My MR2 Story
The BeastThis car owes its existence to the internet. I was a Brain Surgeon resident with no time to do anything, including sleep (hey, getting off track here...) and I saw this ad on USENET's houston.forsale:
Subject: FS: 1987 Toyota MR-2
for sale for parts - engine has cracked head
I really missed having a sports car since selling the Europa, which I had to do when in undergraduate school. How much does a Lotus cost? Only about $2000. A year. In parts. And that is a bitch when two people are trying to live and pay for school on $14K a year total income. College books alone were over $2000 a year.
After some email correspondence, we negotiated a price: $100. So my wife and I took the (Toyota) truck from our home in League City to Katy, TX (about 50 miles on the opposite side of Houston) and checked out the car. It was a mess. They (the previous owners [PO's]) had given it to their daughter who must have played bumper cars with it, then gotten it back and were driving it on the freeway when "it overheated" and they pulled it to the side of the road at a gas station. They called a tow truck, and before the tow truck could get there, someone stole the stereo. They took it to their mechanic, who told them they had a cracked head, and they had it towed home, parked in front of their house. The neighbor across the street then proceeded to back into it (same place) about 4 or 5 times. When I looked at it, the spark plugs were sitting on the side of the engine bay, not in the holes. This means that the car sat for about 6 months with no spark plugs in it. This is the best way to absolutely kill an internal combustion engine.
Well, it was a sports car, and it was a Toyota, and it had potential, so I gave them $100 and we towed it home across Houston during rush hour with a tow rope. I had to take the T-top off so I could breath in the Houston heat, and my wife (Linda) drove the truck. We made it home just about dark, which was a good thing as the battery was dead and it had no lights (or means to open the power windows).
A compression test showed two cylinders with low pressure a likely head gasket (at least.) But what to do with it? Well, 112 HP just was not going to cut it. So, on to surf the net. I found that to get some serious HP out of a 4AGE it was going to cost some bucks. Set of cams? $500. Port/polish? $500. New pistons? $500. Then lets talk injectors and computer, bearings, shims, and gaskets. You get the idea.
Another option was to use a 20 valve motor. Just drop it in and you have a factory stock 160 HP. The block is the same, so everything will bolt up. The 20 valve head has 5 valves per cylinder, variable intake cam timing and a knock sensor. At about 4100ish RPM, the intake cam retards 30 degrees to give more overlap and better breathing at high RPM. See Billzilla's description. There are 4 throttle bodies instead of one on the 16 valve motors. Redline is 8100 RPM. Problem is that the motor was never exported from Japan. OK, it was (and still is) exported to South Africa where it is put in a locally built Corolla RSI ($21K at current exchange rates), but that is it. It is basically a Japan only motor. After some extensive web surfing, I wound up buying my motor for $950 delivered from John's Foreign Engines in Vancouver, WA. Of course there was a shipping delay, and it wound up taking a little over a month to get me my motor, but it did show up, and I think it is a good one. I also suspect that Watanabe is the only importer of JDM motors in the US (maybe the world) and they get "rebranded" a lot.
Now, there are some problems with the swap. First off, the stock 16 valve ECU just won't cut it. I am not saying you can't get the motor to run with the stock 4AGE ECU, but it just won't do it justice. You still need something to kick the cam over, and who knows if the injector maps are anywhere close. So, basically, you need a Toyota factory 20 valve ECU or an aftermarket ECU (another $1000).
Another option is to go with some carbs (carbies to the Ausies). To do that, you still need an ignition system with an advance ($200-500) and a RPM trigger for the cam ($50ish), intake manifold ($300ish or roll your own) and some good carbies, side draft of course ($500). Well, after more web surfing, I found a used pair of DelOrto 40's for $110, with air filters, fuel line and a pressure regulator. I was just about to order some aluminum stock to fabricate an intake manifold for it when a friend of a friend of a friend in New Zealand (isn't the internet wonderful?) found a 20 valve ECU and AFM. $250 later it was at my door, and no, there are no more where that one came from.
So, all I needed now was the time to do the swap. Easier said than done when you are working 500 hours a month for $4 an hour, and making life and death decisions at 3AM with no sleep, while you drill holes in peoples heads with a hand operated twist drill like your grandpa used to use in his garage. Sometimes even with the patient sleeping. I eventually had enough of that fun and quit. This gave me much more time, but no money at all, which was actually not that much less than I was bringing home before. Fortunately I had already bought almost everything I needed, including the folding shop crane. So, I got after it.
