The boost intake tubes in the Corrado are made from a plastic. The ideal boost tubes will be immune to battery acid, remain intact under extreme temperatures, maintain internal pressures, and look good. The OEM tubes in the Corrado perform all of those functions well. However, there is always the cosmetic appeal of getting something aftermarket to set your engine bay apart from the others.
For awhile, there was a market for aftermarket boost tubes. Some were polished while others were powdercoated in colors. I opted for one of the more popular boost tubes choosing naively because I thought the mandrel bent steel would better withstand the Corrado battery acid corrosion test and would not flex under pressure.
In real life, these aftermarket tubes failed all of the above criteria. They were easily etched from the battery acid, didn't fit well with existing boost hoses, and could not maintain pressurization. I was totally surprised at how poorly these performed in real life. While using the boost checker tool discussed in an earlier post, I found that these tubes were incapable of holding any postive pressure. The problem wasn't design but rather poor craftsmanship and no quality control. A simple check fit would have made these flaws evident before presenting them for sale to an unsuspecting public.
The CO Potentiometer is a vital part of the fuel system on the G60 Corrado. It is positioned high up on the last boost tube near the throttlebody. There is an O-ring which seals this sensor tightly. There is a snap ring which fits into a grove which locks the potentiometer in place. On this example, the potentiometer mount was misaligned making proper positioning of the O-ring impossible. In addition, the grove for the snap ring was too far to apply any pressure against the O-ring. The result was an O-ring with no surface on which to seal and enough space to fit two O-rings. Add to that, the mounting points on the tubes didn't meet the mounting points underneath the fan near the intercooler making proper installation impossible. The improper angles at the ends of each tube also made proper connections to the boost hoses difficult stressing the hoses to meet the new tubes.
My advice, use the OEM boost tubes. They don't look as sexy as a polished tube with a tuner logo, but at least they work. I can't say that for the aftermarket boost tubes. These go into the crap parts bin. 
Comments