I'm looking for some fabrication help
 

I got the race car back last weekend, but there was a bit of an over-sight on the build. We put all this spanky new fuel system stuff in the trunk, but never bothered to install a firewall between the trunk and the rear-seats. After reading through the rules for time trials, I'm not totally sure it's illegal (otherwise, how would people with wagons ever built legal cars) but I'd rather be safe than sorry.

So, I'm looking for someone that's got the tools and experience to help be fab up a sheet metal or aluminum bulkhead between the trunk and rear seats on my WRX. I figure I can get away with something as simple as a few panels riveted in there, but it will still require some somewhat detailed cutting of the panels, and some forming to make it fit.

And I need to get it done by the end of the week in time for the Saturday time trials.

Can anyone help me out, or point me in the right direction for someone that can? Thanks in advance!

I've seen Kevin do some amazing things with some tin-snips. :lol:

:lol:

Scott, I think Rusty at C&C has a lot of experience with fire walls and stuff, from all his stock car days, I bet they could put something together for you.

I was thinking about C&C and the Benson Brother's, but I think timing is going to be a big problem. I'm still swamped at work, so I'm kinda ass-out for time to drive the car somewhere, drop it off, pick it up, etc... I'm sorta forced to finish this thing up from 8pm to 2am every night this week. :( Plus it's not driveable right now, I need to re-ground my battery in order to drive it anywhere to begin with.

I think if I can source the tools and some sheet aluminum or steel, I can probably sort something out myself, but I don't know where to get that stuff from.

In all seriousness, you could probably build a workable solution with a sheet of aluminum or two, some tin snips, a drill and hardware. I think soem sources for metal fabbing have been posted here and there on the board too.

No doubt, I just need the supplies, tools, and was hoping for someone with some experience to help so it's a 90 minute job, instead of a 6 hour job.

just fill your trunk full of teddy bears. In the case of an accident they will absorb all the fuel leaving you a good 15 seconds before they explode.

scott the autoshop i intern at can do it we have done some stuff like that. and a firewall isnt too complicated so it wouldn't take us that long. id say id do it at my house for the cost of dinner but i don't have a rivet gun unless you would be alright with it being welded but im not the best at welding. just leaving some options open as a last resort.

Welding will be too permanent. I'm starting to get the feeling that I'll be stripping the interior and ending up in FP sooner rather than later, in which case I'll want to add to the cage a little and properly weld in a firewall. Right now, I'm just looking for a stop gap to make the car fire-safe if that swirly can springs a leak.

Can you get it into the shop sometime this week? I'm willing to pay real money, not just eats, if you guys can get me in and out of there quickly.

ill call them tomorrow and see if they can. they arent super super busy so it shouldnt be a problem especially if its just pop rivets. depending on what day it was in there it would probably be either me or this guy matt. friday im pretty sure it could be me because i dont think i have to coach powder puff any other day it would be matt.

i dont even think it would be too steep. probably 2 hours of shop time + materials and tax id say ~$200 but dont go quoting me.

Mark Sipe is the man!

Debbie mentioned my issue to Mark yesterday, and last evening he came by to help me with the bulkhead.

We cut out some sheet aluminum Mark had and bolted it between the seat support rods and the rear deck. It's not exactly a "firewall" as it's not sealed, but it's an additional layer of protection if my fuel pump or swirl can springs a leak.

I may try to go back over it with a rubber mallet, a drill, and some sheet-metal screws and really try to seal it up (Mark thinks this would work pretty well), but I've got a laundry list of other things to get done on the car before Saturday, so I'll only get to it if I have some spare time.

That said, does anyone know if the WRX's tach signal line is a 50% duty cycle square waveform, and what line I'd need to tap into at the ECU?

Engine speed signal at the ECM is Connector B136, Terminal 9 (you have a svc. manual don't you?) and according to my info all it says is it's a waveform signal. No duty cycle info... if that helps at all.

Hey Scott. I just saw this and thought you would be interested.
http://tunerzine.com/articles/216/images/_DSC3103.jpg

That's pimp! Looks a bit nicer than mine, though mine probably has less gaps between the trunk and passenger compartment.

Does someone sell that thing?

You can check beatrush I guess.

Scott, it's like $160 from Beatrush, IIRC. I can source it from a contact down south if you need it. Pretty simple piece, but their stuff is top-notch. That said, it's not meant to be a firewall, so I'm not sure what it would do in terms of tech.

For $160 I'm not gonna rush out and buy one. Mine seems to be fine. To really serve as a firewall, both mine and that one will need some aluminum tape to seal up the gaps, but that Beatrush one certainly looks nicer than mine... though who knows if it will work with the crazy fuel pump/swirl can setup I've got behind it bolted to those vertical crossbars.

If you've got something functional that works, roll with it. I was thinking about it solely becuase I could cover the back with dynamat and give myself a somewhat effective trunk barrier instead of a piece of foam, since my STi is staying a street car for the most part, but doing all that would then effectively isolate the sub in the trunk and make it pointless. It works with the stock seat, but since I want to find a passthrough anyways, I'd just end up hacking through it.

I did grab their cooling plate because I found one cheap, but a copy on ebay is $30 and it's a piece fo metal. All you're paying for is not spending 4-5 hours crawling around, trying to figure out mounting points and figure out what hardware to use. At some point, that's worth it, but not if you already have something functional.

You never know, I'd think it would sound better with a dynamat lining than having a bare piece of sheet metal there. Bass is so omnidirectional anyway, and plus you'd lower the higher frequency road noise from the trunk. Just thinking out loud here...

The worst part about road noise in an Impreza is because the rear struts mount inside the passenger cabin. The rear topmounts are actually bolted to the rear deck right behind the rear seats, so no amount of trunk shielding is really going to make a big difference on road noise. That's one of the big reasons the Legacy (and now the new Impreza) have gone to a multi-link rear, so they can mount the suspension components under the trunk.

I never thought about that but it makes sense. Would it help even the slightest if you removed the rear seat and filled that pocket over the strut with sound blocking material? Like chunks of a memory foam mattress.:D

That might help with the higher pitched noise, but there's not really much you can do, especially if you're running pillowball top mounts.