boodlefoof
07-05-2006, 02:13 PM
Hey all, (sorry this is a long post...) it has been awhile since I last posted. I've been a bit busy studying for the Virginia Bar Exam, but I have managed to spend a little bit of free time working on the old Datsun 240-Z project while the wife was out of town for the past few weeks visiting relatives.
Anyway, for those not familiar with the project it is a 1973 Datsun 240-Z that I hope to make into a street legal driver that can put to the burger stand on Friday night and achieve over 200mph at an open road racing event the next day! At least, that is the plan... we'll see if I can manage to keep my bowels under control as I try to break the 200mph barrier...:drive2:
So, previously I performed some body work to the car, lowering the roofline, raking the windshielf and creating a custom partially fiberglass body. There are some pictures of the chop top job in this thread (https://www.pro-touring.com/forum/showthread.php?t=7476)
And so, on to the more recent work... building a spaceframe for the car...
Before I began building, I spent quite awhile trying to finalize my suspension design so that I could model the spaceframe around it. To help in this respect, I first did some reading, asked some questions on this site (thanks guys) and then began mapping coordinates on the Suspension Analyzer software. It is harder than it seems... I spent quite awhile trying to create an unequal length A-arm front suspension that would maintain a stable roll center laterally. It was pretty tricky.
Finally, while finding the dimensions of a C5 steering knuckle/hub assembly I serindipitously discovered that my overall car width would be equal to that of a C5 'Vette. So, I decided to use the C5 dimensions as a baseline on the front suspension. For the rear suspension, I will be going with a Satchell link solid axle layout. I will reduce the anti-dive somewhat and try to stabilize the caster change throughout bump when I finally incorporate the suspension onto the Datsun.
After getting the suspension points roughed out, I had to design the frame... Since I had my basic dimensions, I first began looking at what other spaceframes looked like. I also got some advice from a member here and over at CC.com (Preston - who has a killer spaceframe first gen Mustang).
I then began to tinker with a freeware programe called GRAPE that Preston recommended and I put down the coordinates. When all was said and done I came up with a design that would fit my modified Z body (pretty well anyway) and that would put the suspension where it needed to be, all while maintaining a fair amount of torsional rigidity. When finished, I anticipate having a chassis with well over 10,000 pounds per degree of deflection (closer to 15,000 according to GRAPE). It should weigh around 300 pounds with the full roll cage. Remember, this car has only a 92'' wheelbase, hence the relatively light frame weight.
So, on to the build... I first ordered some steel tubing from a local metal supply house. I ended up ordering lengths of 2x3x.083, 2x2x.095, 2x2x.065 and some 1.5x1.5x.065. Round tubing will be ordered later to complete the cage (man that stuff is expensive). The rockers use the 2x3 tubing, while most of the other main rails are 2x2x.095. The diagonal reinforcement pieces are mostly 2x2x.065 and the 1.5x1.5 will be used solely as part of the trans tunnel and to support the rear of the body behind the rear axle.
Then, I purchased a large 4x8' piece of 3/4'' plywood and marked it with a grid to help keep measurements in line. I tried my best to level the plywood as well since the garage floor has about a 2* slope to it. When I laid the tubing down on the plywood I screwed down pieces of wood around each piece to keep them from moving while welding.
I then proceeded to cut... first I cut off the front of the car (forward of the windshield). Then I began cutting pieces of tubing and welding the front snout together! I made sure to tack each side of each connection prior to finishing the welds. I did this to try and minimize any deflection due to heat.
The front snout began with the front firewall piece (a rectangle). I then attached the lower frame rails (which attach the lower control arms) and subsequently the upper frame rails (for the upper arms).
Once the front snout was completed (aside from some supporting cross sections) I began the rear piece. This was much easier because I decided to go with a solid axle. All the rear needed was the rear firewall and the rails which will mount the anti-roll bar and shocks. It will eventually be further reinforced with a cross brace and will tie into the roll cage overhead.
After getting the basics of both the front and rear snouts created, I then proceeded to bridge them with the 2x3 tubing and some 2x2 cross braces. Below is a link to my progress. Forgive my website if it shuts me down... I have limited data transfer.
