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Build Diaries => Reventon => Topic started by: Robert on April 04, 2014, 06:02:33 PM
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I just came home from purchasing my Reventon from lamboreplica. Nice quality! I feel like a kid at Christmass!
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Good luck !
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Bet you are super excited, looks really good. Congratulations!
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That looks really nice! You have to be happy.
Now starts all the W O R K !
You can do it.
RT
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I lengthened my snowmobile trailer, so the body would fit on it. LOL
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::thumbup nice bro!!! Glad it worked out. Now, go have fun.
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Thanks lambo brothers! ::beers
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Here is a few pics of my progress for the engine cradle/ chassis section.
I will be able to remove the drivetrain from the bottom of the car. I had to scrap the idea of using OEM drivetrain mounts, because I did not have space for the trans mount. I fabricated the drivetrain mounts and used urethane bushings. :CSS
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A few more pics of progress. I welded d.o.m. ( drawn over mandrel) pipe in the tube. If you have a bolt passing though a section of tube, welding a piece of pipe ensures clamping torque. You do not want to crush the tube, when you torque your bolts. I added some gusset tubes for more strength.
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Looks great! Wasting no time on this build! ::headbang
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Good fabrication skills you have there. Looking great!
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I need some engineering advice. I have model of my rear suspension using www.racingaspirations.com (http://www.racingaspirations.com). At 4 inches of travel ( the shock travel) I have 2.9 degrees of negative camber. What do you guys think?
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From my experience -.5 to -1.5 is good for the street. Up to -2.5 for racing applications. Also the rear should be half of the front...
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From my experience -.5 to -1.5 is good for the street. Up to -2.5 for racing applications. Also the rear should be half of the front...
2.9* will make the car EXTREMELY darty, almost scary on the cambered roads that we have here
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Robert, how about some clarification on your shock travel. Are you saying that you have 2" up and 2" down? Your camber would be set at ride height, right? What are you trying to do with this car? What are you trying to achieve? What knuckle and A-arms are you going to use on the fronts? What suspension components are you going to use in the rear?
Jim
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In the sim, try raising the inner mount of the upper arms, that should change the gain #'s
Does it calculate squat, anti-squat, dive and anti-dive numbers, what about bump
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Robert, I agree with 01L that we need more info to help but what info we already have just does not seem right. Four inches of shock travel in compression? It would have to be all compression to yield NEGATIVE camber. What is the total travel of your shock? What spring rate are you using that would allow that much weight transfer and compression? You would have to get down to a 100lb spring which you just do not want and then it would have to be a 12 inch spring to have any compression left at ride height and then it would have to be at least a 7 inch travel shock to fit the 12 spring and 7 shocks just do not work on these cars, and the issues continue to compound from there. Four inches of travel at the shock would be five or even six at the wheel and you would have bottomed out and ripped a fender off way before camber angles ever became an issue. Consider what your gain is at about 1-1/2 inches of travel, which would be 2 or so at the tire (depending on the motion ratio of the shock mount), and this would be all of the travel that you would want or need. Also, verify that your lower arm is close to parallel with the ground plane at ride height so that the upper arm does all of the gain. AB is right about raising the inner mount of the upper arm, and a longer arm will also be less gain. A general rule of thumb is that the upper arm wants to be 2/3 of the lower arm length, and the lower length is generally set by the limitations of the steering linkage.
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In the sim, try raising the inner mount of the upper arms, that should change the gain #'s
Does it calculate squat, anti-squat, dive and anti-dive numbers, what about bump
Robert, I agree with 01L that we need more info to help but what info we already have just does not seem right. Four inches of shock travel in compression? It would have to be all compression to yield NEGATIVE camber. What is the total travel of your shock? What spring rate are you using that would allow that much weight transfer and compression? You would have to get down to a 100lb spring which you just do not want and then it would have to be a 12 inch spring to have any compression left at ride height and then it would have to be at least a 7 inch travel shock to fit the 12 spring and 7 shocks just do not work on these cars, and the issues continue to compound from there. Four inches of travel at the shock would be five or even six at the wheel and you would have bottomed out and ripped a fender off way before camber angles ever became an issue. Consider what your gain is at about 1-1/2 inches of travel, which would be 2 or so at the tire (depending on the motion ratio of the shock mount), and this would be all of the travel that you would want or need. Also, verify that your lower arm is close to parallel with the ground plane at ride height so that the upper arm does all of the gain. AB is right about raising the inner mount of the upper arm, and a longer arm will also be less gain. A general rule of thumb is that the upper arm wants to be 2/3 of the lower arm length, and the lower length is generally set by the limitations of the steering linkage.
