195 MPH on Four Cylinders
With Gene Yetter(Original Photos by M4S Technician-Mechanic Stephen Maki)
(The following is presented as a continuous conversation. In reality it encompasses two hour-long conversations and numerous emails back and fourth between Joe and myself. My complements to Joe for his patience through all my questions and communications, and for his unflagging interest in getting out the terrific story of the M4S. — G.Y.)
Gene: Hi, Joe. How are things? It's been a while since I interviewed you about the Mopar Missile for allpar. It's good to be in touch with you again because I have great respect for your fascinating recollections on projects of great interest to Mopar fans.
Joe: And I understand you want to talk about the old M4S car, the one-of-a-kind Dodge PPG Indy Pace Car of 1985-'86.
Gene: Yes, that one! I saw it at the Walter P. Chrysler Museum in Auburn Hills, but I kind of forgot about it until Steve Maki's pictures of it showed up on allpar.com recently. I've also been interested in recent months in the turbocharged Mopar four-cylinder engines. And here is this special-purpose vehicle with twin-turbo, twin-cam 2.2-liter four-cylinder engine with top speed around 195 miles per hour. It played a cameo role in the 1986 sci-fi movie, The Wraith. I recently learned that you took part in its development in Detroit. So how did that go?
Joe: It was cool. Let me give you the background. The car was paid for and commissioned by PPG Industries. At the time, PPG was one of Chrysler's major paint suppliers, if not the major. Every year PPG would commission a Chrysler product, Ford product and GM product to be built and used as pace cars in its Indy Car World Series. At that time the series was known as CART, for "Championship Auto Racing Teams." Today it's known as "Indy Car." I was working for Specialized Vehicles, Inc. (initials, "SVI") in Troy, Michigan, at the time. The company gets most of the credit for building the M4S.
The M4S was probably the fourth different pace car that SVI built for Chrysler. With the PPG projects, SVI was commissioned to do all the mechanical and assembly work, to build engines and do whatever else it took to make the cars work. We did not do the paint or the body. That usually came from different sources. But focusing on the M4S, the concept for a rear-wheel-drive mid-engine car — which the M4S is — came from some of the minds over at Chrysler. Development got going in 1984.
PPG would get together with Chrysler's styling group, I believe. The company assigned Bob Ackerman to the project. He was a lead stylist — Manager of Product Design, I think. Bob's a talented guy and he wanted to do a mid-engine car. To build a mid-engine car you have to have a chassis to build on. There was some interplay between Chrysler engineering and Chrysler styling about doing the mid-engine car. It's a lot of work to do a successful design from scratch. It costs a huge amount of money.
I remember that Bob happened to be flipping through magazines at the time. In the early Eighties, the mid-engine Pontiac Fiero had just come out. Bob spotted this article about Huffaker Engineering out in California doing a tube-chassis Fiero GT race car for one of the International Motor Sports Association (IMSA) classes [editor’s note: this would not be a production Fiero, but a custom chassis on which a Fiero body could be hung]. So he says, "Hey, do you think we could use this chassis and put our own body on it and make it a pace car?"
Chrysler on the body engineering side had a brilliant engineer by the name of Larry Rathgeb, who had a long history with racing back in the Seventies. He was liaison with the NASCAR teams and spent most of his time working with Richard Petty at Petty Enterprises. Larry was big in the days of the winged Dodge Daytonas and Superbirds. At SVI we knew him and worked with him on many projects over the years.
Larry got to thinking about the project and finally said, maybe we can make this mid-engine chassis work, but we have to have some changes made to it. We contacted Huffaker and had them build a chassis, but with a longer wheelbase than the Fiero's for stability. The Fiero wheelbase was around 93 inches. Larry wanted ours longer and the final length was 100 inches.
If you look at the car from the side, it's got a fairly long wheelbase with a big overhang in the rear. There is an intercooler back there, a big intercooler! The engine is transverse mounted with the crankshaft centerline just forward of the rear axle centerline. The chassis holds the engine and transmission as well as providing pick-up points for the upper and lower control arms and coil-over-shock assemblies. And hanging off the rear structure is the dry sump oil tank, oil coolers, transmission fluid pump, air meters, electronics and a plethora of other items. Also in the overhang is an internal structure to mount the body to the chassis, from which the body could be pivoted open to get to the engine. The entire rear body clip is removable if an engine change or major maintenance is required.
