Cadillac ATS


A while ago I decided I was going to do a proper new school supercar. Something with all the features that are to be expected in the LEGO Technic Community. You know what they are; suspension, a gearbox, opening doors, a working engine, steering, and something fast looking. Probably red. It was time to test my chops and throw my hat into the ring.

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Cadillac ATS

It has been a long time since I have built a supercar. While I enjoy many of the cars others make, I long for exceptional creativity in suspension design, gearboxes, and body style. It was time for me to build another one and contribute to these areas. About two years ago I set out to create a six speed gearbox that would have a more realistic gear change movement. I tried linkages, springs, and so many gears. In a bit of a breakthrough, I offset the two outside changeovers vertically by 1/2 stud. This allowed for the changeover lever to connect all three changeovers as it rotated from a single center pivot point. Once this design was completed, it needed a home.

ATS Transmissions

I have a preference for sedans rather than coupes. Plus too many two-door supercars have been created. Forgive the slight nationalism, but I thought it would be fun to do an American sports sedan, so a Cadillac was the best choice since the demise of my beloved Lincoln LS. The ATS was new, and at the scale would be a little more manageable than the CTS. I worked a little on the scale of the car. Some parts would be a challenge to convey the look, but I was ready to start building.

I started with the front suspension. The new suspension arms allowed for a short/long arm setup. The two different arm designs allowed for a increasing negative camber as the suspension moved through its travel. Additionally, the pivot points on the steering hub allowed for a kingpin inclination to provide an improved caster angle. Finally, I added Ackerman geometry to the steering link. After some work mounting the suspension, and the rack and pinon steering, I had the front suspension done.

ATS Front Sus

The rear suspension was more simple, but still had some unique features. While the real ATS uses a 5 link setup in the rear, I was not too impressed with the results I came up with as too much flex was found at the wheel. I started with a transversely mounted limited slip differential that I have used before. This connected directly to the two half-shafts for the rear wheels. I applied a short/long arm setup for the rear suspension so the tires would keep their contact patch as the body would roll through a corner. Like the front, this created increasing negative camber as the suspension moved through its travel. Normal in real cars, not often replicated in LEGO.

ATS Chassis

Tying all of these parts together was a little bit of a challenge. I wanted the steering wheel to be connected to the steering as well as a HOG knob on the dashboard. In addition, the doors, trunk, and hood should all open. Naturally, the car had to have a spare tire, and various engine options which could be easily removed. The chassis had to be stiff enough for the suspension to function well. Packing this all together took some time. About 9 months, but who is counting?

ATS Left Front

But what took the most time was the body work. This is the part for which I have little motivation, and the important part that would identify the car as an ATS. I had a lot of work to do. And my palmares have not trained me well for this task. After major parts were placed, and the dimension were set (37 stud Wheelbase, 60 stud Length, 25 stud Width), I worked on one section at a time. As the front bumper was part of the chassis, this part was developed early. As did the rear bumper. The headlights are unique for the ATS, so this was done early as well. After the roof was placed I worked on the trunk, which came together rather easily. I worked on the hood of the car, and after two designs I was happy with the result. I then worked on the grill, and after tinkering with a couple of SNOT techniques, I was able to get most of the distinctive Cadillac grill in my design.

Cadillac Grillz

Then off to the doors. I made seven designs. Most sedans these days have various creases that identify their sedan as different than any other sedan. You will notice the ATS has two, one on the bottom that rises slowly to the rear, and one midway up to the windows that moves along the length of the car from the hood to the trunk. The top line was accomplished by having the angle for the windows start a little lower on the front door and higher by a 1/2 stud on the rear door. The bottom crease was added by attaching some angled plates to the bottom of both doors, which cant slightly inward. Finally, both doors have an upper pivot point that is 1/2 stud inboard to bring the upper part of the doors toward the center of the car. Once I got a design I liked, I had to bring it all together to make sure everything fit well. I adjusted the roof, modified the hood, tightened up the dashboard connection to the doors, and made some changes to the rear quarter panels. There were still some areas where improvement could be made, but I was running out of ideas. I was pleased with the result. Pleased enough to say I was done.

All in all, I was pleased with the result of the car. As this is my first studless supercar, I was happy with how it turned out. The functions were up to my standards, and nothing was compromised as the car came together. While I was overwhelmed with the bodywork, I was pleased with how it turned out. Because it took me a long time to get it to work, it may be a long time before I do another one. I was happy I did a sedan, and hopefully a new moniker can begin in the LEGO community. #supersedan.

Happy Building.

8081 RT


I have said it before; I really like set 8081. It has so many possibilities for improvement. After talking a look at RM8‘s design, I thought I should do a street version of the 8081 to follow up on the 4×4 8081 I built a while back.

The full gallery can be found here, and free instructions can be found here.

