I've read a few posts from members over the years who've tried Gude or other cams on the 5m and been disappointed. I spent a good bit talking to a cam expert long distance several calls discussing cams for my 6mgte. It was finally decided to leave cams stock. I was told changes in cam have a marginal improvement on a turbo motor but sacrifice a great deal in smoothness for your trouble. As for compression, many who are going for all out turbo power lower compression because the turbo is already superheating the intake charge before it gets to the cylinder and that extra 100 degrees or so can cause detonation. An alternative strategy, possibly more effective all around is to invest in a more efficient intercooler and fresh air intake to bring the intake charge temp back down as close to ambient as possible. Turbo is for doing what?.....artificially raising effective compression, right? Corky Bell says somewhere in his book there's no need to build a low compression sled. Now I'm going to contradict myself. The stock cast pistons are the second weakest link in the 5mgte after the stock headgasket which you've already got covered. I'd certainly at this point have some forged pistons made. As long as you are going to anyway, you might consider dropping to 8.8:1 like the 82-83 motor from 9.2:1 if yours is an 84+. Those turboing the earlier motors seem to be able to safely run a little higher boost even with a stock mk3 intercooler and its not enough that you lose alot in off-boost performance or that you can't compensate for in tuning. Thats my .02c on the subject. Good luck.
Phil D.
Phil D.
