Noticed some piston pins on a suzuki engine that where very light and thin walled then saw the forged piston and they where quite thick, theres quite some weight saving to be made here and Ive never heard of a piston pin breaking or bending in anyway, so could it be possible to lighten the ones Ive got on a forged set since they are so darn thick and heavy? could save 40grams by the looks of it!

Mitsubishi 4g15 piston pins are thin adn light compared to A15 ones and mitsu peeps putting big hp into them 350hp no sweat.

It's something to consider.
Although lightweight ones may be made from stronger material. I've seen pistons advertised as having lightweight pins. Although I don't think I'd bother unless I was racing, and trying to squeeze every last bit from an engine.

titanium pins?

twice the strength and half the weight or the same strength and quarter the weight?

not cheap though..

I probably wouldn't bother (speaking for me personally) but if I got a set with lightened pins, done right, I wouldn't turn them away either.

Generally speaking they size the pin diameter/thickness to suit the usage. So you can't 'go nuts' about it. BUT what you can do is machine the pins on a taper, so they are full thickness in the middle and slightly thinner as you travel out to the ends. By the end of it all, i don't know what you'd save weight wize, but it'd be a couple of grams tops I suspect).

I'd also go further and say it's probably only warranted if the rpms are really high and each gram counts.

I believe you'd get a much bigger weight reduction polishing the side of the rod beams flat, and cutting away nearly all of the balance weight region on the little end of the rod and on the rod cap. Basically reducing it all so they are all evenly balanced with one another, but with one rod taken right to the limit fo the weight reduction.

In other words you weigh all the rods, big and little ends, and the heaviest ones to start with, you take the most material off, until they become the lightest, then you machine down all the others to this new reduced weight. And you repeat that, a bit at a time, until one fo the rods is just about out of material on that 'pad' that is there to be machined off as needed for balancing purposes (and not all rods have a lot of material in that respect). Start before that by polishing the sides of the beams. It'll drop a few grams, but most importantly (if done carefully) this will remove any surface irregularities, and actually make the rod stronger rather than weaker (obviously you 'go with the grain' so to speak - polish up and down the rod beam, not across it.)

balancing the rods is definitely something you can diy, and diy to accuracies of closer than 1 gram (probably closer than half a gram) - by simply making a 'balance' scale setup, using a slightly undersize piston pin and a few bits and pieces - you compare one rod to another, on each side of this 'scale' then remove material till they balance (and then swap ends to compare the other end of each rod to one another) then swap in one new rod, and repeat, until all 4 are the same. It doesn't matter (at this stage) 'what' they weigh, as such, just that they are all the same. Obviously when someone professional is then given the job of matching crank counterweights to it, they'll measure the rod weights, but you'll still save some decent money by doing the rods yourself.

Obviously if you need new rod bolts installed (and esp if you are going from stock/old rod bolts to new arp ones, which will alter the clamping force) - it's good practice to get the big ends closed and honed (they machine a couple of thou off the rod cap mating faces, then install the new bolts, torque them up (and the new clamping force will alter rod big end distortion a little) and then they final hone it to the right size to have the right radial tension/rod bearing crush) - anyhoo - if you are having new bolts, get em re-co'd, it's well worth the effort on a high rpm setup.

Yes wise words thank you I saw the tapered pins on bikes, the reason is I have fully prepped and lightened rods that weight exactly as each other and all the weight was taken in most places strategically. Ive looked at my zx14r pistons again and surprised they are pretty thin also. Its pretty tough steel I suppose.

40 grams is quite alot of savings to take from piston area.
Would love 8500-9000rpm with this build.

why lift even 2 extra grams 9,000 times per second (x4)...

I tried to balance my own rods. But I didn't have the right kind of jig to weigh the rod ends. I borrowed a scale that went down to 0.1 grams. But it wouldn't quite play ball.

I weighed the mitsubishi pistons at 296 grams the pins weigh 60 grams while the A15 ones I had weighed 86 grams. The mitsu piston -60grams is 236 only piston only with 86 grams from the a15 pin its 322 grams add that to the lightweight H beam rod which is 440 gsm versus 550gsm for a15 rod = 110grams savings 110 + 16 grams = 126 grams each rod/piston combo or 506 off the complete assembly. Not to mention the mistu piston can have 1mm taken off to make it a complete flat top with valve recesses so maybe another 10grams for a grand total of 546grams, yet cant remember the piston weight of the A15 piston but could be heavier than 330gsm.

Doesnt seem like much but spinning the extra halve a kilo at rpm is exponential in force created in assembly.

I know its anal but Ive got a flywheel/clutch combo thats 4.95kg and after seen how light engineers try and make new engine internals to increase efficiency if I can I try lose weight where I can and retain strength. Alot of nissan stuff is way over-engineered win/win for us enthusiasts.

Theres a formula that corrolates weight at different rpm anyone know? It calculates force I think.