Thank you 76, coils overs are QA!1 ur 4855p. Brand:QA1 Precision Products
Manufacturer's Part Number:UR4855P
Part Type:Coil-Over Shocks and Struts
Product Line:QA1 Ultra Ride Coil-Over Shocks
Summit Racing Part Number:HAL-UR4855P
UPC:806990000293
Coil-Over Shock Type:Single-adjustable
Shock Body Material:Aluminum
Shock Body Finish:Clear anodized
Adjustable Valving:Yes
Number of Valving Selections:12
Extended Length (in):14.000 in.
Collapsed Length (in):10.130 in.
Upper Mount:Eyelet
Lower Mount:Eyelet
Gas Charged:No
Bushing Material:Polyurethane
Bushing Color:Black
Coil-Over Springs Included:No
Recommended Spring Diameter (in):2.500 in.
The lower control arms will be parallel with the frame. Let know what you think, thank you!
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In the sim, try raising the inner mount of the upper arms, that should change the gain #'s
Does it calculate squat, anti-squat, dive and anti-dive numbers, what about bump
Thank you for trying! If you have time, look at the above link.
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Robert, how about some clarification on your shock travel. Are you saying that you have 2" up and 2" down? Your camber would be set at ride height, right? What are you trying to do with this car? What are you trying to achieve? What knuckle and A-arms are you going to use on the fronts? What suspension components are you going to use in the rear?
Jim
Thank you Jim. Check the vsusp link.
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From my experience -.5 to -1.5 is good for the street. Up to -2.5 for racing applications. Also the rear should be half of the front...
Thank you Alan!
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Wouldn't it simplify things if you just went with the C5 suspension all around? You wouldn't have to micro-tune every spec. I would question your ride height at 8". At 5.5", my chassis is 1" higher than stock. A reventon has to be around 4.5", right? Or is 8" just the ride height of the lower A pivot to the ground? ::scratch ::study ::headbang
Ah!! we all love to build, don't we. Jim
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This is the chassis I purchased prints for. I had to change it for the LS4 drivetrain. I do not have dimensions for a C5.
I'll play around with the data input, and lower it.
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I just measured a c6 corvette lower control arm to ground clearance. From the center of the inside pivot point, it measures 6.75" from the ground. The body in front of the rear wheel has 5.625" ground clearance.
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Robert, that is what I suspected, you have 4" travel shocks (14" extended minus 10" compressed), just make sure that the chassis is designed for that travel. If so, when the car is at ride height, the shock should be in it's "Sweet Spot" of 12", allowing 2" of travel in extension and 2" in compression. The extreme camber gain over 4" of compression is a mute point as the shock bottoms out at 2". This shock is hard to work with because there is not much room for error. You need to know your geometry, ride height, and tire and wheel size right now in order to hang it. A 5 travel shock does not seem much different but it is much easier to work with (insert joke here). The 4 shock will not take any spring over 8" long so the 5 has a much better spring selection as well. Either way your spring rates are back in the ballpark.
I have a set of those Chassisworks plans but it has been a while since I looked at them. If I remember right they were based on C5 geometry. If I also remember correctly, they just need to have a little dive taken out and a little more squat put in to allow for the larger rear weight percentage.
P.S. Here is the problem with 8" springs. If you use say a 200lb spring and there is say 600lbs of car on that corner, the spring will compress 3" to be 5" tall. It will coil bind at 4", giving only 1" of suspension travel regardless of your shock travel. A 10" spring still coil binds at 4" but it would have 3" of travel.
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Aldan recommends that the shocks be compressed 1/3 their travel at normal ride height. You will use more compression than extension during normal driving.
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Robert, that is what I suspected, you have 4" travel shocks (14" extended minus 10" compressed), just make sure that the chassis is designed for that travel. If so, when the car is at ride height, the shock should be in it's "Sweet Spot" of 12", allowing 2" of travel in extension and 2" in compression. The extreme camber gain over 4" of compression is a mute point as the shock bottoms out at 2". This shock is hard to work with because there is not much room for error. You need to know your geometry, ride height, and tire and wheel size right now in order to hang it. A 5 travel shock does not seem much different but it is much easier to work with (insert joke here). The 4 shock will not take any spring over 8" long so the 5 has a much better spring selection as well. Either way your spring rates are back in the ballpark.
I have a set of those Chassisworks plans but it has been a while since I looked at them. If I remember right they were based on C5 geometry. If I also remember correctly, they just need to have a little dive taken out and a little more squat put in to allow for the larger rear weight percentage.
P.S. Here is the problem with 8" springs. If you use say a 200lb spring and there is say 600lbs of car on that corner, the spring will compress 3" to be 5" tall. It will coil bind at 4", giving only 1" of suspension travel regardless of your shock travel. A 10" spring still coil binds at 4" but it would have 3" of travel.
Thank you very much for your advise! I will definitely use it.