It was only 2 days to take the old motor out and put in the new one. I dropped the engine/tranny onto some cardboard, then picked up the back of the car with the crane, hooked the truck to the powertrain and pulled it out, then dropped the car back down. To reinstall, I got smarter and dropped the motor in first from the top with no accessories/manifolds on it. Then I put the tranny on it from the bottom and bolted everything back on. Much easier.
Wiring up the motor took 2 weeks. That was a bitch. The harness that came with the motor was chopped off at the firewall, and I had 2 of the 3 plugs with about 3 inches of wire on the ECU. I was fortunate enough to get my hands on a schematic of the 1991 (1992?) AE101 that the motor came from and started soldering and running wires. Two weeks later, she roared to life (literally, with no exhaust after the header.)
Speaking of the (very rare) wiring diagram for a 20 valve motor here it is in digital format. Two gif's, and they are big. Page 1 is 416K, 6600 x 4600, and Page 2 is 502K, 6600 x 4544. Both are mostly in Japanese, but there are some hen scratchings (most not even mine) and enough English on them to figure out what is what. I did the best I could with my (very old) HP Scanjet scanner, scanning them in two pieces and pasting them together, and they were only about a 4th generation photocopy to start with. But, they are immensely better than no wiring diagram at all. IE5 would not load them. I think they might be too big. I can view them with ACDSEE, and Micrographix Picture Publisher. ACDSEE is available as shareware from http://www.acdsystems.com/products/download.htm.
Check out Phil's site on my Favorites page for the ECU pin-outs. They are "almost" right. One of these days, I'll get after it and make my corrections and enhancements and put it up here, if Phil does not mind. Most of the errors are with the O2 sensor and the check engine light. Follow the schematics.
To mount the AFM, I used a Fernco 2" pipe coupling, as you can see in the pictures. Builder's Square (thankfully going out of business now at least in this part of Texas) did not have it, so after searching every hardware store in my area, I used the old plumbing supply store I forgot was at the end of my street. Ask for a Fernco 2" rubber pipe coupling and squirt it with some WD-40 when you put it on. It is a bit small, but with some work and some screwdrivers, you can make it fit. A problem I had with this setup is that the AFM was a bit loose. The rubber coupling was all I had holding the AFM on. It would kinda flop a bit out there, and eventually after six months or so, I noticed that the AFM was sagging. It still worked fine, but I just did not like the way it looked. So, I bought another coupling (under U$3 complete with the clamps) and I welded 5 strips of 1/2" wide 16ga stainless between the two hose clamps, making a "cage". I then reassembled the whole thing and it is now tight and solid. If you don't have a MIG welder, buy one. Best tool purchase I have made next to my metal lathe. Or, you could just get some metal like the strips I used and lay them on top of the hose clamps (after installing the coupling and tightening down the clamps) around the coupling, then place a second set of hose clamps over the strips just inside the first set of clamps, and that would probably work too and not require any welding. Another solution someone else has done is to mount the AFM to the chasis wall next to the throttle body on a 16 valve, or next to the plenum opening on the 20 valve. I forget who it was, but it seems to be working for him. I did not like the idea of the motor torquing in it's mounts and the AFM not moving, stressing the short little rubber piece, so I went with the cage. I call it The AFM Cage. Here is a pic of the K&N air filter, the AFM and the AFM Cage.
The motor came with a factory header that looks real good. Problem is that the starter was on the intake side on the AE101, and the header hits the starter if you try to bolt it up on the AW11 with the starter on the exhaust side. I solved this problem by cutting the header tubes off at the manifold flange, welding on 2 inch extensions and welding it all back together. Another option is to use a later model tranny that has the starter mount on both sides. I was on a low low budget, so that was out.
A close up of the tube I welded on. Pretend the Fram filter is not there.
