Mustang V6 Autocrosser named Mistress

Back in 2002 I bought a new V6 Mustang (red, of course). I wanted a V8 but, in Michigan we just could not afford the incredible insurance rates. The car was driven year around on Michigan roads but was washed every week. My wife named the car "Mistress". Now with 180k miles it still looks good but would be considered a "30 footer". It actually won a "Best in Class" at a local all Ford car show in 2008 (it was raining, the real pretty cars did not come out to play).

In 2010 someone told me to bring it over to the local airport on Sunday for an Autocross. I was hooked on the first run. The car was the wrong tool for the job; a 3300# grocery getter with less than 200 HP. I have always said it was my autocross "learner car" but that is not true. I have as much fun modifying the thing as driving it. Over the last ten years there have been a lot of changes and there are many more planned. The car will never be truly competitive in any class but it is quite a blast to beat people driving much superior equipment.

I have taken the sage advice of long term drivers and not modified the car until it told me what to do. As I learned to drive it, I learned to recognize what it was telling me. We would often have short, one minute arguments out on course as the car explained what it needed while I thrashed it through the curves. Mistress always prevails and wins the argument (always).

Winters spent reading, studying vehicle dynamics, suspension mods, etc. The second season, new Direzzas on the original 7.5 x 16 wheels and so on up to significant engine and suspension mods. The car today is a highly modified CAM car and very different from where it started.

So this is a detailed multi-part saga of where I went with Mistress, why I made the changes I made, and what is to come. We will delve into vehicle dynamics, modification strategy, autocross philosophy and this peculiar form of madness.

Note - From time to time I have found it useful to refer back to an older article. To assist with that I have added a table of contents. If it is useful to you, it is located here:

Mistress Build Log - Table Of Contents

Up to date description and photos of Mistress is here:

Mistress

3.8 or 4.0? Either way, color me interested! I'm always a sucker for an offbeat autocross build!

One other comment. People at events often ask why I don't just go get a GT. I guess I am a "build it not buy it" kind of guy. Make no mistake, I am as competitive a SOB as you will ever find on an autocross course. But I get much more satisfaction doing a little better than expected with an overweight underpowered car. And that gleans even more satisfaction from the display in the garage with a several trophies. Yes, there would be more if Mistress was a V8. But most of those trophies were earned beating V8s. That means I out drove them. I like that!

J-M; It started as a 3.8 from Essex, Canada. So, by the end of the second season running on some sticky tires Mistress had told me that she had incredible under steer. The SN95 V6 cars only have one small anti-roll bar in the front and nothing in the back. The GT cars come with a bigger bar in front and one in the back. I cased out the bars at Summit and, figuring that 1- bigger is better and 2 - the car already had one in the front so I put a 1" solid chrom-moly Summit brand bar on the back axle.

I had not changed the springs yet (soft). It was February, raining & cold when I took it for a test drive. I lived on a five lane highway. I waited for traffic to clear and pulled out of the driveway in a very spirited manner. Did I mention this is an automatic? Did I mention it already had a "J-Mod" installed several years earlier which makes for brutally hard shifts?

Right there, 100 feet from my driveway the car shifted gears as I turned left onto the highway. It went 180 degrees to the right, 360 degrees to the left and back 90 degrees to the right. I ended up sideways looking at my neighbors house as he looked back at me from his picture window. I was stunned (so was my neighbor). Lesson 1 on over steer! Holy crap that happened fast! I slowly drove back in the driveway and took that thing back off the car until I could afford to buy a front bar and some stiffer springs a few months later. More to come...

Does your neighbor still talk to you?

I had a 04 GT and a 94 V-6 and I had much more fun in the beat V6 than my new GT. The best thing I ever did was swap out the 2.73's for a set of 3.73's and a limited slip. It woke up the car like night and day.

