My Turn @ Pulling the Trigger on a Twin Turbo

28mm OD Stainless Steel pipe arrived. However, not a perfect fit by any stretch. Steering shaft would not go down the inside of the pipe and the pipe would not go down inside the bearing boot. So, off to the machine shop and to the machinist who build my motor. First step was to cut off an 8 inch piece to mount into the lathe. He had a 1 inch reamer and the SS stuff was a little hard, but machinable. Steady as she goes and with plenty of cutting oil we reamed out the inside hole first to about a 3 inch depth. The shaft was close to fit, but would not go down that hole at first. He had a hone machine that would due some fine reaming, so that was needed to remove about 1-2 thousands to where the steering shaft would slide all the way in, but without any slop. Next up was back to the lathe for machining the outside diameter. We trimmed and test fit about 4-5 times and ultimately the 28mm tube had to be turned down about 7 thousands and sanded for a nice smooth finish. From the old shaft, we measured the amount that stuck out the front and through the firewall which amounted to about 1 3/8 inches. With both parts fitting, the last step was to drill and pin the new shiny sleeve to the existing steering shaft.

Took about 30 minutes, but steering shaft with new tight fitting sleeve was installed and the two U-joints tightened up. Note the hint of a red line marked on the shaft which was our mark to where the sleeve would exit the rubber seal.

Everything back in place except for the seat before calling it quits. The steering seems to be very smooth with zero binding. The real test will be some driving at highway speeds to determine if all or just most of the sloppy steering play has been removed. My initial assessment is that there may still be some slight amount of play in the entire setup which may be in the shaft that connects with the rack and pinion. But, only a little driving will expose if any and by how much. In all, the machining turned out to be more than expected, but most of it was trying to get the outside diameter turned down a little at a time to get a perfect fit.

 

Took a short test drive around the block yesterday and observed a significant improvement. Steering sloppiness reduced by 90%, but still not as perfect as a brand new car. Seems it will be raining all week here in Dallas, so will look for some time to get under the front end of the car to see if I can easily remove the lower shaft that connects with the rack and pinion steering assembly. That shaft is actually in two pieces, one inside the other and has a little play as the parts are not a tight fit. Will likely try to remove the outer shaft, drill it, tap it, and use a set screw or two to pinch the two shafts tight when completely installed.

 

OMG! Steering now has zero slop and is now equal to a brand new cars steering. My non-stock lower steering shaft had just one U-joint at the rack and pinion. It is made up of two oval steel tubes, one inside of the other. The inner shaft had a slot in it from almost the top to the bottom and the outer tube had a grease fitting for lubing the two shafts. In my setup, I never added grease even though the two shafts were designed to slide back and forth a tiny bit. When installed, the two shafts had a tiny bit of play up and down. With the grease fitting removed, the outer shaft slid out easily from the inner shaft which was attached to the U-joint where the new stainless steel sleeve located. When disconnected, it was easy to work on by drilling out the grease fitting hole to a larger size and taping in threads for a 5/16" set screw and locking nut.

The project turned out to be an easy fix that didn't take too long. No other parts had to be removed to gain access to remove the lower shaft. But, I did have to jack up the front in to be able to slide under the car to view and loosen nuts and set screws. Sorry, at the time, did not think to take a photo or two. Was too focused to tap the outer shaft, reinstall, tighten the set screws and lock nuts, and test the steering. Plus, it was hot in the garage and a little uncomfortable laying on concrete.

 

Well, had not thought about body flex, but I have weld-on frame stiffeners as an offset, just like the ones in your photos. And will drive it some to see how it responds. Plus, there is quite a bit of frame flex when jacking up the car, one side at a time. One other point, my car has the rear tri-link suspension which will help reduce some potential frame twist. BTW, did not notice any up and down motion marks on the two inner and outer tubes. And, did not hear any strange noises when letting the car down from the jack stands. Get your point though and will keep a look out. Think you are absolutely correct on a stock V-6 frame, and particularly the convertible frame which twisted quite a bit without the weld-on frame rails.

BTW, you should check your steering slop while the motor is out. Look to see if the steering shaft has ANY up and down or side to side movement at the firewall on the outside. Much easier when there is lots of working space. Think I could make another sleeve or two, but you would need to send your inside-the-car steering shaft to Dallas for a perfect fit.

 

Upon more thought, think it is possible to use a flat piece of feeler gauge trimmed to fit inside the sleeve within a sleeve to take up any free space and keep the grease fitting. A piece maybe 3 inches long and just thick enough to take up the space should also work. My stock black sleeve looked good from the outside as well. But, once I grabbed the U-joint next to the firewall and tried to lift it up and down and then tried to move it right to left, the slack in the steering wheel showed where the sloppy steering was coming from. The inside diameter of that black plastic sleeve had wallered out to where there was no longer a tight fit.

One last point to make is that when blasting down the drag strip and maybe hitting 130 mph in a quarter mile, sloppy steering made me nervous to think about it.

 

I am referring to the black sleeve in your picture just above the highest U-joint to where the top steering shaft passes through the firewall. Just grab that U-joint and try to lift up (try to wiggle) the shaft in the firewall. Even just a little movement will magnify the sloppy steering wheel. Also try some side to side movement.