For an exhaust system, I built my own. I had a local muffler shop bend a couple of 2-1/4 pieces for me, and I cut/welded it from there. Total cost on the exhaust was $35 including the glasspack. It is a bit loud (ear splitting, actually), but hey, it works, weighs a lot less than the original one and flows fine. The 20 valve will run fine without an oxygen sensor, but give you the error code. I was having problems with a miss, and I thought (incorrectly) it was the oxygen sensor, so I installed one. That was another day hitting every auto parts and tool store in a 20 mile radius looking for a tap the size of a Bosch 4 wire oxygen sensor, 18x1.5mm. I finally found one at the Asian Tool Store 4 miles from the house owned by the guy around the corner, that I usually start looking for stuff at but didn't this time. FYI, it is the same thread as an old style (big) spark plug. Off the top of my head, if you asked for a spark plug for a 1945 Harley Davidson Knucklehead, that would be the correct thread size. There is a spark plug thread chaser every parts store carries that has two threads on it, and the big one is the correct size, but a thread chaser won't cut the threads for you.
Speaking of oxygen sensors, check out my Clip-n-Save (R) page for some tidbits.
I had to figure all this junk out for my 20 valve, as the 16 valve motor had a one wire sensor and the 20 valve ECU wanted a 4 wire sensor. So, I bought an off the shelf Bosch 4 wire screw in sensor, fabricated a mount for the exhaust on my metal lathe, welded it onto the exhaust and figured out which wires go where. Works fine and I get no oxygen error codes. Actually I am down to just one error code now for the speed sensor. To choose the sensor, I just went down the Bosch applications chart for Toyota's until I found one that was a 4 wire. I figured that Toyota would not likely make any major changes in their selection of oxygen sensors.
I recommend you go down to the auto parts store, like Hi-lo, pep boys, etc., and ask to look at their book catalog of oxygen sensors. Look up your application and there will be a picture and wire ID that is sort of useful, when put together with the rest of your info. They still have the book catalogs, even though most of the parts stores now use a computer database.
Eventually I want to put the cat back on and use a more expensive high flow muffler that might actually drop the dB's down some.
Here are some pictures of the first exhaust system:
I re-did the exhaust system to take the edge off. That straight through glass pack did not do much to tame the ear-splitting note of the 4AGE. I think there is a race track somewhere on the Left Coast that lets Formula 1 run with no mufflers, but makes Formula Atlantic (4AGE's) use mufflers because they are louder and the neighbors complain. Anyway, I say screw the neighbors, but you have to keep the pigs happy, so I re-did it. I now have the header coming down, my fabricated 2 to 1 off the header, a short straight run with the O2 sensor, a high flow cat (at least I am pretending to be street legal), a short oval muffler and 2-1/4 "tip". From the 2 to 1 back, the whole system is 2-1/4, and straight (no bends). Bends cause turbulence, turbulence causes restriction. It is a bit short for the motor, unless you want a peak scavenging effect way up on the RPM range, but with the AW11, I did not have much choice: Longer with lots of bends (restrictions=bad for flow) or shorter with no bends (loss of lower power band scavenging). By the SOTP dyno, I can't tell much difference with the new exhaust. Sound wise, it has taken the sharp edge off the "ear splitting" 4AGE note. It is quiet enough to hear the radio now (sort of), but still makes plenty of noise.
A problem I experienced was with a bad miss under load above about 4K RPM. I eventually traced it to a weak ignition (the original AW11 ignitor), and I worked around it by using a very hot plug and messing up the timing. Latest upgrade is the MSD 6A ignition. So, my ignition setup is currently: Factory 20 valve ECU, factory 16 valve AW11 ignitor (some spare wires left over...), MSD 8910HEI adapter for Toyota ignitions (don't forget this part), MSD 6A ignition (no need for two rev limiters, the ECU will do nicely), Accel coil, factory wires (on the list: Magnacor), Bosch copper plugs in the stock heat range. Here is a picture.
My Magnecor Saga, by Dr. Hess
Speedo Cable, Throttle Cable
As we towed it home, I noticed the speedo did not move off of 0, and the odometer did not move. Hum, guess it has more than 80K miles on it. When I took it apart I found the speedo cable was broke, and the tranny end piece was missing. After I got it running, I decided that it would be a good idea to have a speedo, seeing as how you could microwave a potato with the RADAR out in this town. A trip to the junk yard found one MR2, pretty much stripped. I took the cable off of it and found that it too was broke, at exactly the same spot as mine. Well, they gave me the broken cable for free so now at least I had both ends. I used a piece of angle iron for a jig, and welded the two pieces of the (newer) broken cable together, then ground the weld down to sort-of round and fed it through the sheath still in my car. It works great and only cost me time to fix.
