I did search and checked google. I was wondering if anybody has measured the size of the stock pipe diameters of the manifolds and the catalytic converters. I was a bit disappointed to find that the hr y pipe has duel 2 inch diameter pipes that go into a single 2 1/2 inch pipe so im guessing the cats and manifolds are also 2 inch but was hoping somebody could confirm this. I have an 04 touring edition and was going to get a duel 2 1/2 inch catback system (my stock exhaust is in bad shape) but I also have a 07 exhaust sitting in my basement (with a bent mid pipe) that I could use and save my money for something else. Was also going to get high flow cats at some point (whenever my stock cats become unservisable)

Anyways can anyone confirm the diameter of the stock manifolds and catalytic converters. Thanks

 

I can try to measure my cats and stock manifolds tomorrow after work.

 

Thanks. Im mostly curious but also seems pointless running duel 2 1/2 inch exhaust off a 2 inch manifold. And even if I end up getting high flow cats if they are connected to manifolds that have a 2 inch flange I might rethink my plans and just change from the engine back when I get around to swapping it out. Im sure the manifold bolts are probably the only ones I have any chane of getting off without power tools. Although headers look like a complete ***** of an install.

 

Good luck installing headers with the motor still in the car! I looked for a damn measuring tape and the kids have lost it but ill see if the wife will look for it while im at work.

 

Yeah dont think I would have that motivation would probably end up just rethinking my plan. I have probably easily 20 tape measures around my house (conservative estimate) and still have trouble finding them when I need one. Same with sharpies and pencils. They usually all make their way right next to my miter saw or table saw.

 

Well got home from work stupid late and still cant find a damn measuring device!

 

Im kinda surprised nobody actually knows after 200 views. And your the only one with these laying around. Maybe nobody wants to face the fact that their big exhaust is going through little manifolds.

 

Probably because most people dont change headers.. unless TT, or all out N/A, its not worth the trouble and noise for the minimal gain they provide. I had one of the original LTH designs made by Xerd a long time ago.. I had them changed back to stock a month later.. tons of noise for not much gain. And the shop I went to took 8 hrs to change headers out. Though im sure people are curious about the exact measurement of the flange.

 

So here is the measurements I just took. Keep in mind these measurements are not perfect they may be off by 1/8" or so.

Exhaust manifold
1 3/4" for the actual inner piping


2 1/8" for the connection


2 1/4" where Manifold meets cat


2 1/4" Cat meets Y pipe


2 1/4" Y pipe


Going off this I'm thinking whole exhaust is 2 1/4"

 

You the man. Thanks. It looks like 2 inches inside diameter your being generous calling it 2 1/4. Duel 2- 1/2" on stock cats might be over kill.

 

For anyone wondering about the stock y pipe