Mustang V6 Autocrosser named Mistress

In reply to appliance_racer: Thanks, I am glad you are enjoying it. As I noted above I am running on springs that are too soft for the massive sway bars I have. I bought the bars before I had any idea what I was doing. That will be solved when I put a new K member and go with coil overs someday (in a year or two). I have been told several times by more experienced drivers to get stiffer springs onto Mistress. But hey, I have to drive that thing on some pretty crappy roads. It already rides like a buckboard!

Your mods sound pretty typical and spot on for that car. I have gone in a different direction in some areas but then, I have a different car. When I post about the rear suspension mods I did a couple of years ago you may be interested. The upper control arms I made would be directly applicable to your car and they did not cost much. You have already made most of the same modification with the watts link and control arm delete (which, by the way, is better than almost any after upper market arms you can buy).

Fixing the Slowest Part of My Car

Late in the day at a Test & Tune in 2013 I asked a friend of mine, Dave Feighner, if he would take my car out on the course and give me feedback on how it behaves. Dave is a Solo veteran with about 20 years experience and is very good at finding the high/low points in a car’s makeup. He makes cars dance.

Dave took Mistress out for two runs. He then reported that the cornering was excellent & very stable. It handled transitions well and was better at holding the line through bumps and dips than most of the other cars he had driven that day. He also said it could use more power which was no surprise.

At least I think that is what he said… I was having trouble listening because Dave had just effortlessly beaten my best time in my own car by two whole seconds on a 40 second course (expletive deleted). I was beside myself! He wasn’t even trying!

A.J. Foyt once said: “Every car has a lot of speed in it. The trick is getting the speed out of it.” To this day I think on this at nearly autocross event; how would I do if I drove as well as Dave? Where would I be in the results if I was two seconds faster?

The following spring I drove down to central Illinois for an Evolution Performance Driving school with another friend, Steve Alger. We each got roughly an entire season in (50 runs) with an instructor in the car or watching the car. This was great fun & great learning.

I fixed a lot of mistakes, poor techniques, worked on focus. An instructor observed that I was losing concentration near the end of each run and taught me techniques on how to keep it together. It is amazing how hard it is to concentrate that hard for only forty seconds to a minute while sliding around in a car.

We drove home feeling thrashed, dazed and sore. My left knee was bruised and swollen from getting pulled into the door handle on every right turn (hundreds of hard right turns). The following Monday I could hardly walk. It was worth it but not at first; it took half the season for me to bring together the learning and make it automatic. By the end of that season I was on fire. In the groove and feeling it! Counting the fifty Evo runs I made over 130 autocross runs that season at four different clubs.

The slowest part in my car is me. Me, Me, Me. This will never change but it can be improved. This is the same for you and everyone you know. You think you are good? Many people out there can drive your car faster… much faster… than you can.

People spend boatloads of money on their cars and then restrain them with poor driving. Some of those changes make the cars “faster” but also make them less forgiving and harder to drive at the limit (see concussion story above).

It does not matter what motor sport you are involved in: You want your car to go faster? Get thee to a driver’s school. Upgrade the nut behind the wheel. It is time for me to go again.

Upper Rear Control Arms

The Fox Body and SN95 Mustangs come with a marginal rear suspension. This is mainly because the upper rear control arms are on a 45 degree angle. The genius of this design is there is no panhard bar needed. It is a simple design, removes a component and reduces cost & weight.

However, for a performance car this is a terrible design. The upper arms travel in a different arc from each other and a different arc from the lower arms. The only way this can work is if the bushings are fairly soft. If all eight bushings on the four arms were solid the suspension would bind and lock up.

Even worse, side forces will shift the axle left and right on the soft bushing as it pivots around one upper arm or the other. You may notice this on the long curve of an entrance ramp as you accelerate onto the highway. It feels somewhat like the back wheels broke loose for a moment (not likely in a 200 hp V6 car).

