Borla resonator question - (inlet choke)

[Corvette95]

I was lucky enough to be at the right place at the right time to score a new "old" Borla stainless steel exhaust ( cat back). The resonator has the 1 5/8 inlet restriction, which per Marc H, cost horsepower, and he also states the system is great with the resonator removed. So my question is this, has anyone tried to use the resonator and open up the choked inlet and if so, what was the difference in noise and or resonance? Two, does anyone know where I can get a stainless "x" pipe (of any brand) that I could use in place of the Borla? Three, I can try to install straight Vibrant brand resonators (2). Thoughts and suggestions appreciated.

[Corvette95]

Hey! Thanks! Good information! I?m am on mobile so can?t see the pictures right now, is the magnaflow stainless as well?

[XfireZ51]

I originally started out w the MF cat back but swapped out the resonator, which had an internal ?X? pipe but was really a Y pipe, for the SW Xpipe. The internal cheese grater that was in the SW X was removed. Then the 3? ID pipe continues into 3? ID inlet DynoMax Ultraflows. The UFs have C6 Z06 NPP tips welded onto them with vacuum control in the console.

[Corvette95]

I like the idea of the valves, I was/am eventually planning on a B/B Fusion system. That was before I came across this Borla. How do you get vacuum to the exhaust valves also, I see some brands with electric blades. I have found this 2.5 in Ford resonator (would mount upside down so "Ford" isn't visible, or maybe two straight Vibrant resonators. I want something that would "clamp" in instead of weld if possible.

[XfireZ51]

The 92 ZR has the charcoal canister in the right rear corner of the chassis while the 90 is in the front left hand corner. The 92 vacuum line is routed from the plenum to the right rocker panel where there is a hard plastic line running towards the back and over to the canister. The vacuum has been re-routed to the NPP valves instead. I?m using a vacuum solenoid to control vacuum flow to the valves. Most of the time I run w the valves closed.

[Corvette95]

That's what I figured. My 90 is the last year of the front corner charcoal canister. I am thinking pro's and con's of vacuum vs electric. Don't really want to be able to see either a vacuum line or non stock electrical wires. I would hide either some where. If electric, I could run wires from center console cigarette light or accessory a/c port OR maybe I could install an additional secondary pump for vacuum. I like everything neat, so would love to see yours and others installation solutions. I SOOOOO want to be completely done by Dec. 31st! Thats my latest arbitrary deadline!

[Corvette95]

So went by exhaust shop to talk about install options for the Borla. Again, according to Marc H, the Borla resonator has a 1 5/8 in choke. I took the resonator off and found this (pics below). Does this look restrictive? I was going to go with the 3 in straight resonators from Vibrant like Phil put on his car but they will be too short and will have to have an extension if I go that route, I would like to do the stainless flexible extensions but my main question is does this Borla look like it has the choke described by Marc, it is the first Gen Borla. The OD is 3 inches with ID 2.75. I am exhaust illiterate. I am also need good band clamps but not sure what to get and should the be butt type joints?

[Paul Workman]

I pulled the restrictive Borla for an equally restrictive MF cat back. But, the inlet to that resonator too was every bit as restrictive (maybe a tad more!) than the Borla. But, after installing the 3" SW headers I replaced the Mag. Flo resonator with a Stainless Works "X" pipe. The combination did contribute to "seat of the pants", for sure, but it was the top end porting that really woke the LT5 up - transitioned it into an entirely different experience! (And, poring the heads too a year later, put me at the precipice of 510 hp.).

About the only thing GOOD I have left to say about the Borla is there was no droning. I still have the Magnaflo mufflers - with their 3 to 2.25" inlets b/c they don't drone as badly as the full 3: inlet muffs, e.g., B&B or Ultra Max (unless you have one of the outlets gated with a vacuum or manual/electrical "flapper" valve).

If you like the sound, the Corsa exhaust with headers will, according to something Marc Haibeck wrote, provide max performance w/o drone (the Corsa is something like a 2.5 ID or close to that: not a 3" system).

A good breathing exhaust is very important part, far as unleashing the hidden HP burried in the stock LT5 goes. But, from personal experience, the Borla system was an impediment to performance. The only good thing about it was there was no drone with the system.

Just 2 cents from a former Borla owner.

[32valvesftw]

I had a full Borla set up on mine, I had the resonator replaced with an X-pipe. It made a noticeable difference in sound and seat of the pants feel. It did make the exhaust quite a bit loader. If I had to do it again I would have left the resonator in place.

[tf95ZR1]

I replaced my Borla resonator with a B & B X-pipe.
Same day before & after dyno gained 25 hp. I personally
don't find it to be louder at all. Yes, resonance @ 1800 RPM,
which usually happens to be my cruising range.
Damn, but oh well.
Add to that the transmission chatter of a lightened
flywheel makes for a symphonic driving experience!
But at WOT...