I don't believe Huffaker added motor mounts, knowing that we would be using the 2.2 liter Mopar block and a Chrysler transmission. So we bought the chassis and all the suspension pieces, the uprights, the upper and lower control arms. That was our basis for starting the mid-engine, four-cylinder sport vehicle. In other words, "M4S."
Once we had the wheelbase, Chrysler, through Bob Ackerman, came up with a design concept. They had a shop in the Detroit area make a full-size foam model. Have you ever seen anything like that, Gene? Think of the foam as a real dense Styrofoam. The shop makes a wooden buck, and then they glue all the foam to it. Then they start cutting and surfacing it. Cutting foam by computer-aided technology was just coming along then and I believe that's how the foam for the M4S got cut. Then the shape was finished by hand. From the foam shape a mold was made to fabricate the fiberglass body. Eventually the body gets fitted to the chassis we were working on.
While that was happening we had to come up with an engine. PPG and Chrysler wanted something pretty exotic. At SVI we had already built 2.2 turbo packages for pace cars. We had done two or three with turbo. We did our own SVI turbo setups using Garrett turbochargers and a lot of Bosch electronics and stuff like that.
Some background on SVI, the company. Remember Ted Spehar's role in building engines for the Mopar Missile? SVI was originally formed by Ted. However by the time the PPG cars were being built, Ted had left the company. In the early Eighties, SVI was co-owned by Mike Koran and Tom Coddington. Tom was one of the original members of the Ramchargers drag racing team; he had also worked with us on the Missile cars. After he retired from Chrysler he became a partner at SVI with Mike Koran. Tom was in charge of all SVI engineering, with Mike more on the business side of the company.
I was a project manager at SVI. One of my assignments, I was in charge of logistics and a lot of the business aspects of the M4S build, making sure things happened on schedule. I had other responsibilities at the company, like supporting media. We would prep cars for TV and print. We would haul cars out for photo shoots. Sometimes we would provide ad agencies with performance data. Say if they wanted 0-60 or quarter-mile times for advertising. You know, "Here's your Chrysler K-Car versus the BMW, or whatever."
For the M4S project, Tom Coddington thought we should try to build this twin-turbo engine. A few years earlier SVI had been involved with Chrysler in putting a Ford Cosworth cylinder head on a Mopar 2.2 liter block. I don't know if it was a one-off engine. I think it was naturally aspirated, using Weber carburetors or something similar. So now Tom and the SVI group, with some talented engineers, real "engine" guys — they decided they could build a twin-turbo version of the 2.2-liter block using the Ford Cosworth BDG cylinder head with twin rallye camshafts from Cosworth.
The nice thing about the Chrysler 2.2-liter block, the bore centers were the same as on the Ford, so that worked out well. But a problem was that none of the bolt holes lined up to secure the head down to the block. Chrysler went and cast, I think, fifty blocks without head bolt holes in them; and adding a bit of mass to the castings in a few areas. From that we picked the best of the newly-cast blocks, maybe six; the rest were scrapped. I don't remember how many Cosworth BDG heads we bought for the project. Then we started building the engine.
The crankshafts were Moldex billet cranks. The pistons were specially cast to our design by Cosworth. We had a couple of hundred pistons made, to make sure we had plenty of pistons to choose from. The SVI guys put this engine together and dyno-ed it. We worked out all the electronics, built our own fuel injection system using Bosch electronics, and coupled it with twin Garrett turbochargers. That is how we came up with the M4S engine. I took pictures — beauty shots! — of it one night after work. When Hot Rod Magazine did a special on 2.2s, they used my picture on the back inside cover of the magazine, a full-page color shot that I took. It came out pretty cool.
The transmission was the next order of business. Chrysler didn't really have an adequate transmission to handle the torque output of the engine. They had that little 5-speed transaxle transmission. We knew that wouldn't be strong enough, so Chrysler went to Weissman Transmissions out in California and had him build a couple of his own versions of the best we could do with the Mopar 5-speed.
