I was just looking to have a little chat with fellow fiero guys about that dang trunk cutting crossroads almost all engine swappers come to when it comes time to put an exhaust together.

I personally dont think that limited space under the trunk is worth anything, and I honestly never missed mine after I took it out. Some people seem to fight trunk cutting to the point where it costs them serious amounts of power and expressway drone.

Took mine out.....

Made exhaust work pretty easy.

I did not have to cut the trunk with my swap and i do not foresee that as an issue with my next one. I also used and created a True Dual exhaust with 2 Twin Tube glass packs. I put one where the Cat was and the other fit nicely where the Stock muffler was located.

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I sure missed the bottom of my trunk when I cut it out.
I worked out my 3.4 DOHC exhaust so I didn't have to remove the trunk the second time around. Much better. Just as quiet.

[This message has been edited by Steven Snyder (edited 02-28-2008).]

I have a cut trunk, I don't miss it. I like that things are more easily accessible with the removable floor.

i like my turbo a lot more than the little bit of space i lost in the bottom of the trunk .as much as i tried i could not get two sets of golf clubs in there anyways so losing the bottom isnt a big deal .

I cut my trunk and dont miss it at all being I never put anything in there. If I need to carry a bag for a trip to an event, I just throw it in the pass side floor board or behind the seat.

Cut mine out on the week-end....As long as I can fit a small cooler in the trunk I'm happy

I may be a bit different in that I am looking at cutting the trunk to make it larger.

With a modified/raised rear crossmember and the muffler laying flat along the bottom side of the cradle, the space previously occupied by the muffler is now open space where the trunk could be enlarged to. This would enlarge the lower portion of the trunk and allow more stuff back there.

Here are a couple of pics of the open space on my 4.3 car:

When I drop the tech4 out of the 87 I will be cutting the trunk, I won't have to reach WAY down anymore and it will make exhaust eleventy billion times easier.

Dark,

I have to commend you on this thread and the way you have presented it. I have given you a hard time lately but thought that I should give credit where it is due.

Besides that I am actually interested in what might be said regarding the subject.

I have seen some exhaust systems here which I will agree were poorly executed and would have resulted in a loss in power and or excessive noise but I have also seen some which I thought were quite the opposite and cutting the trunk was not necessarily the enabler.

Could you give us an example of an exhaust system which was restricted by the choice to not remove the trunk? Also could you explain exactly what you were able to do differently with your exhaust due to your decision to remove the trunk?

Here is something similar to what I had always thought that I would do if I were to build a 3800. LilDevil commented that it was very quiet and only resulted in a small decrease in power.

I chopped out the bottom 3" of my trunk to make room for the rear "diffuser fascia". Anything that doesn't fit in the modified trunk probably wouldn't fit in the stock trunk anyway, thanks to the odd shape of the stock trunk floor. I can still fit a week's worth of groceries, or a bunch of auto parts, or a backpack and rifle in there, so I'm good to go.

My trunk is cut, and it was my choice, it makes it easier to work on the engine and exhaust is quite easy. I don't miss it for storage capacity, but then again I have a minivan with the wife and kids following me to the shows....plenty of storage room in the loser cruiser

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has anyone ever tried taking out the spare tire and making a "real" sealed trunk up front? Maybe to possibly make up the difference for the rear trunk.

I cut mine, i like the look and i like being able to pretty much stand right over my engine while working on it, not having to bend over everything. Eventually ill make a template and cut something out of diamond plate to sit on top the frame, kind of cutting the trunk area in half but still have something back there for tools i guess. Maybe ill be able to cook on it who knows.

quote Originally posted by fieroguru: I may be a bit different in that I am looking at cutting the trunk to make it larger. With a modified/raised rear crossmember and the muffler laying flat along the bottom side of the cradle, the space previously occupied by the muffler is now open space where the trunk could be enlarged to. This would enlarge the lower portion of the trunk and allow more stuff back there.

I like that. A lot. I'd consider even doing that on my cradle when I have it out again with my DOHC if there's room. Cool! Any more pics, with the cradle out perhaps?

quote Originally posted by KaijuSenso: has anyone ever tried taking out the spare tire and making a "real" sealed trunk up front? Maybe to possibly make up the difference for the rear trunk.

Something like this?

[This message has been edited by Steven Snyder (edited 02-29-2008).]

quote Originally posted by Steven Snyder: I like that. A lot. I'd consider even doing that on my cradle when I have it out again with my DOHC if there's room. Cool! Any more pics, with the cradle out perhaps?

