These pics were sent by a friend who found them on the net. He is going to do it to his Fiero. What does eveyone think about this? They are 10" woofers. He said the fierwall is doublewalled so there is no modification to the outside (engine side) firewall. Just the initial cutting and sealing is required.

I've seen this mod before, though I actually haven't heard what it sounds like. A buddy of mine worked for a car-audio shop, and told me about a similiar installation they performed on an '87 GT. It involved cutting into the firewall (as shown in these pics) and entailed lots of work. The end result, though, sounded "AWESOME," in his words. I don't see why it would hurt your beloved Fiero, other than if you were concerned about keeping it "factory." Then again, I don't know of any Fiero owners who can do that!

Oreif,

I think you came to the right place... I believe that car belongs to our very own fierosound

David.

Any cutting of the structural members will weaken the frame. If you care?

OMG

i am buying 2 ten inch subs when i get my tax return...and i was going to do that exact thing...hmm..im glasd i was gonna do it that way..cause it looks pretty good.

Well I saw the picture in the top left corner and I just felt compelled to comment.
Now I like a killer stereo as well(this setup is really cool!), but the part of the picture that got me started writing here was the shifter(it looks stock to me).
Call me wacky but if I were to go through that much work, I would at least put a short shifter in the car. I would likely spend that much time and effort installing a better ignition system, or porting the exhaust manifolds, rather than putting in big speakers. But then agian i'm of the attitude "all go no show", and I like to be able to hear the engine sound at full throttle even if the music drowns it out a bit.

Greg - that's a 6 year old photo. The website deals strictly with the stereo installation, but there's more than just "big speakers". Perhaps you should go to my website to get the full story, if you haven't already done so.

There's more to my car than the stereo. Most performance items were on the car BEFORE the stereo was installed. Short shifter was almost the last thing I did as it wasn't a high priority...

I've also got:
-shortened shifter
-passenger side glove box
-K&N high flow filter
-aftermarket "dogbone" with poly bushings
-Hypertech Stage II power chip
-160 degree thermostat (required for chip)
-ported exhaust manifolds
-rear sway bar
-poly bushings on sway bars, sway bar end links, shocks and rear control arms
-metallic brake pads
-Michelin low energy (low rolling resistance performance tires)
-Alarm system
-Dual battery system
-High output alternator (110amp)
-High output halogen headlights
-Taylor RED performance plug wires
-Holly RED high output ignition coil
-Wells Professional RED dist cap and rotor
-AC Delco RapidFire sparkplugs

Sorry, I don't have photos of everything...

Now that my car's mileage is getting up there, I'm planning on doing a 3.4L swap, similar to this ( http://www.angelfire.com/on/freddysplace/Page1.html ) with FOCOA style coated headers ( http://home.earthlink.net/~chriswest/Exhaust/28Header.html ) and Borla exhaust ( https://www.fiero.nl/forum/Forum2/HTML/002112.html ). I've always wanted more power, but I don't have deep enough pockets to replace a perfectly good engine before it's time. But when I do, I can assure you I will spend more time than the "average Joe" making sure it's a properly built engine.

Remember, there's always two ways of doing things, the best way (not necessarily MY way) and the way that is FULL of compromises. The second way is where you kick yourself afterwards saying "what a waste of money - no improvement at all", or you're required to "redo" something again.

Thanks for the comments though - no hard feelings.
I just didn't want you to go through life thinking I hadn't thought of the same upgrades you have done.

[This message has been edited by fierosound (edited 02-10-2000).]

Fierosound & Spyder,
How did you guys cut the firewall.. metal cutting saw or a torch?

I wouldn't mind doing this setup myself, but I've never done any sheet metal work of this type, only a bit in shop class.. which is a little different than cutting a hole in the firewall.

Darklord...

DO NOT USE A TORCH!!!!

THE FILLER TUBE FOR THE GAS TANK RUNS THROUGH THAT AREA ON THE DRIVER'S SIDE!!!

Make sure you don't have any gas leaks, or gas that has spilled down along the tube from overfilling.
Use a jigsaw to minimize sparks. Keep your fire extinguisher (near the spare tire) handy when you work.

