Ok, I tried searching, but I didn't find the answer I needed. I have decided to remove the lower portion of the trunks in two of my Fieros. I realize a bunch of you have done this. Is there a preferred method of trunk cutting? I'd rather not learn from my mistakes on this one. I was thinking of cutting the trunk on three walls and folding the left over trimmed material and welding it shut....or just cutting the whole bottom out and welding in a new floor. Also, what is best to do for the carpet? Give me some ideas here, please. Dave
------------------ 1987 GT (my toy-see above), 1987 GT (wife's toy), 1986 SE soon to be VR6, certified master technician/shop owner www.njautobahn.com
For the trunk cutting that I did to my V8, here's what I found. If you remove the carpet you will see the actual trunk pan from GM kindof just "slides" in from the top and is spot welded from the factory. You can save alot of scraped knuckles and sawzall blades if you use an air chisel or drill out the spot welds and then crumple the pan up and go from the bottom and pull it out. Some cutting sill still need to be done in the supported corners.
Then cut a piece of 16G sheet metal the shape of the floor area of what little trunk area you have left. You still end up with a trunk, just not a deep one. Sheetmetal, tackweld or rivet it in place. Layer the bottom of that with the salvaged insulation from the pan area, cut it up and layer it. Then recarpet it and you're done. Even with the exhaust right under the trunk it won't get that hot if it is insulated right. You can even install a heat shield form underneath too.
Are you cutting out your trunk to make a better flowing exhaust ? Hope this helps.
Ok, I tried searching, but I didn't find the answer I needed. I have decided to remove the lower portion of the trunks in two of my Fieros. I realize a bunch of you have done this. Is there a preferred method of trunk cutting? I'd rather not learn from my mistakes on this one. I was thinking of cutting the trunk on three walls and folding the left over trimmed material and welding it shut....or just cutting the whole bottom out and welding in a new floor. Also, what is best to do for the carpet? Give me some ideas here, please. Dave
I used a plasma to cut off the complete lower portion of the trunk and then just went back with a sheet of metal to cover the opening. The idea of using one of the 4 walls to use as a cover would be a good idea if there is enough to cover the opening. I ran into the problem with the carpet insualtion getting to hot and melting after several months of driving the car. Some type of heat shield needs to be put on the cover to keep the heat off the insulation and carpet.
Yeah good point about the plasma. I too figured it would be easier to drop in a clean new piece of metal from the top instead of taking a greasy oily piece and folding it up from the bottom. I hate working upside down.
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01:28 PM
bmwguru Member
Posts: 4692 From: Howell, NJ USA Registered: Sep 2006
I'm doing this to be able to have an exhaust on my VR6 swap. The exhaust manifolds are on the trunk side of the engine. My V8 needs a better exhaust. I have true dual exhaust with race mufflers on it now, but I'd like something quieter for the street, but still able to keep the true duals for ease of tuning the four carburetors....one of these days I'll step into the 21st century with that car and get a wideband O2 for each bank. That and also my wife hates the trunk because she has a hard time getting stuff out of the very bottom. Dave
bmwguru- I think what you have as an idea use on of the existing walls as the new trunk bottom is exactly what me and my dad had in mind. What we did is we cut the sides and the back part of the lower section out and then that made the large front wall like a flap then all we did is fold it up and then rivet it in place. Using that front wall folded up is imho the best way to do it because GM has those creases in the sheet metal that give it strength and also then you dont have to cut a piece of sheetmetal to use for the floor.
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05:10 PM
mafv8 Member
Posts: 559 From: Northville, Michigan, USA Registered: Aug 2001
I just cut the bottom of my trunk out, I just used a Dremel tool with a metal cutting disc, I went thru a few disc's but it did the job I basically cut round the periphery of the lower trunk, then had to cut the lower trunk logitudinally to get it out. Reason for removing it was to give pleanty of room for my new exhuast, which should be done this week, I never realy used the trunk, and with the old flowmaster back there is used to get to hot anyway.
------------------ 84SE, aero body, 4 speed and an injected 355 V8
This is where I cut my trunk out. This way I could tuck up 2 Dynomax Raptor mufflers where the trunk used to be. I plan on fabricating a removable plate to cover the opening to aid in exhaust repair since my mufflers are stacked on top of each other. I don't have the completed pics yet, just the cutout. I'll take some pictures tomorrow if you want to see how the mufflers are located.
Craig
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12:01 AM
darkhorizon Member
Posts: 12279 From: Flint Michigan Registered: Jan 2006
Dave: We just did a 3800SC/4T65eHD install here and the exhaust manifold flange exits on the trunk side. We were able to use a Flotech afterburner muffler with 3" in and two 2 1/2" outltets. The system is small and compact but it fit nicely without cutting the trunk. The key is to use a small muffler like a Spintech or AFterburner (13" L) and some mandrel U bend pipes. You can even add a mini CAT if you work carefully. One importat point to consider; If you go away for the weekend, the Mrs won't have much trunk space for her things and she will be pissed off, that may get you in the doghouse.
------------------ 87GT - with 3800SC Series III engine, 4T65eHD 87GT - 3.4L Turbocharged engine, modified TH125H " I'M ON THE LOOSE WITHOUT THE JUICE "
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09:52 AM
bmwguru Member
Posts: 4692 From: Howell, NJ USA Registered: Sep 2006
Dave: We just did a 3800SC/4T65eHD install here and the exhaust manifold flange exits on the trunk side. We were able to use a Flotech afterburner muffler with 3" in and two 2 1/2" outltets. The system is small and compact but it fit nicely without cutting the trunk. The key is to use a small muffler like a Spintech or AFterburner (13" L) and some mandrel U bend pipes. You can even add a mini CAT if you work carefully. One importat point to consider; If you go away for the weekend, the Mrs won't have much trunk space for her things and she will be pissed off, that may get you in the doghouse.
We trailer the V8 if we leave the state, so the trunk is useless to us. Her VR6 I am still up in the air about the exhaust I want. The engine sounds sweet with a Magnaflow on it, but I'd like to keep the dual exhaust look. Besides, my wife doesn't pack much. On her last road trip, she had a small duffel bag for all her stuff. Dave
Thanks...I think. I kinda like when she flips me off. It's her way of showing affection. We are best friends and do almost everything together....including our annual New Year's eve drinking and driving contest (we split a few bottles of champange and play Forza2 until we can't drive straight or pass out). . . . Anyway, back on topic. I cut the trunk tonight and it came out nice. Tomorrow I will weld in the new floor and seal it up using Mercedes body sealant (damn this car will be spoiled). Dave
