Same dyno, same day 1 hour and 40 minutes apart, SAE weather corrected. Best run of 3 baseline dyno pulls of the stock catback compared to the best of the 3 dyno pulls with the Magnaflow catback. The baseline dyno with stock catback was 383 rwhp, 376 rwtq. Dyno with Magnaflow catback was 387 rwhp, 377 rwtq. Pretty much gained 3-5 rwhp and tq throughout the rpm range. I've said for a long time that a catback was more of a sound mod than performance mod and I'll still maintain that position. But I will say that the Magnaflow gives my Jeep a much more mature and exotic sound. With headers, it's quieter than the stock catback at idle and cruising, but the internal x-pipe in the front muffler raised the WOT tone to a higher pitch. It sounds more exotic and less like a Harley. I like it a lot. As always, I will do my best to dyno test each and every mod I perform on the Jeep. This way, you can decide for yourself whether the mod is worthwhile. The best prices I've seen on the Magnaflow catbacks from board sponsors is around $825. I will post sound clips when it's not so late.
Thanks Patrick, good info and write up. This will help people who are undecided on particular mods and budget. Nice work! :thanks:
Yes, the stock system isnt too bad. I would say out of all the exhaust out there the most you are going to gain is about 10. Which either way doesnt really matter...
I recently removed my Corsa due to the external noise and attention after the 426 install. I have run the Kooks/Corsa combination on my 06 and 08 Jeep. I recently installed the Magnaflow 3" catback and am very happy with the sound. Far more quieter in the cab almost stock like with no drone at all. Most likely due to the internal wrapped X-pipe. Very nice sound at 1/2 throttle to WOT. I have to agree a well made system.
Ill stick to my stock exhaust untill someone with my same mods and race weight of 5090 out runs me lol.
True that, but what you do not see (until at the track) is the WEIGHT reduction from replacing the OEM exhaust. hehe
By the way i was looking on the magnaflow website and it says the system for our jeeps has 2.5" tubing and someone above said they installed a 3" magnaflow cat back? Whats up with this? Do they have a new system.
The Factory system on the Jeep SRT8 is 2.75" not 2.5". Except for Mopar/Corsa which is 2.75" all after market systems for the Jeep are 3".
I noticed that my Magnaflow catback is 3" up to the rear mufflers where it necks down. The ID looks like it gets down to maybe 2.25" inside the rear mufflers. I'm going to put the Jeep back on the dyno and run with the rear mufflers hooked up and then dyno with them off. This way, I'll find out if there's any restriction in this step-down. If there's power to be found, I'm going to re-install the rear section of my stock catback since the rear mufflers are completely flow-through and a constant 2.75" size. I'll report back soon.
You should check with Magnaflow. They told me the SRT8 cat back did not utilize a Tru-X muffler only the 5.7L system. I asked the about an x-pipe and they said they saw no benefit with the tru-x muffler or the x-pipe on an SRT.
There are photos from 06 showing the cut away of the stock system. The rear resonators have a tube running through the center BUT the tube is missing like 4" in the center so the "can" does fill........and the can is full of fiberglass. So the point is the tube is not constant connected.
That's a photo I haven't seen before. With my Magnaflow 12599 and the stock resonators, I don't feel that badly about not having a higher flow system since I got rid of the BB. That's like an inch gap with vents in the other two chambers. Here's what the 3" x pipe looks like:
So Patrick can we get some 1/4 mile times after your headers and exhaust were installed and tuned.....like to see if ur times are consistently near 12.4's.... Thanks
