Exhaust: Cat won't fit TH downpipe

[#1HotRod]

Banging on this for hours. New 2.5" Hooker cat-back system is installed...looks great. Then fitted new TH downpipe, & like every rodder knows there's always lotza work & stuff goes wrong. The downpipe is quite longer that stock, so no room reinstall cat. Got a cutout w/ dump with downpipe & it can be cut down to fit, but not cat. Stock cat is 18 1/2" & only 10" open space. Live in Ca., so if not now will eventually need install cat. Our cats much different common ones because of the big flange. So...How on earth to make stock
18" long cat fit, or (easier route) find a 10" cat to fit 3" downpipe
that also will bolt to flange on exhaust
Should be common prob everyone w/ TH downpipe.
Posted similiar in Smog section but thought better coverage here.

 

[re-evaluating]

Cat

The TH downpipe can be ordered with a high performance cat instead of a test pipe. Just call who ever you bought the TH pipe from and order a cat. Red Armstrong (Quad Air) can provide it if you bought it from an individual or somewhere else.. It will bolt right in...

 

[#1HotRod]

Thanks Dave was hopeing so. But....will it funtion well-enough to help pass omissions when time comes down here in smog-unfriendly Ca? Is there a very-effective one that also fits? Or must we rely on a good smog chip for that? Car not radical, just putting in usual- 50lb'ers, adj fp reg., Walboro pump, better chip, etc., but no motor mods.

 

[86BLACKT]

I just bought a high flow cat last month from Full Throttle. Mike sent it to me in 3 days. I think it was $139 plus shipping.

 

[are_one]

I had the same problem as you. Come emmisions time I just put the old downpipe on my "special" converter setup. I had to make a short flange that would bolt to the cat-back and special cat, but if the TH converter works that would be much easier.

 

[86BLACKT]

I had an emissions chip burnt for me by Eric Turbotweak, I passed in Maryland on a dyno emissions test

 

[Marc87GN]

I went through this with the ATR Crossflow cat-back using the TH downpipe. I told Aggressive the space that I had between the 2 and ATR custom made the 3" 3 way cat the length I needed.

I was going to go with the TH cat, but I believe it's a 2 way and not a 3. The ATR cat I received was about 14 inches with the pipe they added and w/o the additional length welded, it's about 11.5-12 inches I believe.

 

[#1HotRod]

Cat for TH DP

Thanxx guys. The TH cat seems a natural & cheaper than I'd thought. I'm gonna have Eric do a street chip, so also will do a smog chip. Hay Marc...are you saying that ATR is 3 way & made yours to order? hope they have one that can fit a 10" open space (I can safely cut the TH pipe only about 1" to make for 11" open space). Either way I'm not as worried now about satisfying smog check. BTY, what is email or tel # for ATR?

 

[Marc87GN]

Re: Cat for TH DP

Originally posted by #1HotRod
Thanxx guys. The TH cat seems a natural & cheaper than I'd thought. I'm gonna have Eric do a street chip, so also will do a smog chip. Hay Marc...are you saying that ATR is 3 way & made yours to order? hope they have one that can fit a 10" open space (I can safely cut the TH pipe only about 1" to make for 11" open space). Either way I'm not as worried now about satisfying smog check. BTY, what is email or tel # for ATR?

http://www.atrperformance.com/contact_us.php?ATRid=2a2236dcab72b73cf659125e4d3adb3c

Tell them what size you need and they will make it fit. They wouldn't ship mine until I gave them the measurements.

Marc

 

[MSDGN]

I've passed emissions here in AZ many times with a TH cat and it's pretty strict here...

 

[Reaper]

Originally posted by MSDGN
I've passed emissions here in AZ many times with a TH cat and it's pretty strict here...

i second that, we are as tuff as cali here in AZ. get a good emissions chip (thrasher is my fav.) and your set.

 

[#1HotRod]

Luv this site..............

 

[John Wilde]

I just had my hooker system put on this afternoon.
With the cat I had given they had to cut about 2inches
off of the TH DP for it to fit. Damn this thing is silent!