A dirt track street stock race car is hardly refined. Compared to the ultra-sophisticated late models or sprint cars, the bomber stock type dirt track cars are prehistoric. Where chassis in the other classes are purpose built, the bomber stock chassis is generally a twenty to thirty year old street car using twenty or thirty year old technology. Figuring out how to make that aging technology get the most traction on a wet dirt track is the key to being successful. This is where many race teams fail. Our dirt track project car, Madd Maxx is a perfect example of old technology, so we decided to modernize and upgrade the suspension system with some cutting edge technology from AFCO Racing Products.
We talked with Eric Saffell, AFCO Product Manager and Ben Baker, AFCO Engineer, about our project and how to get some stability on the track. With the help of these specialists, we were able to get our driver a car that is solid and comfortable on the track. We’re going to walk you through the steps we took searching for a better suspension. In this article, part one of two, we are going to focus in on the front suspension and follow up with the rear suspension in a subsequent article.
Follow the Rules!
Whenever you make a change, especially a significant upgrade like this one, you need to double check the rules of the track or sanctioning body that you plan to compete in. Where the rules say stock or stock replacement part, you must use a stock replacement part if you plan to stay on the right side of the law. The rules for our local tracks were pretty simple: Racing springs are allowed, Ball joint and ball joint location must be stock plus or minus one inch. No steel or offset bushings, All shocks must be stock type and must be mounted in stock location to stock rubber mounts. Racing shocks allowed.
We took stock of what we were working with in the front end. It wasn’t pretty. The existing shocks were shot, the lower “A” arm bushings were well worn and the upper “A” arms had bent cross links. The springs looked like original stock springs that had seen better days, and they were installed with fixed spacers on the top side of the mounting bucket. Other than the spindles, there wasn’t much worth saving here. When you’re getting ready for a full race season and spending some hard earned money on suspension parts, it makes sense to double check the parts you are planning to re-use.
Our List Of Upgraded Suspension Parts:
(2) Low Friction Extended Length Upper Ball Joint – AFCO Part #20032LF
(2) LF Low Friction Lower Ball Joint – AFCO Part #20039
(2) Lightweight Rear Lower Control Arm Bushing – AFCO Part #20076LW
(2) Lightweight Front Lower Control Arm Bushing – AFCO Part #20077LW
(2) Steel Rear Upper Control Arm Bushing – AFCO Part #20098
(2) Steel Front Upper Control Arm Bushing – AFCO Part #20099
(2) Adapter Bolt from Spindles – AFCO Part #10270
(1) Small Body Steering Quickener – AFCO Part #30052
(1) GM Steering Box U-Joint – AFCO Part #30305
(1) GM Steering Box Coupler – AFCO Part #30315
(1) Shaft U-Joint – AFCO Part #30303
(1) Oversized Bearing for Steering Shaft – AFCO Part #10400
(1) GM Steering Box – AFCO Part #37212
(1) Center Link / Drag Link (70-79 Camaro) – AFCO Part #30272
(1) Idler Arm – AFCO Part #30262
(1) Outer Tie Rod – AFCO Part #30210
(1) Adjuster Sleeve – AFCO Part #30233
(1) Inner Tie Rod End LH – AFCO Part #30208
(1) Inner Tie Rod End RH- AFCO Part #30209
Stock Mount Racing Shock #1020 (1)
Stock Mount Racing Shock #1021 1)
Stock Mount Racing Shock #1022 (1)
AFCO has a tremendous reputation for quality shocks, so we went to our tech support at AFCO, Ben Baker for his recommendation on front shocks. “You are kind of limited to what you can use on your shocks since they have to have a non-re-buildable shock. On the front you can start with 1020 Left Front and a 1021 Right Front. If you need more forward bight and need the car tighter then go with a 1022 on the Right Front.” Baker went on to explain where we should start our basic chassis setup for the front suspension, “For the ’79 non metric Camaro chassis the right front settings normally used are 3.5 degrees negative camber and 3-4 degrees of positive caster. The left front settings are 3-4 degrees of positive camber and 1 degree of positive caster.” According to Baker, we should set the toe out ¼” at the front.
