Pontiac G8 2008-2010 - Muffler Question looking for Patrick G.

First, I'm not knocking anyone else's response or opinion so please cime in.

I just bought a full Kooks long tube/catted x-pipe. I'm having a hard time deciding on mufflers. I am anticipating this to be loud. I just don't want the mufflers to make it any louder.

I'm asking Patrick to chime in because he will be tuning it in the near future. How much if any HP will I be leaving on the table with the stock GT mufflers

Any other mods? I believe its only about 5hp on a bolt on car... but I believe Pat found it to be closer to 10-15hp on a cam car. Actually think it was 14hp on his personal G8.

Either way stock mufflers quiet down Kooks just fine... sounds so much better with real mufflers though.

yep that is correct. GXP net even lower loss over the GT mufflers.

Any other mods? I believe its only about 5hp on a bolt on car... but I believe Pat found it to be closer to 10-15hp on a cam car. Actually think it was 14hp on his personal G8.

Either way stock mufflers quiet down Kooks just fine... sounds so much better with real mufflers though.

Roys showed a 20hp difference from stock mufflers to no mufflers when Fran had it

Thanks for the input guys.

Yes for the very long time being it is just a bolt on car. OTR CAI and soon to be exhaust.

Right now I'm leaning toward Magnaflow. I think Solo's would be too loud and I'm just not feeling Spintech/Flowmaster. SLP could be an option.

I really am trying to avoid having the car sound louder than it's actually moving if that makes any sense. Thanks...

You'll only lose 5rwhp with stock mufflers on a bolt-on car making 360-380rwhp. Personally I would keep the stock mufflers and use washers if it's not loud enough. I'd stay away from the Magnadrone mufflers. You will hate the drone from 1500-1800 rpm. Ask me how I know.

You'll only lose 5rwhp with stock mufflers on a bolt-on car making 360-380rwhp. Personally I would keep the stock mufflers and use washers if it's not loud enough. I'd stay away from the Magnadrone mufflers. You will hate the drone from 1500-1800 rpm. Ask me how I know.

Done. I think you just saved me a good chunk of tuning money :nod:

Quick question for Patrick. Do you do Saturday appointments for tuning??

You'll only lose 5rwhp with stock mufflers on a bolt-on car making 360-380rwhp. Personally I would keep the stock mufflers and use washers if it's not loud enough. I'd stay away from the Magnadrone mufflers. You will hate the drone from 1500-1800 rpm. Ask me how I know.

I agree, I had Magnaflow with a bolton car and they droned like crazy, even on a basic cam car they were annoying. But once you put gears in the car you get out of the drone zone and are really never in that range so its much better now.

Thanks for the input guys.

Yes for the very long time being it is just a bolt on car. OTR CAI and soon to be exhaust.

Right now I'm leaning toward Magnaflow. I think Solo's would be too loud and I'm just not feeling Spintech/Flowmaster. SLP could be an option.

I really am trying to avoid having the car sound louder than it's actually moving if that makes any sense. Thanks...

Solo? Too Loud? Really? My wife loves hers!!!

Done. I think you just saved me a good chunk of tuning money :nod:

Quick question for Patrick. Do you do Saturday appointments for tuning??Yes, I tune on Saturdays and Sundays by appointment.

Solo? Too Loud? Really? My wife loves hers!!!

I ran Kook 1 7/8 with their catted x-pipe for about 2 years before doing an aftermarket axle back. Finally pulled the trigger on some Solo's earlier this year and yes they are loud with the rest of the exhaust, but man I love them. I've not had one complaint on how the car sounds with them either.
Tate

Kooks with the stock mufflers is barely any louder than the stock exhaust manifolds. SLP powerflows sound real nice. I have them on my car and they do not drone.

Kooks with the stock mufflers is barely any louder than the stock exhaust manifolds. SLP powerflows sound real nice. I have them on my car and they do not drone.

Kooks LT + Catted X. Stock GXP mufflers.
Much louder at WOT than stock.
Louder just driving around but not too much.

Solo? Too Loud? Really? My wife loves hers!!!

Yea her. I'm trying to avoid sounding like every hillbilly pickup with open pipes. If stock mufflers are too quiet I'll change them later.

Kooks with the stock mufflers is barely any louder than the stock exhaust manifolds. SLP powerflows sound real nice. I have them on my car and they do not drone.

Thanks that's good to know about the SLP's. Patrick didn't seem to care for the Magnaflow and the SLP's were my second choice.

I have a SLP PowerFlo axleback for sale, if you are interested.

Kooks LT + Catted X. Stock GXP mufflers.
Much louder at WOT than stock.
Louder just driving around but not too much.

I had this setup previously. It is definitely louder and better sounding than the GT mufflers but was too raspy for me. SLP powerflows are deeper sounding but still not very loud and arent raspy at all. Even in my cammed car I can talk on the phone or carry on a conversation without any unwanted noise from the mufflers.

Would you say there is any weight advantage to switching to SLP Power flows as well?

Thanks for the info. I am going to add them to my wish list.

If stock mufflers are too quiet I'll change them later.

I've had the same set up you're about to since December. They are almost a little too quiet, but I half think I feel that way because it's the summer months and everyone else has their loud cars out. I'm going to try the washer mod and see if I like it or not, but I'd MUCH prefer too quiet over any drone or even slightly too loud. This is my DD and I have no interest in being annoyed while driving around.

I will be going with a Livernois cam around the new year, so this exact topic has been on my mind lately.

However, this video from Livernois shows a car with otherwise identical mods to you and I, with the addition of a Livernois cam and a valve job. The exhaust is all relative through computer speakers and whatever camera they used to tape it, but they show his dyno numbers at the beginning. 433hp with the factory mufflers. That's right on par with everyone else with similar mods, and I don't think he would've been in the 445-450hp range with other mufflers. Just my $.02.

http://youtu.be/ERglNwq297I

Would you say there is any weight advantage to switching to SLP Power flows as well?

Thanks for the info. I am going to add them to my wish list.

The powerflows are heavier than some aftermarket mufflers but they are probably still half the weight of the stock mufflers. Im sure they save at least 30lbs total over stock.