posted on February 19, 2015 15:01
Project Land Speed Racer 240SX: Chassis Prep and Roll Cage Fabrication
Ah yes, the beginning of any good sedan type racecar build almost always starts with ruining a perfectly decent streetcar. In the case of Project Land Speed Racer 240SX though, I'm not sure if we are really ruining a perfectly good streetcar. Honestly, from the looks of things, it must have been owned by a series of wannabe dorifto hacks before falling into my hands. If anything, I think we saved it from a continued life of embarrassment running around with its "demon camber," four corded tires, and doing a crap ass job at pulling off that coveted hellaflush style.
God damn, give me a gun, let me shoot this car, and put it out of its misery. Or better yet, anyone have that flamethrower attachment from Call of Duty Black Ops? Let's roast some marshmallows! Ok never mind, there are already too many S13 chassis in the junkyard and the 240SX seems to be making its home on the endangered species list somewhere between the Bug Eyed Frog and the Zululand Black Millipede. We're gonna have to do the "right thing" and save this one… That is, save this one to claim our small piece of history with.
To start off the build of Project Land Speed Racer 240SX, we needed to prepare the chassis for the roll cage construction. This is probably the most therapeutic part of building a racecar, especially if you don't care about how the interior comes out. In our case we started out caring, methodically removing the interior panels with the intentions of selling them for a few bucks. About half way through though, the beer kicked in, we came to our senses, and just started tearing, ripping, and gutting out the interior. It just wasn't worth spending our precious free time getting flaked on or haggling over a few bucks.
Fortunately, we sobered up from our rampage just in time to carefully remove the interior wire harness, which runs throughout the cabin and under the dash. We disconnected it at the super multiple junction box, which is on the driver's side underneath the dash. Since it would be months before we reassembled the car again, we also made sure to label all of the important connectors using masking tape and a sharpie.
We found several interesting modifications to our wire harness. Surely, this one was performed by a highly skilled electrician.
With the interior panels and wire harness out of the way, we bought 20 pounds of dry ice to remove the sound deadening on floorboards. When you do this part, be sure to use gloves, as the dry ice will burn bare skin. Also, make sure you are in a well ventilated area unless asphyxiation via carbon dioxide is your thing. Whatever floats your boat dude. For an older car, the S13 240SX has a lot of sound deadening, which is a bit annoying. On the flat surfaces, it helps to crush the dry ice up into smaller chunks with a hammer and then chisel the sound deadening up once gets cold enough. On vertical surfaces like the transmission tunnel, we taped pieces of cardboard in place to hold the dry ice against the sound deadening.
Monday, January 30, 2012 10:09 PM
I find covering dry ice with a heavy cloth for a few minutes increased the effectiveness of cooling sound deadening. Resulting in much less dry ice usage and bigger pieces of sound deadening getting chunked off.
Tuesday, January 31, 2012 4:10 AM
Hey, that wiring looks as ghetto rigged as my car! I wonder what it is about S13s and bad wiring that seem to go hand in hand?
As always, MotoIQ brings us some of the coolest and well designed new race cars. Can't wait to see how this one turns out. I love my 240SX and it always brightens my day seeing someone do something different with one. Very tired of seeing poorly built "drift" cars all the time.
Tuesday, January 31, 2012 5:10 AM
That is a sweet roll cage.
Tuesday, January 31, 2012 6:34 AM
I miss my "Pig-nose"...(sniff) Died protecting me in a T-bone at an intersection.
It's a shame that the Dorifto posers are sending these cars to the junkyard. Then, like dogs at the pound, they are on borrowed time until the crusher...
Tuesday, January 31, 2012 11:28 AM
High quality workmanship! Are you guys going with a custom simple aluminum dash?
Tuesday, January 31, 2012 11:57 AM
I need to get around to rescuing an S13. I saved a 1959 Ford retractable from the crushers last year, and need to get my "nice" car STi before the Summer, but with the number of poor little S13s I see dragging stuffed animals across the Walmart parking lot, spinning that one Riken Raptor down to the cords, I think I may need to put my Prelude's H22 swap on hold before they're all gone. I can stack it out back with the wife's Corvairs til I can get around to it.