Eventually the car went down to the wind tunnel at Lockheed for aero work. It didn't have tons of downforce but it had enough for a PPG pace car. But that wasn't good enough! PPG had it in their head they wanted the car to go 200 miles an hour! For that we felt the car — in the configuration that you see in The Wraith movie — needed a lot more stability and downforce than we felt it had. So Larry Rathgeb, being the old NASCAR guy, said, "Hey, I know how to make this car stick to the ground. We're going to put some downforce on the rear end with a wing, and we're going to put the wing up high just like we did on the Daytona." So for testing and development purposes only, we put a big Dodge Daytona-type wing on the M4S. Larry Rathgeb's idea! There was a flush rear-deck-level wing in Bob Ackerman's design and it looks pretty nice, but it didn't provide the downforce we were after.
By the way, in a lot of the pictures that I see of the car now, it is sitting up too high. It looks goofy! There's six inches of space between the top of the tire and the top of the wheelhouse. In reality that was our transport mode. When we got to the track we would take out the spanners and lower the car down over the wheels. The suspension uses a coil-over setup on each corner so that was easy to do. I notice that at the Walter P. Chrysler Museum and on several pictures on the Internet, the car is sitting up way too high. In reality it sat real low and the wheels were tucked under the wheelhouses. The car looks really cool with the height adjusted correctly.
In fact, the car was so low, we had jacking points on each side of the car. We built our own floor jacks with pads that were lower than the wheels of the jack, to fit the pads under the frame. Kind of like on a NASCAR car, nice and low. At one time we contemplated putting air jacks on board, like on Indy cars. The car comes into the pits and they hook up the air line and the car comes up for a tire change. At the time we couldn't find an air cylinder that was compatible with the weight of the car. We would have needed four of them. Then you have the secondary problem of packaging the air cylinders.
When we started all our testing and development with the chassis, the body was only primer painted. It was still a little bit on the rough side, but that was good enough for testing. There was no reason to put a $20k paintjob on the car and then go flog the crap out of it. We put a couple of seats inside, and the instrumentation. Not much of an interior. But the car was ready for testing.
First we took it to the Transportation Research Center (TRC) in Ohio for our initial testing. At that point we were just trying to work the bugs out. The first bug: we made about one lap around the very small TRC oval and the Weissman transmission let go. We put in a second transmission. That one did three laps before it let go. Doesn't say much for those transmissions! And it was labor-intensive to replace transmissions because you had to pull the back half of the body off, pull the engine out, then you changed the transmission, and put everything back together. Probably a 12- or 14-hour ordeal.
So Larry Rathgeb and Tom Coddington put their heads together and they decided we should go see Joe Liberty, at his Liberty Gears shop in Allen Park, Michigan, down the block from Ford world headquarters. We had known Joe from drag racing days in the Seventies. Just the nicest gentleman and really smart about transmissions. I had first met him when I was working with Mike Fons. And Joe and Donnie Carlton were pretty good friends. It's a pretty tight community here, Gene. Everybody knows everybody! Especially among Chrysler people.
We took one of the transmissions to Joe, and opened it up down there. Joe looks at it and we started talking about it what we could do better. The work went in baby steps. We'd strengthen one part of the transmission, like make a new cluster from scratch. Then we had to do the main shaft, then the different gears. We eventually set it up to force-filter oil through it because it hadn't been getting enough lubrication.
That is, Joe Liberty did the actual fabrication under the supervision of Larry and Tom. We kept chasing the failures and went through three or four different versions. The first one probably had one set of fixes in it. The next one had that, plus a few more fixes. And the next one, etc. We tested each one as they got assembled. We went and tested and broke things. Then we went back to Joe, and said, okay, now what do we do? He'd redo things and have them ready in a week, and we'd go and pickup the new version. We ended up with a transmission built completely from scratch. A spur-gear transmission (straight-cut gears vs. helical cut), the kind used by a lot of motorcycles, especially motocross bikes. They're very noisy boxes. You can always tell a spur-gear transmission when you hear it. But they are really, really strong. Joe built a wonderful transmission. We spent a ton of money on the transmission alone, too!
Gene: When all the work was done, who owned the transmission? It didn't originate on Chrysler drawing boards.