KentF wrote: J-M; It is a 3.8. . So, by the end of the second season running on some sticky tires Mistress had told me that it had incredible under steer. The SN95 V6 cars only have one small anti-roll bar in the front and nothing in the back. The GT cars come with a bigger bar in front and one in the back. I cased out the bars at Summit and, figuring that 1- bigger is better and 2 - the car already had one in the front so I put a 1" solid chrom-moly Summit brand bar on the back axel. I had not changed the springs yet (soft). It was February, raining & cold when I took it for a test drive. I lived on a five lane highway. I waited for traffic to clear and pulled out of the driveway in a very spirited manner. Did I mention this is an automatic? Did I mention it already had a "J-Mod" installed several years earlier which makes for brutally hard shifts? Right there, 100 feet from my driveway the car shifted gears as I turned left onto the highway. It went 180 degrees to the right, 360 degrees to the left and back 90 degrees to the right. I ended up sideways looking at my neighbors house as he looked back at me from his picture window. I was stunned (so was my neighbor). Lesson 1 on over steer! Holy crap that happened fast! I slowly drove back in the driveway and took that thing back off the car until I could afford to buy a front bar and some stiffer springs a few months later. More to come...

I think you'll fit in here.

This looks fun. I've always wondered how much potential these things have.

That isn't a flaw, that is a feature.

My Maserati Biturbo does that, in the rain, get in the gas just a little to quick, then the boost comes on, and the rear will come around. Don't know what might happen in the snow....

In reply to KentF:

I autocrossed a 97 V6 Mustang I bought new. Over the years I made some modifications, some that worked well and others not. 1) Installed underdrive pulley, engine felt stronger 2) Installed Ford racing springs and KYB shocks from Summit. Improved handling a lot. 3) Added strut tower brace and rear sway bar from GT. Experienced oversteer (which I like for autocrossing). 4) Added limited slip but did not change gear ratio. (I commuted 20 miles each way to work with this car). 5) Added quad shocks by copying axle bracket from GT and purchasing frame brackets from Ford dealer. The frame on all Mustangs is drilled and tapped for this bracket. Helped axle hop a lot. 6) Added dual cat back exhaust. Sounded better but small performance gain. 7) Installed cold air intake. No noticeable improvement 8) Changed to 180 deg. thermostat. Helped keep engine cooler between runs. 9) Changed to 17" wheels and tires. Definitely more grip.

Overall I had a lot of fun with this car, it is still driven on the street in nice weather. I would like to start autocrossing in CAM class, we'll see how the schedule works out, and the age of the driver and the car.

2nd place in my class on Sunday was a new V-6 Camaro with the 1LE suspension option. He outran a Golf R by a couple of seconds.

Stampie: Yes he still did. Although he was a "show car" kind of car guy. About a year later a stunning exquisite custom roadster appeared in his driveway. I walked over there; Whose is this? He answered - Its mine! I just finished it. He had been working on this when he was younger. Stopped when they had kids and, now that the kids were gone had finally finished it after a 25 year hold. I never knew he built custom drag cars. The next year he finished a '32 Chevy he had been working on for 30 years. So, we had a few things to talk about...

In reply to Mustang50:Yup I have had a similar experience which I will chronicle on these pages. Some of the mods work better than others on these cars. It is a bit of an adventure. Autocross is an addicting blast. Where else can you spin your car out, completely around and back and be laughing hysterically the whole time. Not on the road. not on a drag track or a road course. It is a place where you can learn a stunning amount of car control and not wreck, die or run over bus load of nuns. And the adrenalin is still there. My hands are often shaking when I come off course.

In reply to jstein77: Oh yea - The newer V6 engines today. Oh yea. Oh yea...

