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The Saga of the TR-SHO

Michael Wolf

NOTE: Paul Williams brought our attention to this one of a kind TR7 engine conversion. Mike was kind enough to provide a copy of the article he wrote for NESHOC which describes why and how of the modifications.

I first fell in love with the SHO engine when I read an article on it in '89 when the SHO was first introduced. The intake manifold was a sculpture worthy of Michaelangelo (or Michael Schwartz). It was the most advanced engine sold by Ford. I lusted after one.

In the fall of '89 I took a job that required a 45 mile commute. The '79 TR-7 coupe I had been driving to work just wouldn't cut it. I needed a new car and the first one I looked at was the SHO. I realized that while I loved the engine I wasn't a 4 door sedan person. Therefore I settled for a "economical front wheel drive" car to commute to work ( an Eclipse GS Turbo). The TR-7 passed into the hands of my teen-aged daughter. There it resided for a year until the stress of my new job pushed my already shaky marriage over the edge and my wife and I separated. Without my attentions the TR-7 was unsuitable for my daughter so I bought her a Caviler and retook possesion of the TR-7.

I didn't like the TR much any more because compared to the Eclipse it was a noisy, hard riding, unreliable, stone. I had started running the Eclipse at the drags and while it was successful, a couple of minor failures made me decide that racing one's daily driver was not the best policy. Since I had a lot of free time, I decided to swap a better engine into the TR and use it for my racing car. I went to the local auto recycler and asked about "interesting" engines. We discussed several and he offered to put out an inquiry on the salvage net. I said in leaving "you might ask about the Holy Grail an SHO V-6." I never expected one because they had been out only a year and were pretty rare. Imagine my surprise when they called me back and said they had found one. The price was horrible ( I could have bought 3 Chevy V-8s) but lust took over and I emptied my bank account and maxed out 2 credit cards and bought it.

The initial glow of purchase soon faded when the engine sat in my garage and I contemplated the problems in adapting a East/West engine into a North/ south configuration. The first thing I noticed was that the throttle was on the flywheel end of the engine. This would have resulted in the air cleaner being under the dashboard. Not a good location. I wasn't about to loose the intake manifold so I started to study the problem. I soon realized that the manifold mountings were symmetrical. I pulled the manifold off and flipped it. The timing belt cover interfered so it was deep sixed. The bare belts look more sexy anyhow. A little milling to remove some lumps, removal of the spacer between the manifold and the idle air control, and the fabricating of some 1/8" spacers to raise the manifold allowed it to be reattached. I still had to redo the vacuum lines, find a mounting for the DIS module, and reverse the crankcase vent fitting but the rest was easy.

The coils were relocated to the right front of the engine where the power steering pump used to reside. Power steering and air conditioning were tossed (this was to be a race car). I carved some billet aluminum pieces to hold the motor mounts and serve as the alternator bracket (which disappeared with the AC and PS pumps). This was done, by the way, with a bandsaw and files as I didn't have access to a milling machine at the time. A spacer was fabricated to align the water pump pulley with the alternator and a 5 rib belt drove them from the larger (7 rib) crank pulley. The stock tensioner worked fine. Later I made a special underdrive set of pulleys for the water pump and alternator which allowed me to use a 7 rib belt.

The water outlet on the flywheel end was sectioned and made into a right angle by cutting and welding. A couple of pieces of chrome plated sink drain pipe and radiator hose routed the water to the (new) front of the engine. The spare outlets for the heater and manifold heat were plugged (no heater needed on a race car).

Since I had relocated the ignition and all the electrical sensors on the manifold, as well as removing a bunch of "unnecessary" stuff, I rewired the engine, bringing all the wires out to an aircraft circular connector mounted on a bracket in the lower right side of the engine. This greatly improved the appearance by hiding or eliminating the mass of electrical connectors hanging off the right side of the engine. I made a new set of plug wires (needed since I relocated the coils) by carefully removing the ends from the old wires and re-installing them on new (longer, solid core) wires. (I told you I had lots of time on my hands).

Selecting a transmission was next. I discovered that the SHO had a unique bellhousing pattern that was shared by only one (at that time) rear drive application, the Aerostar van. I procured a bellhousing from my friendly Ford dealer for $200 and discovered that, while with a little machining it could be made to fit the engine, It used a unique transmission. Some queries about the Aerostar transmission revealed that it was rare and weak. I contemplated adapting a T-5 but measurements revealed that making an adapter with that bellhousing was impossible and adapting another bellhousing would be difficult. I also realized that the racing I was doing was brackets where consistency was more important than absolute speed. I was also planning on using the stock rear end ( at least initially ). The final decision maker was when I started hearing tales of the weakness of SHO clutches. (This was before the aftermarket started addressing the problem). Therefore I decided on an automatic transmission.

