Poor Design

Most recently, the poorest design I've noticed and experienced was on my 1987 Mitsubishi Starion. This car was built in the time period where car manufacturers were switching to computer systems for cars instead of all mechanical components. Also, in this time period fuel injection was designed. Fuel injection helps better and more accurate fuel flow into the intake system of the head of your engine. With fuel injection, it takes out the manual adjustments and the computer tells how much fuel each injector needs to flow into the head. The computer is also hooked up to a MAF sensor which reads how much air is coming in and how much air is appropriate for how the car is running. Prior to fuel injection was the carburetor. The carburetor was a good system that many could learn how to adjust on there own. In a carburetor, there are a few main parts. You have the throttle body/plate, jets, and adjusting screws. The throttle body is opened, which moves the plate vertically open. Air comes through the opening and is mixed with the gas that the jet is set to push out depending on the settings of the adjusting screws. The adjusting screws are there so if you want to make more power, you add more fuel, and you can just turn the screws to a setting that works well for your setup.

However, Mitsubishi decided to say piss on this all new setup, lets make our own. Mitsubishi went with a setup known as MPI or multiport fuel injection. Also, with MPI, Mitsubishi used two injectors, a primary and a secondary, instead of an injector for each cylinder. The way the primary works is it runs all the time at full operating cycle. After approximately 3000rpms, when the turbo registers boost, the secondary injector turns on and works at full operating cycle until the engine is no longer running in boost. Once the car is back into vacuum, the secondary injectors stops working and puts the full load on the primary injector. Also, the way the secondary injector reads how the car is in boost is by a jumbled mess of vacuum hoses and everyone knows that one tiny hole or loose gap can cause major problems. By not having the injectors in an intake manifold and just setting in jet carbs, there is a long gap between where the fuel reaches the head to where it comes out of the injector and through the carburetor. This causes lag, which is a huge problem. The second you step on the pedal you want to shit and get, but with this setup you stomp on it and it feels like your just sitting still until a second later when the power throws you into your seat.

To fix these problems, My brother and I did a direct port injection swap. In doing so, we took the old intake manifold, fuel system, and cylinder head off. Afterwards, we installed an aftermarket intake manifold onto a b2600 head equipped and ready for direct port injection. Once on the car, we ran new feed lines to and from the gas tank connected to a fuel pressure regulator which is ran to the new FOUR injectors. Thanks to SAFC tuning and logging, we were able to add more air to the tune and start it right up. Proceeding that, we fully road tuned it over the course of the next week. With the new fuel and intake setup, and a bigger turbo I threw on for shits and giggles, I was able to over come the terrible designs Mitsubishi had made in 1987.