I had less success repairing the throttle cable (tried that before I did the speedo cable, and learned from my mistakes - Don't use the MIG welder...), so I wound up buying some "life-line" at the marine supply store, which is a plastic coated stainless steel cable. I stripped the plastic off of it and fed it through the original sheath. I made an end for the foot side and welded it on the cable (MIG welder OK), and made a screw-type cable end for the motor side.
Here is how I relocated the battery in my MR2. I took it out of the engine compartment and put it where the spare used to be. I relocated the spare to the side of the house (weight savings, don't you know.) I had some heavy copper cable (1 AWG) laying around left over from a welding cable extension project I never got around to, and I bought a nice plastic battery box and some snazzy battery terminals that take spade connectors and some connectors at the local marine supply store. Total cost: About $20. I was going to use some 000 AWG cable I had for the same project, but I picked up enough for the job and it seemed about as heavy as the spare. The cables Toyota used are little wimpy guys, so I figured the 1 AWG would be plenty. There is such a thing as overkill, and it is only about 8-9 feet each way anyway. Now I have much more room in the engine area, a lower center of gravity and "better ballance/handling and lighter weight." This mod has to be good for, what, 20 ricepower? At least as much as those big coffee-can size exhaust tips I see everywhere. I mounted all the ignition stuff (coil, ignitor, MSD 6A, MSD 8910HEI) where the battery used to be (see the above ignition link).
Relocated battery box. My wife likes this mod.
I have done all the body work myself, and it is coming along. I still have quite a bit to go, but at least it is getting into the right shape. I have a combat air dam, but I have not put it on yet. I need to make sure that I can get out of my driveway with it on first. I also have some other ideas, but I am going to stay quiet on them until it is done.
I replaced the totally wiped out, metal jabbing seat with a "circle track" race seat, using the original adjustable seat mount. Not much padding, but you can really feel what is happening with the car. Also, it hugs you pretty well, at only 16 inches wide with huge side supports. Pic here. Note the fire extinguisher mounted where the center box thing used to be.
Still a bit rough, but it runs great! Hey, you can spend your money on go or you can spend your money on show. Personally, I would rather have go than show, so that is where the money goes.
Here is a picture of the "good" side. It is coming along. I took the aero trim off so I could do the body work easier.
I finally upgraded the suspension. I have Koni adjustables all the way around now. The rears were back ordered, so I put a pair of el-cheapo (1/6 the cost) Monroe's on the back to last until the Koni's came in. I got real good at doing struts, and I can do the rears in about an hour and a half, bolt to bolt (surgeons say "skin to skin" for timing an operation). I also put a set of TRD suspension bushings in, and some ST springs. That was a job. I broke down and bought a 20 ton press to push the bushings in. A 12 ton would probably do it, but I went with the bigger one. I don't think it is possible without the press. Die hard DIY'ers without a press could take the arms to a shop and get them to press the bushings in pretty cheap, but be careful. I got an email from someone that tried this and wound up having to buy his own press as two or three different shops just managed to destroy his expensive TRD bushings and not push them in. If you want it done right, DIY.
Next, I "upgraded" my motor mounts with a castable urethane. I used the 80 shore (80 Shore A Durometer - 1lb resin/hardener - p/n 8644K11). McMaster-Carr was a joy to deal with. No minimum order, actual shipping charges, no "handling" charges. Good business. I had my urethane less than 24 hours after I ordered it for $4 shipping, as they have warehouses all over the country. Looking at their catalog, they carry everything. I think I could find a drive belt for the Harley's there if I looked hard enough. A few comments on doing the mounts: I cut away part of the old rubber with a hack saw so more urethane would be used for the mount. Make sure you seal the bottom of the mount (when you pour) very well, with plenty of tape and maybe a layer of plastic food wrap. Three of four leaked on me. A suggestion I received (after the fact) was to put the mount taped up and ready to pour in a bucket of sand. The sand supports the tape and it won't leak. I had a bucket of sand right next to me at the time, I just did not think of it. If possible, do all your mounts at the same time. I did two, waited a day, put those back in and did the next two. It is difficult to mix the urethane correctly if you are doing a partial can. The urethane has to be mixed by weight. Different grades of urethane have different mixing rations, and the 80 shore I used has a ration of 2 to 1 by weight (not volume). I did some experimenting, and as best as my crude instrumentation could determine, the ratio of the weights for a given volume is 14:15, with the hardener being a little lighter by volume. So mixing it 2 to 1 by volume will probably be pretty darn close. Make sure you have a method to hold the mounts level while they are hardening.