To cut out the firewall, drill a small hole about 12 inches up from the floor. Insert a wire coat hanger to "feel out" how large an area you can cut out. Use an electric hand jigsaw with a metal blade. It's better to start small - you can always cut out more. The gas filler pipe runs through the area on the driver's side - be careful!!

The "well" is in an 8" or 10" inch channel supporting the firewall. Each end needs to be sealed. Cut some MDF to fit and silicone into place. Some people are using fibreglass to seal this well - whick is probably easier. You need to seal this - otherwise all your bass will be "outside". There is limited space for speaker magnets. Buy high effeciency speakers with small magnets. I recommend OZ Audio 10" 250L subs. I only have 50 watts to each - and look at the results. 100 watts would be even better, but I'd have needed a different amp setup (probably 2 plus a crossover - more $$$).

"Try out" how/where speakers will fit and take measurements. You can use cardboard to help "size" the box you will need to build. This can then serve as a template to help build the MDF enclosure.

[This message has been edited by fierosound (edited 02-10-2000).]

When I did mine, I was scared. There is actually a factory seam there (a small panel) so your basically removing a panel that they installed at the factory , I used a chisel and hammer. There are a few tack welds and a lot of caulking. After I removed the metal, I used spray foam around the edges to seal it. Then I cut away the excess foam and then did the fiberglass over it. (fiberglass, another story)
If I were to do it again, to make it go faster, I would use a pneumatic cut off tool. It doesn’t cut as fast a jig saw but it is more precise and you don’t have to worry about bending a blade or worry about hitting something on the other side. (and it makes cool sparks)

Fierosound you made the comment that you do not weaken the structure by removeing sheet metal from the area.
Well I can't say this any other way but YOUR WRONG.
The strength you will take away is called shear strength. I'm late for work. I'll give more about this later It's IMPORTANT!!!
Trust me, or ask Ogre!

Thanks for the heads up.. I only mentioned a torch because the area around the cutout portion looks blackened, but it could be paint or something else.

As for gas leaks.. I'd like to completely drain the fuel tank while working on the car. Don't want to take any chances at all.

Spyder, do you think removing the panels with a hammer & chisel would be easier than a jigsaw?

Do you think metal reinforcements could be welded or bolted on, under the MDF, to replace any strength lost by removing the panel?

Yes when you cut the metal you will weaken it. When you add the fiberglass, it is now stronger than the metal that was there. Also when you add the box structure, you add more structure to the car which in turn adds strength to the whole chassis. Sort of, like a, UNIBODY.

Fierocious

Thanks for your concern - but mines already been done 6 years ago WITH NO PROBLEMS. Nothing has twisted loose, fallen off, or rattles. It's unlikely I will be ripping out my subs to weld a patch in the panel. It's too late for me to change things!

But it's good you pointed it out for others who may be considering this install. They will have to decide on whether to proceed this way or not. Obviously, ripping the entire firewall out would be a BAD IDEA. If you are really concerned that it may weaken the firewall, I'd suggest cutting out the minimum amount required for clearance for your sub's magnet. In a 10" sub such as the OZ Audio, which uses a small high efficiency magnet, this would only be about a 5" hole!!

I think if you state your information, and alternatives for subwoofer installations, they will be better equipped to decide for themselves. I'm happy to just leave it at that...

PS - where did you locate your subs?

[This message has been edited by fierosound (edited 02-12-2000).]

I wouldn’t drain the tank, fumes would still be present.
Use a jigsaw! I was chicken when I was doing it. (I was not sure I was doing it right) Plus you might want to make it larger than what I did.
Once you install the sub box, you will regain any loss of strength in the removal of the panel.

[This message has been edited by Spyder (edited 02-10-2000).]

Ahhh... I feel much better. Thanks for nullifying my horror that Fiero's were turning into a candidate for the american rice car of the year.

I get miffed at those rice cars with a huge stereo and a coffee can exhaust tip, but are still running like sickly dogs(See the thread about stickers improving horsepower). Unfortunately I really shouldn't comment at all to be honest because I dont have much as far as mods go, but I have lots of plans ready to go once i get the appropriate funds, and now that im starting SOLOII racing I want to stay stock to be in the most basic class since I am a rookie.