8081 RT Front

I took the existing bodywork and frame of the 8081, and chopped out the rear suspension unit to revise the rear suspension design. I wanted an independent setup with a differential. As I have used a couple of times before, I used a floating differential design. The differential is attached to the driveline much like a live-axle set up, but is connected to two independently mounted wheel hubs. I have used this before, and I like the way it works. It allows for a driven axle with independent suspension in a very narrow setup. This way each wheel can move independently, but it does not require two universal joints on each side of the differential. Since the differential is not fixed to the chassis, it has to be braced to the driveshaft. While this set-up is not often used in real cars, it works well for LEGO designs. I used the new wheel hubs, and attached them via a short upper arm, and a long lower arm so the camber would change through the suspension travel.

Moving to the front, I kept the V-8 as in my 4×4 8081, and built the rest of the front around the motor. I used a suspension design similar to 8081, where there are two equal length arms holding the steering pivot. A single shock absorber is used for each side. All told, the car is about two studs lower, due to the new suspension, and the new tires.

It is not much of a redesign, but sometimes I need a project that is not a significant, and allows me to just build something simple.

Happy Building.

Power Functions 4×4 8081


For most LEGO enthusists, when they purchased the set 8081, they quickly modified the set with a Power Functions drivetrain.  It makes sense.  LEGO models are a little more exciting when they are motorized.  But I guess I went a little backwards.  I wanted to do the fun stuff first, and make the most complicated and compact drivetrain I could make.  I posted the instructions here, and they can also be viewed on Rebrickable.com.

But the comments kept coming from people who wanted to see my model motorized.  So I thought it might be a fun addition.  I added a two PF M motors, a 8878 Battary Box, and an IR receiver.  I tried to keep the modifications simple, so I could easily add the motors to the MOD, and take the system out if I wanted to.  The drive motor was placed on a simple mount that connected to the frame.  The power was fed thought a 8z gear to a 24z gear which then connected directly to the V8 driveshaft.  The driveline was unchanged from the V8 down.  The steering motor was mounted laterally in front of the rear seats.  A 20z double bevel gear drove a 16z gear, then a worm gear moved the final 8z gear which was mounted on the existing HOG steering axle.  I removed the passanger seat which is where I placed the battary box, and created a simple mount for the IR receiver.  The added weight required a new shock absorber, so I added that as well.

The model worked alright.  The drivetrain did well to handle the new power, and I could easily control the Crusier.  The steering motor was a little too powerful for the upside down facing steering rack.  It skipped a little under load, which was a problem over rougher terrain.  The drive motor was a little taxed, so a PF XL would have done a little better.  I guess I could add that, but I am ready to move on to my next model.  Stay tuned.

The full gallery may be found here.

Red Sedan


When I got out of college, I started getting back into LEGO; the end of my “dark ages.”  I wanted to make a large supercar, just like everyone else.  But after my first attempt, there were a couple of things I wanted to improve, and the first car did not really look right.  OK, so what needed to change?  I needed to stretch the car, and make the stance a little better, add some features, and make it as real as possible.

See full gallery here.

I used the dementions of the 2005 BMW 5 series as my template.  From these demensions I used the F1 Racer wheels and tires to set the scale, then I determined the wheelbase, got the width, and I went to work.  I first made the rear suspension unit, and then the dual cam V-8.  Then I linked the two with a 4 speed transmission, and a long driveshaft and added a simple parking brake.  It took a little work, but I then added the front suspensions.  I have found it best to use technic beams to mount the front suspension. The A-arms are then attached to this structure, with the shock absorbers placed on this structure and braced with liftarms.  I then connected this directly to the front of the V-8, and connected it to the rest of the chassis with a simple frame.  I used the old steering mounts of the old 8865 supercar, and connected them to the steering wheel through an upside down mounted steering rack.  Of note, the car was going to be big and heavy.  I had to find a way to get two hard shock absorbers at each wheel which limited the suspensions options I had.  In addition, I added a front and rear sway bar, which took a little more space, but it worked.

Then the body.  I worked first on the doors, and the front bumper.  I used a dual pivot design for the doors so they would open even though bricks do not work well with pivots.  Then I did the front and rear quarterpanels, and set the rear bumper in such a way that a full size spare tire would fit.  I then worked on the interior.  I designed a simple tilt steering using a worm gear, and a universal joint.  I made sure to use the great front seat design by Pixsrv, added a rear bench seat, funished the trunk and added all the little compartments in the center console and glovebox.

I finished with rest of the body work.  The roof had a sun roof, and the trunk would have a damped shock to hold open the  trunklid, and added small details and some mirrors.  It was big, and it was done.  I was pleased with my first large car.  It still my most popular on Brickshelf.com.

All in all it was a great experience to learn about how to make a large car, and all the challenges that go with that.  Frankly, since this design, most of my cars have been a little smaller, as it makes the suspension and steering work a little bigger.  Lessons learned.

The full gallery may be found here.

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