Another trip to the recyclers and I had an '87 Aerostar A4LD transmission. The flexplate was the right size but had the wrong bolt pattern. Were I do do the same today I'd adapt a SHO automatic flexplate, but they weren't available then, so I had a machine shop weld up the holes in the flexplate and redrill them to match the SHO crankshaft. Otherwise the transmission bolted right up. The pilot on the torque converter even was the correct size. A bicycle brake cable and a couple of brackets connected the kickdown lever to the SHO throttle, a length of vacuum hose attached the modulator, and I was ready to fit it into the TR.

I yanked the TR's engine and started measuring. The steering rack and front K member were a bit of a problem. Since I didn't want to modify the hood I wanted to set the engine low enough to clear. Also I wanted to set it back a bit from the stock location for better balance and traction. The only reasonable solution was to cut the firewall. Since I didn't need the heater (race car, remember) it's removal left room to set the engine back so it came out behind the K member. I cut the firewall and welded in a recessed section and did a bit of adjusting to the transmission tunnel to clear everything. I then welded up some motor mount brackets and the engine was fitted into place. The stock steering shaft cleared without a problem.

An 18 inch long driveshaft was fabricated to mate the stock rear with the transmission. A couple of weeks were consumed in mating the engine wiring, the stock computer, and the TR's wiring and making up a wiring harness. I then had to check the sensors and fake out the computer for the ones which weren't there. Finally I attached some short straight pipes to the manifolds and welded on a couple of fittings for the Oxygen sensors.

A fuel system was constructed with an electric low pressure pump at the fuel tank pumping the fuel to a billet cannister in the engine compartment. A return line from the top of the cannister to the tank allowed a steady flow of fuel through the cannister. A SHO in-tank high pressure pump was placed in the cannister and plumbed to the fuel rails. I started with the stock fuel pressure regulator but converted to an SX adjustable regulator plumbed with braided stainless lines when I added the turbo. The regulator returns excess fuel to the pump cannister. The stock mass air meter was connected to the throttle body with a combination of rubber stock hose bends and 3" metal tubing.

Meanwhile I was doing extensive modifications to the rest of the car not related to the engine. A six point roll bar was needed to be legal for drag racing. Subframe connectors were fabricated. The coupe was converted into a roadster (20 minutes with a Sawsall). All the suspension bushings were replaced with plastic (Nylon and Delrin) and a lot of refurbishing. Heavy, unnecessary things were removed. The seats were replaced with lightweight racing units. The windows were removed and the interior stripped. Lexan windows were fabricated and a lightweight top constructed. The battery was relocated to the trunk for weight transfer and cleaning up the engine compartment.

As for the wheels They are 15" X 7 with 205VR15 Tires. The trick is I had a set of adapters machined to adapt the odd 4 X 3-3/4" pattern to 4 X 4-1/2 which gave me access to a wide variety of inexpensive aftermarket wheels. The thickness of the adapters (They are 3/4 " thick and made of 6061-T6 Aluminum alloy) made it necessary to use wheels for FWD applications to get the correct offset. However I got all 4 wheels for less than I could get one alloy TR wheel. The adapters are thicker than the center of the wheels so I don't think they'll fail first. The only thing I worried about was the nuts that hold the adapters to the hubs as the nuts have to be cut down to 3/8" thick. I watched them closely and used locktite to secure them and have had no indication of problems. I don't know what car the wheels fit since I shopped for offset and bolt pattern. The offset is of course 3/4 " greater than stock at +2" (5.5" backset on 7" wheels) The wheels are 15 X7" I have 2 sets one from Prime and the other from American Racing. I run 205 50 15 Tires. And had no clearance problems except I rolled the rear fender lip for extra clearance ( the tires cleared but were very close and I didn't want to rub when autocrossing.

After 2 years I was finally ready to roll. The teething problems were minor. Crud had gotten into the fuel pump and caused some fuel problems. The injectors required cleaning after sitting for 2 years. There were a few wiring corrections to be made but these took only a few hours and I was on the road. 10 minutes later I was facing an angry neighbor who took exception to the straight pipes. The car was a blast to drive. It didn't take long to decide to put on mufflers and cats so I could drive on the street. My "race" car became street/strip after a few minutes of driving.

A new interior was constructed and the (heavy) bumpers reinstalled. A bunch of trim pieces were reattached and it became almost civilized. Trips to the strip netted 1/4 mile times in the high 14's about where I was with the Eclipse. The difference was consistency. I could make 3 back to back runs within .1 second time after time. It was fast enough to beat the streetable Mustangs and Camaros (even modified ones). I was happy.

