+ 1 on Mep's parts program. When supplying parts to a builder where no prior relationship exists, if something's not right along the way or worse, in the end,
you---not the builder nor the parts supplier---will most likely be paying for corrections.
Thinking of my own 3.2 > 3.4 build, I chose to define "performance" not as adding HP but as building in endurance/durability. That thinking focused on reducing reciprocating weights, balancing motive parts well beyond Porsche specs, minimizing friction, and refining lubrication. While these can serve +HP... the thinking behind it all cuts a different path. Research led to...
Mahle (among others) will allow you to custom design pistons. My goal = cut off as much fat as possible without sacrificing structural integrity. Mahle will help make design decisions based on owner objectives. Or, supply them a CAD file. Mahle makes one-off prototypes for product inspection prior final production. I found them very helpful.
Ultra strong low weight pins---I forgot metal spec/source. You can find by Googling.
LN Engineering does Nikasil cylinders... and they collaborate with Mahle.
Reducing friction between motive surfaces...
Refining position of rod bore in piston to ease stress on piston, rings and cylinder. Weight reduction is also a factor in rod selection. Very exacting tolerances in all assemblies is called for. Doing this yourself, you can invest as much time as you want to achieve a very high degree of precision. When working with a shop, achieving beyond "standard" precision---provided shop is capable---gets expensive.
Force feed oiling to pins. This is Carillo brand. Other makers do same. Was debate on whether this was worth doing provided a case having squirters... in which case squirters could be sized up...then forget drilling rods. (I liked idea of forcing.) Ultimately there was a noticeable weight reduction per piston assembly that when X's 6... the figure varies depending on assembled components---regardless, the figure is consequential compared to stock parts.
Credit: I will find who did this and edit later.
Cross-drilling crank to aide lubrication---a proposed requirement along with larger oil pump (were one to force feed pins.) Parcel to achieving silky smooth running engine is zeroing out alignment of crank's journals. All bores should be treated same. Boat tailing case to ease airflow inside case. Knife-edging crank weights.
... This barely scratches surface of what can be done when thinking of engineering a build for endurance. Of course parts & work here---similar to adding HP---add dollars to build. While I did not project ROI, and based on not running pizz out of an endurance build, my thinking = eventually endurance-build dollars do have a return (provided car is kept long term by owner.)
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