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Eric, that is true but in my opinion it becomes less true the shorter the shock travel becomes. That would put the sweet spot at 12-2/3", allowing only 1-1/3" of expansion before topping out in that direction. I think if Robert ran the numbers with his simulator, he would find that it does not take much weight transfer at all to get to that. I used Aldan Eagles on my Cobra and mounted them that way and it tops out hard all the time. Maybe that is just my driving but there is not much weight in that car to transfer to begin with.
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Just keep in mind the travel distance of the shock is not the same as the travel distance of the wheel/tire.
For the travel distance to be identical, the shock would have to be attached to the A-arm at the outer ball joint and the shock would have to be vertical. This is not the case. The shock is attached inside from the outer ball joint so that location does not travel as far as the wheel/tire. ALSO, the shock is leaning inward at the top. That produces even less travel because of the angle. (You are basically shortening the one side of the triangle formed by the shock and A-arm pivots.)
This not only affects the travel but if your spring is over the shock, the compression forces are not linear also.
RT
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Absolutely right RT, that goes back to what I was saying about motion ratios in my first answer. Look at Afco Racing Products and there are simple and well illustrated examples of this with some basic calculation tables. It is probably too late now but those Afco shocks are everything that the QA1 is but right at half the price.
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Absolutely right RT, that goes back to what I was saying about motion ratios in my first answer. Look at Afco Racing Products and there are simple and well illustrated examples of this with some basic calculation tables. It is probably too late now but those Afco shocks are everything that the QA1 is but right at half the price.
I will check them out!
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guys I had this salted away it could prove useful
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All well and good info, BUT...when you get all of the data and pieces of this puzzle together and it doesn't quite ride like you thought it should, then what? There are more complex potholes in a build than this that will cause you to pull your hair out. Don't forget to design the ability to repair components of your car after the body gets glued on and positive bump stops so that your tires don't hit your wheelwell liners. IMHO. ::help
Jim
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Robert, I hope our input is incouraging to you rather than discouraging. I am very glad to try and help someone that is making an effort to help theirself....but....that design will never work. Your lower a-arms are way too short, which makes your upper a-arms way too shorter (?). They need to be around 15" and 10". The short arcs of the short arms will make everything happen way too fast and your graphs of them will go off of the chart. As I mentioned earlier, the front lower a-arm design is usually detirmined by the limitations of the steering linkage, so let us look at that one first. 24-1/2" inches is a magic number here, it does not matter what you are building. That is the knuckle to knuckle distance on all of the Mustang type aftermarket rack and pinions. Since the inner lower a-arm pivit should be directly in line with this to avoid bumpsteer, use this to establish that point. Going from there out to the spindle should be in that 15" range. Now use the spindle to establish the upper outer ball joint and work back from there to locate the inner mount to give a correct upper arm length. Remember, a chassis is designed from the outside in, not from the chassis out. Once you have these locations, put the chassis wherever it needs to go in order to attach them. Now, at the back of the car, there should be plenty of room outside the engine cradle to use the same lower a-arm length (depending on wheel offset and others) with the same 24-1/2" centerlines and the same upper a-arm location procedure. If you can, not only do you have economy of parts but your roll centers are as simple as they can get.
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Robert, I hope our input is incouraging to you rather than discouraging. I am very glad to try and help someone that is making an effort to help theirself....but....that design will never work. Your lower a-arms are way too short, which makes your upper a-arms way too shorter (?). They need to be around 15" and 10". The short arcs of the short arms will make everything happen way too fast and your graphs of them will go off of the chart. As I mentioned earlier, the front lower a-arm design is usually detirmined by the limitations of the steering linkage, so let us look at that one first. 24-1/2" inches is a magic number here, it does not matter what you are building. That is the knuckle to knuckle distance on all of the Mustang type aftermarket rack and pinions. Since the inner lower a-arm pivit should be directly in line with this to avoid bumpsteer, use this to establish that point. Going from there out to the spindle should be in that 15" range. Now use the spindle to establish the upper outer ball joint and work back from there to locate the inner mount to give a correct upper arm length. Remember, a chassis is designed from the outside in, not from the chassis out. Once you have these locations, put the chassis wherever it needs to go in order to attach them. Now, at the back of the car, there should be plenty of room outside the engine cradle to use the same lower a-arm length (depending on wheel offset and others) with the same 24-1/2" centerlines and the same upper a-arm location procedure. If you can, not only do you have economy of parts but your roll centers are as simple as they can get.
Thank you 76, the front is factory C4 upper and lower arms.
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I guess that threw the theory out the window.
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Robert, now I am confused about which theory is kept and which is thrown away. If you are trying to copy the Chassisworks plans, it does not matter if it is C4 or C5, either one is well capable of accomplishing O1's idea of not having to reinvent it. If on the other hand you are trying to design your own suspension using the simulator, hopefully this is useful.
