For Borla CATback owners
For Borla CATback owners Two reasons why I need your opinion on how the setup below might flow, sound, and perform:
1. Get rid of the MAC ORY rasp between 2000-2500 rpm. (No setup like this on LS1SOUNDS.COM)
2. Slightly larger cam with AFR heads in my sig.
SETUP: Universal Random Technology 702500 metal CATS. Round 4" diameter 2 1/2" inlet and 2 1/2" oulet 10 1/2" long (counting the inlet/outlet pipe). One welded into each side of my ORY. The REAR Borla CATback muffler will be replaced by a 3" stainless straight pipe ... allowing better flow out both sides ... instead of pushing the exhaust gas through the Borla muffler out one side. This has to be a major flow restriction.
1. Get rid of the MAC ORY rasp between 2000-2500 rpm. (No setup like this on LS1SOUNDS.COM)
2. Slightly larger cam with AFR heads in my sig.
SETUP: Universal Random Technology 702500 metal CATS. Round 4" diameter 2 1/2" inlet and 2 1/2" oulet 10 1/2" long (counting the inlet/outlet pipe). One welded into each side of my ORY. The REAR Borla CATback muffler will be replaced by a 3" stainless straight pipe ... allowing better flow out both sides ... instead of pushing the exhaust gas through the Borla muffler out one side. This has to be a major flow restriction.
So you are just going to run cats and no mufflers. I don't think that will sound good at all. I don't think it's been done. You can try it out. You might just find the new sound. 
LOL! I hope you're right. I remember when I ditched my cats a year or so ago. Just getting rid of them made my car sound SOOOO loud thorugh the Borla muffler. I don't see why it couldn't work the other way around. If it sounds like asswipe, then, I can always put a XR-1 race muffler in the intermediary ... still should flow a lot better than pushing all that air mass through the current Borla muffler out only one tailpipe.
The 'new sound' ... that would be crazy ... hehehe!!!
The 'new sound' ... that would be crazy ... hehehe!!!
Launching!
Joined: Feb 2005
Posts: 238
Likes: 0
hell I am dealing with the same problem... With no plates or any of the plates, the rasp at 2000-2500 is just too crappy sounding. With the block off plate in there, sound on the road is really good but its just TOO quiet at idle. I have LTs, ORY and MS3 cam, I want to here the biatch at idle. I do notice better throttle response and more low end torque with the block off in there but I am sure its hurting HP some.
I talked to Borla today, they recommended changing the regular borla catback muffler to a Borla PRO-XS #40359. Its basically the same muffler that comes on the catback but its 5" shorter and supposedly flows more, although I don't see how since they are all straight through. I don't want to change from the borla to anything else but I gotta get some sound. My car is lowered so a XR1 in the I is not an option.. MAYBE a bullet. I don't want to be hacking up the exhaust just to try different things.
I talked to Borla today, they recommended changing the regular borla catback muffler to a Borla PRO-XS #40359. Its basically the same muffler that comes on the catback but its 5" shorter and supposedly flows more, although I don't see how since they are all straight through. I don't want to change from the borla to anything else but I gotta get some sound. My car is lowered so a XR1 in the I is not an option.. MAYBE a bullet. I don't want to be hacking up the exhaust just to try different things.
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Teching In
Joined: Dec 2004
Posts: 37
Likes: 0
I have a similar setup to what you are planning, I think. I have the FLP header system so I can have a catted y-pipe or ORY pipe. I have the borla cat-back also. If I take the cats out I pretty much HAVE to put the full block off plate in my borla to keep the noise/rasp down. Even then it's still raspy as hell. BUT, when I put the cats in and leave the plate wide open, it sounds NICE. I get compliments all the time from other f-body owners and LOTS of mustang drivers give me the thumbs up on the sound. It's nice and deep and no rasp at all during normal driving. It still gets a little raspy up by the redline, but for the most part I think it sounds awesome.
Like the above post, the car isn't extremely loud at idle but it gets REALLY loud REALLY quick.
Plus with the cats in, it smells better.
Like the above post, the car isn't extremely loud at idle but it gets REALLY loud REALLY quick.
Plus with the cats in, it smells better. Good postings A little rasp at 6000+ is a good thing IMHO. I'm hoping the low-end rasp will be gone. It makes sense to me that this setup will work well. The main thing for me is exhaust flow, but, sound and exhaust tone ranks right up there with the flow, as well. 
If this sounds as good as I think it will sound, I'll do as I planned and replace the Borla muffler with a piece of straight 3" stainless pipe to allow flow out both sides. If nothing else, at least, in cold weather, it with make vapor clouds out both sides ... LOL!!!!
If this sounds as good as I think it will sound, I'll do as I planned and replace the Borla muffler with a piece of straight 3" stainless pipe to allow flow out both sides. If nothing else, at least, in cold weather, it with make vapor clouds out both sides ... LOL!!!!
Teching In
Joined: Dec 2004
Posts: 37
Likes: 0
Yeah, I've actually considered doing the same thing because I never use the block off plate anymore. I figured I could even up the sound and drop a little weight by losing the muffler.
IMO, it sounds the best. There is no rasp down low but it really screams when you get up high. I've got a couple friends that always want to take the t-tops out and drive underneath over-passes to hear the exhaust echo really loud.
You will be happy with the sound. I've yet to find someone who isn't amazed at how good the car sounds.
IMO, it sounds the best. There is no rasp down low but it really screams when you get up high. I've got a couple friends that always want to take the t-tops out and drive underneath over-passes to hear the exhaust echo really loud.
You will be happy with the sound. I've yet to find someone who isn't amazed at how good the car sounds.
Launching!
Joined: Feb 2005
Posts: 238
Likes: 0
Anyone ever tried putting a bullet in place of the borla muffler(in the rear, not the I pipe) and run the cut out closed? Wondering if that would knock out some rasp.. I would like to find a happy median between the awesome idle sound of the open plate but try to cut some of the rasp down. I know you won't get rid of all of it but...if I could split the difference I would be happy. My car with the block off in there is just TOO quiet at idle.. I want to hear that choppy, nasty sounding idle the Magic stick gives.
Accomplished the mission. Rasp is 100% GONE! ... exhaust is sealed. I had 2 high-flow, 10 1/2", RT 72500, universal cats welded in each side of my MAC ORY. Fitment is beautiful, sound is awesome, rasp is gone, clearance great, and the MAC collector was replaced with a 2.5" > 3" Flowmaster collector that was welded into the intermediary.
Anyone think I should replace the Borla muffler with a straight piece of 3" stainless straight pipe for flow out both tips. What do you think it will sound like and how much better do you think it will flow?
(JRP? You listening?
)
... exhaust is sealed. I had 2 high-flow, 10 1/2", RT 72500, universal cats welded in each side of my MAC ORY. Fitment is beautiful, sound is awesome, rasp is gone, clearance great, and the MAC collector was replaced with a 2.5" > 3" Flowmaster collector that was welded into the intermediary.Anyone think I should replace the Borla muffler with a straight piece of 3" stainless straight pipe for flow out both tips. What do you think it will sound like and how much better do you think it will flow?
(JRP? You listening?
) Last edited by JEB99TA; Sep 11, 2005 at 04:00 PM.
