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| Any downsides to a short exhaust run? (Page 1/1) |
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A_Lonely_Potato
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SEP 16, 11:40 PM
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'86 GT(patrick  )
Currently have a massive exhaust leak from my garbage aftermarket exhaust, header looks like its totally cracked in two pieces. Got a bunch of stuff on order to build a whole new system. A question i have though, is if there's any cons to running my exhaust crossover between the trunk and engine rather than the firewall side like the stock routing? I'll be making manifolds out of 1.5" primaries, going into 2.5" pipe because its the smallest i can get without spending a bunch extra on piping. The short run would be a lot easier to fab up, and the only possible reason i can think not to do that is for drone. I'll be putting a resonator in line before the muffler(plan so far is to plumb into the stock muffler) so i think that should help on that side of things. Of course I'll be documenting this for the people like me who have no idea what they're getting into 
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Patrick
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SEP 17, 01:49 AM
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| quote | Originally posted by A_Lonely_Potato:
'86 GT(patrick )
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Thank-you, I appreciate not needing to look up an old thread to see what you have. 
So... no cat?
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jelly2m8
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SEP 17, 05:39 AM
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Honest answer, probably not. most 3800 swappers do rear back towards the trunk exhaust. the length of your exhaust may not be as important as the design of your exhaust,
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A_Lonely_Potato
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SEP 17, 08:50 AM
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hey maybe people are just trying to keep your search game on point patrick
no cat is correct. was removed by a P/O, and michigan does not require emissions testing or any inspections.
jelly2m8, design wont be all that great if im honest. it won't be some performance exhaust. manifolds will be close to stock design, and this wont be any kind of equal length run. i may try to draw something up and ask for suggestions before i assemble.
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Dennis LaGrua
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SEP 17, 10:01 AM
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I have always used a short rear side exhaust system that uses a U headpipe to a cross flow muffler with two twin end exhausts that end in the OEM locations. Moderate sound suppression has been achieved with the SpinTech muffler, but without a CAT, it cannot be said that the end result produced a completely quiet exhaust. This approach was taken as it preserved what little trunk space is available. Some installs that I have seen used a larger Flowmaster muffler. It is quieter but the size of the muffler requires cutting of the trunk to make room or hanging the muffler too low for my taste..
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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A_Lonely_Potato
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SEP 17, 01:53 PM
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Im not really looking for a "quiet" exhaust, per se. my car hasnt had a cat since ive owned it, just the original muffler. i would imagine the resonator may bring it down a little, but i really dont have any idea.
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theogre
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SEP 18, 08:12 AM
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Make sure any exhaust has flex point, spring/rubber hangers, etc. more so w/ short pipe(s) to frame mounted sections or expect w/ break things & often soon.
Example: limited flex @ the doughnut & crap dog bone is big reason why so many L4 break E-manifold. Is why 88 L4 has redesign pipes between manifold & cat w/ bracket to trans bell bolts.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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A_Lonely_Potato
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SEP 18, 06:43 PM
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ill be using rubber hangers, im so very sick of the spring hangers that come stock.
i did totally forget a flex pipe, thanks for the reminder. my dog bone is poly, the engine doesnt hardly rock at all on startup or any other time.
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theogre
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SEP 18, 09:48 PM
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These parts will move & Isn't just things moving you see from engine loads etc.
Exhaust get heat cycled & each section can see away different heat @ different times. Worse often one spot gets cold(er) as air or water hits a spot.
Is part pf why try never opening the Fiero trunk lid in rain/snow that crash cool the exhaust.
Related: Guy had some Jeep kept breaking cast iron E-man because how made allowed heat unevenly & crack @ same V near bottom because all stress loads break the weak V area. After broke 3 times that I know & maybe more finally got rid of that vehicle.
Wrapping Exhaust may keep bay temp down but often parts wrapped don't last long because way too hot & many wraps hold water when cold to rust out the parts.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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pmbrunelle
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SEP 19, 05:42 PM
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