Actually what you are feeling is the rear axle wandering around causing rear steer. I had the car for 10 years before I realized what was going on. Click on the image below to see a video from a test & tune in 2012. The camera is mounted on the doors for a series of runs. Note the shots of the rear wheels you can see the axle moving back & forth about 1.5 inches or so. I have not looked at this in a while - This is a really cool video! (turn the sound down a bit first) This may take a minute or so to load:   

Wheel Video out side of Car

The wandering axle was especially prevalent if I shifted gears from first to second with the rpms near redline. With the car going 40 mph and the back wheels suddenly turning at 80 (remember; this car has a J-Mod on the 4R70W) the wheels break free unevenly, the axle pivits and suddenly the car is going sideways. I don’t know how drag racers could tolerate this set up.

Most of the aftermarket upper control arms just use stiffer bushings. This might help for drag cars but this is an angle winder. An autocross or road track car can’t tolerate even a hint of suspension binding. A common fix mentioned by “appliance_racer” above is to just remove one of the upper arms. This solves the binding problem but the axle will still pivot around the remaining arm unless stiffer bushings are also added to the lower arms. Still, it is a simple improvement and definitely helps.

The full on proper fix is parallel upper arms and a panhard or watts link (or go with a torque arm). Steeda makes an excellent kit but it cost too much for me. I installed a Maximum Motorsports Panhard and designed my own upper arms and towers similar to the Steeda design. It worked brilliantly. The back of the car is always on terra firma and does not have a mind of its own anymore. The design looks like this:

The bushings came from rodendsupply.com. They made the custom front clevis bushing for me. Hardened washers for the spacer. The rear rod eye is lined with Delran. This is not a perfect arrangement. The white towers should be longer and tilt back further (or the links should connect to the car higher and further forward such as on a Nascar. When the car is on the ground the arms are pointing down at the front. They should be roughly horizontal and parallel to the lower arms.

The result is that on launch the torque transmitted through the upper arms to the frame causes the car to squat slightly. If this was a drag car that would be wasting precious power compressing the springs instead of moving the car forward. However, I am not running on a prepared surface and the launch is a minor component of my overall run. It is a compromise I can easily live with to lock down the rear end.

There is a good article in a recent issue of GRM that details this. The Steeda design gets closer to perfect geometry and is better than my arrangement. But this has served me well and is probably better than most live axle suspensions you will find on a Mustang this age. The link below shows the general shape of the towers (pdf).

Link Tower Design.pdf

Wow, I'm amazed at your fabrication skills!

In reply to Sky_Render: Thanks but my welding is not nearly good enough for a structural weld of this importance. I cut out the parts and paid a professional welder at work to weld the split rings on. Then I clamped the parts together and drilled the holes to make sure they would match up. Everything else is purchased.

Oh - One other thing on this mod: There is no longer any room to run tail pipes over the axle. I ran a couple of years with a single turn down. Last year Mistress got true dual Spintech side exhausts with the long tubes. That story is for another day.

Like the rear suspension mods, the basis of Ackerman geometry is the rear axle line staying centred. The result is that you dynamic front end geometry is predictable and you feel this as you drive. The end result is predictable response and more speed. One point on suspension as this is a daily driver, does anybody do long travel coilovers for them. Short suspension travel, stiff springs is the orthodoxy, but... An example oddball Peugeot 504 had huge travel soft suspension, with an extra 180mm of front track and 2.5 degrees of neg they became lovely lift off oversteer machines which negated the enormous body roll. Most fun I have ever had over 80 mph razor sharp transitions from apex to apex :)

In reply to acheron64: Did the 504 have a live axle?

What SCCA Solo Class Do You Run a SN95 V6 Mustang?

Well… None of them work very well. The car does not “fit”. The first ½ season the people in charge looked at my car and put it in G-Stock (now it would be G-Street). This was appropriate except that many of the newer V6 cars have a lot better power to weight ratio, better suspensions, etc.

Let’s face it, my engine is late 70s technology that Ford reverse engineered from Buick and updated over the years. The SN95 is an updated stiffer version of the Fox body dating from the early 80s. The car is outmatched in G-Stock/Street by more contemporary technology and you can’t modify it to break free of the rules limitations in that class.

After my first season I actually read the rules and found that I did not qualify for a stock class because years before I had put urethane bushings in the front suspension. The next available class was Street Touring Extreme. STX is a brutal class. I ran there from 2011 through 2014. It is populated by Subaru WRX’s and Golf GTIs and similar evil little cars.

