I am getting ready to order LT headers, and need help. I have the LM cat-back and wanted to know what would be better as far as getting the most power and eliminating some of the rasp goes.
1) keep LM as is, and get the y-pipe with Random Tech cats.
or
2) get ory, and replace resonator with bullet muffler.
I know alot of you guys have one of the two setups, and really need your help!
Thanks alot!

 

I have option #2 and it's still very raspy.
The only way to get rid of the rasp with a LM and LT's is to add cats from what I've seen.

 

Funny thing when I put my Vig3800 stall in it made most of the rasp go away.

 

I can't detect any rasp with CarSound cats. Longtubes and the LM is going to be LOUD without cats, even if you replace the resonator with a bullet muffler.

Josh

 

thanks for the replies, i guess I'll go with the cats. PPC has a y-pipe with the new Random Tech metallic cats, I guess that'll be my best bet. Does anyone know how much power am i sacrificing by doing this?

 

also, does anyone have the PPC headers? I'm about 99.9% sure i'm gonna get these unless anyone has anything negative to say. thanks.

 

I have the SLP LT's with LM and ORY. It's freakin' LOUD! I'm not sure what rasp sounds like, but I love the sound of my setup. SLP headers look nice, but I was told by Thunder Racing that the Hookers perform a lot better and they're a lot cheaper.

 

I have Hooker's w/ORP and LM.....and left it alone....I love the way it sounds. It is very possible to control the rasp..just have to drive it right.

 

Just get some removable cats and itll uncork about 10 hp without em. Not too sure if a muffler shop will do this or not. This is what makes the FLP system so great.

Mark

 

Defiantly need to put some cats on that beast. That will dissipate most of the rasp but I still think you will have a little bit.

 

thanks for the replies! I can deal with a little rasp, i mean, my stock setup with the LM has a little already. I've just never heard this setup in person and was worried it may sound like a dump truck dragging a metal garbage can! but after hearing from you guys, it sounds like i'll be happy as long as I follow everyones advice and get the RT high flow cats.

 

Another option to adding cats would be replacing the resonator with an oval muffler. That will do a much better job than the bullets. The only problem is you have to reshape the floor pan to make room for it.

I cut and welded my floor pan so I could replace the resonator with a Borla Sportsman offset muffler. I really like this setup because you can control the sound with the gas pedal, and there is no increase in back presure, no rasp and no drone. I ordered the muffler with 4 inch input and output pipe size, so I could just cut the center section out of the resonator leaving the ends there to perfectly fit into the Borla Sportsman.

 

thats a really good idea about the Borla, i never would've thought about that! but cutting and reshaping the floorpan is a little outside my ability.

 

In my own experience running various combinations during the prototyping stages of the PPC headers and Y-pipes, here's what I've found:

The headers with the RT Metallic cats and 3" y-pipe and stock WS6 exhaust - basically just like stock except for the sound of the exhaust pulses in the headers themselves.

The headers and 3" y with no cats and the stock WS6 exhaust - very quiet and similar to stock, but with an attitude. Very minor (what everyone is calling) rasp on high RPM decelleration. Could still hear the actuall headers (as above) For me..... too docile over all.

The headers with 3" y and Matallic cats and RT 3" cat back (which I like VERY much) - Definitely getting some attitude now. nice "rump" on start up and a deeper idle. Very nicly toned sound at throttle application. Not intrusive at all during cruise or driving arond town (as long as you maintain). Very minor deep toned rasp at high RPM decelleration.

The headers with no cats & 3" y and RT cat back - WOW ! I really like this combo... sound reall mean, but not too loud if you don't want it to be. Cruise is definitely a performance sound and it's there, but yet not intrusive. However.... Bang on the go pedal & WOOOOEEEEEE ! There ain't no mistaking that you mean business! It just flat out roars. Big rasp on decelleration... sounds really good in the car though,,, very low toned. Outside the car it's pretty noticable. After I went to the track, the first time with the whole new system (road racing), one of the workers by the 1st turn after the fron straight ... asked me if I had a Jake-Brake on it

The rasp that everyone is talking about is mostly due to the single intermediate pipe. It'll always be there, but you can muffle it out.

The RT Metallic cats do not cut any power unless you're way up there in the HP and cubic inches. All of the installs are getting 25 rwhp with or without the cats (on basically stock engines).

Hope this helps...

I do have a couple M-pegs of the car on the dyno with the last combo. If you have large email (5.5 megs each) I can email it to you.... or I'd be glad to copy to C/D and mail it.

Gordon
www.provenperformanceconcepts.com

 

Here's a link to the last 20 sec of one of the dyno runs:

http://www.provenperformanceconcepts...20MOV03212.avi


Gordon
PPC

 

You weren't kidding about the deceleration.

 

Thanks alot for the info and the link to that dyno run. Sounds really good, I'm just concerned about the loudness and rasp with my LM cat-back after I install headers. I've already been told that my exhaust is about as loud as it can get without the cops taking notice. I'll figure something out. Thanks again !