boodlefoof Posted July 5, 2006 Share Posted July 5, 2006 Hey guys! (Sorry this is really long, but hopefully a fun read - pics attached). I've been posting about building this spaceframe chassis for awhile now. Well, I finally had some time over the past two weeks to start the build. 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 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, 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 suspension. After getting the suspension points roughed out, I had to design the frame... Since I had my main dimensions, I first began looking at what other spaceframes looked like. I then began to tinker with a freeware programe called GRAPE and 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. As per Herb Adams' suggestions, I kept the concept of load paths in mind when designing. When all is said and done, I anticipate having a chassis with well over 10,000 pounds per degree of deflection. It should weigh around 300 pounds with the full roll cage. 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. The rockers will 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 to construct 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. I've attached some pics of the progress below. I haven't had a chance to update my website with a writeup of the progress though. So, attached are a few pictures of the progress too far. I hope they work... I'm not super techno-savvy. Awww nuts!... it says my pictures are too big (around 170KB). I know the thread is worthless without pics! I'll try to get them on my website (which has limited data transfer) and post a follow up, or if somebody knows how to help me out let me know via PM and I'll try to put them up sometime soon. Anyway, happy 4th all! Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted July 5, 2006 Author Share Posted July 5, 2006 OK, put some pics up on the website real quick... hope you can get them. Remember, it isn't done... more bracing to be added as well as the cage. http://www.geocities.com/boodlefoof/Project_Racer-Zframe Quote Link to comment Share on other sites More sharing options...
olie05 Posted July 5, 2006 Share Posted July 5, 2006 Double a-arms in the front is a step forward but a solid rear seems like a step back. Why not use a subframe from something like a 240sx or a 300zx or even an infinity? great project by the way, many props! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 5, 2006 Share Posted July 5, 2006 There are lots of good reasons for solid rear axle, in GT2 I believe there is a pretty significant weight penalty for IRS, and for drag racing its a no brainer. Won't see me swapping my suspension out for a live axle, but it isn't always a bad decision. Quote Link to comment Share on other sites More sharing options...
Shift Posted July 5, 2006 Share Posted July 5, 2006 Have to agree with jmortensen on that one. Less moving parts on something that usually dies on torque. The suspension gain for going with the half shaft/diff design would be minimal. BTW looks great boodlefoof. Though I wouldn't have cut the entire firewall off, but its your car so not going to tell you to do it one way or the other. Well here are some pics that 74_5.0L_Z sent me when I PM'd him about how he did his. Quote Link to comment Share on other sites More sharing options...
Shift Posted July 5, 2006 Share Posted July 5, 2006 Oh forgot to add. You can usually get metal for free. go to custruction sites,or fab shops and see if they have any metal they want to get rid of from a finished job. Usually free or really really cheap. got 2 1/2" X 2 1/2" square pipe in about 6 foot lengths for like $20 from one construction site for 4 of them. EDIT:damn keep on think of more suggestions. as far as front suspension goes, how about 240sx front suspension? parts are fairly cheap and should be easy to adapt onto something like what you're building. Plus camber could be adjusted by adjustable upper control arm instead of adjusting struts and camber plates. just a suggestion, might be a better option out there. BTW I didn't read the first post, I just read the last couple of entries so i apologies if somethings been said before. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted July 5, 2006 Share Posted July 5, 2006 well finally...this is going to be really cool. What springs are you going to use? airbags, coils, leaf springs, hydraulics (had to ask ). Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted July 5, 2006 Share Posted July 5, 2006 Need more pics and an update on this nice project. Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted July 5, 2006 Author Share Posted July 5, 2006 Hey guys, thanks for the words of encouragement. I will certainly keep updates coming as I make progress. I may be a little slower for the next three weeks or so though... I'm taking the bar exam at the end of July so I'll be cramming. However, after the exam I get all of August off before starting my job. I hope to have the front suspension mounted and possibly have the body attached to the frame by the end of September. We'll see if the funds allow purchasing a rear end to stick under there by that time... it may have to wait. As to using the solid axle rear several factors influenced the decision. First, I do plan to have this car run the 1/4 mile on occassion and I wanted more anti-squat than I could feasibly get with the IRS. In addition to that, the solid axle should be better suited for that application for the reasons jmortensen and shift pointed out. Second, the solid axle was simpler to design and will be less expensive to construct. I do plan to take the car to some open road events, and on smooth surfaces there shouldn't really be any appreciable disadvantage over an IRS setup. It will also save quite a bit of frame weight to mount as opposed to the IRS. Shift, nice looking pics! I ended up doing something similar with the wooden braces to locate the frame. As for cutting off the entire firewall, I had to. I've actually moved the firewall back about 8'' and will move back the engine and trans assembly to match. I'm shooting for close to, if not better than, a 50/50 weight distribution. It will make the passenger compartment a little cramped, but this is going to be primarily a race car... and I'm only 5' 10''. In fact, when the body is attached to the new frame... the only part of the original body that will remain (not replaced by fiberglass) will be the roof, the windshield channel and the rear hatch and the doors. Everything else will be fiberglass attached to the frame. As for the front suspension, I've already purchased a complete front suspension assembly from a 2004 Corvette. I managed to snag it for a good price from a 'Vette wrecking yard. I will not be reusing the suspension cradle or the fiberglass monoleaf spring, but will use the control arms, steering rack, spindles, hubs, brakes, and will give the sway bar a try and see if it is adequate. I have only changed the C5 suspension mounting points slightly for less anti-dive (stock is 57%!) and for more consistent caster (less change) during bump. Anybody know if they make delrin bushings for the C5? I've looked and can't find any. I will be using coil-over shocks. Again, I will keep you guys posted as the project progresses. = ) Quote Link to comment Share on other sites More sharing options...