I think the WRX was designed at the gates of hell by demons of speed (speed demons). It is evil incarnate on an autocross course. Damn those cars are fast! And the suspension modifications allowed in STX only make them faster. The only way I could beat one is if the driver was a novice and had no clue how to use the powerful tool he was piloting.

STX does not allow any serious engine modifications (only tune, intake, etc.) so my heavy 200 HP car would never be competitive there against the evil demon cars. If I touched the engine it would jump me into classes that run on Hoosiers and then things get expensive.

In 2015 I finally went to CAM-C. Mistress is still outmatched there but this is different. I can fight back. In CAM I can install ever more aggressive suspension modifications and attack the little 3.8 liter engine. Remember, for me, the modifications keep me going in the off season. It is part of the fun. You can’t keep a good engineer down. If left to his own devices he will find something to modify to work better.

The thing that everyone feared would happen to CAM has happened: People show up with purpose built 700 HP monster angle winder Camaros, Mustangs, Chargers, etc. But on the other hand, those cars are really cool custom machines that have been built up into something very special. It is also a wonderfully successful draw to bring muscle car people into the sport.

The rules are simple and provide a framework for modifications that can be very extensive if desired: K-Member? No Problem! New Heads? Cam? Supercharger? 11” wide wheels? IRS? Have at it! Whatever the car tells you it needs within your budget and the basic rules framework.

No, I can’t compete with someone on a $50k budget to build a custom CAM car. But I CAN compete with someone with a V8 on a similar budget as mine. In STX I had run out of useful things I was allowed to do and had hit a technological wall. In CAM I can progress. I can tinker.

At worst I can make my car more fun to drive. At best, I might even make it competitive someday. I am having fun!

In reply to KentF: Beautiful work on the panhard bar brackets. I installed quad shocks, similar to ones used on the Mustang GT. I used GT frame brackets purchased from a Ford Dealer, and had some axle brackets made by a friend who has a complete machine shop. That seemed to cure my axle hop. Since these quad shocks are outside the frame rails there were no interference issues with my dual exhaust.

I dig this.

In reply to Mustang50: Axle hop is a really bad thing. It can tear up your whole drive train. Can you post or link to a photo of your solution?

In reply to KentF: I'll try to get some pictures posted this weekend. But just look under a Mustang GT and look at the bracket welded to the axle and the bracket bolted to the frame. I believe all of the Mustang frames of that era have the holes drilled and tapped.

In reply to Mustang50: Here are a couple of pictures that Mustang50 sent me (thanks) of the second set of shocks (blue-horizontal) he added to his V6. This is upgrading the rear suspension to a GT arrangement. These extra shocks reduce wheel hop and help tie the rear axle down. I expect they help a lot on a drag car set up (I would not know). They won't do much for an angle winder because they don't deal with the side to side motion rear steer pivoting about the upper control arms (see wheel video above). Ford does not put these shocks on the V6 SN95s because in stock configuration these cars are not much use on the drag track. However, if you start upping the HP and converting the V6 to a performance car you will start needing mods like this to get the rear axle under control. If you have wheel hop you need to add these shocks or do something else to correct it. It will tear up your drive train. My parallel upper control arms & pan hard will do a better job on an angle winder but is flawed for a drag arrangement (the arms are pointing down and will force my car to squat wasting power). The best fix, the full Monty, would probably be a pan hard/Watts Link and torque arm with the upper arms removed. The GRM project Mustang has a torque arm & watts set up. What to do (if anything) depends on how you intend to drive the car, the other mods you have made, the HP, and of course, your budget. 

-- Mustang50 Photos:

In reply to KentF: Thanks to Kentf for getting my pictures uploaded. He is correct in his analysis. I added these quad shocks as an inexpensive way to cure axle hop during my autocross runs.

More Power Required!

As I have noted earlier I ran the first few years with SCCA in Street Touring Extreme (STX). In that class you can only re-tune the engine, change the intake and exhaust and the like. The problem is the 3.8 ltr Ford is very limited by the heads, cam and intakes. Changing the intake, exhaust and the tune will only get somewhere between zero and marginal increase in torque or power.

