Updates on my Govedo chassis plans

[plans4sale]

 Update:

- Most of the turned parts (used in the suspension, as well as mounting points for the rear bumper frame and the door hinges) were slightly modified to better suit their function;

- The upper toe links of the front suspension were shortened by 2 mm at each end, making them 4 mm shorter than before. The default camber angle is zero degrees, however, these shorter toe links will allow for greater camber angle to be set optionally.

[plans4sale]

 Update: I changed the position, length and angle of the steering arm on the front uprights to minimize the bump steer, and to make it possible to use shorter rack and pinion, which means that a wider array of OEM items will work just fine with my Govedo chassis.
 

[plans4sale]

 Though my Govedo chassis plans are no longer on sale, there are a few other alternatives offered for the same chassis design, which I already mentioned in Reply #114 here http://lamboclone.com/index.php?topic=774.105 . Now there is one extra option available. For those who are looking for a complete solution (custom car shops etc), the original 3d CAD model of the Govedo chassis in Rhino's native *3dm file format (NURBS solids) is obtainable for 15 000 Euros. The file consist all the tubes, metal plates and sheets, machined (turned) parts etc required for the chassis, suspension and door hinges. Included are also dimensionally accurate 3d models of 11" and 14" QA-1 coil-overs and Corvette C5 hub-bearings that I modeled after carefully taking measurements from the actual parts. Next to the fully assembled 3d chassis are placed tens of separate chassis sections that are designed to be preliminary assembled and welded on flat MDF jigs, whose 3d models are also included.

[plans4sale]

 - Two newly added tubes in the front end improve the safety in the case of a small overlap frontal crash;

 - The bolt-on detachable engine cradle received a nice upgrade and now its strength is considerably improved, allowing it to withstand the twist and weight forces of a lot more powerful engines;

 - An optional redesigned version of the engine cradle, specifically designed for accepting Mendeola SDR5 ( http://www.mendeolapowertrain.com/transaxles.html ), is now available to existing customers for 50 Euros. The redesign includes: different non-symmetrical X-bracing on the bottom below the engine (allowing for a convenient access to the engine's bottom oil probe), different X-bracing above the Mendeola transaxle and custom mounting points for the latter. However, attaching the engine to the engine cradle via mounting plates and/or tubes is customer's responsibility due to the wide variety of engine choices.

[plans4sale]

 - An optional 3 mm thick metal plate is added to the front upright design to reinforce the lower Corvette C5 hug-bearing's mounting point. Using this reinforcement makes the mounting point about 27% stronger against sideways push & pull forces. However, that extra strength comes at the cost of 53 grams added weight and reduced space for the torque wrench used to tighten the lower ball joint's locknut, so it's up to the builder whether he/she will use the reinforcement or not. The front upright is a robust piece of hardware even without the extra plate, so the latter could be added just in case that somebody wants an extreme strength. A short overview of the optional reinforcement could be seen in the following video (note: the actual plate's design was further optimized for best strenght to weight ratio after I captured the video):
https://www.youtube.com/watch?v=S2gfBa0QSI8

- I replaced the pair of male rod ends used at either side of the steering rack with female ones instead. This effectively re-positioned the installation point of each rod end's locknut outside of the front upright's body, allowing for 5,5-6 mm extra clearance, hence the increased turning angle of the front wheels;

- An upper bump stop metal plate assembly is designed to limit the front suspension's stroke according to the need of every builder. That bump stop assembly shall be welded to the chassis after the suspension is fully adjusted at ride height so that the former could be permanently attached at the proper height allowing for maximum suspension stroke while preventing a potential collision of the tyre with the inner wheel well liner's surface. The rubber bump stop that is going to reach the aforementioned bump stop plate in extreme situations is bolt-on adjustable, providing some extra distance for fine adjustment.

[plans4sale]

 - Several new metal sheets for the chassis are completed;

 - The front upright now has some metal plates redesigned in shape and/or wall thicknesses increased or decreased based on the amount of load they have to withstand. As a result, the new front upright weights in about 4,43 kg*, down from previous 4,9 kg. [Updated] After further optimizations, the weight have been reduced to 4,4 kg.
* A software calculation based purely on the mass of all metal plates excluding the following: Corvette C5/C6/Z06 hub-bearing assembly, brakes, screws, nuts, washers, turned parts and welds. The turned parts are 10 numbers and weight 312 grams total.

[plans4sale]

 After some fine tuning of the front suspension I achieved even better roll angle performance than before. While at default ride height (110 mm), totally vertical front wheels (with no camber adjustment) and testing a body roll at 3 degrees to the left hand side, the front left wheel will incline by mere 0,839 degrees, while this number is -1,616 degrees for the right hand wheel. I measured this by subtracting 3 mm from the left wheel's outside diameter as I take into account the potential tyre deflection due to the generated pressure. This makes for a very reasonable road patch. Maximum degree of inclination for the front left wheel in this test is 0.873 degrees reached between 3,7 and 3,75 degrees of body roll. However, 3-3,2 degrees of body roll is the maximum number allowed by my suspension, because at this point the front left wheel will be lifted by about 45-50 mm towards the wheel well's upper wall, already causing a pressure to the rubber bump stop. If you optionally set the wheel camber angle at 1 degree instead of the default 0 degrees, in this case the maximum angle of inclination for the front wheel will be such that the latter will stay vertical even at the most aggressive body roll. This all is by not taking into account a good sway bar. Obviously, with a sway bar included, the performance of the right hand wheel will be even better, effectively helping the left side wheel, too. On top of that, during high-speed cornering conditions the front left wheel  (presumable that the car makes a right turn, hence a body roll towards the left side) will also gain some negative angle (which, despite the word used, is a very positive thing) due to using dual-link upper arm instead of a single regular A-arm.

