The Willomet Charger

[moparstuart]

That's going to be a rigid and BEEFY Charger.

better for the Jumps   

[Willomet_Motor_and_Fab]

That's going to be a rigid and BEEFY Charger.

I just finished the second interior plate, and started fitting the final inside plate. That will give a full picture of where we're going.

better for the Jumps

I do plan to drive it hard...

David

[JR]

Nice. Any rough idea what the finished curb weight will be?

[Dino]

WOOT!

I had a grin on my face while reading all the way through this thread. Very nice work! As a former auto body guy I do appreciate your eye for detail. And yes, those welds are nice! I will enjoy following your build.   

[Homerr]

Very cool reinforcing.  Are you doing anything for side-impact above the rockers, i.e. the doors?  Or other impact areas?

Or is this more just for general chassis rigidity?

[Willomet_Motor_and_Fab]

Nice. Any rough idea what the finished curb weight will be?

Targeting 3500ish lbs dry weight and before I wedge my 6'3" frame into the driver seat.  The chassis is the largest single weight penalty (250-300ish lbs net plus), and the cage will be 4130 but still 60ish lbs.  For reference, a Roadster Shop b-body chassis weights about 650lbs, and that doesn't include a floor.

WOOT!

I had a grin on my face while reading all the way through this thread. Very nice work! As a former auto body guy I do appreciate your eye for detail. And yes, those welds are nice! I will enjoy following your build.

It was fun retelling some highlights of the build, and I'm glad you're enjoying it.  I've learned a ton through this process, and appreciate your encouragement.

Very cool reinforcing.  Are you doing anything for side-impact above the rockers, i.e. the doors?  Or other impact areas?

Or is this more just for general chassis rigidity?

There will be a modest cage, and some low profile door bars.  I don't want to kill ingress/egress and make it a pain to just get in and drive.  I'm not shooting for a super low ET, so an 8 point should be plenty.  Most everything I've posted is about improving chassis rigidity.

Last night's progress - passenger side interior plate is in, and inner plate is mocked up.  The passenger rail flange is trimmed and welded in preparation for fitting the interior rail plate.




Plate is fit and in.  Working with the rails up close like this, it's easy to see the variations in assembly from left and right.  It makes it impossible to reference and measure from features, and I have to rely on finding level and measuring from set points on the frame table.


Now, it's easier to see where we're going.  The rails are about 7" tall at the crease, and the interface between the torque box and rail is a square 5".  Recall that the boxes are 5" wide and 4" tall, so the interface is width matches the depth and the plates internal to the boxes also align with the overlay plates.






It's a lot of steel up front, but the improved stiffness should be worth the small amount of added weight.  I'm looking to get back out there tonight.

David

[BDF]

Looking good! I like the paint it green idea a lot...

[Willomet_Motor_and_Fab]

I'm not afraid to change a design when it isn't working.  There was a part of the interior and inner frame where they overlapped and created a 1/4" thick segment of rail.  While I acknowledge my offroad fabrication past, this isn't a stunt car and doesn't need 1/4" rails.  I segmented the two plates and replanned my weld steps, and added about 1.5 lbs of lightness to this little bit of of the project.

Rev1 inner frame plates tacked and cleco'd.  I'm building the top and lower plates today and this week.








David

[Mike DC]

                   
Really interesting build.  

You picked some good areas to stiffen.  The OEM rockers/boxes are flimsier than we'd like and there was flex in the front subframe/firewall/cowl structure.  

The lower rad support (I see you've got it hacked off) is another area that could use stiffening, although if you've got a permanently mounted K-frame then that would do the same job.  

What kind of suspension is in store for this thing?  

---------------------


BTW, I think you're being a little optimistic on the curb weight goal of 3500 lbs.  

For reference, a nicely loaded stock 440 R/T is about 3800 lbs.  Some can hit 4000 with extra cabin insulation and the usual roadside emergency stuff.  

After all the cast iron parts under the hood get switched to aluminum (including the block) it might be down 200-230 lbs.  That would probably break it even with the extra steel weight you are adding.  

 

[Willomet_Motor_and_Fab]

BTW, I think you're being a little optimistic on the curb weight goal of 3500 lbs.

Yes I am, but there's a plan. Also, I won't get in a twist if I tread water at 3800.

What kind of suspension is in store for this thing?  

Magnum Force transformer up front and a torque arm/watts link in the rear.

David

[Mike DC]

This might do you some good.  It's a partial list of 68/69 Charger component weights.  It was mostly done by holding the part in my hands while standing on a bathroom scale.  Some of them aren't perfect but it's all in the ballpark.

