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07-08-2017
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#1 |
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Join Date: Jun 2016
Location: Prior lake
Posts: 65
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A tired old question..... and I'm sorry
I looked in the search function... admittedly I am not forum savy...and found not a lot in the results. Funny thing is I'm sure I've seen it here before.
Anyway. Had the yellow car on a lift the other day looking for anything out of whack and doing a diff fluid swap and I kept looking at the exhaust and the 4 cats....and I'm wondering does it need 4 of em? It seems to me that's an early 90s attempt to please the epa and not much else, especially with the lt5 wanting more flow and all. Do people eliminate just 2? Would it garner any gains? It's got a magnaflow cat back on it now if that makes a difference. I've been talking to DRM about a few goodies next year and intake and headers seem to be The best first step when spring rules around. So either way it's not staying this way for long. Sorry again for what I assume to be a repeat question. |
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07-08-2017
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#2 | |
  
Join Date: May 2007
Location: Peoria, AZ
Posts: 9,120
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Re: A tired old question..... and I'm sorry
Quote:
4 cats ? There are only two cats are the calling the center line resonator at cat? That's for noise cancelation only.
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GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director  91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V |
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07-09-2017
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#3 |
 Join Date: Jan 2015
Location: Marietta, GA USA
Posts: 1,148
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Re: A tired old question..... and I'm sorry
As mentioned above, if your exhaust is stock, you should have two cats near the engine going into a single resonator, then two mufflers in back.
I think your future plans to improve the exhaust are good. I don't know of anyone who hasn't been happy afterwards (except sometimes sound/drone is an issue at some RPMs). Have you seen Marc's information about stock exhaust vs, aftermarket? I think you'll find it under the Articles or Presentations sections on his site: http://www.zr1specialist.com/ |
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07-09-2017
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#4 |
 
Join Date: Dec 2003
Location: Arcadia, OK
Posts: 3,392
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Re: A tired old question..... and I'm sorry
On early models, with the cats integrated with manifolds, aftermarket cats were installed by owners downstream of original cats. I have recommended that procedure to customers as a less costly means to pass emissions when the original cats were bad.
Consequently, it looks like 4 cats. Sent from my iPhone using ZR-1 Net Registry
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. Last edited by A26B; 07-10-2017 at 11:58 PM. |
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07-10-2017
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#5 |
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Join Date: Jun 2016
Location: Prior lake
Posts: 65
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Re: A tired old question..... and I'm sorry
Ok. I'm dumb. Not sure what I was thinking.
Has anyone ever cut the resonator itself out and gone straight pipes to the mufflers? maybe add an x pipe to keep back pressure? wouldn't mind more bark, but not looking to be an obnoxious *** either |
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07-10-2017
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#6 |
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
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Re: A tired old question..... and I'm sorry
Lots of Zs w/o cats, w/o resonators, (Stainless Works) X pipes and straight back to mufflers of one type or another. Then there's Corsa cat-back systems many like, ESPECIALLY if drone is an issue (to some more than others). B&B Fusion is their mufflers with the NPP gates some like.
IIRC, Mike 100 is using C6 Z06 cats (3"inlet/outlet), X-pipe and custom NPP with manual control. Headers, X-pipe w/o resonator, or Corsa and free flowing mufflers are generally good for 25-35+ HP depending on other factors...to give you a rough idea... |
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