The lower shaft looks like a stocker. My lower shaft is a steel tube within a tube with U-joints on either end. The inner tube has a slot to where a grease fitting tip will fit in that slot and when greased, allow the two tubes to slide in and out (or up and down with ease), if necessary. Think my lower steering shaft came from Flaming River, maybe the upper shaft as well. Look at this: 1994-04 Mustang Shaft Kit - Power - FR1509P - Steering Shafts / Slip-Collapsible Shafts - Steering Shaft Kits - 1994-04 Mustang Steering Shaft Kit My car uses this one for a power steering and rack and pinion setup, but my upper looks a little different than pictured as mine is a fixed length shaft (rather than what appears to be a shaft within a shaft) without the kinda hidden nut (and maybe a set screw) on the back side of the upper shaft.

BTW, the bulge on the firewall is the part that is actually mounted on the inside of the firewall with two studs and nuts to hold in place. Look at the photo above of the 2008 Mustang part to where the nose of that part pushes through the firewall.

 

The more I look at your photo and note the differences in that Flaming River steering shaft replacement, the more I now believe that my sloppy steering issue is isolated to the slightly smaller steering shaft of the Flaming River replacement.

 

Finally went to an 1/8 mile drag race track today. Temps were 62 degrees in the afternoon, full sun, and light wind. Conditions were perfect. The track was well preped and re-preped several times. A number of classes of cars were present and running, including Pro-Mods and a few rail dragsters. Fastest guy I saw made it down the track in 4.00 seconds at over 180 mph. Did not spend much time watching the various classes of cars. They even had 3 classes of junior rail shaped race cars. I fit in-between several of the classes with a Test and Tune run. Was by myself. No video. Did not even do a data log of my runs as the laptop was left at home. Just wanted a couple of passes without any issues on my part or with the car.

My first pass turned out to be the best. The car was set with the street tune (about 400whp). My reaction time at .591 was pretty slow. 60 foot time was 2.047 seconds, also kinda slow. 330 foot time was 5.296 seconds. 1/8th mile time was 7.982 seconds ET, and 89.02 mph. I did feel some minor tire slippage, but the car ran straight and I kept on the gas, hopefully at full throttle.

Waited about 45 minutes and got to make a second run. Heated the tires some, but did not do a long enough burnout. My line block was working well to lock the front tires, but with no braking on the rear tires. Staged, got setup on the tree, saw the green light and hit the gas on my 500whp tune. Launched hard and straight, shifted into second and the wheels started spinning on 10.5 inch rims with air pressure set on the Nitto DRs at 20 psi. The rear of the car kinda started drifting to the left slightly while the rear tires were spinning. Had to let up on the gas for a moment, then back on the gas again. Finished the pass with .621 seconds reaction, 2.057 seconds for 60 foot, 5.40 seconds for 330 foot, 8.286 seconds for the 1/8 mile ET, and 83.9 MPH.

Headed back to the pits and thought things over and what to do about the tires slipping. Lowered the rear tire pressure to 16 psi to get more rubber on the ground. Was about ready to get back in line and run the 600+ whp tune when one of the Pro-Mod guys hit the wall real hard at the end of his pass. The track was going to be shut down for an hour or so to clean up the mess, tow the car, pick up parts, and clean the track of fluids. The car also caught on fire, but the driver escaped sorta unharmed per the announcer. Was not willing to wait at least an hour plus for another pass and headed for the house before sundown. Hope to get a chance to return to the track soon. It's only 30 miles away and has only been open about 2+ years. The track and setup was real nice, clean, smooth, and a long runout with 2 turnouts.

Think lowering the tire pressure ahead of time before the first pass will help. And, the fuel tank was almost full for extra weight in the rear. Plus, will make sure to do a longer burn-out for each pass.

 

It was another beautiful day in Texas; high 60s, sun, and just moderate winds. Headed out to the local Interstate for a data log run. Had the laptop and the X4 on-board and plugged in. For some reason, could not find the latest (or any for that matter) config.sys files which spell out which data elements to data log. So, no data log of this run. Traffic was mild and was easy to get pretty good spacing in front and the rear for a clean test.

Success, sorta. Had set the tune for SP2 on the eBoost controller which is 15 psi of boost and 500 rwhp. Was on the side of the road at a ramp to enter the highway. Some slipping tires in first gear. But, the car tracked straight. The car shifted into second and this time no slipping of tires. Yea, problem solved. Since the last track outing, went back and looked over some of my auto trans settings, particularly the 1-2 shift, the torque converter lock up MPH in 2nd, and the amount of time to make the shift which was set previously at zero seconds. The adjustments worked perfectly.

Will say that the car really pulls hard, especially with wide tires and rims which really help. Really wanted to get a data log of the pull. Shut the car down after hitting 90.

Next up will be to test the data logging again. Was able to find the config.sys file so with all that working and several more days of nice warm weather, should be able to get a 0-100 test on the data log.

 

Finally found my config.sys file and did a street driving data log. MAF needs some small fine tuning. And, seeing some Bank to Bank A/F variances at low throttle. Those parameters used to be something I could tune with the 2004 PCM, but SCT has removed those for some reason during updates this summer/fall. Am trying to track down what happened and IF those parameters are still tunable, but at a different tuner level (think dealer or master tuner). Will update when more info on that subject becomes available.