Guest Zedhead Posted July 5, 2006 Share Posted July 5, 2006 John, What a great project, I am watching with interest. Let me know if you are able to find delrin bushings for the C5. If not, Delrin is easy to machine and I could fab some up for you. I would just need a detailed drawing. I would do it for the cost of the Delrin--doing my part for a fellow Zedhead. Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted July 5, 2006 Share Posted July 5, 2006 you my man are crazy! got some balls to just cut your project in half but man thats a cool project! much props! mike Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted July 5, 2006 Author Share Posted July 5, 2006 Zedhead, thanks for the offer. I'll let you know if I find any. If not, I might have to PM you about it. Now that I have the parts it is just amazing how much compliance there is in these factory rubber bushings! ON3GO, thank you! Yeah, when I first started chopping on the car to lower the roofline (see http://forums.hybridz.org/showthread.php?t=101672&highlight=chopped ) it was a little scary... But then I told myself, "well, I only paid $150 for the car... so if it completely falls apart it's no big loss!" When I went to cut the front off, I didn't even have to think twice about whether or not I wanted to do it. Quote Link to comment Share on other sites More sharing options...
Shift Posted July 6, 2006 Share Posted July 6, 2006 So whats going to to power this? The upper piece looks like its to narrow even for a lL6 engine. Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted July 7, 2006 Author Share Posted July 7, 2006 Shift, I've toyed with a lot of different ideas, ranging from a turbo flat 6 to a 32 valve Gen I small block Chevy to a Viper V10. Currently, the plan is for a Chevy LS small block of some sort. We'll see what funds allow... I'm also playing with the idea of hanging a pair of turbos on some home-made 180 degree headers. It will be wide enough, even with the V8. The upper section of the front snout is 33'' from rail to rail. Also, the upper rails are low enough (only about 15'' above the lower rails) so that the cylinder heads will be above those rails. I plan to mount the engine directly to the firewall with an engine plate. Quote Link to comment Share on other sites More sharing options...
preith Posted July 7, 2006 Share Posted July 7, 2006 There are lots of good reasons for solid rear axle, in GT2 I believe there is a pretty significant weight penalty for IRS, and for drag racing its a no brainer. Won't see me swapping my suspension out for a live axle, but it isn't always a bad decision. That rule has changed. It's not as bad now, but there still is penalty. It used to be a 100lbs, but it's now something like 2% of the total minimun weight listed in the GCR. With that said, almost all of the SCCA Runoffs front runners are using a live axle. Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted August 7, 2006 Author Share Posted August 7, 2006 Hey guys! Well, I had to take a few weeks off there right before the bar exam. Too much studying to have time to work on the Z. But, I finished the exam a few days ago and started back in on the project! First, I wanted to let you guys know that I put in some work on the frame "writeup" on my website. So in addition to the photos you saw earlier, the link towards the top of the thread now also includes a description of what is going on... but it is basically just the same information from the first post in this thread. Second, I've begun work on the front suspension. I've mounted the control arms and the steering rack and will be mounting the sway bar and fabbing the coil-over shock mounts soon. Additionally, an up-to-date writeup of the suspension work is on my website. http://www.geocities.com/boodlefoof/Project_Racer-Zsuspension.html Enjoy! Quote Link to comment Share on other sites More sharing options...
bradz240 Posted August 8, 2006 Share Posted August 8, 2006 It really looks great! Keep up the good work! I'm anxious to see what you come up with for the windshield. Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted August 8, 2006 Share Posted August 8, 2006 That is very cool. I love the idea of using C5 Corvette suspension up front What kind of price did you end up paying for all of the suspension pieces from that wrecking yard? Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted August 9, 2006 Author Share Posted August 9, 2006 Brad, yeah I'm anxious to see what I'm going to do about the windshield too! For now the bodywork is on hold while the frame and suspension is completed. Justin, the entire front suspension and steering setup came out to about $1500. This setup was from a 2004 car and aside from a little surface rust on the rotors, it is like new. Hopefully I can sell off a few of the pieces I'm not using and make back a few bucks too. Next step... buying a rear axle housing so I can put together that rear suspension! Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted August 29, 2006 Author Share Posted August 29, 2006 Another update... rear suspension is basically built! Pics and a writeup are on my website beginning at: http://www.geocities.com/boodlefoof/Project_Racer-Zsuspension4.html Quote Link to comment Share on other sites More sharing options...
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