I am doing the full non-sequnetial mods to my car this winter and have a question. I cut out both my Tca and Pre-control because I was told by a superior member that I could. After I cut them both out I welded the holes back shut. After doing some reasearch I found that I was supposed to drill the opening for the Tca and tap it with a 3/8 npt and then use a cast iron pipe plug. Has anyone done like I did and just welded the hole shut? I am only worried that the cast iron has a different expansion rate than the metal I welded and therefore may cause cracking. Lastly what are the downfalls of cutting the precontrol out rather than welding it at the 90 degrees? The only thing I could think of is that you now have a larger cavity for the airflow to fill to be pressurized. Am I right?

 

You are right about the expansion rates. Your weld will eventually fail and may get ingested by the motor. I did the pipe plug fix this weekend and will let you know if the removal of the door makes a difference compared to my previous poor man's non-seq set up.

 

The weld is located on the exhaust manifold so there is no risk of the engine ingesting it. Rather, the turbo exhaust turbine would be at jeaopardy. As for removing the Precontrol flapper, you created a knife-edge that exhaust flows against which might mean some undesired turbulence. Personally, I would dremel the edge down to avoid this.

 

Thank you gentlemen your comments are greatly appreciated. I am going to drill them out and use the cast iron plugs and also demel down any sharp edges. Thanks!!