Joe: Good question. I'm not sure. The Liberty transmission that we ended up with to the best of my memory did not have any formal Chrysler Engineering drawings made of it. It is a safe bet that Joe Liberty made plenty of sketches and reference drawings so that he could keep everything straight in order to build multiple copies of the transmission. I remember speaking to Doug Shepherd, a Chrysler engineer and former SCCA Pro Rallye champion, about this transmission because he was contemplating having one built for his rallye car.
Finally after huge expense and a lot of labor we had a transmission that would live. That engine put out a ton of torque for the time and a fair amount of horsepower. It was a 2.2-liter four-cylinder engine that put out probably 440 lbs. of torque, and at least that much horsepower, on just a few pounds of boost. If you really boost the engine, adjusting the waste gate on the turbochargers, you are going to create a lot of horsepower.
Eventually we took the car to Moroso Motorsports Park, a combination dragstrip and road course down in Florida for testing. We also tested up at TRC. A lot of the testing didn't require top professional drivers. Between myself and a couple of the engineers we test drove and put a lot of miles on the car ourselves. We would test at speeds that were okay for us. In Florida, when we decided to do some really hard road-course testing we hired championship racer Joe Varde. He had raced for Chrysler in one of the IMSA series. He was a very good guy. I knew him from many years back. He lived in Florida and when we tested at Moroso, we called on Joe to drive. When we did speed runs up north on the big oval at TRC, Graham McRae drove. He is another top professional driver, who was in the U.S. from his home country, New Zealand.
After we finally worked out most of the bugs we made a couple of unsuccessful high-speed attempts. By that I mean we got it up to only 185. But, then 190. It was at TRC and Graham McRae was driving. When we got a little frustrated that we weren't up where we wanted to be, Larry suggested we change out the rear tires and put the same size tires as up front, on the rear. In other words we were going to change the final-ratio, to get more rpm's out of the motor. The engine wasn't quite reaching its point of optimum horsepower and torque, maybe because of aerodynamics. We weren't generating enough power considering the rolling circumference of the rear tires. The only way we could get more rpm was to sacrifice a little bit of that rolling circumference. Changing the circumference of the tire is like changing a gear. We couldn't have changed transmission gears at the track; and anyway we would have had to have another complete transmission ready to go with another gear set in it.
We had been running slicks on 16-inch wheels. So we changed to a smaller diameter rear tire. And Bob Duffield, I think, one of the SVI engine guys, tweaked the waste gate on the turbo to get more boost. I think Tom was there and knew that we tweaked the turbo. We got the car up to 195 and some change. But that's when we lifted the head! Blew the head gasket, in other words. Too much boost and the gasket gives way. That's why a lot of high-boost performance engines are O-ringed. The damage is not too great; and in our case the M4S block wasn't damaged. But that was the end of our speed runs. PPG was satisfied and we didn't try to go really fast after that. There was no reason to beat the car to death anymore!
At that point it was time to get the car finished, and make it look pretty. So off came the big wing. The car went into the paint shop and got a really nice paint job. It had a beautiful interior created for it. It became more creature comfortable and, in the 1985 season, it went into service as a pace car for PPG at all the Indy Car races. From the time of concept to the time it went into service on the tracks took about a year. It was used on the circuit and retired at the end of 1985. I remember that because I left SVI in the Spring of 1986. But the M4S was extremely high maintenance and somewhat prone to breakage. I guess PPG didn't want to keep supporting it because, if something happened to the clutch, say, it was a 12-hour job to get to the clutch to fix it. It was just not easy to do.
Then the M4S car became more of a display piece. They'd parade it around every once in a while but they didn't try to flog the car much anymore. The M4S was a popular car. Chrysler liked to use it in the auto shows. They'd have it at the new car show. They'd have it on display here and there. Now it's in the Chrysler museum.
Then came the movie. In The Wraith you'll see the real car in only a few scenes. The cars in nearly all of the movie scenes were movie cars. Chrysler allowed the movie company to build some cars out of the mold. Basically those were dune buggy cars. They threw the body on top of a dune buggy and most of them got wrecked or exploded. Although collectors apparently still have one or two of those. My only connection to the movie, I made sure the M4S got to Arizona for filming. Logistics was part of my job. One of our mechanic-technicians, Steve Maki, went to Arizona with the car. He called me everyday back in Detroit and give me an update. If he needed something I got it to him and stuff like that.
