Thread: Borla XR1 Muffeler and no Res?

a few ca guys have cut the hole to a 3 inch hole in and out on the factory cat, then welding the headers 3 inch down pipe to the factory cat.

or you need to find tog, or slp headers, both are carb compliant.

Originally Posted by silenthaven

So no power difference at all. Not trying to max out. To be clear this is my set up 104 autolites, 180 tstat, Overkill tune, k&n intake, zzp 3 inch downpipe, powerlog, 3.5 pulley and that pfyc borla catback muffler system. Now the 3 inch catback will do no good or better? Will at least adding XR1 borla mufflers sound better than the pfyc borla mufflers (assuming you have some idea of what they sound like :/) Not trying to sound v8 just trying to sound clean with a bit of volume and intimidation at a v6 level. Current setup sounds only slightly better than probably stock mustangs... idk

Want more flow.. Get rid of the plog/Dp and go with a set of headers. With your current setup there's no way your out flowing what you currently have.

The only mufflers from Borla that I've heard on the 3800 are the XS pro (that's what I ran stock and what I still run on my 3" setup). It's slightly louder but that's a giving going from the stock 2.25 to 3" exhaust but I'm also running a large 32" resonator that quiets it down. Only reason I went with 3" over 2.5" is because I got a hell of a deal on the piping and was way cheaper then what the 2.5 piping was selling for.


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Borla's, yes! No resonator, no!

YouTube. There a bunch of 3800 guys that run the XS I'm sure you'll find a few videos to compare


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Get to researching


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Originally Posted by Tonkin2000GT

What exactly does a resonator do? I have a camed/supercharged 3800 with slp headers and slp catback with no resonator or catalytic converter I do know what you mean you can't get it to sound like a v8 but it sounds good it has a deeper rumble to it. It does have a raspy sound when you get on it and let off quick or rev it real high not under load but it's a v6 I've come to the conclusion that there is nothing I can do about it.

When I found out my muffs were rusted out I thought I'd do some research around the web. From what I read the resonator, the longer the better, helps reduce drone from the exhaust if you have no cat.

I don't have a cat (or a cat-back for that matter), and I figured for the right price I should just do a res while I'm hacking up a couple exhausts because drone is bleh, and these cars you really do need mufflers. So, I found a cheap solution: buy brand new resonator the right width from a member here for a good price, bought a complete '07 exhaust off of Craigslist with 40k on it for $35, sell cat off of that. Total investment around $35.

And I just loath that raspy sound when under acceleration then backing off, anythign to avoid/keep that to a minimum I told myself.

Personally, unless your pushing a metric-ton of power the 2.5" exhaust seems to be just fine. (from what I've read) And unless it's turbo'd and/or cammed then spending anything extra on exhaust on a GP just seemed pointless to me, like spending 1k to try and sound like a V8 as some people do. The only essential thing seems to be getting rid of the restrictive U-bend on the 6th gens. I'd rather spend the money on power mods than exhaust, if I was trying to spend money on this old thing, lol.

Just my $0.02, from what I've heard(literally, lol)/read. I'm still a noobie though, so pardon me if I got anything mixed up.

Originally Posted by silenthaven

Thats what im doing. Not much on the xr1s not to mention my question is so specific.

Yup because 99% go with what's been proving to sound pretty damn good. That's why XS pro come up so much.



And yes the longer the resonator the better. Kills drone especially that god awful drone you tend to get during deaccleration. It'll never sound like a v8 so don't try to even it to sound like that.


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Originally Posted by REDCRAPGP

Yup because 99% go with what's been proving to sound pretty damn good. That's why XS pro come up so much.



And yes the longer the resonator the better. Kills drone especially that god awful drone you tend to get during deaccleration. It'll never sound like a v8 so don't try to even it to sound like that.


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Is the resonator worth having like how much does it fix? I just figured it would restrict the flow so why bother same with the cat.

Originally Posted by silenthaven

so youre insinuating that the xs pro are better than xr1?

No what I'm saying Is the XS pro have been used on wbody by several several people. Why reinvent the wheel? There's a reason why because they sound pretty damn good. Or you can get a set of those XR1, go through the hassle of welding them on.. And hope that you like it.


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Originally Posted by Tonkin2000GT

Is the resonator worth having like how much does it fix? I just figured it would restrict the flow so why bother same with the cat.

No it's a straight through design, it won't restrict flow. These cars sound like ass without a resonator


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Originally Posted by Tonkin2000GT

Is the resonator worth having like how much does it fix? I just figured it would restrict the flow so why bother same with the cat.

Have you ever seen the inside of a resonator?

After installing my Borla XS's (PO removed resonator), I went about two weeks before the drone made me pull out my hair. No resonator makes a HUGE difference.

I believe the XR-1 is more of a racing muffler, and is louder than the pro-XS. My favorite sounding set up on a 3800 is a glasspack in place of a resonator, and
two borla pro-xs mufflers at the rear. It's not raspy at all, and the glasspack gives it a bit of a unique sound too it.

It's a 3800.

It's always crappy sounding.

You can try and mask it all you want.

Big resonator, catless headers, and a quiet set of mufflers and larger diameter piping that probably isn't needed is going to net the best exhaust note without a turbo.

What's the best stainless resonator to use? Does it matter where you put it?