MR2 San Rebuilt

Somewhere along the line, I had my machinist repair and rebuild the damaged cylinder head. That was, luckily, entirely uneventful. They were cheap, timely, and the head came out looking good. At this point, I had everything that I needed to complete the rebuild. I hired Dustin for 5 days and took several days off of work to complete the engine build. Additionally, I took the old engine out of MR2 San in preparation for the rebuild and installation of the new engine. The rebuild went somewhat smoothly with a few hiccups. Modifying the oil pan for the ARP main studs to clear took longer than anticipated. Dustin did this for me with a Dremel in about 3 hours. The threads for the head studs were a little rusty and needed to be cleaned. Dustin used a thread tap to do this for me. A small piece of the upper oil pan broke off upon torquing down the lower oil pan and was rattling around inside the block. We had to remove the freshly sealed lower oil pan and tilt the engine until it fell out.

After the engine was installed, one of aptly named hoses from hell (due to their placement on the engine) was leaking. I had to adjust the hose so that it was more tightly installed. I had accidentally crushed the ends of the copper coolant hoses that go to the heater upon removal of the original hoses and had to pound in progressively larger deep sockets until it (mostly) rounded out again. I had re-used the original alternator, but it had a different plug so I had to custom wire it. The wires were all the same colors so I wrongly assumed like-colored wires should match up. This assumption was incorrect and the alternator was barely being used until I wired it correctly. The lower oil pan leaked somewhat until I added extra FIPG sealant. Lastly, the original knock sensor and wiring broke, so I had to replace both (I used ATS Racing’s GM knock sensor kit and shielded microphone wire). There are still a few unsolved issues with the engine, but it mostly runs great. The issues are that sometimes it just dies and / or refuses to start, and it seems to leak / consume about a quart of oil every 1500 miles. The spark plugs look perfect and the compression is good, so I am inclined to think its the turbo and / or leakage. I do see some evidence of leakage and Dustin has told me he sometimes smells and sees a little bit of oil burning; although he is the only one out of a few that have followed my car while I am driving it and after I stood behind it while it was dynoed. The engine now has 6000 miles on it and has been through two autocrosses, lots of spirited backroads driving, many 7000+ RPM runs, and one run to 115 MPH. The other major projects on MR2 San have been brake and suspension related.

In addition to a new engine, MR2 San has all new polyurethane suspension bushings, new tie rod ends, new ball joints, rebuilt two piston front brake calipers from a turbo model, an adjustable Wilwood brake proportioning valve, stainless steel braided brake lines, K-Sport adjustable front sway bar end links, and new Fortune Auto coilovers. The Fortune Auto coilovers are one of the three last sets to ever be made (due to low sales) and have all of the upgrades including Swift springs and roller bearings. I keep them adjusted to full soft for street driving and around 4 clicks under full hard front / 6 clicks under full hard rear for racing. They are set to the lowest setting they can be without rubbing on the stock wheels (about 2.5 inches lower than stock) and the recommended spring pre-load (1/4″). Great coilovers overall, although they are sometimes just a tad bouncy on the street. My steering wheel is currently shaking off and on at about 70-80 mph on the highway, but I suspect that is due to the front left tire being out of balance from damage caused by having the coilovers set just a little too low for one of my autocross events. The suspension bushings have made a world of difference to the ride quality and handling and, as long as they don’t start to squeak, I would recommend them to anyone. I did run into one issue around the front sway bar end links being too short. They would bolt up just fine, but sometimes would flip around and wedge against the coilover housing causing extremely stiff steering, bent end links, and slightly damaged coilover housings.

I have also dynoed MR2 San recently and it got about 190 WHP @ 13 psi and about 195 WHP @ 16 psi. I suspect the reason for such a small increase in HP given +3 psi is that it is the exhaust that I have installed. Originally, I used an aftermarket 3″ Motoria exhaust. This caused it to overboost to fuel cut at high RPM. In diagnosing this issue, I installed a stock exhaust system, which is about 1 3/4″ at its smallest diameter. This solved the problem, so I believe I was overboosting due to too little back pressure, reducing the efficacy of the stock wastegate. The ultimate solutions to this problem are installing a custom aftermarket wasgate (costs about $500 and involves a lot of labor), porting the stock wastegate (costs about $50 and involves slightly less labor, but may not work), or running an aftermarket turbo kit (costs about $2000 to $3000 depending on which kit and also gives a nice bump in HP, but cannot fully be utilized without an aftermarket ECU and fuel system which is another $2000 to $3000). I plan on trying the second option next. I already paid for my new 3″ exhaust and am awaiting delivery.

Anyways, that about sums it up for now. I will be adding new posts and / or pages as MR2 San matures.


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