A Labor of Love – My AW11 MR2

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AW11 is the chassis code Toyota assigned to the mark 1 (first generation) MR2 when it was introduced in 1984. It has affectionately become the nickname of all first generation MR2s (similar to the RWD Corolla with chassis code AE86 being called the Eight-Six). The MR2 was a two-seater rear wheel drive mid-engined sports car that wasn’t a European exotic. The engine (4AGE) was designed by Toyota with Yamaha (cylinder head) and a supercharged version (4AGZE) was soon developed as well but not made available to the USDM until 1988.

My pops bought a 1989 supercharged model brand new. This was only an option in the US for ’88 and ’89. It’s still parked in his garage and is driven sparingly (195K+ miles). I spent many hours of my youth in that car, great times. Right before I turned 17 I bought a 1991 MR2 turbo (SW20) and drove the piss out of that car for 4 years. I did a lot of stupid things in that car but it protected me (hey, I am still here today) and it taught me how to drive properly and improperly.

I have owned quite a few vehicles since I sold that turbo, a Civic Si and even a Suzuki GSXR 750 to name a few but they didn’t feel right. The mid engine layout not only offers nearly 50/50 weight distribution and turn on a dime capability but has unique characteristics – for example, when under hard braking, the nose doesn’t dive like a normal car. Basically it just feels different. In May of 2010 I stumbled across an ’89 supercharged MR2 being sold by the original owner on craigslist (pic above) and decided to buy it for a very fair price.

I drove it that summer and shelved it for the winter in our 2-car garage. My wife and I found out we were going to be blessed so the spring was dedicated to painting/prepping and setting up the nursery. But once that was done my wife’s car went outside and the MR2 was centered in the garage and the work/fun started.

Here are a few pics before “surgery:”

(More here:

http://thestrangestbrew.com/?p=467http://thestrangestbrew.com/?p=467

I also built up a cache of parts from Two’s R Us (some pictured here). I still haven’t added up all the receipts for the parts, I don’t think I want to know how much I actually spent.

The entire suspension was removed and rebuilt. Prothane Bushings all around, new upper and lower control arms, steering bellows, ball joints, wheel bearings, inner tie rods, Koni Adjustables (Yellows) and TRD springs (one of the last sets in the US) along with new rotors, pads Goodridge SS lines (and eventually Ford Racing Brake Fluid).

Pulling the motor out of an MR2 can be a little tricky and challenging, disconnect everything, driveshafts, fuel lines, feed the wiring harness thru the firewall etc… but this car’s setup is essentially a front wheel drive transverse mounted engine but in the rear. The compartment is pretty tight for the regular 4AGE so the addition of a supercharger and piping on the 4AGZE makes you wonder what the engineers were thinking. And the amount of coolant I drained out was ridiculous.

Then be set to lift the engine, remove the engine supports and lower it onto a piece of cardboard on the floor. Jack up the rear end as high as possible and pull it out on a piece of cardboard or tarp. When the rear spoiler is about 5 ft from the ground, the engine will just barely clear.

I proceeded to work on the engine. It had good compression and I didn’t have time to do a 100% rebuild so I left the top end and bottom end as is. I wanted to be able to have it ready for the summer and I am buying a spare motor to rebuild perfectly over the next year. That way it will only be off the road for a week when that swap is ready.

All the gaskets and seals were replaced, the distributor was rebuilt along with a new oil pan, starter, alternator. I also swapped out the crank pulley with an NST unit (red anodized), the SC was replaced and with a re-routed vacuum line setup boost can reach 13.5 psi (up from the stock 7psi). I also added a boost gauge to keep tabs on the pressure and the “Grunt Box” to prevent the lean condition at lower rpms. While everything was apart I added a Fidanza flywheel and Clutchmasters Clutch.

Getting the engine back is pretty straightforward. Here’s the empty engine bay, to make it easier just remove the rear trunk lid and spoiler.

With the engine back in place, it took a little while to get all the wiring properly rerun, the nest of vacuum lines properly hooked up and after fixing a fuel leak it was mostly buttoned-up. Bleeding the coolant system is somewhat of a challenge with this car. The radiator is in the front so with piping running the length of the car you will need 12.8 liters of coolant! It actually holds a nearly identical volume of coolant as my Tundra. Bleeding air bubbles tends to be more of a chore than the average car. It took me about 2 hours to get it purged (have been told it takes about 45 mins for a seasoned mr2 mechanic to do it). The front and rear suspension components were finally completed and installed.

I have typically done most of the necessary routine maintenance on my vehicles and have helped with about half a dozen engine swaps, clutch replacements and various overhauls but I never attempted anything this involved completely on my own. It didn’t end when the motor turned over. Setting the timing with the aftermarket pulley kit was a challenge and working out all the various bugs like replacing a malfunctioning VSV no longer available from Toyota and researching/determining the suspension settings I wanted all gave me a great learning experience. Replacing the speakers and head unit and steering wheel rounded out the remaining changes. I really thought I knew MR2s before, but I didn’t. My recommendation to everyone out there: Get the shop manual for whatever car you own, a decent set of tools and start figuring things out by doing them; there are few things more empowering than truly knowing your car.

 

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7 COMMENTS

  1. I have only ridden in a regular elise and loved it. I refuse to buy a car brand new and can’t see a reason to dump too much money into a car like a porsche or ferrari when i can have the fun i have now in my mr2. But if we won the lottery I would absolutely buy a brand new elise (or exige).

