Hi-Flow Cat w/ muffler elimanators ??

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Jul 17, 2006 | 06:59 AM

bdaly84

Thread Starter

Racer

Joined: Jan 2006

Posts: 287

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From: Forest Hill Maryland

Hi-Flow Cat w/ muffler elimanators ??

Is anyone running a hi-flow cat with muffler elimanators? I just failed emissions, so I think first I am replacing my stock 23 year old cat. I do have the muffler elims. and I dont know how it will sound with a hi-flow cat. Just trying to get some input.

Jul 17, 2006 | 08:48 AM

bdaly84

Thread Starter

Racer

Joined: Jan 2006

Posts: 287

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From: Forest Hill Maryland

Geez, no one has a hi-flow cat with elims. I know someone out there has this setup.

Jul 17, 2006 | 09:51 AM

jsinga

Pro

Joined: Oct 2003

Posts: 506

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From: Savannah GA

I can tell you mine got louder when the cat was busted out (it got plugged when a pre-cat came apart)

JS

Jul 17, 2006 | 04:43 PM

CentralCoaster

Team Owner

Joined: May 2002

Posts: 24,337

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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed

I do.

Stock manifold with some minor port work
84/85 front Y pipe w/ no cats
4-bolt flange welded to a 3" high flow carsound cat ($50)
welded to a modified 86-91 dynomax rear Y pipe
welded to muffler eliminator pipes
with dual chrome tips.

The cat back cost me $150 used, plus $60 to get it welded up.

It sounds healthy as an ox. You'll get some popping on deceleration and shifts sometimes, that's the fuel burning in the cat without mufflers behind it. You definitely want the rear hatch vent too for cruising around town.

In-car noise/resonance is very reasonable.

Don't waste your time with clamps, if everything isn't perfect they'll leak. I would also recommend buying mandrel bends from summit, and a 3"x2" wye and getting a muffler shop to use those to build the catback from scratch. It'll cost you under $300 total, will fit better than the 'bolt-on' pieces, and be all mandrel.

Last edited by CentralCoaster; Jul 17, 2006 at 04:46 PM.

Jul 17, 2006 | 05:17 PM

zr1fred

Race Director

Joined: May 2006

Posts: 10,691

Likes: 71

From: Phoenix Arizona

It will be loud! Try running it with just the cat on, and you'll get a good idea. (Yes I've had them!)

Jul 17, 2006 | 11:30 PM

madmatt9471

Team Owner

Joined: May 2006

Posts: 21,473

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From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----

Yes I do have this set-up exactly! I have the 2 1/2" Y pipe w/muffler eliminater's w/ a Random Tech Super Hiflow Cat. It boosted the resonence in the Vette. So I made sure the tips of the muffler's were extending beyond the rear bumper. It helped quiet a bit. Now I am getting the Be-quiet sound matting for the inside(under the carpet) to help out. And now I am also going to install these http://store.summitracing.com/partde...5&autoview=sku these will help w/ the resonence and act as resonaters(they are staight thru, I am awaiting them soon! and I'll let you know when they are installed and how they sound)

The resonence was not really that much more but I wanted to keep the ride inside as quiet as possible. I don't care how loud it is outside but inside it must be comfortable! The power difference was so substantial I would not,WILL NOT put the stock 3 cats back on till it is time for smog then put the Hiflow back(takes about 30 min's to change out after it is up on jack stands) It made such a big difference in the pull and complimented the other mod's I have done!

Here is my set-up http://forums.corvetteforum.com/show....php?t=1438979

I let you know on the addition of the two resonater's I'll have installed this week!

Thanks,Matt

Jul 18, 2006 | 06:19 AM

bdaly84

Thread Starter

Racer

Joined: Jan 2006

Posts: 287

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From: Forest Hill Maryland

Thanks guys, I am going to go with the Random Tech cat. Who's got the best prices on them??

Matt: I emailed you, thanks man.

Jul 20, 2006 | 05:05 PM

sandman21

Intermediate

Joined: May 2006

Posts: 32

Likes: 0

From: Arnold MD

I have muffler elims on my 92 and it is loud, like centralcoaster said you really hear it on downshifts and ever once in a while you'll hear it pop, It sounds good though and I will say that I am happy with mine.