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Robert, now I am confused about which theory is kept and which is thrown away. If you are trying to copy the Chassisworks plans, it does not matter if it is C4 or C5, either one is well capable of accomplishing O1's idea of not having to reinvent it. If on the other hand you are trying to design your own suspension using the simulator, hopefully this is useful.
[/quote 76, you have been a great advisor! You are the expert on this forum!. I have the 15/10 calculated.
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O.K. then and thank you. I thought we were on the same page here. As you play with the 15-10, keep this in mind. All suspensions are compromises, there is no perfect setup. How the compromises are handled determines the quality of it. You are looking for it to be consistent and predictable. That makes it driveable. It does not matter as much where the graph lines of the travel are, but that they are in consistant patterns without quirky directional changes. Now I have a few questions. First, how did you get your last reply INSIDE the quote box? And second, What is an expirimental mechanic and painter?
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O.K. then and thank you. I thought we were on the same page here. As you play with the 15-10, keep this in mind. All suspensions are compromises, there is no perfect setup. How the compromises are handled determines the quality of it. You are looking for it to be consistent and predictable. That makes it driveable. It does not matter as much where the graph lines of the travel are, but that they are in consistant patterns without quirky directional changes. Now I have a few questions. First, how did you get your last reply INSIDE the quote box? And second, What is an expirimental mechanic and painter?
[/quote
He left off the bracket after "[/quote"
He left off the bracket after "[/quote".
I just said that. I know you did. ::headbang
Now that we have opened up the can of unpredictability, we have to say that two more factors enter the picture relating to how well the suspension design will still fail. DRIVER ABILITY and the SPEED OF THE VEHICLE.
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Thank you everyone for your input. I am always humble to those more knowledgeable than me.
I crunched numbers last night, ran out to the garage with my tape measure several times.
The wheels are 18x9.5 with a 2.2 off set, tires 18/285zr30 11.5 width. I will have to cheat the length of the lower control arm a little. 14" lower control arm is the best I can do. I will have to trim the quarter panel lip a little.
http://www.vsusp.com/#0.8%26project_name%3Adefault%20values%26trim%7Bbody_roll_angle%3A0%7Cfront.left_bump%3A-8600%7Crear.left_bump%3A0%7Cfront.right_bump%3A-8600%7Crear.right_bump%3A0%7D%26front%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A0%7Cframe.center_to_upper_mount_x%3A0%7Cframe.bottom_to_upper_mount_y%3A0%7Cframe.center_to_lower_mount_x%3A0%7Cframe.bottom_to_lower_mount_y%3A0%7Ccontrol_arms.upper_length%3A24800%7Ccontrol_arms.lower_length%3A37500%7Cknuckles.hub_to_upper_x%3A15000%7Cknuckles.hub_to_lower_x%3A13000%7Cknuckles.hub_to_lower_y%3A13000%7Cknuckles.hub_to_upper_y%3A13000%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A0%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A1%7Ctires.section_width%3A33500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26rear%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A15238%7Cframe.center_to_upper_mount_x%3A51587%7Cframe.bottom_to_upper_mount_y%3A26670%7Cframe.center_to_lower_mount_x%3A48158%7Cframe.bottom_to_lower_mount_y%3A1904%7Ccontrol_arms.upper_length%3A23393%7Ccontrol_arms.lower_length%3A35560%7Cknuckles.hub_to_upper_x%3A17881%7Cknuckles.hub_to_lower_x%3A9207%7Cknuckles.hub_to_lower_y%3A12011%7Cknuckles.hub_to_upper_y%3A11244%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A5588%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A0%7Ctires.section_width%3A28500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26pref%7Bdiag1.px_per_mm%3A200%7Cdiag1.front_or_rear%3Arear%7Ctab.active%3A1%7Cunits%3A0%7Cshow.f%3A1%7Cshow.ca%3A1%7Cshow.k%3A1%7Cshow.w%3A1%7Cshow.t%3A1%7Cshow.rc%3A1%7Cshow.ic%3A1%7Cshow.fvsa%3A1%7Cshow.tl%3A1%7Cshow.kpil%3A1%7Credraw_during_drag%3A1%7Cchart.x_axis_center%3A0%7Cchart.x_axis_window%3A10%7Cchart.x_axis_num_steps%3A21%7Cchart.x_axis_field%3A%5BFR%5D.wheels.diameter%7Cchart.y_axis_fields%3A%5BFR%5D.general.roll_center.y%7D (http://www.vsusp.com/#0.8%26project_name%3Adefault%20values%26trim%7Bbody_roll_angle%3A0%7Cfront.left_bump%3A-8600%7Crear.left_bump%3A0%7Cfront.right_bump%3A-8600%7Crear.right_bump%3A0%7D%26front%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A0%7Cframe.center_to_upper_mount_x%3A0%7Cframe.bottom_to_upper_mount_y%3A0%7Cframe.center_to_lower_mount_x%3A0%7Cframe.bottom_to_lower_mount_y%3A0%7Ccontrol_arms.upper_length%3A24800%7Ccontrol_arms.lower_length%3A37500%7Cknuckles.hub_to_upper_x%3A15000%7Cknuckles.hub_to_lower_x%3A13000%7Cknuckles.hub_to_lower_y%3A13000%7Cknuckles.hub_to_upper_y%3A13000%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A0%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A1%7Ctires.section_width%3A33500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26rear%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A15238%7Cframe.center_to_upper_mount_x%3A51587%7Cframe.bottom_to_upper_mount_y%3A26670%7Cframe.center_to_lower_mount_x%3A48158%7Cframe.bottom_to_lower_mount_y%3A1904%7Ccontrol_arms.upper_length%3A23393%7Ccontrol_arms.lower_length%3A35560%7Cknuckles.hub_to_upper_x%3A17881%7Cknuckles.hub_to_lower_x%3A9207%7Cknuckles.hub_to_lower_y%3A12011%7Cknuckles.hub_to_upper_y%3A11244%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A5588%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A0%7Ctires.section_width%3A28500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26pref%7Bdiag1.px_per_mm%3A200%7Cdiag1.front_or_rear%3Arear%7Ctab.active%3A1%7Cunits%3A0%7Cshow.f%3A1%7Cshow.ca%3A1%7Cshow.k%3A1%7Cshow.w%3A1%7Cshow.t%3A1%7Cshow.rc%3A1%7Cshow.ic%3A1%7Cshow.fvsa%3A1%7Cshow.tl%3A1%7Cshow.kpil%3A1%7Credraw_during_drag%3A1%7Cchart.x_axis_center%3A0%7Cchart.x_axis_window%3A10%7Cchart.x_axis_num_steps%3A21%7Cchart.x_axis_field%3A%5BFR%5D.wheels.diameter%7Cchart.y_axis_fields%3A%5BFR%5D.general.roll_center.y%7D)
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Just to add to the confusion of suspension design, especially on the front, a line drawn vertically through the inner pivot points of the front a-arms will not intersect the inner pivot of the tie rod. This is because most street vehicles have ackerman built into the design. This places the outer tie rod center out past the upper and lower ball joints on the spindle. It is the length and vertical placement of the tie rods that determines bump steer, not that they intersect the line of the ball joints and inner pivot. For more information about this read the Carroll Smith books and "How to make your car handle" by Fred Puhn.
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Right again 01, when a driver says that a car handles like a dream, be certian that there is no such thing. Just like a chain, when a suspension is pushed to it's limit, it will show you what charactoristics need improvement. What the driver is really saying is that they have reached their limits well before the car did. That is why with a rookie racecar test we put an experienced driver in first to get a baseline. That way we know whether to work on the rookie or the racecar.
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I need a new phone, the lense is scratched. Here is a little progress.
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Thank you everyone for your input. I am always humble to those more knowledgeable than me.
I crunched numbers last night, ran out to the garage with my tape measure several times.
The wheels are 18x9.5 with a 2.2 off set, tires 18/285zr30 11.5 width. I will have to cheat the length of the lower control arm a little. 14" lower control arm is the best I can do. I will have to trim the quarter panel lip a little.