The urethane motor mount mod is not for the feint of heart. It definitely firms up the mounts to a point that the motor does not move at all. This is good for performance, but it also means that the majority of the motor vibration is transmitted to the chassis, bringing out previously unknown squeaks and adding a lot of feeling transmitted through your seat. Especially if you have an aluminum circle track seat with about 3/16 inch of padding. As with most performance mods, it is a balance. To get higher performance some comfort, convenience, driving ease, outside power band, money, etc., has to give. There is no free lunch.
While waiting for the urethane to harden, I built a strut tower brace. Total cost: 7 lbs stainless steel: $7. Argon for the MIG welder: $9. (I just traded in my little bottle on the next larger size to drop my argon costs.) The bar is made from 2", 14 ga stainless steel. The strut tops are from 16 ga stainless with 1" box stainless around them. I built the box around the top because all of the strut tower braces I saw were only bolted or maybe welded to a piece of sheet metal. There is an opportunity for flexion at the joint of the bar and the sheet metal. The way I have it, the bar is welded to the 1" box steel in a box around the top. The steel box is welded to the sheet metal and the sheet metal is bolted to the strut tower. I figure there is a lot less opportunity for flexion this way.
Actually, I don't think I had driven the car enough to tell the difference with and without the brace. I was asked if the TRD bushings improved the handling, but I can't tell, as I replaced the dead shocks with Koni's, put new (lower) springs on, the TRD bushings, and now the strut tower brace all at the same time. Yes, the car definitely handles much better now, but who's to say which component added what. I can conclude that putting $1000 worth of performance parts and a weeks worth of labor into a 13 year old car will definitely improve the handling.
As for a proportioning valve in general, I just modded my AW11 by removing it completely. Unfortunately, my master cylinder took this opportunity to give up, so I replaced that as well. Before it went out, I took the car for a brief test drive, and the braking had increased very noticeably. I would say just seat-of-the-pants, 20% or more. I used to get front wheel lock very soon, and the back rotors hardly had the rust scraped off them. After that brief run, the backs are definitely getting used now. The only issue is if I now have too much juice going to the back or not. After putting the new master cylinder on and driving it some, I think that the front's are still locking before the backs. You want to avoid too much in the back. The front brakes need to lock up first, otherwise if the rears lock up first the rear of the car comes around to say hello to you when you hit the brakes hard. This is usually considered a bad thing. So, if I have too much at the back, I will buy a little adjustable brake proportioning valve from Summit to put inline with the rear to crank it down some. Others who have done this say they did not need the rear valve, and I think they are right.
Well, there was this group purchase... So, I bought a 9lb aluminum flywheel. There were some delays in getting it made, as I forget how many flywheels we had total, but it was quite a few and many different types. I did a bunch of work figuring out what fits what on the 4AGE's, (see Clip-n-Saves). The flywheel arrived the day we were loading up the moving truck to move from Texas to Arkansas, so I did not get to put it on for a while. I also bought an ACT Street clutch set. Good thing, too, as the clutch I had in there was a Korean made POS that the PO had put in by some mechanic who obviously bought the cheapest thing he could find. Well, when I put the 20v motor in, the clutch disk looked brand new. 2K miles later when I put the flywheel in, there was less than 25% life left in the disk. Moral: Don't use cheap clutch disks when you boost the HP by 50% and drive "spirited." But, at the time, I did not have the money for the ACT clutch, so it all worked out. The original flywheel weighs around 18 lbs, and the new Fidanza aluminum flywheel weighs exactly 9lbs with the hardware. I have had no driveability problems. It actually idles smoother than the stock one did. I think it revs faster and will accelerate a bit faster, but that is just seat of the pants. Overall, I am happy with the purchase.
How's the car run? Pretty darn strong. I never drove a stock MR2, so I have nothing to compare it to, but it pulls hard, will out drag a Honda Prelude and I am happy with it.
Note that I run it with the timing belt cover off. Looks cool, runs cool but watch the fingers! Of course, nobody's fingers should be anywhere near my motor but me, and I know where not to put them when it is running.