Seb's Goblin #454 (2008 SS/TC donor) - Registered

[Sebnuts]

Had a good weekend. Managed to finish all of the fab work on the rear!

And it's completely bolt on.

Only time will tell on performance, but I'm really happy with the way it looks.

Up next, I need to finalize the mods on the front suspension. Unfortunately, it won't be bolt on, gonna have to poke some holes in the chassis.

 

[Sebnuts]

With the rear fab work done, I couldn't resist throwing the springs and tires on and letting it support it's own weight

 

[Sebnuts]

Moving on to the front, I put the new plasma table to work and made a drill template to accurately locate the new control arm and coilover mount points.


Borrowed this beast of a mag drill from work. Heavy SOB but made the drilling easy once I got it in position.


Just need to prep the holes a little with a flap disk and we'll be ready to weld in the new mount tubes.


I needed to relocate the coilover mount point on lower control arm too. For this I plasma cut some brackets and used another 3D printed fixture to make sure everything was in the correct position:

The new bracket also has a mount point for the sway bar.

Next up on the list is front sway bar mounts. This is the design I have currently. I'm not in love with it but it's the best I've come up with so far. I'll continue to noodle on it this week, but I'll probably start cutting parts and see what it looks like mocked up this weekend.

 

[ATMironov]

I ended up placing my sway bar above the frame. This was the best place I could manage using a straight bar and angled arms. You don’t seems to have those restrictions though. Haha.

Andrew's Extended Track Goblin - 08 SS/TC

Wait!!!!! You got pressure sensors in your brake lines????? Yes sir. Both front and rear. I have an active brake bias controller on my control panel, and the AIM Dash will do the math to tell me the actual bias so its repeatable. All the info is also logged, so after a session I can see how...

dfkitcar.com

Andrew's Extended Track Goblin - 08 SS/TC

Freaking sweet. Brady cut these for me today, looks super good. can’t wait to get it on the car. for anybody who’s interested, his email is [email protected] That turned out really nice!

dfkitcar.com

 

[Sebnuts]

You don’t seems to have those restrictions though. Haha.

Nope, gonna put the tube bender to work on some thin wall DOM lol.

The layout I currently have is heavily inspired by the Lotus Elise:

 

[Desert Sasqwatch]

AARRGGHH!!! I want one of those! I had to do my relocation drilling the hard way! But, wow, yours did tun out nicely! Break out the welder and get things welded up. Curious to see how it will turn out.

BTW, what front swaybar are you planning to use? Make, model, diameter?

 

[Sebnuts]

BTW, what front swaybar are you planning to use? Make, model, diameter?

I'm going to bend my own out of chromoly tubing. I still need to finish my ride and roll rate calcs to determine the OD and wall thickness, but it will probably end up being thin wall 3/4"OD.
I can get bushings that go as low as 14mm and as high as 28mm, so I'll have plenty of wiggle room if I want to retune in the future.

 

[Sebnuts]

Chipped away at the front end some more this weekend.
I made some new ball joint mount plates to relocate the roll center and allow for the use of high misalignment spacers on the heim joints.

I also got the ARB mounts tacked in. I don't think they look too out of place.

It clears the intercooler and ducts, pretty happy with that. I didn't put the radiator in yet to verify that the coolant lines clear it, but I'll be doing that first thing next weekend before welding anything in solid.

I have 2" of bump travel and over 2" of droop travel now with no binding, big win
I need to finish up the design of the new tie rod arm mount and maybe get that fabbed up next weekend.

 

[ATMironov]

Chipped away at the front end some more this weekend.
I made some new ball joint mount plates to relocate the roll center and allow for the use of high misalignment spacers on the heim joints.

Be cautious on the thickness of those ball joint mounts.
They are pretty notorious for bending. DF sells a beefed up version. I think they are made from 3/8 plate.

 

[Sebnuts]

I think they are made from 3/8 plate.