[url]http://www.vsusp.com/#0.8%26project_name%3Adefault%20values%26trim%7Bbody_roll_angle%3A0%7Cfront.left_bump%3A-8600%7Crear.left_bump%3A0%7Cfront.right_bump%3A-8600%7Crear.right_bump%3A0%7D%26front%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A0%7Cframe.center_to_upper_mount_x%3A0%7Cframe.bottom_to_upper_mount_y%3A0%7Cframe.center_to_lower_mount_x%3A0%7Cframe.bottom_to_lower_mount_y%3A0%7Ccontrol_arms.upper_length%3A24800%7Ccontrol_arms.lower_length%3A37500%7Cknuckles.hub_to_upper_x%3A15000%7Cknuckles.hub_to_lower_x%3A13000%7Cknuckles.hub_to_lower_y%3A13000%7Cknuckles.hub_to_upper_y%3A13000%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A0%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A1%7Ctires.section_width%3A33500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26rear%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A15238%7Cframe.center_to_upper_mount_x%3A51587%7Cframe.bottom_to_upper_mount_y%3A26670%7Cframe.center_to_lower_mount_x%3A48158%7Cframe.bottom_to_lower_mount_y%3A1904%7Ccontrol_arms.upper_length%3A23393%7Ccontrol_arms.lower_length%3A35560%7Cknuckles.hub_to_upper_x%3A17881%7Cknuckles.hub_to_lower_x%3A9207%7Cknuckles.hub_to_lower_y%3A12011%7Cknuckles.hub_to_upper_y%3A11244%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A5588%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A0%7Ctires.section_width%3A28500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26pref%7Bdiag1.px_per_mm%3A200%7Cdiag1.front_or_rear%3Arear%7Ctab.active%3A1%7Cunits%3A0%7Cshow.f%3A1%7Cshow.ca%3A1%7Cshow.k%3A1%7Cshow.w%3A1%7Cshow.t%3A1%7Cshow.rc%3A1%7Cshow.ic%3A1%7Cshow.fvsa%3A1%7Cshow.tl%3A1%7Cshow.kpil%3A1%7Credraw_during_drag%3A1%7Cchart.x_axis_center%3A0%7Cchart.x_axis_window%3A10%7Cchart.x_axis_num_steps%3A21%7Cchart.x_axis_field%3A%5BFR%5D.wheels.diameter%7Cchart.y_axis_fields%3A%5BFR%5D.general.roll_center.y%7D[/url] ([url]http://www.vsusp.com/#0.8%26project_name%3Adefault%20values%26trim%7Bbody_roll_angle%3A0%7Cfront.left_bump%3A-8600%7Crear.left_bump%3A0%7Cfront.right_bump%3A-8600%7Crear.right_bump%3A0%7D%26front%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A0%7Cframe.center_to_upper_mount_x%3A0%7Cframe.bottom_to_upper_mount_y%3A0%7Cframe.center_to_lower_mount_x%3A0%7Cframe.bottom_to_lower_mount_y%3A0%7Ccontrol_arms.upper_length%3A24800%7Ccontrol_arms.lower_length%3A37500%7Cknuckles.hub_to_upper_x%3A15000%7Cknuckles.hub_to_lower_x%3A13000%7Cknuckles.hub_to_lower_y%3A13000%7Cknuckles.hub_to_upper_y%3A13000%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A0%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A1%7Ctires.section_width%3A33500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26rear%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A15238%7Cframe.center_to_upper_mount_x%3A51587%7Cframe.bottom_to_upper_mount_y%3A26670%7Cframe.center_to_lower_mount_x%3A48158%7Cframe.bottom_to_lower_mount_y%3A1904%7Ccontrol_arms.upper_length%3A23393%7Ccontrol_arms.lower_length%3A35560%7Cknuckles.hub_to_upper_x%3A17881%7Cknuckles.hub_to_lower_x%3A9207%7Cknuckles.hub_to_lower_y%3A12011%7Cknuckles.hub_to_upper_y%3A11244%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A5588%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A0%7Ctires.section_width%3A28500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26pref%7Bdiag1.px_per_mm%3A200%7Cdiag1.front_or_rear%3Arear%7Ctab.active%3A1%7Cunits%3A0%7Cshow.f%3A1%7Cshow.ca%3A1%7Cshow.k%3A1%7Cshow.w%3A1%7Cshow.t%3A1%7Cshow.rc%3A1%7Cshow.ic%3A1%7Cshow.fvsa%3A1%7Cshow.tl%3A1%7Cshow.kpil%3A1%7Credraw_during_drag%3A1%7Cchart.x_axis_center%3A0%7Cchart.x_axis_window%3A10%7Cchart.x_axis_num_steps%3A21%7Cchart.x_axis_field%3A%5BFR%5D.wheels.diameter%7Cchart.y_axis_fields%3A%5BFR%5D.general.roll_center.y%7D[/url])
Robert, if it was mine build, I would use a bit different setting just to make sure the outer wheel's camber angle is not affected by more than 1,5 degrees during high-speed cornering, where the car's body usually rolls by about 3 degrees. While your setup from the link above have very nice settings to keeping both wheels vertical while crossing bumps or holes simultaneously, the camber angle of the outer wheel while cornering and say 3 degrees of body roll is 2,976 degrees. The latter means that this settings basically act nearly identical to equal A-arm setup and makes it easier to lose control over the car and wear the outer tyre protector quicker than normal. If it's not possible to change the wheel hub and the length of either A-arms on your suspension, I would recommend to slightly lower the joints of the upper A-arm connecting to the chassis. Under the "Frame" settings bar, if you change the "Frame bottom to upper mount Y" from the current 10,5 inches to 9,25 inches (i.e. 1,25 inches down), the outer wheels camber angle will be affected in the following way:
Car body roll of 0 degrees --> outer wheel's camber = -0,751 degrees (it's always good to have about 0,5-0,75 degrees negative camber while in neutral position)
Car body roll of 1 degree --> outer wheel's camber = -0,127 degrees
Car body roll of 2 degrees --> outer wheel's camber = 0,399 degrees (2 degrees is the most common roll angle)
Car body roll of 3 degrees --> outer wheel's camber = 0,888 degrees
Car body roll of 4 degrees --> outer wheel's camber = 1,309 degrees (really agressive high-speed cornering)
Of course, we should not forget the caster angle, which additionally helps to gain some extra negative camber while cornering, so the above numbers are just to giving a rough idea and will not represent the actual camber of the wheels.