    “Simplify, then add Lightness.” -pure genius

  2. I drove rear drive Japanese sports cars for years (280Zs, 300Z), but when I bought a Lotus Exige with the supercharged mid-engine Toyota engine (i.e. an MR2 with better suspension and crappy British electronics), it was a world of difference. Nothing else drives the same as a mid-engine, rear drive car. I’ve done so many things with that Lotus that would’ve left my Nissans turned around and facing the wrong way (at best).

    • Regarding; “Nothing else drives the same as a mid-engine car’ And …”that would’ve left my Nissans turned around and facing the wrong way”

      First quote modified, as I have never seen a rear engine front drive car.

      Hi! Michael,

      Let me back stop you a bit and offer another experienced and considered opinion regarding mid engine vehicles.

      The correct terms for mid-engine vehicles is is ‘Front’ Mid-engine & ‘Rear’ Mid-engine.

      As regarding the ‘superiority’ of rear Mid-engined vehicles over RWD’s, it depends. The last iteration of the MR-2 certainly didn’t have any advantage over the front Mid-engine Miata or Honda S-2000.

      One of the problems with the layout of Rear mid-engine vehicles is ‘Polar inertia’, resulting in ‘Snap-Over Steer’. The first and last MR-2 had this in abundance and other issues. Most people are not skilled enough to deal with this situation in a production vehicle. Most don’t even know what is going on and how to deal with it or prevent it. I like the challenge of making an edgy car like the MR-2 or ‘911’ work, but they can bite even the experienced track drivers and the pro-drivers.

      Most production Mid rear-engine vehicles are constricted to a box of limitations that negates, to a degree, the advantages of that arrangement. In vehicular racing form, the box is eliminated, and compensation is available in the form of big and little’s, wheelbase, and lower Cg’s due to lighter exotic materials. And high HP to weight advantages for the principle mechanical entities, rear down force, and ‘ground – effect. All of these elements help to reduce polar inertia/snap steer.

      I too own a Lotus, and I bought it for the same reasons that you profess, make them superior. In its day my new 73′ JPS Europa could walk the talk, but a few years later, my new 75’ ‘Cosworth-Vega’ sure could give it a run for the money, and with a lot more confidence then the Europa afforded, despite its ‘live’ rear axle. The Europa could bite, not as easily as a 911, but when it went, it was gone.
      it was usually initiated by throttle lift in the turn and/or braking, which unweighted the rear suspension, reducing contact area due lighter contact loads and camber changes. There are more complications then that, one having to do with dynamic amplitudes not generally initiated by the lighter rear weight of a Front mid-engine vehicle.

      Today, the Europa just feels dated compared to my Miata’s, despite much lighter weight and suspension tuning over the years.

      I know, subjectively anecdotal, but backed up with several thousand of hours of track time over forty years in everything from a 68′ Spitfire to a Formula 5000, that coupled with a degree in mechanical engineering with an emphasis on the study of suspension and chassis design, brings some degree of expertise to the subject.

      So it just depends, with production vehicles it’s a toss up. Purpose built race/formula cars, not so much.

      In the Le man’s series, the Panos LMP-1(front mid-engine) was simply out classed and overpowered by the Audi ‘LMP'(rear mid-engine). Times through the corners were nearly identical and came down to fractions of a second, mostly due to Audi’s power advantages exiting the corners.

      And your comparison of the Exige handling to a a very dated 280Z with late sixties engineering, that and the weight disadvantage both ‘Z’z’ bring to the table versus your Exige, is like comparing Tomatoes to Bananas.
      My latest, recently completed, purpose built track car, a Lotus Seven ‘Type’ car is a front-mid engine with an LS drive train. I in no way would compare its performance to the Exige. In a contest between the cars at PIR, my sports racer would probably lap the Exige in around 3 laps. Its advantage… around 200 less pounds and about 200-250 more ponies. Its advantage having nothing to do with engine layout.

      Enjoy your Exige, a fun car for sure, but its perceived advantages are mostly due to its light weight and P/W ratio.

      Regards and keep the shiny side up Michael … Tre

      http://mcsorley.squarespace.com/442_model

      http://en.wikipedia.org/wiki/Caterham_7_CSR

      http://www.google.com/search?q=lotus+seven+ls&hl=en&prmd=imvns&source=lnms&tbm=isch&sa=X&ei=Q189ULrpB4HQiwKXtIG4Dw&ved=0CAgQ_AUoATgU&biw=1274&bih=650

      • HOORAY!!!!!! This is the best, most informative, and well written automotive comment that I have read in a long time, anywhere. It is literally my dream to do what this guy does and to think as quickly about cars and handling. I have recently rebuilt my aw11 4agze, and am very excited to learn its characteristics and behavior in a very conservative and responsible manner. Especially since I have driven FF cars my whole career. Any particular tips for a driver like me, beside those implied from your previous post?

  3. MR2s are sweet and those 4AG engines are awesome! I’ve seen my share of huge side draft carbureted, supercharged, and turbo charged units over in Okinawa, Japan as a teenager. I’d love to get my hands on a ’86 Corolla “Hachi-roku” (86). Nice write-up! Especially like the picture of your kid behind the wheel!

    • thanks dom,
      those motors really are great, the 20 valves can be screamers too. i had an ’87 rwd corolla gts (with 4ag) but it was the coupe, not the more popular hatchback. motor was good, tranny needed syncros but when i got to tearing it down the rust was worse than i expected so it had to go. it’s hard to find those in good condition anymore after every idiot kid wants to take them “drifting.”

      The little guy loves cars, we gravitates to steering wheels no matter what car/truck he is in.
      It might not be realistic if the car nazi’s get their way but I hope he has a chance to be an enthusiast when he gets older.

      • The car nazi’s will never stop, but neither will we… He’ll have something fun to drive when he grows up and so will my daughter. Freedom will prevail.

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