Matt Cramer, a longtime regular on the GRM message board, is also an engineer for DIYAutoTune.com, a supplier of MegaSquirt ECUs and other engine management solutions. He has also written Performance Fuel Injection Systems for HP Books.

Admit it: If you were a kid in the 80s, you wanted to be like Michael Knight when you grew up.

An additional tip for this topic: If you think that the car is cutting out because the overboost protection in megasquirt is activating when it should not, you might consider checking the vacuum source line to the wastegate and/or the boost controller. Do not just turn off overboost. Engines run rather poorly when a rod is attempting an escape through the wall of the block. Talk about your school of hard knocks.

Cars run great on too much boost! For a very short period of time.

No such thing as too much boost, just too weak of an engine.

If you are overboosting, you either did not build the engine right, need a bigger wastegate, or have the wrong size turbo. Either way, boost is not the problem.

Last turbo engine I built I had programmed to have a limiter for the boost. When you hit the limit, the fuel was cut completely. Pretty eerie when it activated, which it would only do on a long straight with floor to the floor acceleration. All the noise just stopped happening until the engine slowed enough to reduce boost below the danger level. First time I hit it, I figured I had blown something vital but wondered why no noise of parts hitting the pavement. Second thought was wait, lean burn equals disaster, but then immediately afterward, no fuel equals no burn.

Today you would more likely implement over-boost protection via an ignition that omitted every other spark until the boost backed off. It would just flatten out until boost dropped, or a solenoid on the wastegate triggered by the ECM.

Cutting fuel will do a handy job of cutting boost. Exhaust gases have much more pressure and volume than the same approximate mass of raw air. That is rather how engines work in the first place.

If you use EAE type acceleration enrichment, the first injection pulse for each cylinder after cut will have an additional amount of fuel to compensate for the fuel that normally would be condensed out on the runner walls. Otherwise, the first cycle after cut will be quite lean. People get away with it because the chamber will also have been cooled significantly, so running lean once or twice will not hurt.

The guy who built my engine used nylon vacuum line for the wastegate pressure signal line. Nylon melts in the vicinity of hot, glowing exhaust bits. I found this out one day when said line melted, I was accelerating, and the MS3 Pro ecu I was running cut the ignition right at peak boost. When I let off the pedal and eased back into it, I got a nice, large boom and fireball out the exhaust. The overboost protection setup in my car only cuts the ignition, but not the fuel. Unburned fuel keeps the chambers nice and cool, but it does tend to flash ignite inside the super hot housing of the turbine. It was fun for a few spool up and boom giggles once I caught on to what had failed, and I was impressed by the reaction speed of a modern ecu to protect the engine, but I did not want to push my luck. Said vacuum line has since been replaced with the same silicone that is used on Caterpillar engines.