9,25 inch (http://vsusp.com/?tool=2d#0.8%26project_name%3A9%2C25%20inch%26trim%7Bbody_roll_angle%3A0%7Cfront.left_bump%3A-8600%7Crear.left_bump%3A0%7Cfront.right_bump%3A-8600%7Crear.right_bump%3A0%7D%26front%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A0%7Cframe.center_to_upper_mount_x%3A0%7Cframe.bottom_to_upper_mount_y%3A0%7Cframe.center_to_lower_mount_x%3A0%7Cframe.bottom_to_lower_mount_y%3A0%7Ccontrol_arms.upper_length%3A24800%7Ccontrol_arms.lower_length%3A37500%7Cknuckles.hub_to_upper_x%3A15000%7Cknuckles.hub_to_lower_x%3A13000%7Cknuckles.hub_to_lower_y%3A13000%7Cknuckles.hub_to_upper_y%3A13000%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A0%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A1%7Ctires.section_width%3A33500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26rear%7Bframe.susp_type%3A0%7Cframe.bottom_y%3A15238%7Cframe.center_to_upper_mount_x%3A51587%7Cframe.bottom_to_upper_mount_y%3A23495%7Cframe.center_to_lower_mount_x%3A48158%7Cframe.bottom_to_lower_mount_y%3A1904%7Ccontrol_arms.upper_length%3A23393%7Ccontrol_arms.lower_length%3A35560%7Cknuckles.hub_to_upper_x%3A17881%7Cknuckles.hub_to_lower_x%3A9207%7Cknuckles.hub_to_lower_y%3A12011%7Cknuckles.hub_to_upper_y%3A11244%7Cknuckles.hub_to_strut_axis%3A14000%7Cknuckles.strut_incl%3A8000%7Cwheels.offset%3A5588%7Cwheels.diameter%3A1800%7Cwheels.diameter_expl%3A35000%7Ctires.size_convention%3A0%7Ctires.section_width%3A28500%7Ctires.aspect_ratio%3A3000%7Ctires.diameter_expl%3A50000%7Ctires.width_expl%3A7620%7D%26pref%7Bdiag1.px_per_mm%3A200%7Cdiag1.front_or_rear%3Arear%7Ctab.active%3A0%7Cunits%3A0%7Cshow.f%3A1%7Cshow.ca%3A1%7Cshow.k%3A1%7Cshow.w%3A1%7Cshow.t%3A1%7Cshow.rc%3A1%7Cshow.ic%3A1%7Cshow.fvsa%3A1%7Cshow.tl%3A1%7Cshow.kpil%3A1%7Credraw_during_drag%3A1%7Cchart.x_axis_center%3A0%7Cchart.x_axis_window%3A10%7Cchart.x_axis_num_steps%3A21%7Cchart.x_axis_field%3A%5BFR%5D.wheels.diameter%7Cchart.y_axis_fields%3A%5BFR%5D.general.roll_center.y%7D)
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A few pics of progress. ::toothy I finally bought a new phone!
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What control arms are you using on the suspension? Corvette? How did you select your mounting points for correct geometry?
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The front control arms are corvette C4, the dimensions were on the chassis works blue prints.
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88 C4 correct?
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No, the control arms and knuckles are the second generation design for the C4 corvette.
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So, the they are 88+ ? I believe the 87 and under are a different length than the 88...
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Yes 84-87 are different length AND bolt pattern than the 88-93. They won't interchange with the 88-93 version. The 84-87 also used a shorter spindle.
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I have 1995 model year.
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This is the wheel I decided to go with! TSW Nurburging. ::thumbup
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A great deal on Ebay. I purchased my 2 rear tires from ebay, Hankook Ventus 305/30zr19 for $280, with free shipping. What a great deal. I had discount tire mount and balance them. I asked the manager if I could buy road hazzard on the Hankooks, he said sure. I purchased road hazzard for $40 per tire. Being frugal can be fun!
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those rims and tires look really nice!
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those rims and tires look really nice!
Thank you!
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I finally started making my rear control arms.
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Good job, nice to see you using a jig, I made a reversible jig with the bottom arm on one side the top arm on the other, no sense in wasting the big chunk of steel.... Plus having the jig allows future fabrication.