Steve was probably my all-time favorite of our technicians at SVI. He's a talented technician and he would do anything. He never seemed to get tired and we put in a lot of long days and nights. He was a great guy to work with. I correspond with him now a little bit by email. I haven't seen him in many years. He was with the M4S for the entire time when it was out in Arizona for the movie. The movie crew was not allowed to touch the car. Steve was the only one allowed to touch the car!
There was another movie made with the M4S. It was called, Meeting the Challenge. It was a made-for-TV movie, basically a half-hour commercial for Chrysler. I have a tape of it somewhere. It was on ESPN or Speed. It has several segments: one segment with Joe Varde, another with Kal Showket. Kal and Joe were both IMSA champion drivers. They raced Dodge Daytonas in IMSA. Another segment of the film featured Carroll Shelby, and they did a segment with both Carroll Shelby and Graham McRae. Graham was driving one of Carroll's Cobras. Then they did a segment with the M4S on our speed attempt down at TRC. It was a pretty cool movie narrated by Sam Posey.
Gene: I thought I read on a forum recently that Bob Ackerman was initially not eager to let the M4S be used in the movie.
Joe: I'm not at all sure of that. If Bob was not keen on using the M4S in the making of The Wraith, I honestly don't remember. However if it were true, maybe it would be due to the fact that the M4S was his "baby." Bob poured all his creative talent into that car and was extremely proud of the results. He would have been highly protective of it and everything it represented. I can tell you that Bob is one really great guy. He loves cars and motorcycles. In fact, I purchased one of Bob's old motorcycles from him back in about 1987 or 1988. I have not seen Bob in a long time but I understand Steve Maki keeps in touch with him. Hopefully Bob will come back to Michigan sometime this summer.
Gene: Where does the name, "The Interceptor," come from?
Joe: I think the Interceptor name is something that came out of The Wraith movie. We never called the car by any other name than M4S. I never heard it called Interceptor until many years later.
Gene: What's happening these days at SVI?
Joe: SVI still exists in its original location in Troy with Mike Koran as owner. Tom Coddington is no longer a partner. Last I heard, SVI is smaller than it used to be. When I was there, our shop manager was Dan Knapp. Dan had raced with the Ramchargers. He loved fuel cars and drove his own dragster prior to joining the Ramchargers. Later he had a chassis business. He built Dodge Colts. He built the chassis on our Duster wire car. He built the D5 Hemi Colt for Chrysler. He built four of the Colts, I think. He was one talented guy. He died of cancer and it was sad that he passed away, sometime in 1984 or '85. At that time SVI had about 40 employees. When I left in 1986, it had about 60 employees. Ted Spehar is retired and living in Leonard, Michigan. He retired from a company called Katech Engine Development (Clinton Township, Michigan) building engines for the factory Corvette GT1 team — that won LeMans five or six times!
Gene: About you, Joe, I remember you told me that, after the Missile team broke up, you went to finish college? Now I learn you were eventually back in cars and racing working at SVI.
Gene: Yes, of course I came back to cars! I couldn't stay away! I graduated college in 1976 with a major in business management. Afterwards I went out to California until about 1978, and then came back to Detroit. I worked in another place here for a year and a half and then went to work at SVI around 1981. I was there through 1986. Then I moved to another company. I really loved working with Tom Coddington. A lot of the other people at SVI were wonderful people. Our Missile teammate, Dick Oldfield, even worked there for awhile. It was a great place to work and we did cool stuff through the years. Now I'm an engineering manager at my present company, Johnson Controls. The business studies have never held me back from any technical work. I know what questions to ask and I understand the results. I spent a number of years at Ford as a body structure engineer. For the last 16 years my area of expertise has been plastic injection molding of under-the-hood components. In engineering today, we follow a disciplined analytical approach to problem solving. Not so much instinct and trial and error as in the past! We draw from many sources: product knowledge, structured engineering procedures, and tools like computer-aided engineering and finite-element analysis to come up with workable design formulas.
Gene: I'm wondering where does the M4S fit with all of the company's other activity in K-Car and turbo powered cars. Or in other words, did the work on the M4S and other turbocharged pace cars influence the marketing of turbos in Chrysler vehicles like the Shelby Z, the Daytona, the Chrysler Laser, etc.
