After the 6.4 swap any recommendations on exhaust pipe sizing?

WadXpress · Nov 14, 2021

My cammed 6.4 srt motor should be here in 2 weeks and I just thought about the exhaust piping size. I already run 1 7/8 ARH headers and 14” magnaglow mufflers( which may be to loud after the swap) but the piping is all factory sized. Should I have it upsized from the cats back? If I go with a roll pan when I do the exterior I’ll probably dump them after the rear axle but for now it’s the dual out the rear. Any thought or recommendations about size and back pressure, x-pipe etc? Thanks

crazykid1994 · Nov 15, 2021

Dual 3” pipe all the way back with an x pipe and 2 mufflers would be my go to. Or a crossover style muffler instead of the x pipe and 2 mufflers to save a few dollars.

RedSRT4Me · Nov 15, 2021

Another vote for 3" exhaust piping

WadXpress · Nov 15, 2021

Yea I believe 392 cars have factory 2.75” piping. So I think 3” should be good with a x pipe. Now the hard part will be picking mufflers

crazykid1994 · Nov 15, 2021

I’m a huge fan of borla after the catback kit I put on my truck. Corsa sounds to high for me where borla sounds deeper in my opinion. But I know that’s very dependent on each vehicle and each specific setup.

WadXpress · Nov 15, 2021

Also what makes it tough is when people don’t post what exhaust they are running especially on the cammed 6.4 videos

WadXpress · Nov 15, 2021

2018 6.4 challanger MMX MAX effort 6.4 cam

2k18 challanger SRT8 running MMX MAX EFFORT 6.4 cam, stainless works 1 7/8 longtubes, high flow cats, circle D 3200 stall convertor, borla exhaust. Built by ...

youtu.be

I like the way this borla exhaust sounds and this is the cam I’m getting. Just gotta figure out which borla mufflers these are. Borla atak?

Crooks1130 · Nov 15, 2021

Not exactly what you are looking at, but I ran an electric cutout directly after the Y pipe on ARH long tubes. It is stupid loud when open but had an annoying rasp. I got on Amazon and found a TotalFlow 645 mini muffler that is 4” long and welded it onto the turndown of the cutout. Is still crazy loud and was just enough to pull the rasp out of it for a clean sound. The cam chop is very nice with it and seriously turns some heads.

When the cutout is closed, everything runs through the factory exhaust so I have the best of both worlds.

All I have is small sound clips of idle with the 5.7 but I’m in the middle of a 6.4 swap right now. Should be cranking it for the first time by the end of the week.

WadXpress · Nov 16, 2021

Crooks1130 said:
Not exactly what you are looking at, but I ran an electric cutout directly after the Y pipe on ARH long tubes. It is stupid loud when open but had an annoying rasp. I got on Amazon and found a TotalFlow 645 mini muffler that is 4” long and welded it onto the turndown of the cutout. Is still crazy loud and was just enough to pull the rasp out of it for a clean sound. The cam chop is very nice with it and seriously turns some heads.

When the cutout is closed, everything runs through the factory exhaust so I have the best of both worlds.

All I have is small sound clips of idle with the 5.7 but I’m in the middle of a 6.4 swap right now. Should be cranking it for the first time by the end of the week.

You plan on keeping the factory exhaust for the 6.4? You don’t think it’s too small? I get you can just open the cutouts but the factory exhaust seems like it will be too small

Crooks1130 · Nov 16, 2021

WadXpress said:
You plan on keeping the factory exhaust for the 6.4? You don’t think it’s too small? I get you can just open the cutouts but the factory exhaust seems like it will be too small

I honestly haven’t thought about that. I rarely “got on” my 5.7 with the cutout closed, it was more for cruising. Although it was nice to have it closed at the track until right when you do a burnout lol.

I’ll have to do some research about back pressure and all to make sure keeping the stock won’t mess anything up. 3” into duel 2.5 on the ram vs 2.75 duals all the way out on the SRT8’s is quite a difference.

Im more paranoid right now on if this thing will actually crank up and run. No reason that it shouldn’t, but with the time and money I’ve got in it right now, it’s got me on the edge of my seat lol.

WadXpress · Nov 16, 2021

Crooks1130 said:
I honestly haven’t thought about that. I rarely “got on” my 5.7 with the cutout closed, it was more for cruising. Although it was nice to have it closed at the track until right when you do a burnout lol.

I’ll have to do some research about back pressure and all to make sure keeping the stock won’t mess anything up. 3” into duel 2.5 on the ram vs 2.75 duals all the way out on the SRT8’s is quite a difference.

Im more paranoid right now on if this thing will actually crank up and run. No reason that it shouldn’t, but with the time and money I’ve got in it right now, it’s got me on the edge of my seat lol.

Lol I bet. Plus the im doing a ported intake and a cam so that’s why I think I need to upsize the factory exhaust

crackerjack1957 · Nov 16, 2021

Probably get a better deal going thru Nick@GotExhaust

By Vehicle - Dodge - Ram - 2009-23 Ram 1500 Classic - Stainless Works

stainlessworks.net

Wild one · Nov 16, 2021

Crooks1130 said:
I honestly haven’t thought about that. I rarely “got on” my 5.7 with the cutout closed, it was more for cruising. Although it was nice to have it closed at the track until right when you do a burnout lol.

I’ll have to do some research about back pressure and all to make sure keeping the stock won’t mess anything up. 3” into duel 2.5 on the ram vs 2.75 duals all the way out on the SRT8’s is quite a difference.

Im more paranoid right now on if this thing will actually crank up and run. No reason that it shouldn’t, but with the time and money I’ve got in it right now, it’s got me on the edge of my seat lol.

Stock dual pipes after the muffler are 2.25",most aftermarket catback exhaust kits up that to 2.5". A big single 4" is another option to consider especially if you plan on doing a rollpan and turndowns after the axle down the road.

Crooks1130 · Nov 16, 2021

WadXpress said:
Lol I bet. Plus the im doing a ported intake and a cam so that’s why I think I need to upsize the factory exhaust

I’ve got a “Demon” cam from Demon Motorsports in this one that I took out of the 5.7
Specs on it are:
220/231 .582/.582 112+3

I’m just going with a ported 5.7 intake on it for now and see how it performs. From what I understand, the 6.4 intake gives it more low end torque. I’m running 4.56 gears in a 6 speed and already had a hard time getting traction on drag radials. Not sure if more torque is what I’m needing lol

WadXpress · Nov 16, 2021

I do like the idea of a tame muffler and then cutouts by I always see people complaining that they leak or don’t work. Anybody have a suggestion on a x pipe or catalytic converter brand? Or are they all about the same

WadXpress · Nov 17, 2021

Damn borla mufflers are almost 300 bucks a piece

ews25 · Jun 1, 2022

What'd you ever do here? My (not cammed) Scat pack 6.4 is up and running and I need (want) to upgrade the factory exhaust, which in my case is the old 2.5 y pipe into a single 3 all the way back to the right rear. Thinking about having the shop cut the y and run side by side 2.5s into a dual in dual out Borla ProXS at the stock muffler location.

WadXpress · Jun 1, 2022

I did 3” into a x pipe into dual borla atak 3” mufflers and dumped before the rear axle

hemihustlin · Jun 2, 2022

WadXpress said:
I did 3” into a x pipe into dual borla atak 3” mufflers and dumped before the rear axle

i bet that sounds amazing!

BlackGold6.4 · Jun 2, 2022

I have single exhaust so I'm looking at a muffler from FlowMaster, it has dual 3' in and single 3.5 out ..

After the 6.4 swap any recommendations on exhaust pipe sizing?

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