=======================================

Unibody shell (completely bare) - 635 lbs (lighter than you'd think!)

front bumper/brackets assy – 50 lbs
(just the A-shaped brackets – 10 lbs each)

front fenders – 30 each
(bare, solid metal)
hood - 65
front grille frame  - 18 (bare)
complete grille assy - 30ish
front valance  – 10
(with lights installed)

K-frame - 45
(bare)
LCAs – 10 each
(with mounting shafts)
factory swaybar - 12
(with all brackets)

****  total of 927 lbs up to here  ****


doors  – 75 each
(almost complete, all glass/trim/vent windows/outer handles, but no upholstery or paint)

trunklid – 30

dashboard frame  – 17
(bare)
instrument cluster – 6
(complete)

front bucket seats – 47 each
(complete, intact, w/tracks, but not headrests)
back seats – 25 upper, 25 lower
(complete/intact)

door/side panels:
upper 4 – 13
lower 4 - 12

center console – 16
(complete, automatic top plate, no shifter)
(just the top plates – 6)


**** total of 1315 lbs up to here****

[Derwud]

Great place to loose a socket...

Awesome work, I have been following this on another site as well..

[Willomet_Motor_and_Fab]

This might do you some good...

That's a great list, and thank you for sharing it.  I recall the unibody being lighter than I had imagined.  You highlight areas where I intend to focus:

front bumper/brackets assy – 50 lbs:  I bought a TIG machine specifically so I could work with aluminum, so I'm going to try my hand at fabricating a sheetmetal aluminum version of the bumper.  I might also buy a glass or CF one.
front fenders – 30 each:  Can't do much here except simplify the core support mounting and eliminate the headlight buckets to suit my planned grill design.  They do get slightly trimmed to match the rocker beams, but I may have to build new fender arches to clear the 305 fronts.  I doubt I can net any weight savings.
hood - 65:  I'm seriously considering a Speedkore CF hood.  They're expensive, but knocking 50 lbs off the front of the car is hard to pass up.
complete grille assy - 30ish:  Like with the bumper, I'm building an aluminum grill assembly and support structure.  Not sure what that takes out, but probably a little bit.
front valance  – 10:  Maybe I squeak out a pound or two with the slightly enlarged intake opening, and the light buckets will likely be used for brake ducts
trunklid – 30:  I think I could pull up to 5 lbs out of this with extensive use of my punch and dimple dies.  Again, Speedkore CF is a serious consideration.
front bucket seats – 47 each:  The heaviest Recaros are 31 each, with all their seat-cooling-and-heating-lumbar-adjustable goodness.  The lightest seat I could legitimately enjoy for longer than 2 hours has a CF back shell and weights 15.5 lbs.
back seats – 25 upper, 25 lower:  What's a back seat?

The lower rad support (I see you've got it hacked off) is another area that could use stiffening, although if you've got a permanently mounted K-frame then that would do the same job.

Going back to this comment, I'm uncertain about the lower front support.  I have the XV piece, and it would work well with some fitting, but I'm considering leaning the radiator forward and building a tubular support structure.  I definitely have plans to expand the K member, and will run a lower shear plate/tube structure.

Great place to loose a socket...

Awesome work, I have been following this on another site as well..

I’m trying my best not to close up the rails with my tools inside, but there is still a long way to go.  I thought I recognized your screen name, and I'm glad you're enjoying the build.  Thanks for the feedback.

Again, the conversation on this site is great.

David

[Willomet_Motor_and_Fab]

Fine fitting the top plates, which consumes a crapload of time to get the open corner welds set just right.



On the plus side, I'm finally getting a feel for welding these original 14ga rails. It's been challenging finding the right setting without bringing up the contaminants on the inside of the rail where there's still some old corrosion and (now) Eastwood primer.  I broke the process into two, and have used it successfully several times now.

First pass with .045 wire.


Cover pass with 1/16


More to come. It should only get up to 105 today.

David

[68pplcharger]

Looks like it'll be pretty solid. Love the Rocker frame rails

[MxRacer855]

Great job. I love this thread! 

Jeff

[Willomet_Motor_and_Fab]

Great job. I love this thread!

Thanks, Jeff. It’s a lot of fun to build, and I’m pulling ideas from some great threads here.

Looks like it'll be pretty solid. Love the Rocker frame rails

When I saw this particular chassis while visiting The Roadster Shop, I immediately knew what I wanted to do.