Tuesday, January 31, 2012 12:50 PM
I would have said the cage is just way too beefy...before i saw the video...so what no room for 2.5" x.250 DOM??? lol
Looks good I love the fitment and the door bars and floor plates are pure sex
PROTIP: use LN2 next time for the sound deadening, did my last S13 in 25 minutes...I told you on facebook to hit me up, could have saved you hours HAHAHA
Tuesday, January 31, 2012 2:53 PM
I've never had to use chemical assistance to remove sound deadening. A good chisel, hammer, good technique, and a proper Canadian winter worked for my SM and MR2. Even not in winter I find if it's below 25 (celcius) its not a big deal to chip out.
Side note, on AW11 MR2s there are cast iron chunks bolted to into the chassis inside of the seat mounting portion. Vibration damping?
Tuesday, January 31, 2012 6:26 PM
I think the worst effect the Dorifto guys have is they drive the price for clean S-cars through the roof. They did it with Civics and then DSMs :(
Tuesday, January 31, 2012 7:55 PM
The roll cage looks bad a$$ Chuck!
Tuesday, January 31, 2012 8:56 PM
I've been building a 240sx for a few years with an eye to land speed racing and time attack. I origianlly started welding in the all of the rear braces to a large bar welded between the rear shock towers, just like your cage. But the more I think about it the more I regret it.
The rear is not a strut design like the front. So the majority of the rear chassis forces are going through the four points that the rear subframe conects to, not the shock towers! If you're willing to extend the kickers through the floor, there is actually a decent lateral beam directly above where the rearmost rear-subframe mounting locations are. Then if you want to get real trick add that bottom x to just above the foremost rear-subframe mounting locations are.
Here's my tower bar I'm considering cutting out.
And here is Hot Lap Motorsport's (in Spain) latest. It is the closest attempt to what I'm thinking about, concentrating on having the kickers tie in directly above where the rear subframe ties into the chassis.
Wednesday, February 01, 2012 4:41 PM
@dru - def on the right track there, triangulate the towers down to or even through the chassis. I'don't like holes in the car esp where your second pics show, that's sure source of dust and crap. The bolt-on solution I use in my Nissan works well for that same area - there is a top brace you cannot see here over the towers, welded tubular steel https://lh6.googleusercontent.com/-wCywk5Ih520/TynovRFr1XI/AAAAAAAAKIM/1XFI80-NloY/w500-h376-k/RSTB_w_brace_5.JPG
bottom bolts through the holes where the OEM gas tank goes. Not a bad setup at all for mixed use car.
Wednesday, February 01, 2012 4:44 PM
@Chuck - I also started using spot weld bits when I pulled the radiator support out of my U13, what PITA that would have been and the car would have had so many holes drilled in it - but the spot weld bit mostly ate the metal i was removing anyway. Nice tip!
Wednesday, February 08, 2012 2:25 PM
"A lighter color will reflect heat and ultimately lower cabin temperatures whereas a dark interior color like black can make life a bit more uncomfortable for the driver."
In fact, color plays no role in radiation absorption, transmission and reflection. Surface finish though does. Please take a look at my thermo radiation notes from last semester, there is an interesting table in there too:
Thursday, February 09, 2012 10:35 AM
Who are you planning to run with? I'm currently prepping my Impreza for ECTA to run at the Ohio Mile.
Wednesday, February 15, 2012 12:49 AM
Freezing the sound deadening out of my Z32 was incredibly satisfying, but boy do I feel your pain about those sticky wheelarch tar mats.
I eventually figured out that by slowly going over it with a heat gun, they could be softened to the point where you could peel them off the sheetmetal in one big piece.
A lot of sticky gunk was left behind, but a turpentine-soaked rag cleaned it up real good. No damage done to the undercoating either.