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If the motor is past its half-life, you may want to consider having it opened up and the seals replaced.
No point building up the boost only to blow out the motor.
Given local experience here, Only budgeting $15,000 for the upgrades seems optimistic.
great point! I was told by the importer that he checked the compression and everything looked good. I’m going to recheck it anyways. I’m prepared to pull the motor if I need to. Would be a nice excuse to paint and clean the engine bay.
Did you install a boost gauge yet to see how low the boost is? Did you swap the spark plugs and spark plug wires, drain the coolant, replace all the cooling hoses yet?
These cars made about 200hp at the wheels in stock form. If you're wanting a dyno sheet that says 400, that is about double the heat you'll need to deal with. My advice is get it running smooth on the stock turbos before making big changes. If you've got your heart set on big power, I would go in this order:
1. Baseline dyno pull to see what it's making today. With an unknown setup, I would do dyno pulls in 3rd gear to put less load on the engine (shorter gear means it spends less time making heat ). Ask them to point a fan at the oil cooler as well as the radiator. Most dyno shops that can add the dyno's wideband to your tailpipe and MAP sensor to one of the vacuum lines, it's nice to have that data included on the dyno chart. Ask for a dyno chart with zero smoothing in the torque curve, because that can help identify misfires. If you can be there to watch the dyno session, get a camera on a tripod recording the tailpipe, so you can see if there are any puffs of smoke and hear misfires. Try to record at high framerate, and angle the camera so you can see puffs of smoke a few feet after the tailpipe. Keep the camera far enough away that the microphone can still capture the sound cleanly. UMS Tuning has a good reputation, I think that's a good choice if they are nearby for you. Tell them your power goal, intended usage, and budget, and they can help advise what to do next. If you find a cat-back exhaust you like, it might make sense to install it before the dyno. Don't replace the cat converter without O2 sensor data, you don't want to let a rotary engine run lean.
2. ECU, new engine harness, additional ground wires for the battery and engine and ignitor, wideband O2, injectors, fuel rail, fuel pressure sensor, fuel pump, fuel filter, oil filter pedestal, oil pressure sensor, oil temperature sensor, and dyno tune. For the fuel pump, be sure to upgrade the wiring and the electrical bulkhead connector. The factory bulkhead connector is barely adequate for the stock fuel pump current draw, it's known to melt with the extra current that an aftermarket fuel pump will draw. In my opinion that is a lot of things to change at once, I would try to avoid changing anything more than that. Note that the goal of tuning is to make sure the ECU and fuel system are working, not to make 300whp. If the car doesn't drive smoothly, the standalone ECU plus all those sensors should give UMS Tuning enough info to help find and fix any problems quickly. Don't be surprised if he finds things that need fixing, these cars are 30 years old and weren't perfect to start with.
3. Get sticky tires (200 treadwear, like Yokohama A052 or Bridgestone RE71R or Falken RT660) and a good alignment before adding power. Take the car to autocrosses and make sure it's predictable and easy to drive. Drive it for at least a month, fix any handling weirdness BEFORE adding power. If it has the original suspension bushings and pillowball joints, replace them before adding power. Don't push hard on the street. If you've got a laptop computer, record datalogs and learn how to watch them to see max temperatures and max boost and wideband O2 readings.
4. Turbo, V-mount radiator and intercooler. Personally I would add two more O2 sensors to the exhaust manifold so you can measure AFR for each rotor. That's not exactly cheap, but neither is an engine rebuild from one rotor running lean or experiencing a misfire that was hard to hear. I would spend money on that plus at least one EGT sensor before spending on an electric water pump. Be sure to address the ducting for the intercooler and radiator, if the V-mount kit doesn't include it. Depending what oil temps you have been seeing in ECU datalogs, consider upgrading the oil coolers. Depending on coolant temps and air temps, consider a vented hood and possibly a fan to pull air through the intercooler.
Good luck, these are fun cars. IMHO you don't need even 300whp to enjoy them. I would spend money on track time and tires and maintenance and cooling mods before adding power.
Last edited by scotty305; May 10, 2024 at 12:35 PM.
....If one of the solenoids in the box throws a code, might as well replace the whole unit. Taking the box apart is problematic and other solenoids are likely to code out soon. Also if one nipple breaks on the box, you have to replace the box.
On my friends RZ, the screws holding the box together had come loose and the box was in sections.