They use a slightly smaller rocker beam, and set everything up to use C6 suspension parts, which I'd prefer to keep the factory rails and use Magnum Force parts.  They use 10ga everywhere (.134"), whereas I'm using 11ga (.120 or .125 depending on the shape of the material), along with a planned .095 4130 cage.  They rate their chassis for up to 2000 hp.  I'm going for about 35% of that figure, so I'm sure 1/8 will do.

David

[Hemidog]

Sweet welding skills! 

[68pplcharger]

You'll be fine at 700hp, overkill for sure. Nice thing is you'll have room to increase hp later on down the road. My car is around 1000 hp mark and I only did a roll cage on top of frame ties (1/8" seam welded to the stock floor), all behind the firewall. In front of the firewall: Tied the frame below the core support, Gusset the k frame, install 1-3/4" roll cage under the fenders from the shock tower to a 1/4" plate bent to the shape of the firewall (welded to the fire wall and tied to the roll cage inside). Also some tubing triangulating the shock towers top side to the center of the firewall. Rigid as hell and allows for some road racing fun. Yours is beyond that with a roll cage on top. should be a lot of fun.

[Willomet_Motor_and_Fab]

Sweet welding skills!

Hey, thank you.  Lots of trial and error and spent argon preceded these photos.

You'll be fine at 700hp, overkill for sure. Nice thing is you'll have room to increase hp later on down the road....

I'm comfortable at that level, too.  I could never make full use of the 550hp I had in my Cadillac, and even 350hp seemed like all I could handle in my boy-racer STI.  I can't imagine "needing" more than 700hp, especially since I don't have a sub 11.49 ET in mind.  I still recall when 500hp was on the ragged edge for a street car.  Now, it's just a conversation starter.

Then again, your power rating has a comma, and that's pretty F'ing cool.

David

[Finn]

Damn, everything looks so clean and organized! Nice work!!

[Mike DC]

  
I would worry less about the horsepower taxing the frame and more about the huge sticky tires.  

Using 0.120" seems fine though.  The factory subframes were only like .070" thick at best, with the rocker boxes even less.  

[2fast4u]

 

[Willomet_Motor_and_Fab]

Damn, everything looks so clean and organized! Nice work!!

Thanks man.  I try to keep the shop organized, since clutter distracts and frustrates me.  I sweep at the end of each day, and when a project segment concludes (like the rockers or these front rails), I pause for an afternoon to do a full clean up and blow out the metal and dust that gets everywhere.  I'm kind of picky about it, but keeping a clean shop is one key differentiation I have over many larger shops, and you never know when a client wants to visit.

I would worry less about the horsepower taxing the frame and more about the huge sticky tires.

Using 0.120" seems fine though.  The factory subframes were only like .070" thick at best, with the rocker boxes even less. 

Looking around at some autocross builds, my planned 305/325 tires will seem pretty average, but they're definitely larger than what came on it originally.  I really like working with .120 in general.  It's a minor step up from 14ga, so open corners are easily welded with .024 wire on the mig (loads of puddle control), and I usually do two passes on the TIG (.045 and 1/16) to get the profile I like.

Weekend progress:
If y'all are tired of looking at front frame rails, too bad.  There's still a good ways to go, but we're down to final fitment and welding.  All the plates are welded, blended, and required only minor refitting to account for shrinkage.  All the Clecos holes still line up, which is a good sign.  I also went ahead and added a gusset to better transition the shock tower to the outer frame plate.  Acute angles like that on a structural area bother me.


Why go through all this effort to expand the front rails?  Here are two photos to illustrate.  Before:


After:


The section height at the critical connection is about 2x from factory.  While the inner fender sheetmetal does transfer loading from the front rails to the firewall and the rest of the unibody, it's not up to the task by itself given the handling goals for the car.

Final task is prepping the rails for welding - making sure the control arm hardware doesn't interfere with the lower plate and welds, grinding the uneven flanges on the upper part of the rail, and making sure I seal up the new frame shape from any water intrusion.  Just taking my time, mocking up, and setting up the weld sequence.


Busy week ahead of day job stuff, but I'm grabbing the hours where I can.

David

[68pplcharger]

Looking around at some autocross builds, my planned 305/325 tires will seem pretty average, but they're definitely larger than what came on it originally.  I really like working with .120 in general.  It's a minor step up from 14ga, so open corners are easily welded with .024 wire on the mig (loads of puddle control), and I usually do two passes on the TIG (.045 and 1/16) to get the profile I like.

I set mine up for road racing/autocross as well. I've got 315-35-17 tires in the back. I fit them into the stock wheel wells with some messaging of the outer wheel well. You can go larger if you take the lip down or roll it. Front I fit 275-40-17 but had to flare the fender by two inches and roll the lip. Car handles pretty awesome.