Here is the cradle for the 4.3 car. The front and rear crossmemebers are 2x3x1/8" (the stock engine mount pad is also removed, but not in this pic).


Here is a side shot once the mount 4 engine/tranny mount brackets were welded on:


Here is a pic of my SBC cradle also with a raised rear crossmember (slightly different than the 4.3 one):


Here is an underside pic of the SBC car showing the muffler placement (3" in, dual 2 1/2" out camaro muffler):

[This message has been edited by fieroguru (edited 02-29-2008).]

quote Originally posted by KaijuSenso: has anyone ever tried taking out the spare tire and making a "real" sealed trunk up front? Maybe to possibly make up the difference for the rear trunk.

This comment made me think about the pics of the early pre-production mock-ups of the Fiero- LOL on what a nice storage compartment it WAS before they entertained "reality!" I LIKE the headlight covers that ARE NOT part of the front hood though! Wish those had made it to production...

[This message has been edited by FieroFanatic13 (edited 02-29-2008).]

quote Originally posted by Steven Snyder: Something like this?

yeah that's exactly what i was thinking, is that as deep as it can be made though? seems like it's still too shallow. Is that your's? I'd love to see a build thread.

quote Originally posted by FieroFanatic13: This comment made me think about the pics of the early pre-production mock-ups of the Fiero- LOL on what a nice storage compartment it WAS before they entertained "reality!" I LIKE the headlight covers that ARE NOT part of the front hood though! Wish those had made it to production...

ha this would be perfect except for all the pieces parts that make the car safe to drive (like the brake booster/master cylinder assembly....)


I dunno seems like if someone really needs to cut out the rear trunk for exhaust and also really need the space to haul luggage, this could be a possible option (at least to fit a small suitcase or a few duffel bags)

I use the front spare tire section for storage as well (rarely carry a spare) and have also looked at enlarging the front area slightly. When people move the battery to the front, they normally notch out the plastic spare tire floor and use some of the space behind the radiator and over the steering rack/front crossmember. My though is to make the notch across the entire width of the plastic spare tire carrier and use as much space as possible.

Here is an old pic when the battery sat on the front crossmember (88). Notice all the room around the battery and in front of the battery.... a custom front spare tire section should be able to free up quite a bit of space.

quote Could you give us an example of an exhaust system which was restricted by the choice to not remove the trunk? Also could you explain exactly what you were able to do differently with your exhaust due to your decision to remove the trunk?

When I went to the track, I had an opportunity to race a near identical car as 3800SC swap, he was a bit heavier, but had 1.9 rockers an intercooler, and tightly bent 2.5inch exhaust, and my no intercooler, no rockers, 3inch free flowing exhaust, car produced the IDENTICAL track time.

I suppose there are a few variables there that would explain this other than that, but my personal feeling is that the exhaust was a big restriction.

Taking out the trunk let me eliminate a 2inch radius 180degree bend and replace it with a bend with a 6inch radius fully mandrel bent. I could also put a big 3inch cat in if I needed, without any extra consideration, and my tips could be placed nice and tucked under the bumper, which I have seen was a challenge for some of the trunk keepers to do.

The exhaust you show here looks to be very small, it looks almost like 2.25 to me, which would show huge power loss. In the full sized wbody 3800's I see at least 20HP going from a 2.2inch downpipe to an aftermarket 3inch, and thats with a stock pulley. Word on the street is the n/a guys pick up almost 10 when they get a nice cat in their downpipe.

I basically built the same thing as 'Lildevil's above, but used a 3" cat to the same 2.5" "mufflers" as in the picture. It's not as loud as the Flowmaster 80 I had on my last swap, but it sure isn't quiet by any means! I had cut the trunk out before doing the exhuast, but now that I look at it afterwards I don't think I had to. I may either put it back in, or make a new one to use up any and all extra space there. I have a habit of filling up any space with crap though, so maybe it's better I don't. Don't think I have pics at the moment... Dark - any thoughts on using the same setup above, but replacing the tube "mufflers" with actual mufflers, like from the new-ish Malibu's? (smallest OEM style real muffler I've been able to find) I'm looking for "sleeper", not "HELLO" listen to my engine.. LOL The Flowmaster would give me a headache after an hour, looking to prevent that if I ever finish the car. I'm thinking with the 3" pipe / cat to a 3"-2.5" splitter, I'd still be more open than using 2.25" cat / pipes.. And back towards the main subject, in the last car I never even put a floor back in the trunk, and I really didn't miss it all that much, considering I couldn't use that rear space at all..