It is kind of like trying to vacuum through a straw. You can use as big a hose as you want but you still only have that straw in the middle of everything. In the STX years I put in a new tune. This upped the power perhaps 10 HP on 93 octane. I also put in a KN filter in the stock intake although I do not believe it did much.

With the above minor changes launching the car in first gear with the automatic was fine ( The torque converter adds torque up to about 15 mph). After that acceleration in first gear is only half bad. But redline in first is about 44 mph then you have to go to second gear. Second gear is a dog and you lose 10ths of a second every time you press your right foot down.

The 4R70W trans will not shift if you put it in first or second. You are in control and redline in second is about 84 mph with the engine limited to 5700 RPM by the tune. This works fairly well for autocross. You just have to lift 1 second before the shift or the back will break free with a squawk and a bang . It is hard on the equipment and could spin you out. For a few years I ran with a special “autocross tune” that would cause Drive to only be third gear (sort of a three speed slap stick with no forth gear) but with the redline in 2nd so high I think I only used it once. The current tune does not have this and is the same for street or course.

Comment on Tunes. I got mine from VMP in Florida. They did a nice job and I highly recommend them. It is on a STC Tuner and allows me to make a variety of quick changes such as changing the revs per mile for different tire diameters, different gears, Fan on temperatures, shift points, shift pressures, air fuel ratios and more.

For example, if I am driving in winter on slippery conditions (Ice Runs anyone?) I can lower the shift pressure making shifts softer and decreasing the likelihood of spinning out (see sway bar story near the start of this thread). I can change the program when I switch from the 16” all seasons to the 17” or 18” race tires. If you don’t do that you can hit redline just before the automatic up-shifts. What I am saying is, I don’t know why people buy chips. I have an infinite number of chips. And VMP can email me a entirely new tune when I change something significant in the engine.

So last year (2016) I went to CAM. Floodgates open on engine mods for the little 3.8 ltr. For years I had held back because the mods required are expensive and I felt you had to do them all at once. Last spring I reasoned that the major significant engine mods could be broken out in at least four phases with a season or two in between. It spreads the money over a few years.

To get Mistress up to GT power and well beyond this is what I have planned out. Phase 1 was complete in 2016. Phase 2 is this year. After that… we will see. It depends on what Mistress tells me out on the course. A write up with photos on Phase 1, Part 1 next…

Phase 1 – Tune, Exhaust, Cam & Roller Rockers.

This engine is severely restricted by the cam, the valves and intake/head ports and the stock exhaust in that order. The intake and throttle body are not a factor until you fix the items above. If you do all of them you should be running 260 to 280 HP (So they say – We shall see…).

This is a lot of money but I found you can break it up. Phase 1 is a high lift cam with roller rockers. I combined this with long tube headers and new exhaust. If you know this engine your response should be that these changes lowered low end torque significantly and you would be right. It does still have enough torque to break the sticky Bridgestones free on launch but only if I power brake it. This is the price for running with only Phase 1 for a season. However, at 2000 RPM the engine comes alive. The way this car is geared it spends a lot of time on an autocross course between 2000 and 5000 RPM so I can live with the low end torque for a while. Phase 1 – Part 1 Cam, Roller Rockers, Springs and pushrods are Comp Cams Brand from Super Six Motorsports in GA. Tom Yentzer there is a fount of information. Tell him what you have, how you use the car, where you would like to take it and how many phases you want to take to get there. And then just listen. He has decades of experience with these engines. He can recommend the proper cam, the rods, springs, everything. Tom can also recommend other appropriate mods (and whether they are needed or not) for the car throughout the entire drive train depending on the power you are making and how you use the car (sticky drag strip/unprepared airport tarmac, etc.). Excellent service but it is a small operation so some things will take time.

Something I noticed while doing this work: The entire engine and drive train on an SN95 Mustang is offset about 2” to the passenger side. Balance and/or driver comfort presume. I had this car all these years and never noticed until I did this work last spring.

Phase 1 – Part 2 - Exhaust

Ceramic Coated Long Tube Headers and H-Pipe Cross Over from Mac.
The headers fit fine with the following exceptions: They interfered with the heat shields on the engine mounts on both sides. I was able to bend the shields out of the way. They interfered with part of the engine mount on the driver side. I was able to trim it out of the way with a multi-tool.