Greg,

I hate to say it, but I am slightly more concerned with asthetics than performance. I plan on doing the usual, new plugs & wires, K&N filter, etc. but if I do a lot of engine upgrades, the car will go faster.. and I drive too fast already.

I figure it'd be cool if I add some IRM scoops (for both function and looks), Tom's decklid scoop (same reason) and again, hood vents.. driving lights.. same reason I guess. Tinted windows.. they look cool, but I do have sensitive eyes, and my sunglasses never seem to be dark enough.. and well. I just like loud music, so that explains why I want big subs.

But I'm not gonna go put a V8 badge on the car when it has a V6, or something dumb like that. Not sure about the wing, I'll get the factory one if I can, but if I can't get a good price, I'll go with an aftermarket one. Or even one from another car, I like the 99 grand am spoiler. (I'm sure with a bit of work it could be made to fit.. tho I've never seen one on a Fiero, so I'm not sure how it would look)

Point is, I'm going for asthetics as well as function, instead of spending a lot on engine performance (tho I plan on getting new brakes etc) because right now I feel I'm too irresponsible to have a really fast car. (stock V6 should be plenty fast to get me in trouble.. hehe)

Fierosound I was not knocking the sub install, just telling the tech side of things I personally wouldn't do it but it does look awsome! Del Sols had problems with flex so much infact if you auto cross them the rear window falls out of its tract. The Fiero is a lesson in structural and shear strengths. If even a small portion is reduced the space frame is compermized that is the design of the beast. However, sometimes cars are over engineired and have a little fat to be trimmed! I personaly bought the Fiero for a well handleing car not for a big stereo install. If I wanted a stereo car I would get a SUV!

I hadn't bought the Fiero to build a "kick ass" system for competition. But after hearing all the BS from the Car Audio stores, I decided they were mostly ignorant of any unique concept. They were mostly filling the trunk of EVERY car they worked on with a sub-box(s) and amplifier(s) and couldn't conceive of any other layout. They kept saying things like "you can't build a great stereo system in a Fiero, buy an SUV (or other car)".

I decided to build what I wanted using my own concepts. I used some of their advice, but mostly devised my own methods for installing everything and made my choices. Shops can't be trusted. Too often they install something, and once you get home, you have to redo some things - you can tell they rushed and did a less-than-perfect job - and you paid GOOD MONEY for this??

Afterwards I competed to SHOW these Car Audio stores what I'd accomplished. They were impressed (and pissed) as I was beating their customer's cars!! I even beat one guy with a Honda Civic with a $30,000 CDN "professionally installed system" in his car. In fact I took "1st Place" AND "Best of Show" at one event (2 trophies) - he came in second. He was really pissed, and complained bitterly to the shop that did his professional install and to the judges, calling into question their "qualifications". At events afterwards, I always came in 2nd by a few points, even though nothing was changed in either car - I wonder why?? I can only guess the attitude of the judges had changed for some strange reason!!

But now I DO have a GREAT HANDLING CAR and a kick-ass BIG STEREO INSTALL in one car
- a Fiero, and I'm more than happy with that!

[This message has been edited by fierosound (edited 02-11-2000).]

Has anybody thought of trying a rotozip? It's like a small router. The depth of the bits can be adjusted to suit the job. I never did like using a jigsaw very much. I've worked with wood more than metal and there are much better tools to use on wood than a jigsaw.
As for the structural integrity, couldn't the hole be framed in with a heavier gauge metal, riveted, and glued with some industrial strength glue like what's used to glue the frame work in the hood of a car?¿ Maybe an offset angle iron? " ¬ ". You guys have my gears going! I'm thinking of putting this on my long to do list. If I can afford it, overkill is the way to go.

keep in mind while doing a firewall speaker install like the top of this thread that ventilation for the ECM must be provided. An overheated ECM is a dead ECM.

The vehicle battery needs to be disconnected before you start messing with any of this.

