Question about Flowmaster Catback + LT Headers - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Ject · 12-04-2010, 11:43 AM

I have the Flowmaster American Thunder Catback system installed and here shortly I'll be installing some Longtube headers with a 3" intermediate pipe next week.

Well the Catback system is 3" and then tappers down to fit the stock header/cat 2.5"

So my Question is, has anyone done this combination yet? Did you have to 'cut' off the tapered spot on the cat back and replace it with 3" pipe?

Im kind of at a lose right now but I think I have to cut the 2.5" tapered spot on the cat back and weld some 3" pipe to fit the intermediate pipe (non cat).

Thanks in advance

RedRyder · 12-04-2010, 12:52 PM

Well you don't really have to. How it usually works is the 2.5" part is used to connect to a long tube short system (Long tubes and midpipe) both ARH and Kooks offer them and they have a 2.5" taper as well.

You could cut off the 2.5" taper on both the cat back system and the midpipe from the headers system and weld in a 3" intermediate pipe. But I'm not sure how much is to be gained from doing that. The Flowmasters will straight up bolt on to both those short systems I mentioned.

I have just the cat back currently but when I put on headers I'll just leave the 2.5" little choke point since I don't really think it is choking the system all that much.

Post some videos when you get done

EDIT: Just reread your post and realized you already have a header system with a 3" end. In that case, cutting and welding would be a good option. Don't know which header system you have but you might need a little extra 3" piping to fill the gap.

Ject · 12-04-2010, 06:41 PM

Quote:

Originally Posted by RedRyder

Just reread your post and realized you already have a header system with a 3" end. In that case, cutting and welding would be a good option. Don't know which header system you have but you might need a little extra 3" piping to fill the gap.

I'm thinking this is what I'll have to do.
I have they Dynatech SuperMAXX headers and 3" intermediate pipe. (no cats)

Appears best bet will be to cut the 2.5" tapered part on the Catback off.
Replace it with the same length but in 3" pipe.
then just slide the headers + intermediate pipe into place.

metallicide · 12-04-2010, 06:46 PM

I have a sound clip up right now...look a few threads down and you will find it

Kooks LT with Flowmaster AT exhaust. Sounds GOOD but a slight drone problem. Video does it no justice.

Agent orange · 12-09-2010, 05:07 PM

i just got my ARH long tube 1 7/8 short system installed with my flowmaster 3" catback exhaust. sounds perfect! and well performed with tune! thanks for racers edge tuning.

12-04-2010, 11:43 AM	#1
Ject aka Patrick Drives: '10 Camaro 2SS '04 Silverado Join Date: Jan 2009 Location: Derby Kansas Posts: 3,072	Question about Flowmaster Catback + LT Headers I have the Flowmaster American Thunder Catback system installed and here shortly I'll be installing some Longtube headers with a 3" intermediate pipe next week. Well the Catback system is 3" and then tappers down to fit the stock header/cat 2.5" So my Question is, has anyone done this combination yet? Did you have to 'cut' off the tapered spot on the cat back and replace it with 3" pipe? Im kind of at a lose right now but I think I have to cut the 2.5" tapered spot on the cat back and weld some 3" pipe to fit the intermediate pipe (non cat). Thanks in advance __________________ Current Modifications: Your average Bolt-ons & Suspension Upgrades GForce Engineering: 9" Rear End, Strange Pro Iron Case w/Moser Nodular 3.70:1 Detroit locker, 3.5" Solid Drive Shaft

12-04-2010, 12:52 PM	#2
RedRyder Drives: 2010 VR 2SS/RS M6 Camaro Join Date: Feb 2010 Location: Atlanta, GA Posts: 499 View My Garage	Well you don't really have to. How it usually works is the 2.5" part is used to connect to a long tube short system (Long tubes and midpipe) both ARH and Kooks offer them and they have a 2.5" taper as well. You could cut off the 2.5" taper on both the cat back system and the midpipe from the headers system and weld in a 3" intermediate pipe. But I'm not sure how much is to be gained from doing that. The Flowmasters will straight up bolt on to both those short systems I mentioned. I have just the cat back currently but when I put on headers I'll just leave the 2.5" little choke point since I don't really think it is choking the system all that much. Post some videos when you get done EDIT: Just reread your post and realized you already have a header system with a 3" end. In that case, cutting and welding would be a good option. Don't know which header system you have but you might need a little extra 3" piping to fill the gap. Last edited by RedRyder; 12-04-2010 at 01:18 PM.

12-04-2010, 06:46 PM	#4
metallicide Drives: 2010 Camaro 2SS Join Date: Jul 2010 Location: Illinois Posts: 398	I have a sound clip up right now...look a few threads down and you will find it Kooks LT with Flowmaster AT exhaust. Sounds GOOD but a slight drone problem. Video does it no justice. __________________

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12-09-2010, 05:07 PM	#5
Agent orange socal ht5 Drives: 2010 Camaro ss Join Date: Dec 2010 Location: Valley village CA Posts: 469	i just got my ARH long tube 1 7/8 short system installed with my flowmaster 3" catback exhaust. sounds perfect! and well performed with tune! thanks for racers edge tuning.