My 3800 swap is moving along and I need to plan on building an exhaust. Here are my thoughts:

1. Dual outlets are a definite.
2. A flex tube is a plus, but I'm not sure if my poly mounts will really cause much engine movement
3. A catalytic converter is a plus, but not required (I don't live in an emissions county, but I will move soon)
4. Stainless is a plus
5. All welded construction is a plus, but I don't mind clamping it together since I can do that at home (and not pay anyone or have the car towed to a shop)
6. Quiet is a plus
7. Resonator tips to hush it down
8. There will be no trunk modifications

Here's the 3 best configurations I've seen so far:

Fast Fieros


CosVegFiero


Darth Fiero


Any advice on building this thing? Any online merchants you guys would like to suggest?

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1988 Fiero GT "Rolling Thunder"
Restoration Project
Soon to have 3800 SC III
"I'm a Rolling Thunder and a Pouring Rain... I'm coming on like a Hurricane - ACDC"

Trunk or no trunk? If no trunk then keep it simple with a 90 to 180 muffler 90s out to tips......add a flex if not using stock manifolds....

Wasn't there someone that had, or was selling manifolds and crossover that plugged into the stock Fiero piping? If so, that would probably be the best option for the least work, no? Just mount and go.

quote Originally posted by MstangsBware: ...keep it simple with a 90 to 180 muffler 90s out to tips...

That's the configuration I've shown in the pictures. I'm more looking for muffler suggestions, tubing suppliers, and maybe where to get a flange with the 90 oriented correctly.

quote Originally posted by dobey: Wasn't there someone that had, or was selling manifolds and crossover that plugged into the stock Fiero piping? If so, that would probably be the best option for the least work, no? Just mount and go.

West Coast Fiero sells headers that fit on the 3800SC engine and route the exhaust in the stock location. You will still need an improved exhuast system with larger muffler and pipes. The WCF system has a reputation as being a bit restrictive so if you are only concerned with a stock fit they might be for you.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's 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 "

I'm not looking to spend $1000 on an elaborate exhaust. I just want to build my own using the stock headers from my 3800.

quote Originally posted by dobey: Wasn't there someone that had, or was selling manifolds and crossover that plugged into the stock Fiero piping? If so, that would probably be the best option for the least work, no? Just mount and go.

I did that recently on my series II 3800.. used stock 3800 manifolds, cut the crossover pipe, had a local pipe shop bend me 2 short pipes, used a 2 into 1 and ran it down to the stock exhaust.. that 2 into 1 was a 2 in exhaust tip at autozone for $14. I just cut the one end so the it was flush and on the other end i welded the male end from the 2.8 y pipe... so it can seal on the pipe running to the Cat.
problems so far are...
the Bad:
1: restrictive exhaust with the 2 in pipes collecting into ( 1 ) 2 in pipe.
2: It aint for racers.
3: HP loss....

the good: 1: the car is super quiet even with a hollowed out cat and a burned up muffler.. .at idle you almost cannot hear this thing run unless you are behind the car.....
2: with a cold air system that runs out to the side molding behind the drivers door.... the supercharger is awesome and loud when it kicks in.. can hear it over the engine very well... people can hear that thing.
3: I don't need to have a 1000 watt Amp and 4 15in woofers to hear my radio.
4: ect., ect.
5: helluva lot cheaper to build a Y pipe than to replumb the whole system for us guys born with a tin spoon and not silver.. all parts totaled up to about $45 including having the pipes bent.
Does it work? Mmmmmmyeah... for a daily driver car i'm fully content with its sound and performance..
I can show some pictures of it in the car if ya want to see, it isnt impressive, but the workmanship and welds are great.

To cut down on skilled labor costs, I used preformed 90s with one flared in. 2" if I remember correctly. I used the stock headers and made a flnge that would bolt on to the rear manifold. My son helped me weld a pipe at the right angle to start the pipe downward where it needed to be. From there I started fitting the right angle tube pieces together how I wanted them. In the end they curved down from the manifold, passed between the engine and the cradle, sweeps around under the cradle at exactly where the old configuration did, curves on around horizontal with the rear where I attached a straight through muffler. You would like my choise of mufflers, it's loud. My son then tacked each of the 90s together with one tack weld. We unbolted the whole thing, put it on the bench and he welded completely around at each joint. I then went to the auto store and found a tail pipe with a suitable bend and clamped it to the muffler. In the end the only ugly ole clamps were on each end of the muffler, with the bolts pointing up. The muffler mounted exactly where the stock one did. I then wrapped everything from the header to the output of the muffler with exaust insulator tape to keep the engine compartment temerature as low as possible. I found a chrome forked pipe end that I instlled on the end of the tail pipe so that car retained some of it's original 2M4 personality. I know you're looking for something different than I did, but you could still use the preformed 90 idea. It worked well and looks pretty good. You could easily put a 1 into 2 muffler on for your duals look. Cost was very low. Funcionality was great.

quote Originally posted by Rolling Thunder: ... 8. There will be no trunk modifications Darth Fiero ...

Keep in mind that Ryan had to make a slight mod to the trunk to accommodate this thicker muffler. He cut the front lower-half edges of the trunk in three places, at the sides and bottom, to free up the lower front trunk sheet metal. He then rotated lower edge of this panel toward the rear of the car approximately an inch and tack welded it back in place, to allow some additional clearance between the trunk and this muffler. The modification is pretty much invisible, looking at the trunk.

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RickN
White 88GT 5spd (<10K miles)
White 85GT (SC3800 Series II w/ AOD)
White 99 F250SD 7.3PSD 6spd
1956 Ford 860 Tractor w/ Freeman Loader
20Ft H&H Tilt Bed Trailer

I'm liking this setup a bit:



Anyone care to comment on it?

Here's where we are at on Jeff's 88 Swap. Have not yet decided on mufflers. Thinking of installing 2 smaller hi flow cats in place of the mufflers then using an insert of some type behind the tips. The mufflers are the shortest glasspacks from Summit - not sure what it will sound like with either configuration (loud). In the pics below, you will see that if we use the glasspacks, we will have to do some "modification" to the passenger side muffler to get it to fit. So far, we used 2 - 3" mandrel bent 90's, 1 - 3" 180* mandrel bent pipe, 2 - 2.25" mandrel bent 90's and the 2 Summit glasspacks - less than 100.00 in it and we will be using the tips he already has. The higgh flow cats are on thier way via a buddy in Dallas for "FREE"! We will "cut" the Down/Y pipe and add a "flex" joint once we decide which way to go.




Pat

quote Originally posted by katatak: ... Pat

Are your mufflers touching the cradle? If so that will transmit a lot of sound into the passenger cabin.

I remember people making a fuss about Spintech mufflers. Any thoughts on those? How about Supertrap mufflers?

quote Originally posted by RickN: Are your mufflers touching the cradle? If so that will transmit a lot of sound into the passenger cabin.

No they are not touching - theya are just sitting there - not mounted up yet. We need to do some more trimming and fitting to get it right but I think it will work out fine. Hope to have it finshed up next week.

Here's what I did on my series 1 swap from the stock manifolds.

I used 2 J bends and one U bend. All 2-1/2" pipe up till the 90s after the muffler. the 90s to the tips were from the stock exhaust, those are 2" pipe.
I did cut the trunk though because I didn't like having such sharp bends that would be required otherwise. There is also room for a flex joint just after the flange if you wanted one.
Total cost including muffler and cat about 300$ canadian I did all the welding myself.