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Bob Williams
Working on the next 3800 swap, it works now!!!

(old picture!)

[This message has been edited by Riceburner98 (edited 02-29-2008).]

I didnt know of a "small" stock muffler existed really, I have been looking for some decent stock mufflers that will allow some flow still, but I have yet to find one.

I will look at these malibu mufflers, but I dont know the flow characteristics. The problem we have with the supercharged car, is the fact that exhaust flow pays back horsepower by the ton. If I found a setup thats large and quiet and still will flow better than stock I would use it, but its tough finding quiet and flow, period.

quote Originally posted by Jefrysuko: Could you give us an example of an exhaust system which was restricted by the choice to not remove the trunk?

As you can see from the picture, I chose to forego chopping up my trunk and went with a muffer-less exhaust. Because the 5.3 LS4 is kinda big, Ryan gave me two options...1) Install a complete system with the dual cats and mufflers, but this would require him cutting out the bottom of the trunk based on the girth of the LS4, or 2) Don't alter the trunk at all, but I had to choose to install a partial system and use one of those flexible steel weave joint connectors? I've had those older straight cat back pipe racing exhausts for the longest time on the car, so I'm hoping the engine isn't too loud w/out the mufflers. Ryan's test driven the car for almost 80 miles and seems to think it's not too bad. It definitely growls, but hopefully not the wake the neighborhood roar. We'll see! I considered some muffled can tips but once I saw those Corvette tips, it was a done deal.

I just couldn't bear chopping the trunk of a car I've owned for 18 years as petty much OEM and I actually can fit an oversize golf bag in the trunk now, and to loose that ability is a no go for me.

Blkcofy

My trunk is completely removed right up to the upper frame rails. Gone. Makes more room for.. A turbo.. maybe?

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Chase Wakeham,
Concept Fabrications

My take on it is that if you are building a 1/4 mile track car, then do whatever it takes to make the car as fast as possible, and if that includes cutting the trunk then so be it.

Me, on the other hand, I don't intend on taking my car to the track and when I did my engine swap, no trunk cutting was one of the ground rules. And I intend to someday rework the front compartment to make it more efficient in terms of packaging.

I actually just finished up my "reduced trunk" today. I kind of like the idea of a little trunk in the car. Since mine is a 308 GTB replica with a SBC, I'd like to be able to have a small set of tools etc in the car with me. (as well as some other junk and some additional space. I may even move the battery into the corner location as well). Like some others on the forum, removing the entire trunk wasn't really an option for me either.

(Mainly because the rear fascia for the 308 needs that bottom area to mount to).

I didn't just cut the entire thing out... but instead, I left the very bottom for 2 reasons. 1. For sort of a "built in hanger" for the Flowmaster 80 Series. and 2. The mounting point for the rear bumper/fascia. I don't have any pics of the mounting hardware taken yet, but the muffler sits on a few mounts in the lower portion of the section I cut out.

For the trunk floor, I just fabricated some sheet metal and incorporated it with some of the original trunk floor. (The original trunk metal is nice and thick and has those "bosses" / ridges to make it pretty rigid. I installed and tack welded some sheet metal and some 1/4" metal for 2 supports in the center (even though the sheet metal alone was pretty rigid by itself).

Finished everything off with some GM Seam Sealer like in the original Fiero Trunk.

After the Seam Seal "sets up", I'll give it a quick sanding then primer and paint the trunk black. The seam seal goes on a bit thick, but levels pretty well in a day or so.

Here are a few pics of the new "reduced depth" trunk:






And the area for the muffler:

(If you notice those rivets along the bottom..., I've actually taken a spun ceramic "heat mat" designed for industrial boilers, microwave transmitters and very high heat applications and I sandwiched it between the original trunk metal and a new "outer layer" which I made. It wraps up along the bottom of the new trunk as well. Just so the trunk doesn't get blistering hot and make the cooler of beer warm

Ps. Once the muffler is in place, I modified 2 OEM Fiero Heat Shields that "go around" the muffler. They "close up" the rest of the hole so it doesn't act like a scoop under the car.



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I'm not driving too fast, . . . I'm flying too low.

[This message has been edited by 3084me (edited 03-04-2008).]

