Tube polishing, cont'd
This is the debris that came out. The black pile is from using the wire wheel and the sandpaper flapper. Maybe 2 tablespoons of crud. The initial scouring took out most of the oily dirt. Note the sparkles of Al in the pile as those tools do work the surface back a bit and take off the tiny nubs from the casting.
The silver pile is the aluminum taken off in grinding. It's 1-2 teaspoonfuls.
The whole operation took almost an hour per tube. Maybe not the most valuable use of time. I've been mulling this over since I started modifying the 928 so 15 years. "Can ya port that intake manifold?" Just had to give it a whirl.
A friend asked how much power it'd yield. I had to be honest: "Something between 5 hp and 0.5 hp." I don't have high hopes but if it's 5hp, I'll be super happy. Assuming 300hp a 1% increase in air flow would net 3hp. Then again, I'll never know.
Just a few more pre-build things to get done, like fix the wiring harness, and it'll be assembly time.
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1980 928S Euro x2
1987 944 N/A
Last edited by GlenL; 05-06-2018 at 09:47 AM.
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