Pre-CAT info???

GreenMarine · #1 07-14-2006, 03:07 PM

Hey guys... I searched and wasn't able to find info on this... I need to find out the Input diameter and Output Diameter of the two stock Pre-CATs... I am buying new CATs as soon as I find out what size I need... Please someone help...

Thanks

Earthworm · #2 07-14-2006, 04:10 PM

Me too. A while ago it was thought that (V6?) Mustang cats were a decent replacement to our pre-cats.

mbtoloczko · #3 07-14-2006, 04:34 PM

inlet ID: 1.71", outlet ID: 1.61"

GreenMarine · #4 07-14-2006, 04:44 PM

Quote:

Originally Posted by mbtoloczko

inlet ID: 1.71", outlet ID: 1.61"

Totally positive dude? Would it be a PITA to adapt a 2" in and 2" out to the stock pipe or would you just have a new pipe made?

mbtoloczko · #5 07-14-2006, 04:51 PM

Absolutely positive. I've measured it numerous times, and I have it recorded in my database of SVX specs. Note that those are ID values. Tubing is typically measured in OD. The tubing before the precat will mate up perfectly with 1.875" OD tubing, but that stuff is rare. Thickwalled 2" OD will also have about the same ID as the tubing before the precat.

GreenMarine · #6 07-14-2006, 05:02 PM

Quote:

Originally Posted by mbtoloczko

Absolutely positive. I've measured it numerous times, and I have it recorded in my database of SVX specs. Note that those are ID values. Tubing is typically measured in OD. The tubing before the precat will mate up perfectly with 1.875" OD tubing, but that stuff is rare. Thickwalled 2" OD will also have about the same ID as the tubing before the precat.

Reason I ask is because I am ordering some Random Technologies Metal Substrate CATs (7000 Series)... I can't stand my stockers ratteling and crap all the time... It's time to get the clean refined Ferrari noise back... The smallest 7000 series CAT that they make has 2 inch inlet and outlets... I imagine that that is OD and not ID... So pretty much any exhaust shop will beable to do the job right? It's not really hard is it? I mean hard as in making the 2 inch CAT mate up with the 1.875 inch pipe.... Or would you say that I could just hack off the pipe all together and get that ("Mid-pipe" is it?) made out of 2 inch pipe then installed as one single piece with the CAT.... What would you do?

Beav · #7 07-14-2006, 07:25 PM

Save your money. Replacement 'main' cats also replace pre-cats functionality. You can replace them with pipe.

mbtoloczko · #8 07-14-2006, 07:30 PM

Quote:

Originally Posted by Beav

Save your money. Replacement 'main' cats also replace pre-cats functionality. You can replace them with pipe.

Odd as it seems, at least one person on the board has reported improved peak rpm power when he reinstalled his factory pre-cats.

Green, the 2" metal substrate cats will be designed to slip over 2" OD tubing. All exhaust components are like that (at least the many pieces I've seen with all the exhaust variations I've built). I'd recommend butt welding a short section of 2" tubing to the OEM tubing a few inches past the O2 sensors and then welding the precats to that 2" tubing.

GreenMarine · #9 07-14-2006, 08:39 PM

Quote:

Originally Posted by Beav

Save your money. Replacement 'main' cats also replace pre-cats functionality. You can replace them with pipe.

My Main CAT is non-existant anymore... I have the three piece Stebro... Except my piece that replaced the main cat is not a CAT at all... It is a hollow chaimber with sound materieal in it... Stebro calls it a "Euro Resonator"... I've heard a Stebro with the High flow cat and mine and mine is quite a bit louder under full throttle...

GreenMarine · #10 07-14-2006, 08:40 PM

Quote:

Originally Posted by mbtoloczko

Odd as it seems, at least one person on the board has reported improved peak rpm power when he reinstalled his factory pre-cats.

Green, the 2" metal substrate cats will be designed to slip over 2" OD tubing. All exhaust components are like that (at least the many pieces I've seen with all the exhaust variations I've built). I'd recommend butt welding a short section of 2" tubing to the OEM tubing a few inches past the O2 sensors and then welding the precats to that 2" tubing.

Cool, I'll see what the exhaust shop can do when I go there tomorrow

Earthworm · #11 08-10-2006, 04:58 PM

So what did you end up doing with this? Were there any other cats you were considering using? What did everything cost?