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Good job, nice to see you using a jig, I made a reversible jig with the bottom arm on one side the top arm on the other, no sense in wasting the big chunk of steel.... Plus having the jig allows future fabrication.
Thanks! A reversible jig is a great idea!
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I finally finished my control arms. I welded these together very hot! Failure is NOT an option!
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Wow those are nice!
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Wow those are nice!
[/quote Gracias Amigo!
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I want to thank everyone who gave me advice on correct geometry and lengths!
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A few more pics of progress! The elevated control arms will give me 6" of frame to ground clearance, and very good chamber, with body roll.
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I freaking finally fabricated my rear upper shock mounts. This should give me 6" of chassis ground clearance, and proper shock stroke.
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Very nice job on this one! ::beers Thanks for sharing! Good to see you keep on the safety side and do the welds properly with pre-heating. You may already have this in mind, but I will tell it just in case. I would suggest a few extra reinforcements here and there.
1. One may be an additional member added to the upper rear control arm (pictured below). That will unload a good portion of forces from the lower control arm joints (bushings?) next to the wheel hub.
http://i.imgur.com/24LVAnF.jpg (http://i.imgur.com/24LVAnF.jpg)
2. Then, you may add one vertical tube to connect the horizontal ones on the chassis where the first coil-over is located. That will increase the strength significantly as the massive bottom tube will help support the upper ones when pressure forces are applied to the coil-overs during acceleration or high-speed cornering.
http://i.imgur.com/ArEhOhc.jpg (http://i.imgur.com/ArEhOhc.jpg)
3. Also, one removable cross-section tube (or even better, a X-brace) to connect both sides of the upper mounting points will help a lot.
http://i.imgur.com/Ksls4Ch.jpg (http://i.imgur.com/Ksls4Ch.jpg)
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Thank you Plans! I'm waiting for my rod ends to come for my upper A arm link. You have some great advice. Thank you for taking the time!
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I fabricated my front upper shock mounts. These should give me 6" of chassis to ground clearance and proper shock stroke.
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A bit more progress, with upper A arm link. I received my front wheels and tires this week! This baby will be on the ground soon!
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I pulled the drivetrain, and removed the suspension / cradle assembly for final welding. I am holding off welding the rear shock and control arm brackets, until the body is placed over the chassis. I want to make sure wheels look correct in the wheel wells.
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My ace mechanic says the chassis is ready to place on the Floor with the tires! 1.5 years, and countless beers to get this far! I really need to pick up the pace!
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It's great to have a trusty mechanic around when you need one.
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Don't forget to take breaks for tea parties!
People always try to calculate the total build price, but no one ever figures in BPH (beers per hour). This addition to the cost can really make the price go up!
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You have a great mechanic there! Chassis is turning out great. You will be so excited once you have it on the ground with the wheels on, it will push you to get it finished.
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Robert, great work! What rating coil overs did you use on front and rear...they look like QA1's (450lb front, and 2x250lb rears, standard 10" compressed)
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Thanks guys! Yes they are QA1, I used 250# for the rear, and 400# for the front.
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She is finally setting on the floor1 ::bounce
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Congrats, kinda makes it real doesnt it????
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::salute Hats off to you and all the tube chassis guys, celebrate the achievement.
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Thank you Lambo brothers! I still have a long way to go.
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How did you determine the spring rate for your front suspension? 400# seems a tad stiff. Of course, probably no two cars will have the same frt/rr weight ratio but I figure mine will be close to 40/60. Here is a website to figure the spring rates if you care to give it a try.
http://www.ridetech.com/info/spring-rate-calculator/ (http://www.ridetech.com/info/spring-rate-calculator/)
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Trust me, 400 lbs springs is the minimum for such kind of a car. I would use anything between 400 and 600 lbs. During a sudden stop or high speed cornering over 90% of the car's mass will immediately transfer to the front end, thus the front/rear weight ratio will play quite a small role.
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Nice!!! Keep up the good works!!
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I spent some time out in my garage today.
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Hi Robert, very nice progress so far! Putting the body over the chassis for the first time is quite a dream for most kit car builders! ::beers I suggest that you may want to add some extra tubing just in case. I quickly drew some lines where I think it's most likely to strengthen the chassis. Yellow lines represent larger size main tubes, and white lines are thinner reinforcements. You can add some triangulation in the central tunnel, too. As a side effect, this will also help you shift some weight to the front axle.
Cheers,
Bobi
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Thanks Bobi. I will put in your tubes! ::thumbup
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Good progress Robert, the body looks good on the chassis!
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hi robert are you building reventon if so can u give me so info on your build im building one to
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hi robert are you building reventon if so can u give me so info on your build im building one to
what would you like to know?