I still have to weld in a few more braces, but this is basically what it looks like at present...
http://www.geocities.com/boodlefoof/...t_Racer-Zframe (http://www.geocities.com/boodlefoof/Project_Racer-Zframe)
Anyway, for those not familiar with the project it is a 1973 Datsun 240-Z that I hope to make into a street legal driver that can put to the burger stand on Friday night and achieve over 200mph at an open road racing event the next day! At least, that is the plan... we'll see if I can manage to keep my bowels under control as I try to break the 200mph barrier...:drive2:
So, previously I performed some body work to the car, lowering the roofline, raking the windshielf and creating a custom partially fiberglass body. There are some pictures of the chop top job in this thread (https://www.pro-touring.com/forum/showthread.php?t=7476)
And so, on to the more recent work... building a spaceframe for the car...
Before I began building, I spent quite awhile trying to finalize my suspension design so that I could model the spaceframe around it. To help in this respect, I first did some reading, asked some questions on this site (thanks guys) and then began mapping coordinates on the Suspension Analyzer software. It is harder than it seems... I spent quite awhile trying to create an unequal length A-arm front suspension that would maintain a stable roll center laterally. It was pretty tricky.
Finally, while finding the dimensions of a C5 steering knuckle/hub assembly I serindipitously discovered that my overall car width would be equal to that of a C5 'Vette. So, I decided to use the C5 dimensions as a baseline on the front suspension. For the rear suspension, I will be going with a Satchell link solid axle layout. I will reduce the anti-dive somewhat and try to stabilize the caster change throughout bump when I finally incorporate the suspension onto the Datsun.
After getting the suspension points roughed out, I had to design the frame... Since I had my basic dimensions, I first began looking at what other spaceframes looked like. I also got some advice from a member here and over at CC.com (Preston - who has a killer spaceframe first gen Mustang).
I then began to tinker with a freeware programe called GRAPE that Preston recommended and I put down the coordinates. When all was said and done I came up with a design that would fit my modified Z body (pretty well anyway) and that would put the suspension where it needed to be, all while maintaining a fair amount of torsional rigidity. When finished, I anticipate having a chassis with well over 10,000 pounds per degree of deflection (closer to 15,000 according to GRAPE). It should weigh around 300 pounds with the full roll cage. Remember, this car has only a 92'' wheelbase, hence the relatively light frame weight.
So, on to the build... I first ordered some steel tubing from a local metal supply house. I ended up ordering lengths of 2x3x.083, 2x2x.095, 2x2x.065 and some 1.5x1.5x.065. Round tubing will be ordered later to complete the cage (man that stuff is expensive). The rockers use the 2x3 tubing, while most of the other main rails are 2x2x.095. The diagonal reinforcement pieces are mostly 2x2x.065 and the 1.5x1.5 will be used solely as part of the trans tunnel and to support the rear of the body behind the rear axle.
Then, I purchased a large 4x8' piece of 3/4'' plywood and marked it with a grid to help keep measurements in line. I tried my best to level the plywood as well since the garage floor has about a 2* slope to it. When I laid the tubing down on the plywood I screwed down pieces of wood around each piece to keep them from moving while welding.
I then proceeded to cut... first I cut off the front of the car (forward of the windshield). Then I began cutting pieces of tubing and welding the front snout together! I made sure to tack each side of each connection prior to finishing the welds. I did this to try and minimize any deflection due to heat.
The front snout began with the front firewall piece (a rectangle). I then attached the lower frame rails (which attach the lower control arms) and subsequently the upper frame rails (for the upper arms).
Once the front snout was completed (aside from some supporting cross sections) I began the rear piece. This was much easier because I decided to go with a solid axle. All the rear needed was the rear firewall and the rails which will mount the anti-roll bar and shocks. It will eventually be further reinforced with a cross brace and will tie into the roll cage overhead.
After getting the basics of both the front and rear snouts created, I then proceeded to bridge them with the 2x3 tubing and some 2x2 cross braces. Below is a link to my progress. Forgive my website if it shuts me down... I have limited data transfer.
I still have to weld in a few more braces, but this is basically what it looks like at present...
http://www.geocities.com/boodlefoof/...t_Racer-Zframe (http://www.geocities.com/boodlefoof/Project_Racer-Zframe)