[plans4sale]

 I made most of the changes required for the door hinge mounting plate and they could be seen in the video I recorded today:
https://www.youtube.com/watch?v=XM3k26gb73Q

[plans4sale]

You do good work, wish your chassis was available before I started building mine.

 Thanks! My Govedo chassis plans were available for pre-order since end of 2012 at extremely low price back then (initially from 70 USD, current pre-order is 500 Euros and final price after one month will be 3000 Euros with the actual custom hinges manufactured and included in the price) that grew over the time, and most of the chassis design was ready at late 2013. My initial chassis design was very simple, but I though that I could make it even better, so I put lots of effort to perfect it where I saw opportunity for improvements. Over the past two and a half years I made many upgrades, but the overall structure and size is almost unchanged, so basically my early customers and my more recent customers get nearly identical chassis with a few exceptions here and there. And in most cases it's easy to upgrade an earlier chassis with the new additions, because most of them are just that, additions. These include: new sheet metal, new removable engine cradle (not part of the main chassis), new rear bumper frame (also removable), optional X-brace on the roof, new suspension arms and uprights, larger diameter for the roof tubes, etc. I has a basic door hinge design two years ago, but now I completely redo the work and make it more robust and bolt-on adjustable. Next month I expect to be able to show photos of the first customer chassis with installed working hinges.

 Cheers,

 Bobi

[autopro]

You do good work, wish your chassis was available before I started building mine.

[plans4sale]

 The Govedo chassis now features an optional X-brace reinforcement to further increase the chassis strength and protection of the occupants. It comes in two variants depending of what the builder will consider as the better option to suit his or her application:

 a) Just a single tube in a "front left to back right" configuration (or opposite for RHD cars) that allows to preserve the original headroom for the driver and lowers the passenger's room by 35 mm;

 b) Two tubes in a X-brace configuration that offers maximum possible strength at the cost of 35 mm reduced headroom for both persons inside the car.

 There will be several extra laser cut plates that I will design in next days. The new addition to the roof and options for installation could be seen at the bottom of this image album: http://imgur.com/a/pekFu

[plans4sale]

 A few weeks ago I had the chance to go and check again the first built prototype Govedo chassis and thanks to some testing of the actual suspension I was able to collect very useful data of what's good and what could be improved even further. There are two major improvements now:
1. I slightly redesigned one area of the front upright (wheel hub) to increase the amount of free space around the steering toe link;
2. I also shortened a bit the upper control arm toe links (the pair that replaces the upper A-arm) to allow a greater increase of the negative camber angle (up to -1,2 degrees), while maintaining the default camber angle of 0 degrees. Previously, the default camber angle for the front wheels was still same at 0 degrees, but the longer upper control arms allowed only for up to -0,6 degrees optional negative camber angle, and 0,6 degrees positive camber angle (the latter is not necessary at all). With -1,2 mm degrees of camber angle, each front wheel's upper outside wall will be shifted by about 11 mm inside the wheel well.

[plans4sale]

 I added two optional small cross-sectional plates to the rear hub that will further reinforce the bolt pattern area where the Corvette C5 hub-bearing is mounted. Both pieces will add about 75 grams combined to the total weight of the rear wheel hub. That reinforcement is usually not necessary for when the engine's power is in the range of sub 500 HP.

[plans4sale]

- I did some tiny improvements on the rear wheel hub, as well as on two of the mounting points of the chassis where the upper rear A-arm is attached. These changes will allow for a greater clearance when using thicker (longer along the axis of rotation) nuts for the QA1 rod ends. The front wheel hub is under a similar redesign now;

- Recently I also started to design the metal plates that will serve the role of mounting points for installation of the door hinge;

- The roof will receive an optional X-bracing to further increase the overall stiffness of the chassis and roll-over protection for the occupants. However, this addition will reduce the headroom with about 40 mm, so it's up to the builder to decide if he/she will use that reinforcement. A good compromise will be to use a single diagonal tube going from the passenger's side C-pillar up to the driver's side A-pillar. This way, the driver will still enjoy a maximum headroom while the passenger side will be 40 mm shorter.

 I also made some new renderings to show the current chassis and suspension design. The first 4 images n the top show an earlier state of the design, while the ones at the bottom are newer: http://imgur.com/a/pekFu

[plans4sale]

 - I optimized the rear wheel hub (a.k.a. upright) by redesigning all metal plates and changing a few wall thicknesses depending on which areas are most affected by the pull forces and twisting. Now the rear wheel hub is up to 20% stronger in certain areas compared to the previous design, yet the weight is reduced from 8,5 kg to 8,1 kg.
 
 For comparison, the NAERC rear wheel hub (used mainly in the replica Diablo and Murcielago builds) weights 5,62 kg while providing a lot lower overall stiffness and transfers 95% higher negative load to the A-arms during sudden acceleration or heavy braking. Considering that my suspension uses only one coil-over per rear wheel, while NAERC's uses two coil-overs per rear wheel, the weight penalty on my wheel hub is not as big as the basic figures suggest. My Govedo rear wheel hub uses a massive 10 mm thick mounting plate for the C5 hub-bearing assembly, while NAERC's rear hub uses two separate plates with a combined thickness of 8,28 mm whose bending resistance is as low as an equivalent of a single plate with wall thickness of about 7 mm. Another interesting comparison with the NAERC rear wheel hub: My upper A-arm is located 77 mm higher, while the lower A-arm is 41 mm lower, both helping to reduce the push or pull forces transferred to the mounting bolts, rod ends and chassis.

 https://youtu.be/e35qusPtzP8