The flange on the passenger side had a minor interference with the transmission oil pan (probably would be fine with a stick). I was able to trim a bit off of it and got about 1/8” clearance.

The cross over pipe was a bust. I bought it intending to cut it up and put high flow cats in from Magnaflow. There was not much left of the original cross over pipe. It was poorly made and did not fit up very well. I had to make a couple of cuts to make bends and keep from hanging too low. Also the crossover tube did not fit up properly and had to be moved.

Granted I spliced in the cats but I would have been better buying the loose pipes and fabricating the thing from scratch.

Exhaust is a 2.5” diameter dual side exhaust from SpinTech (the GT version not the V6 version). I can’t go over the axle because of the rear upper control arm towers. It was well made and fit up well. It sounds about as good as a V6 can get and with the cats in there it does not drone on the highway.

If you were to use this exhaust you would want to go with the SpinTech full length stepped sub-frame connectors. They hug the underside and provide space for the tail pipes. The tail pipes are too low as it is and would be almost un-workable with regular sub-frames. They are well made also.

I am going to add some skid plates to guard the tail pipes this year. You can feel the difference with the sub-frame connectors. The car does not feel like it is trying to rip itself apart on course now. It feels more solid and predictable. Wish I had done it sooner.

I painted the entire exhaust except the headers and SS cats with silver exhaust paint. I touch up the tail pipes now and then when they scrap the ground in driveways. I ran last season and had a lot of fun. The weekend after the engine was back together we drove 500 miles for a two day autocross event. Everything worked fine. As I write this Mistress is on the lift with the intakes removed. Tomorrow the heads come off and some shiny ported heads and intakes from Super Six are waiting to go on. Phase 2 has begun.

As you can see in the photos I put the O2 sensors back in. I spliced the wires to lengthen the harnesses. I know I could go with O2 deletes but one of my goals/methods is to be able to re-tune to stock and get the car back to meeting requirements if needed. Or at least close to it if possible. No codes, no issues.

I like the fact that you hopped up the V6. What made you decide to do that instead of swapping in the 4.6?

Aren't the stock V6s in HS now?

Awesome work man. I want to see moar!!!!

In reply to Sky_Render: Why do this instead of swap a 4.6?

1 – Madness

2- BINBI – I’m a “Build It Not Buy It” sort of guy. Could be considered another form of madness.

3- I get immediate gratification when I PAX higher than people driving cars that should be faster than me. The problem is that it does not happen often enough (usually finish mid field). I want more, I want that fix. It drives me mad.

4- In Michigan the auto insurance rates are basically a scam and are so high that we could not afford insurance on a GT (madness on the part of the people running that state). So this is what I have and I am too stubborn to change it now even though we moved to Wisconsin.

5- I like a challenge. I like the underdog. I have always had a fondness for Sleepers. I am the underdog.

6- I like this car. It is dated but it is fairly simple to work on. It is old enough that I am not afraid to take it apart (well.. just a little afraid, but that does not stop me anymore).

7- It gives me something to do in the winter – It is cold here in the winter. You get cabin fever, another form of madness.

8 – I have put so much into this car that there is no really going back. What the hell, let’s see where it leads.

9- Putting a 4.6 in is also a lot of work. If I hopped up that motor I would quickly overrun the rear axle and have to swap in an 8.8. This sneaks up on that threshold (300 HP or so). Also, this car is 100# to 150# lighter depending on what stats you are looking at. For autocross, that could be good.

In reply to Ricky Spanish:

I think you may be right. It seems I heard the SN95 V6 cars were switched to H-Street now. That would be a better place for them. However, when I started they were in G-Stock. No match for those cars and I had already modified my way out of that class with urethane bushings. That jacked me straight into STX. As noted above- classing these cars is difficult. They don't fit anywhere.

In reply to Spinout007: Thanks Spinout007 - More to come for Mistress. Head replacement (Phase 2), modified Harness Bar, Data Logging, special tools, detailed list of mods with pricing, Plans for Phase 3 & 4 (if needed) some interesting venues in this area, and a little madness.

I think you should bolt a positive displacement supercharger on it next!