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Do you have to cut the trunk for the stock manifolds to exhaust system for the 3800? by iluvsd619
Started on: 07-08-2012 02:50 AM
Replies: 13 (1215 views)
Last post by: PaulJK on 05-27-2014 02:37 AM
iluvsd619
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Report this Post07-08-2012 02:50 AM Click Here to See the Profile for iluvsd619Click Here to Email iluvsd619Send a Private Message to iluvsd619Edit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have to cut the trunk for the stock manifolds to exhaust system for the 3800? I can't find any full info on this.
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Niterrorz
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Report this Post07-08-2012 03:44 AM Click Here to See the Profile for NiterrorzSend a Private Message to NiterrorzEdit/Delete MessageReply w/QuoteDirect Link to This Post
ehhh i have done a 4.9 with a similar trunk side mani and i did not cut mine. also i have seen duel small mufflers that were placed where the exhaust tips are. i think that if you wanted to take the time you could get around having to cut the trunk with the stock mani.
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Old Lar
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Report this Post07-08-2012 07:20 AM Click Here to See the Profile for Old LarSend a Private Message to Old LarEdit/Delete MessageReply w/QuoteDirect Link to This Post
No, not if you do the engine install correctly.
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revin
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Report this Post07-08-2012 09:12 AM Click Here to See the Profile for revinSend a Private Message to revinEdit/Delete MessageReply w/QuoteDirect Link to This Post
No cut trunk. Never have. Go buy some tubing 'dounuts" cut them in half and you will have the bends.
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iluvsd619
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Report this Post07-08-2012 12:51 PM Click Here to See the Profile for iluvsd619Click Here to Email iluvsd619Send a Private Message to iluvsd619Edit/Delete MessageReply w/QuoteDirect Link to This Post
No cutting the trunk! You guys are awesome! Thank you.
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Dennis LaGrua
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Report this Post07-08-2012 01:34 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by iluvsd619:

No cutting the trunk! You guys are awesome! Thank you.


I have always done these swaps without cutiing the trunk BUT you will have to live with an exhaust system that is much louder than stock. There is not much room for anything but a small muffler and short pipes. Two popular mufflers that will fit and allow you to keep the trunk are the Flotech Afterburner and the Spintechs that are made to order. Your muffler will have to have a maximum case length of 13".
My 3800 system uses the 3" afterburner crossflow muffler (dual 2 1/2" outlets) and Heddman "Hot Tips" resonators and its still quite loud. On my 4.9L install we will use a Spintec with a 2/12" in and dual 2" outlets for noise reduction.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, 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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Alex4mula
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Report this Post07-08-2012 02:29 PM Click Here to See the Profile for Alex4mulaClick Here to Email Alex4mulaSend a Private Message to Alex4mulaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:


I have always done these swaps without cutiing the trunk BUT you will have to live with an exhaust system that is much louder than stock. ..



Total BS. When all you can do is pay cheap to people to do work for you maybe. You can do something like this or even better and have something that will not be much louder.

http://www.fiero.nl/forum/Forum2/HTML/121048.html
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iluvsd619
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Report this Post07-08-2012 09:52 PM Click Here to See the Profile for iluvsd619Click Here to Email iluvsd619Send a Private Message to iluvsd619Edit/Delete MessageReply w/QuoteDirect Link to This Post
Wow. Those sound good. Thanks for the link.
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Dennis LaGrua
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Report this Post07-08-2012 11:01 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Alex4mula:


Total BS. When all you can do is pay cheap to people to do work for you maybe. You can do something like this or even better and have something that will not be much louder.

http://www.fiero.nl/forum/Forum2/HTML/121048.html


Thank you for the polite and courteous reply.
My exhaust systems use a muffler and dual resonators. They are not cheap or use cheap components. I've heard the Magnaflow muffler referenced in that post., It is not low and many others that I have seen have been installed with cut trunks or have pipes that hang below the cradle. If you are telling us that these mufflers are almost as quiet as those used with a full size muffler, & long pipe exhaust I consider that an exhaggerated claim.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, 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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MountainHiBlue87GT
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Report this Post07-09-2012 12:59 AM Click Here to See the Profile for MountainHiBlue87GTSend a Private Message to MountainHiBlue87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
http://www.westcoastfiero.com/exhaust/exhaust.html

WCF has an answer to your question, call them.

Regards,

David

------------------
1987 Fiero GT - 2006 3800 Series III Drive by Wire; Ported & Polished by TrippleEdge; 1.7 Yella Terra Full Roller Rockers; VS Cam; 3.1" Pulley; Tuning by Darth; WCF CAI & 1 5/8 Stainless Headers, 3" Exhaust, Power Steering & Much More; MSD Coils & Wires; Porsche (Brembo) Calipers on 13" Viper Rotors; 18X8 TSW Indy Wheels; Paint by Phoenix Auto in California City.

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iluvsd619
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Report this Post07-09-2012 01:07 AM Click Here to See the Profile for iluvsd619Click Here to Email iluvsd619Send a Private Message to iluvsd619Edit/Delete MessageReply w/QuoteDirect Link to This Post
I know, CW makes headers, so we can use the stock system, but I don't think he makes a system for 3800 manifolds. I know he can do it though.
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Darth Fiero
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Report this Post07-09-2012 06:27 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'll second the suggestion of Magnaflow mufflers. They are certainly the quietest I've ever used (that were a performance style muffler).

Now, having said that, there are two kinds of exhaust noise that should be considered here. One kind is called drone, or that low frequency noise that permeates the passenger cabin. The other kind is the exhaust note (and noise) that is heard from behind the car, mostly.

Drone is hard to get rid of, but I've had the best success using Magnaflow mufflers. Although I will admit I've also had some success by reducing the diameter of the exhaust pipe size I've used exiting other brands of mufflers. The smaller the pipe, the more quickly the exhaust flows thru it which raises the frequency of the exhaust note. One of the past swaps I did used a Holley Flow-Tech Terminator muffler which usually produces a lot of drone, but on that car I used 2.25" diameter pipe on both muffler exits going to the tips and it seemed to eliminate most of the cabin drone noise problem. However, this car did have a very loud exhaust if you stood behind it (just wasn't loud inside the car).

FWIW, the flowmaster mufflers seem to generate the worst drone type noise.

Here are some pics of exhaust systems I've made that hang off the stock rear exhaust manifold. None of these systems required cutting the trunk...








-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

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iluvsd619
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Report this Post07-09-2012 08:44 PM Click Here to See the Profile for iluvsd619Click Here to Email iluvsd619Send a Private Message to iluvsd619Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thank you Darth for info. Very nice systems. Thank you everyone for the input. Now when someone needs to search for Fiero 3800 exhaust systems and trunk issues, they now have a thread to look for. This is wonderful info. I'm ready to do many future 3800 Fiero swaps thanks to the Fiero Community.
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PaulJK
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Report this Post05-27-2014 02:37 AM Click Here to See the Profile for PaulJKSend a Private Message to PaulJKEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by iluvsd619:

I'm ready to do many future 3800 Fiero swaps thanks to the Fiero Community.



If you're planning to do them in california, you'll need to include (california-grade) catalytic converters (which none of the above exhaust systems have) then you can cut the trunk.
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