In reply to TED_fiestaHP: As the discussion moves into some future planning on my engine mods I will get into the pros/cons of turbos verses superchargers in an autocross application. If you live in a cold place, look around for some ice rally cross action and get that Maserati out on the ice. If you find a club that will run on mostly bare ice (no snow banks) you can have a blast in that Maserati out there. SCCA - Saginaw Valley Region in Michigan runs events like that. They get everything from custom built ice runners to Corvette Z06 on snow tires. It is a blast. Link--> Ice Runs

So.. Initial Suspension Upgrades - Second Season of Autocross. After adding only the large rear sway bar and making the car totally un-stable and un-safe I put on a Summit 1-3/8" solid chrome-moly bar and the 1" rear bar. I also put Ebach Sportline springs all around and Billstein shocks.

Prior to this the car heeled over like a sale boat in the corners. Now it was very stable and fairly well balanced. It also rides like a buckboard. However, I know now that the bars overwhelm the springs. A front bar that diameter is massive. If you look at the car coming at you hard in a corner you can see it still leans a bit even with that big hunk of steel. This is not because the roll bar is twisting. It is because it is basically crushing the outboard spring. I need stiffer springs but I also drive this car everywhere in summer (and up to recently most winters).

It already has the ride qualities of that little red wagon you had as a kid. I am willing to forgo that a little until I finally put a new K member and coil overs on her. The photo below kind of shows what I am talking about. By the way, a word on Ebach Springs - IF you live in the rust belt and drive in the winter - They sometimes have a cracking problem at the base where water and salt sit in the control arm. Corrosion takes its toll and they can crack right at the tail. I had to replace both front springs last year with some H&Rs of about the same spring rate. The photo below is at the Road America Motorplex in 2015.

You can see the car is leaning a good bit in spite of the heavy sway bar. It is crushing the outer spring. Another factor in that discussion is the lowered roll front center because the lower control arms are slightly pointed down due to the lowering springs. That makes the "moment couple" between the center of gravity longer giving the center of gravity more torque to heal the car over. That is why the front tire is almost off the ground (sometimes it does catch air).

It is quite likely that the car would catch more grip if the springs were slightly taller. This is because the roll center and gravity center would be closer together (like they once were). That would keep that inboard tire better planted. Two tires are always better than one. The lesson here is to properly match your new suspension components. More is not necessarily better. Here is a link to a video of my right front tire last summer. You can see what I am going on about here. This is why a K member is on the future modification list to put the front geometry back where it should be. Right Front Under Car Link

The Lift, The Diff, & The Concussion – Part 1

An SN95 V6 Mustang comes with an open differential. This is fine for getting groceries but is a problem on an autocross course. When trying to accelerate out of a corner the inside wheel just spins and the outside is just a rudder. You have to go to a “point & squirt” method of driving which means you get on the gas late at each corner and lose 10ths of a second at every turn.

After a couple of seasons of driving the car whispered to me out on course that it needed a new differential. Actually it screeched and smoked about what a terrible driver I was but somehow I got the picture. After some research I decided a helical gear differential would be the best for me since my car was underpowered (why waste HP heating up clutches).

These things are fairly highly rated in autocross world. I chose an Eaton Detroit Tru-Track for my 7.5” differential. 

I spent an hour jacking up the car on stands as high as I could get it and while laying on the cold concrete loosening cover bolts when I had a revelation: I am going to have to lift this 30# thing in and out of the pumpkin 20 times to get the shims right. This is miserable. This is recreational maintenance and I am NOT having fun.

I put the bolts back in and spent the rest of my money that season on a mid-range scissors lift. It goes up about four feet. It is “portable” although it weighs 900#. Best purchase I ever made for the shop. I could not afford, or fit, a two post lift but this works just fine. They cost around $1500 to $1800.

I also bought some 8’ jack stands from Harbor Freight and cut them down to work with this lift (safety first). Now I could sit on a little Harbor Freight roller stool with the rear axle right in front of me. Suspension work? Tire changes? All wonderful. You can even raise the car just a little for engine work (easier on the back). It fits in a regular garage. I did need to make 4” tall wood ramps so the Mustang clears it easily driving in/out. I normally just park on top of it.

