Project Silvia’s Girlfriend – Part 1


Although most Japanese import engines end up in the yards due to the Logan's Run conception of old age that seems to apply to cars in Japan, this one actually crashed its way into the junkyard before it could even reach the 50,000 miles that seems too high over there. The power steering pump had been hit hard enough to crack the corner of the block–another thing that lowered the price. It was just cracked through the power steering pump mounting bolt hole in a corner of the block that's easy to fix. We had the crack welded up and put a thread insert in the mangled hole. 

(If that photo makes you dizzy it's probably because I can't find an intentional photo of the repair. This one is zoomed in and flipped over from a picture of the block upside-down on the engine stand…)


Other than the crash damage, the engine was in remarkably good shape. The cylinders still looked freshly honed, the bearings looked new, and the intake ports were black and nasty. Engines that are driven hard have lots of fuel flow washing the ports clean. Gently driven intake ports look like crap.


The combustion chambers really showed evidence of nothing but a pampered life in this engine's past.

The factory turbo from the S14 was the one part we did salvage from the melted engine. It was a perfectly good T28 that can easily make an everyday 270 wheel hp on 91 octane California crap. More importantly, the factory turbo inlet and outlet plumbing bolts up, which is critical to making the turbo get along with the A/C compressor.

All the turbo nerds I know are of the opinion that Extrude Honing the turbine housing has pretty good odds of making a worthwhile improvement in turbine efficiency. Of course, we had no way to do an A-to-B comparison here, but educated guesses are better than uneducated ones, and all the nerds making this suggestion had serious turbo testing time logged on Garrett's gas stands, so it seemed worth a shot.


This is what $100 (at the time at least…) of Extrude Honing does to the turbine inlet finish.

Interestingly, the finish near the end of the volute is less finely polished. The amount of material removed by Extrude Honing depends on the pressure the extruding goo is exerting at that particular point. In theory, the pressure will be highest where it is most interfering with fluid flow, so the lack of smoothness on this last bit of the volute should indicate that it is less important there… Maybe.


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