Vortech5300

I changed plates in the borla cutout from the 2 3/4" hole to the 2 1/4" hole to try to take out the dredded rasp, dog barking etc under normal acceleration and it seems to have quieted the car down some, especially inside but the rasp **** is still just as loud and had no effect on it. I guess next I will try the completely closed plate to test the effects of the rasp with the exhaust going completely through the muffler. If it still has no or little effect on the rasp, then ***** it, I guess I will run no plate at all and really **** people off. Is there no way to get a good clean, loud sound out of the borla without the rasp? Whats causing the rasp? the cutout or the borla muffler? Thought about changing mufflers but some members told me its the cutout, not the muffler so...Car is lowered so I can't fit a bullet muffler in the I pipe. Any ideas other then changing the exhaust all together? Or live with it? Sounds like total **** when accelerating through town and light to medium throttle, especially around 2300rpms.

LSUxBlake

iTrader: (3)

I had the same exact problem as you. No matter what plate you use, as long as it has any size hole in it the rasp will come through. I noticed the same thing even with my electric cutout on it, as soon as i'd tap it open just a bit, the rasp would come out the right side. It's just the nature of that exhaust. I ended up getting rid of it and going with hooker, and it has no rasp now If you want to keep your borla, put the fully closed plate in, that will clear up about 85% of the rasp.

kcshaner

Fully close it off, it will help

Vortech5300

Thanks guys! Going out now to put the closed plate in and see what it does. If the car is TOO quiet for me, then I will just run no plate at all and really let it rip! I like the sound of the exhaust with the big holed plate but its the rasp that I hate so...Guess its just part of having a cut out in there for max power. I could stick an electric cut out in it and drive it closed but when racing open it I guess but...I want the loud sound. Don't really want to switch systems but...

Vortech5300

Put the block off in there and its quiet as a church mouse. Sounds OK when on the gas hard, no rasp and pretty clean sounding but its just TOO freakin quiet at idle and low Rs. Sounds like a stock car thats missing or running bad. right now I have no plates in it at all and i am about to **** some people off. Guess I need to shop for cat backs now.

2000LS1Z28

Vortech5300, apparently you don't listen when guys who've had experience with this speak...THAT FREAKIN' ANNOYING/NASTY SOUNDING RASP IN THE MID RPMS IS BECAUSE YOU HAVE AN ORY (NO CATS)!!! I don't know any other way to get my point across when answering your question. Well anyways, that's why (catless Y-pipes create "rasp" on LS1's). It just sounds a lot worse with some systems (Borla, Loudmouth, Flowmaster) than others to which it is reasonably minimal (Hooker, SLP Dual/Dual, SLP 2OTL). Just bite the bullet and sell the Borla so you can replace it with one of those better ones I mentioned if you're dead set on running a "single exhaust/cat-back" set-up with your ORY. Like mentioned before, the Hooker (Aerochamber muffler) and SLP Dual/Dual cat-backs do a nice job of toning down the rasp while still sounding pretty clean...

BUT...If you want to get rid of that mid-rpm range rasp all together, have a highflow catted Y-pipe put on...OR ditch the cat-back/Y-pipe set-up for a true dual/X-pipe that does NOT have any rasp at all without cats and sounds 100x better than your current Borla.

Mike

Vortech5300

BELIEVE IT OR NOT, but it seems that running NO plate at all is actually SLIGHTLY less prone to the rasp then any of the other open holed plates. It will still rasp but it seems to require more throttle to get it to do it, also its actually quieter inside the car with the cut out FULLY OPEN then with the holed plates. I guess there is less turbulance or something to make noise. It is actually louder at the rear of the car now which is to be expected. I am gonna roll like this for a while and see if it bothers me, now 1/4 throttle doesn't seem to rasp, only 3/8 throttle and up. Prolly just gonna put a QTP elect. valve in there and when I NEED it quiet, I can have it quiet easy enough and when I want it loud I can do that to, all without losing 5-8hp by running through the muffler on any of those cat back systems you mentioned.

Vortech5300

BTW I cant believe how quiet it was through the muffler with the cut out closed, sounded like a stock car I **** you not. That must be one freakin packed muffler to know off that much sound considering its OR-Y and LTs and a big freakin cam.

JEB99TA

iTrader: (32)

I've got a small cam by today's standard and, with the plate closed, on a 112 LSA, it sounds nowhere near stock at idle, cruising, or WOT. I have the solid plate in right now and love it, but, my rebuilt QTP electric cutout will be back this week from the rebuild and the solid plate will go back on the garage wall hanger. The ability to open it up on a moment's notice is just too tempting to not put it back on the Borla's.

I have thought about running the 2-3/4' plate with a Borla XR-1 inline with the intermediary pipe. I think it would sound sweet. A lot of people here have recommended it. Seems like it would be loud, deep, and badass. I'll let you know if I decide to do it.

Rescue Ranger

iTrader: (10)

Sorry if this is a little off the topic, but I just recently bought an 2002 Z28 that came w/ borla catback..

How did you remove the plate completely? Is there a write-up on this? (*whistles* going to do a serach)

JEB99TA

iTrader: (32)

It depends if you have the adjustable Borla exhasut or not. If you do, the right side tailpipe unbolts from the rest of the exhaust ... just behind the right rear wheel, so you can change the plates. If there's no obvious 3-bolt flange there, then, it's not the adjustable Borla Catback, so, you can't change plates out.