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Originally Posted by serialk11r
Can you quantify the amount of mass that can be trimmed off pistons/rods/(anything else I missed that people swap out?)? And would you happen to know what effect this has on friction? (I read that piston rings, piston skirts, and rod bearings are about 40% of overall engine friction, and that piston rings make up a big portion of that...so not expecting much)
Also can someone share with me the effect of reciprocating mass on response and acceleration...reciprocating mass hits 0 velocity at top and bottom of stroke but the increased peak velocity as speed increases should have an effect right? Something I haven't thought much about.
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I'll get to the other post, when I have time to sit down and run through it.
As for the frictional losses; it'll depend on the engine as to how much friction is where. For instance, push rod vs. SOHC vs. DOHC. Is the DOHC work on a rocker (hydro or not?) or is it a bucket style?...rod ratio, bore stroke ratio, bore size, ring design, etc...all are factors. Timing belt/chain designs play a roll. This is why I wouldn't both trying to guesstimate what is what. Of all of this the only thing that I can really change is the shortblock, as getting into reworking timing components and making a custom head is a big job and a lot of money.
As for reciprocating mass, think of it from square one. What makes the crank turn? Combustion in one chamber. What does this have to overcome? For a 4-cyilnder (easy to think of a 4-stroke) you then have to overcome the forces of one cylinder going through exhaust stroke (pressure), one on intake stroke (slight vacuum or negative pressure) and one that is compressing the intake charge (more pressure). Now beyond that, you also have the frictional losses of each cycle (as friction will vary from load of each of the four strokes). Now also think of the energy used to turn all of the reciprocating mass as it does require energy to accelerate it.
Neglecting the mass as purely mass would be much like assuming that picking up 200 lbs is just as easy as 100 lbs...but now an engine is much more complex than that simple example. Perhaps saying catching a 20 lb pound medicine ball and throwing it back compared to doing the same with a 10lb medicine ball. You have to catch it and then throw it back...accelerating in two directions.
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Originally Posted by Dimman
What? This isn't my 'Engine Tech' thread? Dammit...
Have they got to the point where they can economically machine MMC for a 2 piece rod? Article says they are mostly net-shaped forged, with a fancy high-speed boring operation, since the matrix is aluminum and silicon carbide. And silicon carbine is usually on the side doing the machining operation rather than the receiving end.
Also what is the cost difference between normal 4340 and 4340M/300M?
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We aren't working on pricing on rods, yet. It is planned down the road and pricing will be brought up as it plays a big role in the aftermarket industry. However with the pricing on pistons, we are trying to keep it down and rather market competitive to others out there.