Once the new A Arms arrived we bolted in the new upper ball joints. These just bolt in and the AFCO ball joints come with the mounting hardware, so it’s not a difficult job. We recommend using red thread locking compound on the mounting bolts so they don’t loosen with vibration. The AFCO ball joints we ordered were extended length so it’s a good idea to check the ball joint in the spindle before mounting it to ensure that there is the correct amount of threads for the castellated nut and cotter pin.
The lower ball joint is a press in style ball joint that should be tack welded into the mounting boss after it’s pressed flush into the housing. There’s no need to get excessive on the welding unless the mounting hole is worn and rounded out. If that’s the case, it’s better to get a new A Arm for the primary use piece and keep the old A Arm and welded ball joint for a back up emergency piece.
We bought new wheel bearings and packed them with grease. Baker, AFCO’s circle track guru, told us “if you want to have the absolute best there is, there is a process that polishes these bearings for lower drag”. We thought that was a little over kill for needs but it’s nice to know that we still have room to upgrade if we needed.
We had the brake rotors turned and installed new brake pads in the calipers. Removing all the old compound from the rotors is important if you want your new brake pads to work like they are suppose to. Don’t cheat yourself here. With the rotor and brakes taken care of, we installed the spindle to the A Arms and mounted the brake calipers and rotors. Because we were doing a full suspension upgrade, we replaced the idler Arm, tie rods, and drag link with new components.
Once you have everything stripped make sure the upper control arm shafts are straight by either rolling them on something flat. Ours were bent beyond straightening so we ordered some new upper A Arms. We checked the lower A Arm mounts for proper alignment. The bolt holes on the mounting brackets for the lower A Arms were a bit elongated from wear, which is not unusual, so we welded 1/2” ID washers to the control arm mounts and drilled out the holes to 9/16” for the new bushing hardware. It’s important to check and double check the mounting brackets with a length of straight steel rod through the mounting holes to make sure they line up perfectly between the front bracket mounting holes and the aft bracket mounting holes.
To cap off the front end suspension upgrade, we added a new AFCO GM Steering box and AFCO 2:1 Steering quickener for precision steering. Changing all the links, ball joints and bushings and leaving a sloppy 20 plus year old steering gear box would have been a sin, so we bit the bullet and made the smart move by installing a new tight gearbox.
Our front end suspension was now ready for the track and with the steering upgrades, our driver would be set for handling that was far superior to the original setup. Pressed for time (as usual), we skipped a very necessary part of chassis set up in favor of making it to the track. By-passing scaling the car, we took the beast to the track and were planning on using driver input to tell us how close or how far away we were with the setup. This is not the optimum method, especially when your diver has less than 8 races on dirt under his belt. But that was our plan and we stuck with it. Surprisingly, we pulled it off and the recommended starting setup from Ben Baker worked extremely well. How well? Check out the video below and see how our driver did in the first race of the year with a new front end suspension and steering:
#29 MADD MAXX MAKES IT TO THE TRACK WITH NEW AFCO FRONT END SUSPENSION:
The driver was impressed with the stability of the car. It’s obvious that the track was a little slick by watching the front ends of the other cars, but our project car had more grip and less push entering the corners. The driver was so comfortable that when he got out front, he was still pushing the limits and smacked the wall coming out of turn 2. Our plan to correct the corner-off push up to the wall is to change the rear suspension with some more parts from AFCO Racing. We’re convinced that these improvements will take a tank-like handling bomber stock and turn it into a circle track cadillac. With the front end upgrade, we were half-way there. Watch for the Upgrading Our Street Stock Suspension Part 2 for the changes we make to the rear end suspension in our effort to take MADD MAXX into victory circle.