Joe: Those cars were already being built. The M4S was altogether different having been built from scratch. The turbo Daytonas and such were already in production. They were around by 1984. In fact when Chrysler built the Arizona proving ground back around 1984-85, our SVI crew took one of our earlier PPG pace cars out there, a Dodge Daytona that we built before there were production Daytonas. In the SVI project we actually took a four-door K-Car and built a Daytona out of it. We built the body from scratch starting with a clay model. SVI had a true metal craftsman, Ron Fournier. He built the car with steel body panels. It was a beautiful car. It's still around somewhere. It got the 2.2-liter turbo. SVI always used the Chrysler four-cylinder block, but we would do our own engine builds, incorporating SVI tricks into the head and block. It would design and fabricate its own intake and exhaust manifolds. Bosch electronic fuel injection components completed the package to make some really great engines.
One nice thing, when Chrysler opened the Arizona proving grounds near Phoenix in January of 1986, I got to go out there on official business. The company was worried that the new five-mile oval had a bad spot. The paving crew had left some heavy equipment parked on the new surface for an extended period. We got to take a blue pace car out to Arizona for high-speed test laps, with Joe Varde driving. The result was we could tell the company that there were no bad bumps on the new track.
For the official opening of facility, the company wanted to run two Lasers and two Daytonas for 24 hours, with scoring by NASCAR, and have the cars set new 24-hour records. Back in 1954 when Chrysler opened its Chelsea (Michigan) proving grounds they did something like that. Where they had NASCAR come out and they ran four cars at racing speeds for 24 hours. So they did something similar with two Dodge Daytonas and two Chrysler Lasers, ran them on the Arizona oval for a ceremonial 24 hours.
Since I was out there with the blue pace car for the track test, they invited me to drive two of the three-hour shifts in the 24-hour run. I had spent a lot of time over the years test driving SVI cars built for PPG at the Chrysler proving grounds at Chelsea. Chrysler knew me, knew I was a good driver and could do all this stuff. So Coddington and Koran back home at SVI said, sure, let Joe stay and drive. I wasn't afraid to drive for three hours in the middle of the night — up near 130 miles an hour. I drove one of the 2.2-Liter Turbo Daytonas in the middle of the night for a three-hour stint, and I did another three-hour stint at dawn in a Laser. The morning is a tough time when the intense morning sun is shining through the guard rail. The 24-hour runs ended at 8 a.m. It was pretty cool. But when we were on the track doing our own testing, we did some drafting and could manage to get up to 140 or 150 miles an hour.
Gene: I found a comment that appeared in Popular Mechanics in October 1986 (Vol. 163, No. 10, p. 79) that the engine in the M4S foreshadowed the power plant projected to go into the twin-turbo, twin-cam, Italian-made Chrysler TC by Maserati cars that came out in 1989. Did you have any idea in 1984-'85 that the you were pioneering a project to have international recognition down the road?
Joe: We probably didn't think much about that. But, referring to the Popular Mechanics article, there may be more to it than was printed. Chrysler had a press event at Chelsea early in early 1986. I was there with the M4S and I was told to expect a writer from one of the publications — whether it was Popular Mechanics or not, I don't remember. I was told to take this writer for a ride on the big oval and then allow him a turn at the wheel. I drove two or three laps between 100 and 130 miles an hour and then we switched seats. He promptly dumped the twin-disc clutch and snapped one of the half shafts. Ride over! I was worried he'd write a negative review but he never mentioned the incident and his article was nicely done.
But I can't blame the guy. It was just bad luck. For anyone who has ever driven a car with a multiple-plate clutch, they are like a hair trigger. You can't feather the clutch at all and it doesn't engage like a street-car clutch. It is definitely violent. What probably happened is that the guy let the clutch out, with the car making an abrupt move. Then he stabbed it back in thinking it was about to stall the engine — and he gave it a TON of gas and snapped the clutch out. BING went the half shaft. Hey, that's life. By the close of business the next day we had everything put back together.
Gene: Joe, many thanks for the great background on the Dodge-PPG M4S Pace Car.
Joe: My pleasure.
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