# Custom vs. Prefab Cat-Back + Cat Delete Question



## Stephen Hopkins (Feb 6, 2006)

I'm wondering if anyone has any experience with deciding between a pre-fab catback system vs. having it custom fabricated at a muffler shop? I've gone the custom-fab route with past vehicles and have been extremely impressed w/ the price/performance ratio. At the moment I'm planning on simply having a summit racing x-pipe and flowmaster delta 40s installed with stock pipe and tips. I'm pretty sure I can have this done for at or under $300 from a small shop I know and trust. Any input or comparissons with a comparable low priced cat-back system?

Also, what is the diameter of the stock pip? 2.25"? 2.5"? I'm currently at school and don't have access to a jack. When I'm home for spring break in about 3 weeks i can get it up on jack/stands or on the lift at the muffler shop and get a better look...

Also i'm considering having the cats deleted. By looking at a stock photo of the undercariage it looks like there are 2 sets of cats, i.e. 2 cats per exhaust path. 

http://www.newagegto.com/X04AR_PN002.jpg

Would I have both sets deleted or just the second set farther back which appear to be past the O2 sensors. Will having both deleted cause any check engine lights? Will just having the second deleted avoid that possibility? Or am I completely misreading the undercariage photo and there's only one set per exhaust path?

Thanks in advance


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## PEARL JAM (Sep 6, 2005)

One converter per side. That other, smaller looking thing is the resonator. (Also one per side.)
Before I put my headers on I was running stock exhaust with the Flowmaster Delta 40's, those alone provided good sound and a noticable increace in power.:cool


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## Stephen Hopkins (Feb 6, 2006)

I think deleted resonators, summit x-pipe, and undecided mufflers are the way i'll go. Can anyone comment/compare the following mufflers:

Dynomax Ultra Flo
Summit Stainless Steel (polished)
Flowmaster Delta 40

Any input on the cheaper mufflers like Dynomax Super Turbo, Dynomax XL 3, and Dynomax Thrush Turbo? How do they sound and how do the affect performance?

And PEARLJAM... any chance your Flowmaster Delta 40s are for sale?

Thanks


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## CrabhartLSX (Feb 12, 2006)

Stephen Hopkins said:


> Can anyone comment/compare the following mufflers:
> 
> Dynomax Ultra Flo
> Summit Stainless Steel (polished)
> ...


Certainly. I can say from some experience that the Dynomax Ultra Flow is the best out of those mentioned. The summit mufflers follow the edelbrock design philosophy, and flowmasters are just flowmasters, mediocre to the last degree.

The other ones, such as the super turbo, are meant to keep sound lower and decrease velocity, as far as what i would do, you cannot go wrong with a couple dynomax ultra flows, deleted resonators, and an X pipe. 

As far as sound, i have an ultra flow on my truck, and while it is a see-through design, it's a very quiet muffler when compared to most anything else, at least while the cats are on.


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## BuffGTO (Dec 29, 2005)

I would say don't delete the cats. Various reasons:

1) Smell
2) Emissions passing
3) High Flow cats like Random Technology barely loose any power. I got RT cats for my headers from Dezod Motors (Place I bought my headers and exhaust)


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## CrabhartLSX (Feb 12, 2006)

BuffGTO said:


> I would say don't delete the cats. Various reasons:
> 
> 1) Smell
> 2) Emissions passing
> 3) High Flow cats like Random Technology barely loose any power. I got RT cats for my headers from Dezod Motors (Place I bought my headers and exhaust)


it's all in the tune though. If you have a good dyno tune, it's possible for a car without cats to still pass inspection. That, or just put some foam up the tailpipe for the sniffer. Random Tech makes some good cats though, although $300 might seem a little steep.


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## smkdu (Sep 22, 2005)

I have always built my own exhaust for all my vehicles, however I do need to find out the 05-06 Duel split exhaust diagram. Does anyone have or know where to find the under car diagram? and also if they knew the distance between the 2 exhaust tips would help me out a lot.Thanx


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## smkdu (Sep 22, 2005)

I have an 04 and want to try to cut out my stock rear bumper to setup the dual split exhaust.


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## BuffGTO (Dec 29, 2005)

CrabhartLSX said:


> it's all in the tune though. If you have a good dyno tune, it's possible for a car without cats to still pass inspection. That, or just put some foam up the tailpipe for the sniffer. Random Tech makes some good cats though, although $300 might seem a little steep.


Not true. There is no way in tuning to tune around a catless section and pass emissions unless you use something like LS1 edit or EFI live and turn off those sensors OR run an O2 simulator. 

Like the emissions guys in NYS are not gonna see the foam. That's a BS trick.


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