SilverR1_04

Just got 'em installed, (axleback)... I don't think I'm too impressed.

They don't seem to be too much louder than stock, but it is noticeable, and it's a bit more raspy.

Power wise? Can't really decide. I could be crazy, or maybe I'm just getting "use to" the power of teh car, but it certainly did not seem any better. If anything, it seemed a bit restrictive; a bit less responsive...

Granted it is just a axle back system, so I wasn't expecting a grand difference, but I do feel like it was a waste. Maybe even worth selling and getting something else.

Also, it seems the flanges used to mount it (to the rubber supports) are inconsistent. I understand they are hand welded and will not be perfect, but I had a huge gap difference from the tip to on one side in comparison to the other. This weekend I will remove them and try to bent the flanges to make them as equal as possible. They look aweful now.

I will take a quick audio/video clip and take some pictures with my digital camera tomorrow then (hopefully) figure out how to post it on here. Were can I host a video at?

Anyone else have JBA? What do you think of them? Power? Sound?

don_w

I was planning on using them... but maybe not now. Keep us posted on what you think about them.

SilverR1_04

Yeah, gimme a couple days to get use to it....

I don't like to jump to conclusions and bash on JBA for nothing, that wouldn't be fair...

Daniel60

Your used to hearing a rather quiet muffler but feeling the torque and now it sounds noisy even when your not really jumping on it. Having said that I mean this. You can think you are losing horsepower. With these new mufflers they are making better sound but not anymore performance in my opinion. Though I have read that Mac's gives you 3 more horses and seven more pounds of torque but I don't know this source.

SilverR1_04

Honestly, I wasn't looking for more horse power, just looks and sound was good enough for me. Heck, maybe some better gas mileage. I'd just hate to lose any horses in the process...

Daniel60

So do you think you are really losing horsepower or are you just obessing.

SilverR1_04

I can't tell for sure.... only a dyno could really tell for sure when there is such a small increase or decrease.

I'll give it a couple days and get back to you all.

I was hoping someone else would have the same setup and tell they're experience.

Looks and sounds good, minus the fact the tips are not sticking out straight, I'll fix that this weekend.

I'll take an audio clip and some snap shots and post em later..

Daniel60

To be totally honest with you when I first had my Mac's installed I felt the same thing. My wife said she couldn't tell any difference.

Cappi

I had the MACs installed & they produced EXACTLY that on the dyno,
3HP & 7 lbs of tq.

Not noticable enough to feel, you need a lil more than that to feel a difference,...

F1Fan

Hi SilverR1_04,

I have a set of JBA's rear mufflers installed with a set of JBA's shorty headers with Ti colored ceramic coating. The sound is amazing, my '05 GT sounds like it has a big block in it when I'm on the gas hard and is just a little bit throatier than stock when cruzing and around town. If I'm not on it, inside the car sounds like stock SPL but much deeper, outside the car sounds like a powerful, muscular machine, I love the new sound! I can't say about power as I installed the JBA headers, JBA rear mufflers, Steeda CAI, Diablo Predator computer tuner, Steeda motor mounts, Steeda G-Trac Brace, Steeda Adjustable Street Panhard Bar, Steda HD Panhard Bar Brace and Eibach Pro Kit all on the same day. But I can tell you that this car now really hauls the mail is is amazingly responsive to throttle at any engine speed. Also the car's rear end is not nearly as clunky as it was and the axle is much better located under the car now.

One thing though is that the car really needs a set of good struts and dampers now because the Eibach springs are stiff enough to make the car bounce to much once in a while over undulations of certain frequencies. The bummer is that Bilstein sport and Koni sport struts and dampers are not comming out until 2006 if at all per Bilstein and Koni. I may just buy the Eibach Pro System Plus kit in a month when they come out and give the kitted springs back to JBA.

I'm going to Brother's Performance to get a Magnaflow Tru-X pipe with high flow OBDII compliant cats installed later this week and then get the car baselined down at SoCal Tuning. Then I'll swap the stock rear cans back in while it's on the dyno and make a few more pulls on the car again. Even if the JBA's doesn't produce any more power I'll probalby keep the JBA cans just for the sound because they're really amazingly good sounding, beter than the Borla and Magnaflow systems I've heard on other '05 GT's. For some reason the Borla and Magnaflow systems both have a very european sound to them, more like the snarly sound of a sporty six cylnder engine than the big huskey V-8 sound of an American muscle car. It could be the design they both used, being basically simple perforated pipes with SS wool packed around them vs. the more traditional American style chambered muffler sound that I'd prefer on this car, but as my brother-in-law always says, "it is what it is."

I'll post back once I've had a chance to get the new Tru-X Pipe on and have the car's ECU program optimized on the dyno. I'm hoping to see about 320+RWHP or so on the dyno once the ECU is optimized for the complete system as installed.