I think I'll miss my trunk, but after blowing the motor the last track event I was at, I think I'll be trailering for the racing events from now on. The V8 fiero has just the bottom removed but has all the room I need for show events.

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yellow 88 GT, not stock
white 88 notchie, 4 banger

quote Originally posted by fieroguru: Here is an old pic when the battery sat on the front crossmember (88). Notice all the room around the battery and in front of the battery.... a custom front spare tire section should be able to free up quite a bit of space.

That's where I have my battery now, and did in the pic below of my front "trunk." Nice location! It keeps the CG low and the battery towards the center of the car. Gives some storage room too..

quote Originally posted by Steven Snyder: Something like this?

quote Originally posted by KaijuSenso: yeah that's exactly what i was thinking, is that as deep as it can be made though? seems like it's still too shallow. Is that your's? I'd love to see a build thread.

Yeah it can go deeper. I had the battery underneat the trunk "floor" toward the rear of the compartment. It can't go deeper over the whole width; the frame rails aren't very far apart up there. Without the battery up front you could probably get a few extra cubic feet though!
I don't have a build thread for it, sorry..

[This message has been edited by Steven Snyder (edited 03-03-2008).]

I didn't cut mine. All I did was upgrade the cat. Everything from the cat back is stock routing using larger pipe.




With only one bank crossing over the pipe can be smaller without causing any restriction. For those who don't have to deal with emmisions you could use a simple "Y" junction where the cat is. Mine is done in 2" pipe to the cat and 2.5" out though they make the cats with 3" out also. Something different anyway.

[This message has been edited by Fieroseverywhere (edited 03-04-2008).]

quote Originally posted by ccfiero350: I think I'll miss my trunk, but after blowing the motor the last track event I was at, I think I'll be trailering for the racing events from now on. The V8 fiero has just the bottom removed but has all the room I need for show events.

I was hoping that this thread would clear up the "my trunk is gone after I cut it" thought that goes through everyones head when they hear trunk cutting.

Remember everyone, your just losing the bottom section!

quote Originally posted by darkhorizon: I was hoping that this thread would clear up the "my trunk is gone after I cut it" thought that goes through everyones head when they hear trunk cutting. Remember everyone, your just losing the bottom section!

Been there, done that. To me losing the bottom section eliminated the usefulness of the trunk. No more full-size flat storage. No more room for road trips. No more room for camping gear..

[QUOTE]Originally posted by Steven Snyder:

No more full-size flat storage. QUOTE]

This was my biggest issue with cutting the trunk. If I get a flat I don't want to have to strap my blown tire to the decklid to get the car home or to the tire shop. This was the main reason I found another way.

yea the bottom section of my trunk holds two small laundry bags( second one sticks up a little), which is key for me when i go home. plus im a road trip kind of guy and i love taking my car on vacation and stuff.

quote Originally posted by darkhorizon: Remember everyone, your just losing the bottom section!

Believe it or not but some people have items that they want to put in their trunk which don't fit without the lower section. I for one can not get two sets of golf clubs in my trunk without the lower section.

I was spoiled when I had my trailer (it had 3-4 times the Fiero storage)... Since it has been sold, I have continued to go on lengthy (up to a week) road trips annually and storage space is a premium. That's why when I cut into my trunk it will be to make it larger not smaller.

The lower portion of the trunk is the perfect size for my tool box.

the only thing i use my trunk for besides a few parts and "things" is my sunroof. the stock trunk is almost a perfect fit to put the sunroof in without worry of it breaking or hitting anything, when i do my turbo on my 3800 i plan to cut the trunk but still not sure how it will be cut, maybe i can just push it "in" and still keep the depth in the rear of the trunk for the sunroof, has anyone done something like this? or am i stupid for puting my sunroof in the trunk?

Sunroof has a padded holder in the front.. why use the trunk?

quote Originally posted by fieroguru: I use the front spare tire section for storage as well (rarely carry a spare) and have also looked at enlarging the front area slightly. When people move the battery to the front, they normally notch out the plastic spare tire floor and use some of the space behind the radiator and over the steering rack/front crossmember. My though is to make the notch across the entire width of the plastic spare tire carrier and use as much space as possible.

I intend to do that someday. If you take out the spare tire tub you notice there is a LOT of room that Pontiac didn't take credit for. Yeah the frame rails are close together, but it's a lot more than the width of a battery. You could free up a lot of space if you built a custom tub.