Recently I made box frame steel stands that the front tires set on with the 4’ jack stands under the back axle. With the car up on those supports I can lower the lift, put a sheet of OSB sheet on it and I have an adjustable height place to lay down under the car to do exhaust, transmission, sub-frame connectors, etc. I highly recommend getting one of these if you are serious about working on your race car and can’t afford a two post lift. It is good for regular cars too! Here it is the first day I got it: Here it is with the front supports and jack stands. The supports are made from 2.5" square tubing 3/32" thick.

Details on what lift that is? It appears to be just what I have been looking for.

The Lift, The Diff, & The Concussion – Part 2 The following photos show the progress of installing the new Tru-Trak in my 7.5" differential. I did not change the gear ratio at the time (in the class I was running in that was not allowed). It still has the original 3:23 gears in it today. Note that the Tru-Trak is substantially stronger than the original stock spider in this car. Also, since this is not a drag car launching on a sticky prepared surface I am not concerned about grenading the diff until I get well over 300 HP. And it is lighter than an 8.8. Here is the shop set up for the work. Note the directions from the Ford Manual on the chair. The drip pan. The lights, etc:

Here is the original open diff. Note the spider gears at the center. This is a weak link on these things:

Problem: To pull the axles you have to remove the antilock brake sensors. Over the years the plastic sensors had expanded and welded themselves into the casting. No amount of lube or teasing would get them out. They finally both broke as I tried to remove them. I opened up the hole with a Dremel tool before installing the new ones. Hopefully that will not happen again.

Removing the ring gear. The vice is clamped on the old diff with the gear above it about an inch. You can slowly drive off the gear with a drift. Put some cardboard or a rag between the gear and the vice before it drops:

I made a fixture out of wood to hold the new differential still so I could properly torque the bolts:

Checking the gear lash with a Harbor Freight dial indicator:

This photos shows the shims you use to set the lash and a close up of my rig to measure lash. This is an iterative process requiring you to install the differential, torque the bearing caps, measure the lash, remove it all, change the shims and do it all again. No fun if you are lying on your back.

Final shot shows the completed and lashed helical differential installed and ready for the cover. The next section will discuss the dramatic affects this had on the car and my head.

In reply to Dusterbd13:

Dusterbd13 - I can't read the nameplate on the lift, it has gotten scraped off. It is an off brand unit, made in China (hence the jack stands before going underneath). The welds look good and it works well. The vertical hydraulic power unit also serves as a lift jack with wheels to help move the thing around. Residential delivery is tricky. It is big and very heavy. To unload it from the delivery truck I recommend hiring a tilting bed Tow Truck. When we moved a couple of years ago that is what we used to get it on and off the moving van. Search: "6000 lb. mid-rise scissors lift". I am seeing some very similar units at: DerekWeaver.com.

The Lift, The Diff, & The Concussion – Part 3

It is amazing what one change to the car can make. People often spend a lot of money for little or no gain. The more experienced drivers will tell you not to spend any money until you have a season or three of experience. Then the car will tell you what it needs and you will be able to understand. As mentioned above, I had a few heated 1 minute discussions with my car the season before installing the differential. Mostly it told me what a terrible driver I am. But it also told me it needed the torsion limited slip differential.

An amazing difference; I could now make the car dance through the curves. The problem was to make it dance to the same tune I was singing. With both rear wheels pushing the throttle is very effective at slipping the rear end out and rotating the car to the next curve. It took a season or two for me to learn how to handle this powerful but touchy tool.

This type of differential is really not a "limited slip". There is nothing "limited" about it. There are no clutches that allow some partial slip between the wheels up to a certain point. The torque is instantly mechanically balanced and transferred back and forth to whichever wheel has the most traction until they both break free at once. It immediately got me in trouble on the second run of the season.

Exiting a tight right hairpin with too much speed the car was plowing off course and was about to miss the next element. I implemented my new found tool and hit the gas which kicked the back end out to the left rotating the car to point in the right direction. However it was now drifting sideways toward two cones off the driver’s door as it continued to rotate.

