars in the future. And everyone knows what a classic car looks and sounds like, and that is what I am trying to achieve, but at safe low volumes.

Thanks again for any input, I can tell you guys are knowledgeable and also care about our HHRs.

donbrew

Maybe moving the muffler to a spot where the noise can't get into the cab? The tailgate is a great place for road noise.

I seriously have never cared about the sound of a muffler, except maybe in my 62 VW.

gio89kid

Ok, well it sounds like I have one option then.

Try the SP2 and then go back to stock. I just kind of wanted confirmation about it from someone who has tried it on the 2.4L.