Shortly after getting it on the road I was sent my notice for my biannual smog check. I approached this with some concern as it wasn't very stock. Imagine my surprise when the car passed with less than 1% of the allowable emissions. The only snag was that the car didn't have a smog pump. Of course SHO's don't have smog pumps, but TR-7's did and the rules said you have to retain the same smog control equipment when you do an engine swap. The solution was to buy an electric smog pump for a Corvette and plumb it into the exhaust (after the oxygen sensors). I'm sure it doesn't do anything useful but it satisfies the rules.

Like most project cars the TR is never finished. The top follows the English style of assemble it yourself and is a bit of a pain, so I decided that the only time I'd put it up was when drag racing (required). Therefore I drive the TR only when the weather is nice, which in Albuquerque is most of the time except for a 4 week period around Christmas. This gives me time for major projects which take the car out of action for extended periods.

The first winter was spent in stripping the paint and repainting to Porsche Guards Red. The next year went well, with no major problems. However I hadn't as much time to race as before since I had remarried (I didn't spend all my time working on the car). I started to autocross it and discovered a few truths.

 1. The TR-7 is a poor handling car compared to a Miata (on a par with a 
    Mustang or Camaro)
 2. Truth 1 is exacerbated by adding 3x power.
 3. While an open differential can be balanced by weight jacking for drag 
    racing, go around a corner and you get copious amounts of smoke and not 
    much forward motion.
 4. A well modified car in SCCA Solo 2 gets classed with all out race 
Still, I had a reasonable amount of success (when the race cars were otherwise occupied).

I enjoyed more success in drag racing. However I was still nagged by the thought that my "economical front wheel drive" everyday (when it was raining or cold) car was just as fast ( but not as consistent). The last straw was that guy in the very hopped up (race only) VW that was running low 14's. Therefore I decided that the next winter's (95-96) project was to be an altitude compensator (supercharger). Since Albuquerque's drag strip is at 5000 feet cars typically run a second slower here than at sea level.

Perusal of the ads and inquires to manufacturers revealed that it would cost $3-4000 to buy a supercharger kit (which would have had to be modified anyhow) That was a bit out of budget. I was therefore forced into the low budget approach. A trip through my spares boxes uncovered a turbocharger (AirResearch TO-5 with a Y-4 compressor and a .58 A/R turbine) which I had swapped for some years earlier. I knew it had come off a 2.3 Liter engine that made about 300 hp. By researching the markings on the case I came to the conclusion that it would be workable though not optimum. I ordered a bunch of exhaust tubing mandrel bends of various sizes and the car went up on jackstands. The location for the turbo was obvious. The setback of the engine left about 18" from the radiator to the front of the engine. A perfect location. The turbo was installed with the exhaust turbine on the right side. By sacrificing most of what little ground clearance the car had, I was able to route 2" pipes from the stock exhaust manifolds under the K member and up to the turbo location. From the turbo exhaust I ran a 3" tube down to a flange just behind the radiator. A cap on the flange can be easily removed for racing. A 2 1/2" pipe curves off from the 3" and wiggles through a small opening on the right side of the engine to a Products for Power high flow catalytic converter alongside the transmission and then to the rear where a "turbo" muffler resides. It exits below the bumper via a 3" chromed tip (salvaged from the old sidepipes). A 1.5" H&K wastegate is mounted between the collector at the inlet to the turbine and the exhaust side.

The intake starts with the stock mass air sensor (equipped with K&N filter) mounted on the left inner fender. A 3" hose/pipe combination attaches it to the turbo inlet. The air charge temperature sensor and the crankcase vent hose attach to the pipe section. From the turbo the air flows up to the left and around the end of the radiator to the intercooler (from a Volvo Turbo). The exit from the intercooler comes around the right end of the radiator and across to the throttle body. The wastegate pressure line is tapped into this tube.

For ease of plumbing the oil return the turbo must be higher than the oil level in the sump. By far the largest hassle I had was getting the oil return to operate properly. I tapped the oil feed from a T at the oil pressure pickup on the flywheel end of the block. After several ill fated attempts at simpler methods to return the oil drain to the pan I finally dropped the pan and drilled a hole in it and installed a bung (3/4" pipe). The oil feed can be as small as -4 line (1/4") but the drain has to be at least -12 (3/4"). I set the wastegate at 7 PSI.

After a couple of false starts, one of which had me proceeding down the freeway with a fog of smoke rolling out the tailpipe from a non-functional oil return scheme, I got it sorted out. I was able to use a Hypertech chip set up for a stock engine by raising the fuel pressure to 60psi but this hurt my gas mileage. Total investment in the turbo conversion was about $500 counting the stuff I swapped for the turbo. I expect you could duplicate the installation with a new turbo for under $1K.