With just a few feet to spare I was off the gas and spinning the wheel to the left. The rear end dug in on some rougher pavement and the car spun around the cones just off of my door as if it was on a tether. "Good Save!" shouted a friend who was watching.

However, inside the car this overly aggressive maneuver was violent and painful. It felt like a collision with something solid. When the back tires dug in it was with a loud bang as the rear suspension absorbed and then released the kinetic energy. I was thrown to the left with such force it wrenched my back. My helmet hit the roof of the car at the top of the window so hard that I could barely finish the run. I came to a complete stop for a few moments to regain my bearings and look for my wits.

My last two runs were poor; concentration broken. Two days later I was into the doctor’s office; “I feel terrible, I can’t think, I can’t remember things & my head hurts”. Prognosis – concussion. I guess the car won that discussion also. It took most of that summer before I had truly recovered.

SCCA requires top end Snell certified helmets for damn good reason even for a fairly benign motorsport such as Solo Autocross. The SA-2005 Snell helmet I was wearing was designed to keep your skull from splitting open in a crash. I believe the newer ones are starting to deal with concussion issues but there is only so much they can do.

I did two things: 1 - I installed a new four point harness from Team Tech in Saginaw, MI. This now helps keep me laced into the seat and not bouncing around in the car (shoulder and seat belts are great but are designed for front impacts, not side forces). A harness will also lower your times because it is hard to drive while hanging on to the wheel for dear life. 2 – I bought a small sheet of 1” roll bar padding from Speedway, cut a piece of it into a rectangular block and bolted it inside above the driver’s window. That will not happen again to me no matter how much I overdrive the Mustang!

Things to come: Mistress gets a custom proper parallel arm 5 link rear suspension.

Running in STX (really? That car in STX?)

The slowest part of the car.

Data Logging and videos as a learning tool.

The search for more power: Tunes, Cams, Rockers, Intakes, Heads, Long Tubes, 4.2 Stroker, etc. List of mods with sources and prices and comments.

Mistress at Gratten Raceway 2013:

In reply to KentF:

I think you will like the 4 point harness. I have a 5 point in my MGB and being planted in the car is very helpful piloting the car around course. Changes that improve things from a drivers perspective can be very worth the money spent, last summer I put a steering quickener and electric power steering on my MGB and closed in on the field. It was a lot easier to catch the car in a slide and I was able to go through the slalom sections with my hands in one position on the wheel.

In reply to KentF:

I'm enjoying your thread here with a slightly unusual car. I figured I give you the info about a set up I had on a '96 cobra. Use all or none just thought you might like to know about another sn95.

H&R race springs with koni yellows, Bumpsteer kit, 1/2 maximum mtrsprt wheel spacers on the front, Fays2 watts link with left upper factory control arm removed (poor man's 3 link), MM subframe connectors , Ford Motorsport LSD with 3.55 ratio, Cheap "saleen" knock off wheels in 17x10 all around, 315-35-17 kumho v710 all around.

My local club at the time usually had very small and tight courses so the stiff springs and watts link really helped transitions. I had been autcrossing for a few years before putting this car together. This set up worked well for me as I had to "grow" into it with my driving skill. Last note I can't recommend these springs for a daily. Just too stiff. Fun on the course tho!

In reply to MGS10:

Thanks! I very much like the 4 point harness from Team Tech. This was 2013 after the head injury. Also that summer I was learning to drive with both feet so it helped a lot. The harness clip can accept straps from the bottom but I did not get them at the time. I still may add them. I installed it to new anchors down in the crack at the back seat. This is "OK" for autocross but would never do for track racing because it pulls down on you. In a crash your spine would be crushed. I have noted after an autocross I sometimes have a sore back from this thing pulling down on me at a 45 degree angle. I finally have a proper harness bar (Cipher Auto) on order from Andy's Auto Sport. It will arrive next week. That will improve the positioning and make it safer to use.