Latch

iTrader: (8)

So I just did a long tube and TSP ORY install, I already had a Magnaflow catback with a 3" DMH cutout in the I-pipe. With stock manifolds and cats the cutout was super tame, and the Magnaflow was damn near silent. But with the headers and ORY... holy ****, the cutout sounds like a machine gun at 3000 rpm and up. I've always heard sound clips online of raspy LS1s, but I'd never really heard it in person. It's the worst god damn sound I've ever heard!

On the other hand, the Magnaflow now sounds awesome. Still super quiet at highway speeds, but man does it sound great when you're on the loud pedal. There is zero rasp. I think I'll be selling my DMH in the near future and putting the cap on the cutout.

Thanks Magnaflow for saving me from the god awful rasp!

Raise

iTrader: (31)

Magnaflow does sound smooth as hell. And probably the best muffler for an ory setup

Stippy17

iTrader: (5)

Put a turn down on your cutout. Rasp will disappear. Ask me how I know.

1994_383_Z28

iTrader: (1)

True...

*02WS6TURK*

iTrader: (13)

Werd. I put a turn down on my DMH too. His biggest issue is, he doesn't have a cam in it

camaroboricua

iTrader: (23)

WHat?!?!!? He has the worlds first LS1 that runs without a cam!!!!! hahahaha Just messin with ya man!

Latch

iTrader: (8)

Really, a turndown is all that's required to tame the rasp? Sounds a little too good to be true. I was thinking it was going to need like a bullet muffler or cats to tame the rasp. If all it needs is a turndown I might just do that!

I like the way the cutout sounds up until it starts rasping at 2500... if I could just get rid of the rasp it would be perfect.

Stippy17

iTrader: (5)

I have a cell phone vid of my car idling thru the muffler, and opening the 4" cutout and idling out of it. I'll send it to you if you'd like just PM me your number. I don't like to free rev my car otherwise I'd take a vid proving my car has no rasp. Just straight loudness!

tittan1500

iTrader: (8)

Get a better y pipe like a flowmaster merge and that will help with rasp and you will pick up some HP

HoLLo

iTrader: (17)

I'm running a true dual setup, xpipe into dual SLP Loudmouth II mufflers, and when I added turndowns to the end of the mufflers, it definitely cleaned up the tone a LOT. So, I agree, add a turndown.

sweet99ss

iTrader: (41)

That's weird. My exhaust setup-Pacesetter 1 3/4 LT's, Pacesetter ORY, 3" cutout before axle into magnaflow catback. My setup has no rasp it just sounds ****** mean! It's way to damn quiet to me with just the magnaflow and the pitch isn't deep enuf.

MikeWS6

Magaflow sounds pretty quiet and weak with out a cut out. A little rasp never hurt anyone

Midnight02

iTrader: (8)

Great thread. This might prove to be the fix I'm looking for.

H/C/I + 1 7/8" LT's + ORY + 3" cutout in the Y-pipe of a Flowmaster (yes, I know it's crap) catback. I crack the cutout open 30%-40% to add a little volume and still get the benefit of the tone of the muffler (without the terrible restriction). The rub for me is the rasp from 2000 -2500 rpm. Driving me crazy.

Which fix is most likely the best solution (for getting rid of the rasp) -- turndown coming out of the cutout or replacing the entire catback with Magnaflow (or possibly Hooker)?

Latch

iTrader: (8)

So I did go ahead and put a turndown on the cutout. It didn't really help the rasp. It does make the drone a little more tolerable on the highway however.

As nice as the merge is on the TSP ORY, it's possible that the 2.5" reducer on the end of the merge is contributing to the rasp. I'm tempted to cut off the 2.5" section and have a proper 3" merge welded on.

Black96z28

Id love to see pics of where it is located on the exhaust, possibly a vid of it for referencing.


No you trolls I know where they generally get put, I have one on my car and the only time it annoys me is on deceleration, the rest is just loud.

Better yet, does it sound anything like this? I just recorded it today and it pops at higher rpms, but what annoys me is the mid rpm band ear ******* on decel.

redlineracing

iTrader: (1)

The reason you're hearing the popping is because of the lack of backpressure. I had the exact issue when I was running an open Y on my SS while I was in between catbacks.

If you guys hate rasp soo much, install a catted Y. Hands down the single best thing to do for helping with rasp.

HoLLo

iTrader: (17)

And out comes the backpressure claims.

redlineracing

iTrader: (1)

If I am incorrect in my statement just say no. There's no need for sarcasm.

Black96z28

Generally with our cars, beside the fact that by design LS-series motors have a higher tone. Rasp comes from inequalities in the flow of the exhaust.

These inequalities are mostly construction or design flaws for merge pipes (ie: y or x pipes). When you take the flow from the headers and merge them together at an extreme angle, the flow from each bank will fight the other at the merge point and make a pulse in the flow.

Pulses cause resonance which equates to vibration, drone and rasp. The less drastic the merges are, the better the flow and the better the sound.

Shamelessly copied pics from another forum to illustrate my point. Some of you may recognize these parts below, I am not saying they are 'bad' parts, but I know for a fact that their design causes rasp.

Bad merge for rasp.


Good.


Again too extreme of an angle, raspy.


Lol c5, but look at the merge.