Under NO condition must a torch or other hot cutter be used to make the cuts you people are making. Even then, the rule is STUFF the gas tank and work out side. if there is no breeze use a fan. If you allow fumes to build up you're in tremendous danger. (I think it is a teaspoon of gasoline at stoic is equal to one stick of dynomite. Might be a table spoon. ain't much either way.) If you hit the pipe and spill fuel stop imediatly. clean up the spill and wait untill the fuel is dried up completely.

As for structural issues,,,, Yes, it could increase body flex. I don't know how much. Keep you cutting as small as posible. Consider using an 8" woofer. you're dealing with a pretty small space. A pair of 8's should work well.

Fiberglass does not compensate for the steel removed. First of all it's very likely that the glass will crack loose from the steel in fairly short order. If the glass is exposed to the engine compartment you create both a fire risk, and posibly a carbon monoxide inlet. You would be better to form a sheet metal pocket that is series spot welded into the hole and sealing that with hard solder.

[This message has been edited by theogre (edited 02-11-2000).]

I’m sorry. This thread is just a small portion of what is involved with a subwoofer install of this nature.
I sometimes forget that everyone hasn’t done the research and seen what others have done and what exactly is being done. I will try to shed some light on this subject.
So let the questions continue and I will answer the best that I can.
Please note: This is one of the many ways to do a subwoofer installation. You decide if it right for you.

I reread the post and noticed that on this thread that there are not much references on what exactly is being done and why.
The problem: due to the depth of speakers, the seats of the car would have to be positioned forward to the point of being uncomfortable. Having enough air space is not a problem.
A solution was discovered where the magnets of the speakers could be placed into a small cut out of the rear fire wall.
The rear fire wall behind the seat actually consists of two totally separate walls which are anywhere from 2” to 3.5” apart.
There is air in-between them. (a gap)
On just the inside firewall (inside the car) there is a place where you can make a small cut out, just large enough for the speaker magnets. After doing the cut it must be sealed. I used fiberglass.
Then you build a box similar to the one at the top of this thread.

As far as structural integrity: fierosound has had this install in his car for SIX YEARS with no problems.
If you are worried about the integrity, don’t try it.
Please visit fierosounds web site for even more info.

The main topic of concern here is possibly weakening the car's structure.

The cuts are within a C-channel welded to the firewall sheetmetal. The C-channel is there to strengthen the firewall and to prevent vibration, not the other way around. The integrity is still there, the same as your boxed frame sections that have holes in them for access to nuts or bolts.

I'd be MUCH MORE CONCERNED with T-top kits, Convertible kits, and body kits that require your to saw major structural portions of your car off!! Or those Lambo kits that require you to saw your car in half to extend the wheelbase!!

I was reading all this and I just want to say that you should FILL up the gas tank before you cut the firewall.(just incase you "god forbid" cut the fill tube and start a fire) A empty gas tank will explode not a full one.

Hey with all this talk I got one question.....Fierosound just come on down Sunny Florida and do this for me OK ?!?!?!

Uhh Please .....

I was thinking about the comment that orge made about ECM cooling. If a persons really worried about it they could always mount a small computer cooling fan to help with cooling. I was forced to move my wifes ECM due to restrictions from mods. I mounted a miniture cooling fan and its worked great (3 yrs now) in keeping the ECM cool. I ran it to a 5 amp fuse in the block.

Just my .02c

I would have to say that this is one of the better sound systems that I have seen in a Fiero. It is definitly better then having two large boxes behind your seats and loosing valuable seat travel. The only thing that I don't like is having to rip the interior apart and cutting holes in the firewall. Very nice job on the installation.
I will still stick to my box plans which will hold 2 10 inchers with a lose of 1.25 inches of seat travel. My first box had 2 Kenwoods and the sound was great. It also takes 30 sec. to install/uninstall. This will come in handy at the track. The box itself is quite heavy and the extra weight does not help with 1/4 mile times. When I made my first system I removed the rear speakers, installed the sub's, a 200 watt rms amp and I kept the stock Radio and front speakers. This time I will change the radio and the front speakers but the rest will remain the same.