Borla pro xs

[umbertorock04]

Just installed some mac longtubes on my foxbody(huge pain) and i decided to switch to a mac pro chamber and borla mufflers while i was at it. I noticed however that the borlas were 2 1/4" in diameter and i was wondering if that will affect performance since the pro chamber is 2 1/2 diameter and the borlas are 2 1/4" ? I also noticed that when i shook the mufflers up and down something that felt like sand would move and i was wondering if the mufflers have gone bad? Thanks for any input!

[FoxBodyNick]

lol well I dont know much about the issues your having but i sure would love to hear it when its done! i just ordered a set of Spintech Super Pro streets. and was debating if i wanted the borlas or not.

[umbertorock04]

I had heard some good things about spintech as well, but i had these laying around so im trying to make use of them. And thanks anyways ill try to post up a video when i get them put on.

[umbertorock04]

I recently installed the Mac long tube 1 5/8" headers, mac prochamer and dumped the borla pro xs's and it feels like it lost its low end torque completely. It pulls really good from 2500rpm and up but on the street i need as much low end torque as possible especially since it has the aod. It feels really sluggish from a complete stop. Im thinking the setup is a little too free flowing? Should i switch back to an h pipe or get different mufflers that may give a little more back pressure?

[Z06killinsbf]

Change the mufflers. You'll actually increase scavenging if you put 3" mufflers on it. The LT's will drop a little low end but make up for it on the top end. I put MAC 1-3/4 LT's, PC and Dynomax CB on a stock fox and stock it wouldn't spin from a roll but after it would. You don't want back pressure in an exhaust and you want it as free flowing as possible.

[sspstang]

My car has macs on it.

[umbertorock04]

I have 2 1/4 mufflers on it, i thought that maybe that would have increased velocity since the prochamber is 2 1/2? I thought longtubes may increase the torque/ lower the powerband? I have intake matched ported gt40ps is that helps.

sspstang: how did it feel after the macs?

[sspstang]

I have 2 1/4 mufflers on it, i thought that maybe that would have increased velocity since the prochamber is 2 1/2? I thought longtubes may increase the torque/ lower the powerband? I have intake matched ported gt40ps is that helps.

sspstang: how did it feel after the macs?

When I came to the cruise, everyone said my car sound good. Honestly I always thought 2 chamber flowmasters sounded the best on the foxes, but these macs sound excellent. I have the pro dumps. Its not as loud, as the 2 chamber flows, but it sounds good. Its like it actually has a sound rather then just a loud roar.

[crapstang]

My car has macs on it.

macs ftw

[umbertorock04]

How loud are they inside the cabin? Any drone?

[sspstang]

How loud are they inside the cabin? Any drone?

No, nothing like flowmasters. You can hear them a little bit, but I can hear my magnaflow on my truck and its ran out the factory tail pipe.

[umbertorock04]

I was considering magnaflow before as well but i guess not anymore lol. So maybe going with mac 3" will return a little bit of that low end torque to where i'd be quicker from a stop?

[sspstang]

I was considering magnaflow before as well but i guess not anymore lol. So maybe going with mac 3" will return a little bit of that low end torque to where i'd be quicker from a stop?

I would look into the macs, they sound good IMO, and this is coming from a flowmaster guy.

[Z06killinsbf]

I like the Spintechs over the Mac/Flows. Has a more aggressive sound. I have Magnaflow Magnapacks on my '66 and they are loud as fuck. I want to put Spintechs or 1 chambers on my car.

[crapstang]

I like the Spintechs over the Mac/Flows. Has a more aggressive sound. I have Magnaflow Magnapacks on my '66 and they are loud as fuck. I want to put Spintechs or 1 chambers on my car.

I hated flowmasters, they weren't that aggressive, but had the worst drone I have heard from an exhaust system. The macs on the mach are just right imo, but that's on a 4.6 not a 5.0, so idk how well it applies here