I took it to the strip for the first time and decided to make a run with the cap on the exhaust to get a baseline. As I pulled up to the line my competition literally hopped up to his side in a mid 70s 440 Dodge with 18" wide slicks and the carbs sticking through the hood. Full open headers made it difficult to hear my engine as he made a huge cloud of smoke in a burnout. Then advanced to the line. The lights went down and he jumped out about a car length which I overcame up by half track. I crossed the finish line a full half second ahead of him.

Opening the exhaust and fine tuning the fuel pressure improved my time to 13.7 at 104 mph which was a second faster than my best before the turbo. A strange effect was, that after the first few runs, I had a lot of trouble getting a race. I'd pull up to the staging lanes and no one would get in line beside me to challenge. I got several solo runs that day. One amusing incident was when the rider of a Ninja bike came over and asked if I'd run with him. I agreed, and he asked what times I was running. When I told him, he wandered off and I later saw him run another bike. I guess I scared him.

There is some turbo lag and the car had a definite bog between 2000 and 3500 rpm. It could be improved with more fuel pressure, but not eliminated. Therefore I contacted Ted Beraux for a custom chip. His first effort improved the bog and allowed normal fuel pressures (and restored my gas mileage) but hurt the top end. After consultation he did another chip which seems to have restored the high end, but I haven't had an opportunity to go to the strip with it.

Reliability seems to be better than stock, which isn't saying much, but is OK for a 17 year old car. Remarkably the stock radiator and rear end have been OK although I'm sure they are marginal. The transmission has not shown any signs of stress but the stall speed is way too low for the engine. The lack of a limited slip is a serious handicap in autocrossing. The rear brakes (drums) won't hold the engine well enough to load the torque converter and get the boost up at launch. Otherwise it is quite satisfactory.

One of the advantages (disadvantages) to building a vehicle as unique as this is that you don't just pick up your Summit catalog and order a goodie. If you want it you make it yourself. This adds a lot of time but not much money. I only have about $12,000 total in the car at this time (and several thousand hours). This is good because my new wife is very frugal and doesn't share my love for fast sports cars (she drives an Explorer).

So, what did I get for all the effort? It's still noisy and even harder riding but definately not a stone. Removing the top made it a much more fun car. It gets a lot of comments. Mostly "What is it?" "Wow!" "Cool!" etc. I've had spontaneous offers to rent it for a couple of hours. I've had trouble explaning to the guy I just beat that "no I don't have a big block in it". It took second place in the competition category at the SCCA car show at the state fair. I can drive it any time the weather is nice, as long as I avoid speed bumps. It gets 25MPG in town. I haven't taken it on a long enough road trip to get a mileage reading (I'm a car nut, not a masocist) but would expect 30MPG. It kicks serious butt at the strip and I don't have to worry about that Toyota pulling up next to me at a stoplight (even if it's a Supra Turbo). In fact I have yet to meet a street driven car (in street trim) that gives me a serious challenge. Extensive suspension work, including a torque arm rear suspension, and BFG T/A R1 racing tires have made it a better autocrosser. It needs a limited slip rear end but I'm currently the E Modified points leader in the local SCCA Solo 2. This is due in part to the lack of serious competition in that class this year. And best of all it isn't a ___________(fill in the blank) with a 350 Chevy in it. I believe it's truly one of a kind.

Was it worth it? Absolutely! Would I do it again? No, been there, done that.

What would I do differently next time? I'd start with a car that was a bit better in stock form and I'd plan from the start that it was a street/racing car and leave in more creature comforts. Also I'd select a transmission more in the mainstream that I can get hop up parts for.

What advice would I give to someone thinking about a similar project? It is not for the mechanically inept. Expect to do it all yourself. The lack of brand names in the forgoing isn't an ommission. I truly didn't use many ready made pieces. If you want to pick up the parts at your local speed shop, use a 350 Chevy. Have access to a machine shop or be good friends with a machinist. Plan carefully before jumping in. Read a lot. I recommend the shop manuals for the SHO and the vehicle you're going to swap into, How to understand and modify Ford Fuel Injection and Electronic Engine Control by Charles O. Probst, and Turbochargers by Hugh MacInnes. Make friends with (or become) someone who understands computer controlled engines. Double the amount of time and money budgeted for the project. Then go for it.

What's next? The wife says if I want to start a new major project I have to sell the old one. So I guess I'll spend one more winter on the TR. I think I'll put in a better transmission with a high stall converter and a lower first gear. I'm currently in the process of getting a Ford 8.8" rear end prepped to replace the stocker. While the stock rear end has held up OK so far I really need limited slip and I want to go to 4:10 gears, neither of which are avaliable for the TR. It also has 11" disc brakes. This should improve launches enough to get it into the 12s as well as help me on the autocrosses.

After that, a Miata with a SHO V-8 sounds interesting. Or a Northstar powered Fiero. Maybe swap a VR-4 drivetrain into my Eclipse. So many choices and so little time (and money).

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