I'm extremely curious on how your challenger is doing, performance wise, with the 3" exhaust.
@RyzRT and I have been talking somewhat extensively on this subject through direct messaging in the ForumZ and he's given me sound advice on sticking with the 2.5" exhaust with my 5.7.
What are your thoughts on it so far? Do you think your lack of performance issues might have something to do with not getting enough back pressure due to the 3" exhaust from engine to the tailpipe?
I've been actively searching for a thread like this and yours has been exactly what I've been looking for.
Something else that I'm curious about...I have my heart set on long-tube headers but that doesn't mean I can't change my mind. All of that being said, what are everyone's thoughts on long-tube headers that have a 3" outlet connected to 3" hi-flow catalytic converters reducing down...to say...2.5" exhaust systems? Could this possibly work or would it be disastrous?
I listened to the Borla 2.75 and the Corsa 2.75 exhaust, which is what I was told the Mopar Scat Pack 1 kit came with. I did not like the sound of either one of them but loved the deep throaty sound of the Magnaflow Competition.
Everything I read on here said to listen to all of the exhaust you could find and get the one you like and as I was trying to get a Scat Pack stage 1 to save my warranty I figured .25" would not make much difference in the exhaust from the Mopar kit.
I studied all the Scat pack Kits 1,2&3 and what each one changed and decided that since I was doing the Exhaust I would save time and money by doing the whole thing at once. Stage 3 changes the exhaust manifold to headers.
The high flow cats were a gamble so I called Dale at prefix racing to find out how much adaptability the stage 1 tuner had for the air flow changes and was told that it should adapt ok. At this point it seems to have done so.
The JBA headers and mid pipes with high flow cats are both 3" but the outlet on the mids was for stock exhaust which was 2.125 on the auto I believe, so I had the reduction cut off and added 3" extensions, so I am 3" from the collectors back.
It is a little loud inside the car, so I am wrapping the trunk in dynamat, but there is no drone issue when cruising down the freeway. It just gets loud when you get on it. I love the sound of the Magnaflows.
As far as the performance goes, I have not dyno'd the car but my BUTT DYNO says we picked up significant HP and Torque. My only problem is that I spin the tires when I launch enough that I have lost time on the 0-60 times. So I need to get stickier tires to get better traction. Spinnin ain't winnin!
The thing you need to remember is I put a stage 1 mopar ecm on with the exhaust upgrade which really woke up the other mods. So you will need a tuner to use the headers and exhaust upgrades.
Just for the record I was told that I would get a constant CEL with the high flow cats.
Without the tuner The other mods didn't do much and I did throw a CEL shortly after I put on the Stage 1 tuner but I believe that it has or will adapt as it hasn't thrown one now for quit a while. We'll see.
I hope that helps The car runs like a raped ape and I plan on Cams, Titanium valve springs and 5/16 push rods next but I don't think I will change the heads as the stock heads flow really nice. I might change my mind. but either way when I do I'll have to go to a stage 3 Mopar tuner.
As for the 3" exhaust being too big, maybe, But .25" isn't a big leap and I got a lot of why nots to go with the too bigs from people who do this for a living. So like everything, It comes down to opinion and as I was going to get the cams I thought why not.
Ryzrt is probably right I should have gone with a 392 to begin with but I loved this RT plus, color and interior and Shaker and all the things about it and with the added money for the bigger engine with the other upgrades it was easier to come up with the occasional few thou in cash then to make bigger payments every month on the car and the increase in insurance ect. So once again it depends on your finances. I am retired (fixed income) but I have a small business on the side that nets me a few thousand every so often, but is not constant and I like tinkering with engines and stuff.. So this is what works for me. Once again it is about Opinion.