Great job so far Steve! I love this do it yourself stuff!!! It's what hot rodding and drag racing is all about...innovation and making due with parts available! Of course having said that...leave it to some drag racing supply company to take something simple and inexpensive and make it expensive in production quantities! (i.e.-the $8000 Junior Dragster)
Steve, What method are you using to locate the suspension in relation to the rest of the car? Are you measuring from each of the other wheels or using templates - or some other way?
I took a bunch of different measurements from several locations before I cut the car. Even then I still missed a couple and have had to measure another car that I have. I am centering the lower control arm adjustment, the strut trod adjustment, and then experimenting doing coarse camber/caster adjustments by placing the suspension, clamping it down and running it through the travel. The slots in the upper control arm mounts are about 1 1/2 inches so I will center them also. Should give me plenty of latitude one way or the other. I hope to be able to start welding them in place tonight. More pics if I do.
That is great. I know enough to know that there are plenty of measurments that have to be made. I took a course at the local tech college on building race cars. We spent some time on the front and rear suspensions. You make it look easy and I know it is intense work that requires a lot of tedious work. You should try to include some of that in your description - it might keep someone from cutting their car only to find out that they are over their head.
Wow, that is a lot of progress in a very short time. It looks really nice. Based on the pictures that you have posted, it looks like you will have between 5.5" and 6" of suspension travel at the lower mounting point of the shock. Have you decided on the spring and shock package you plan to use yet? Have you determined how high the upper shock mount is going to be from the frame rail? I understand that the upper mount location is going to be partially determined by the clearance of the spring and the upper control arms. You are mounting the lower portion of the shock as far outboard as is possible with the stock lower control arms which is good from an independent motion-rate perspective. This may cause the spring/shock to have to be laid over at more of an angle to clear the upper a-arm. This is not really a problem, it just necessitates a slightly stiffer spring and possibly a shorter shock package. From my guesstimates, I think you would be looking at a shock with either a 6" or a 7" stroke so as to not bottom out or top out the shock at the extremes. The steeper the shock angle from vertical, the shorter of a stroke that would be required. This would give you about a 13" compressed height and about a 20" extended height. From this, your mount point would be just about centered above the frame rail and between 10" and 12" up above the frame rail. You mentioned a cross bar to go between the lower control arm mounts as a support structure. Take a look at the rack mount bracket that is used to mount the Steeroids rack on 67-70 Mustangs. It bolts to the Belly Bar mount holes as well as using a slotted plate that the lower control arm bolt goes through. Two pieces of 3/16th plate plasma cut and welded together will still clear oil pans, steering linkage and provide a strong cross member tying the lower control arm mount points together. So are any of these guesses close? I just ordered a bumpsteer gauge and a digital caster/camber gauge, digital protractor and the upper a-arms, slide mounts and ball joints. You have been a very bad influence on me.
I will have answers for all of your questions soon. Wanted to do a quick reply to let you know. My girlfriend thinks I am a bad influence as well.......
Caster/camber I have found out that with the stock steering box and doing the shelby drop the max caster I can get is +7 degrees because of the box location. I only drive this car on the street here locally, small town, generally 55 or less, and the rest on the drag strip. So I am thinking I might go 7 degrees, should make it go nice in a straight line. Still at -.5 degress of camber. Any thoughts from anyone?
From everything I can find online, the +7 caster should work fine with no real downside. Since these cars are so light, the increased steering resistance should hardly be noticeable. The camber setting is right where all the resources that I have indicate works best. Have you measured the camber at full droop and full rebound? If so, what is the range that you are seeing?
Any decrease in camber will make the steering more sensitive. That is great for road racing, not so good for drag racing. I ran a hill climb Mustang with -2 camber and +5 caster. It would hold a straight line on the freeway but if you cranked the wheel you could turn it on a dime. It turned like it was riding on rails. I would think that you would want somewhere near the factory camber settings.
These are the measurments I have so far, and this is with everything in the center of its travel, so there is quite a bit of room for adjustments. With the wheels straight ahead and car at ride height: + 2.25 degrees caster -3/8's camber With the suspension at full compression, wheels straight ahead: -5.5 degrees camber +10 degrees Caster Wheels straight ahead, suspension full compression: +2 degrees Caster -1.4 degree Camber At ride height, wheels straight ahead: wheels turned full right: +2.75 degrees Camber -2.5 degrees Caster wheels turned full left: -3/4 degrees Camber +2.75 degrees Caster Originally the center of the upper a arm mount was at 5 " in the front and 4.5 " in the rear. It is now at 4" overall, front and rear. A friend has a Pontiac Grand Am that runs 9.20's and his caster is set at 11 degrees with zero degrees camber. I have driven the car at 9.20 and it runs straight as a rail, and drives around town nicely also. I believe I am going to try for +6 degrees caster and -.5 degrees negative initially. I am taking it to an alignment shop Monday, with the engine out and bars simulating the shocks at ride height. I want to make sure this is all correct and all the right adjustments are attainable before I finish welding everything up. This picture is as it stands now, everything tack welded. I will do some finishing to it to enhance the appearance of the mounts, maybe taper the ends of the a arm mounts to the frame and gusset the engine mount area to the frame. I do not like the way the rubber boot does not fit on the ball joint on the bottom. The ball joint does not stick out of the control arm at all, so there is no place for the boot to grab on to. These are pictures of both sides ready to go to the alignment shop for a test alignment, and pictures of the passenger side forward bar/upper shock mount being fitted. The way the bar sits it leaves me a shock dimeansion at ride height of 13 inches. I now have about 15 hours labor, and probably about 20 hours of just sitting there figuring it out, and internet research.
The more positive caster you have will make the car harder to steer when not moving, because you'll be lifting the front of the car, turn left that side will lift and turn right and that side will lift, have someone watch the height of the vehicle while you're turning and you'll see what I'm talking about. But the car should go straight without a problem.
Progress today I got the right bar attach point welded in and the bar mounted and welded. I plated the front attach point with 1/8th and welded up the factory mounts on the frame first. Just getting this piece bent correctly and notched and the plate made and welded added another 3 hours.
I took a friends car out today that has +11 degrees caster and drove it around town, drives comfortable enough to play on the street, mainly all I do is straight line with 5.14 gears, but I am going to probably end up with 5 to 6 positive.
Both sides finished and welded in Both sides are in enough to take it to the alignment shop next week for a quick check to make sure everything adjustable enough.