The original ones that came with my kit were 1/4" plate, the ones I made are the same. I didn't realize they sold a 3/8 version, strange that they wouldn't just supply that as the standard if the 1/4 version had issues.
I may just beef it up with some gusseting if needed.

 

[Rauq]

Be cautious on the thickness of those ball joint mounts.
They are pretty notorious for bending. DF sells a beefed up version. I think they are made from 3/8 plate.

For reference, when my kit was built the upper and lower brackets were the same thickness. I bent my original lowers. (I thought) Newer kits come with thicker lower brackets. If your lowers are not a least a bit thicker than stock Goblin uppers, there may be some risk there.

 

[Sebnuts]

Newer kits come with thicker lower brackets. If your lowers are not a least a bit thicker than stock Goblin uppers, there may be some risk there.

99% sure all of my stock steel brackets were the same @ 1/4", I'll have to double check now.

 

[Rauq]

99% sure all of my stock steel brackets were the same @ 1/4", I'll have to double check now.

They used to be in the store, but I don't see them anymore. Maybe I misunderstood what comes in newer kits.

 

[Joebob]

They used to be in the store, but I don't see them anymore. Maybe I misunderstood what comes in newer kits.

They did the change over to the thicker brackets somewhere in the mid 300s. I am #270 and paid for the AT "upgrade" brackets before they were standard. I think they went thicker steering arms and then went thicker brackets. Just part of the continuous improvement.

Joe

 

[Sluggonaut]

I'm 364 and the upgraded brackets were still an option at the end of 2021. The beefier steering arms were standard then, but the brackets weren't standard yet.

 

[Sebnuts]

Good progress this weekend.
I verified that the front ARB location clears all of the radiator plumbing and intercooler ducts

Finished welding everything up - Frame mods are done and we're ready to find a powder coater!


Originally I wasn't going to put an ARB on the rear, but I figured that would end up biting me in the ass later down the road, so I went ahead and added some mounts to the subframe

They're in the same location as the factory Cobalt ARB mounts, so an ARB from a non SS Cobalt is still an option.

Or a custom one using the same mounts & bushings that I'm using up front.


I still need to finish fabbing up the front steering arms and order some new springs. Ideally I can get all that done while waiting for the powder coater.

 

[comegetjoe]

Going all out. WHAT A BUILD!!

 

[Sebnuts]

I finished up my ride and roll rate calcs today and got new springs on order.
The general goals were ~2Hz frequency with a roll stiffness of 3°/G. Here's what I ended up going with:

Front Setup:
Roll Center Height - 1.5in
ARB Rate - 170lbs/in (custom 3/4"OD x .120"Wall 4130 tubing)
ARB Motion Ratio - 0.69
ARB Wheel Rate - 82lbs/in
Spring Rate - 200lbs/in
Motion Ratio - 0.65
Wheel Rate - 84.5lbs/in
Frequency - 1.92Hz/115cpm
Front Roll Rate - 352ft-lbs/°
Front Roll Rate Distribution - 44.6%
Front Total Lateral Load Transfer Distribution (TLLTD) - 41.9%

Rear Setup:
Roll Center Height - 3.3in
ARB - None
Spring Rate - 220lb/in
Motion Ratio - 0.95
Wheel Rate - 198lbs/in
Frequency - 2.15Hz/129cpm
Rear Roll Rate - 438ft-lbs/°

 

[Keckster]

Pretty similar setup to my spring rates. I've currently got 300 in front 220 rear. Haven't done any anti dive geometry in front yet but will lower spring rates once I do

 

[Sebnuts]

Pretty similar setup to my spring rates. I've currently got 300 in front 220 rear. Haven't done any anti dive geometry in front yet but will lower spring rates once I do

You need to be careful with lowering the rates on the stock front end, you're pretty limited on bump travel. If you have the "new" style bent plate ball joint mounts, you can overbend the upper mount a few degrees (basically get it to match the angle of the upper control arm) to help some.