One cat as opposed to two cat's??
Thread Starter
Launching!
Joined: Jan 2002
Posts: 249
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From: NY
One cat as opposed to two cat's?? I just put Hooker LT's on my car, and I brought it down to the exhaust shop and the guys said that the exhaust would flow better if I put one cat after the two pipes in the ypipe connect. Is this true? I need an answer cause I want to get the y-pipe to be made within the next couple of days.
Thanks
Joe
Thanks
Joe
Re: One cat as opposed to two cat's?? You mean they are suggesting you run a single cat behind instead of two in the Y-pipe? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
The best flowing single cat I've ever seen numbers on was a bit above 500cfm (big 9000-series Random Tech). Even if you put this big boy behind your Y-pipe it would cause a bigger restriction than a pair of bullets in parallel. Assuming a regular 2.5" or 3" bullet cat (RT or Car Sound) behind each header flowed a conservative 330 cfm, you'd be looking at 660 cfm of total flow capacity through the two pipes. This is 32% more flow than the single 9000-series RT I mentioned earlier.
Now, if you could find some monster cat that flowed like 700 cfm, then maybe it'd be close (of course two of those would be even better <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> ).
Unless I'm missing something two cats in the Y-pipe is the way to go.
The best flowing single cat I've ever seen numbers on was a bit above 500cfm (big 9000-series Random Tech). Even if you put this big boy behind your Y-pipe it would cause a bigger restriction than a pair of bullets in parallel. Assuming a regular 2.5" or 3" bullet cat (RT or Car Sound) behind each header flowed a conservative 330 cfm, you'd be looking at 660 cfm of total flow capacity through the two pipes. This is 32% more flow than the single 9000-series RT I mentioned earlier.
Now, if you could find some monster cat that flowed like 700 cfm, then maybe it'd be close (of course two of those would be even better <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> ).
Unless I'm missing something two cats in the Y-pipe is the way to go.
Re: One cat as opposed to two cat's?? Also keep in mind that the further away the cat is from the engine the longer it takes to "light" up for emissions purposes...This is all assuming you ARE doing this for emissions... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
TECH Resident
Joined: Mar 2002
Posts: 770
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From: WA
Re: One cat as opposed to two cat's?? I have the same problem. No cat clearance. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />
Putting the cat after the Y is not a good idea.
1.The Cat is too far back to operate correctly.
2.Putting the cat after the Y collector will hurt flow badly. Two flow better than one. The Y section is already a bottleneck.
Putting the cat after the Y is not a good idea.
1.The Cat is too far back to operate correctly.
2.Putting the cat after the Y collector will hurt flow badly. Two flow better than one. The Y section is already a bottleneck.
Joined: Nov 2001
Posts: 34,629
Likes: 2,550
From: Schiller Park, ILL Member: #317
Re: One cat as opposed to two cat's?? LT1 cars have the cat after the Y. Why would that not light off fast enough in an LS1 setup? Just make sure the cat is good and hot before the test.
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Thread Starter
Launching!
Joined: Jan 2002
Posts: 249
Likes: 0
From: NY
Re: One cat as opposed to two cat's?? Truthfully after hearing the response I'd rather just put the two in and get it over with. If the Carsound cat's can only flow at best 300cfm and I'm pushing anywhere from 300-400cfm out of each header than one cat is really going to restrict flow alot. I'm still open to anyone's suggestions or comments. Please keep them coming.
Thanks
Joe
Thanks
Joe
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