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Piston Weight

belize1334

Well-known member
Joined
Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
Does anybody have numbers for the typical weight of stock pistons as well as the usual aftermarket players?

The reason that I ask is that I was doing some calculations and I determined that the single biggest effect from a stroked motor is that the peak piston acceleration of a stroker-motor is rougly 18% greater than that of a normal 2.0L motor. Actually it's 17.9% for a 2.3L and 16.9% for a long-rod 2.4L. So, if you were thinking of doing a stroker with OEM rods, you'd have to figure a lower power tolerance due to the greater force necessary to maintain reciprocation. But, if you knew for instance that your aftermarket pistons weighed roughly 20% less than OEM, then it'd be a was (F=ma). So, that's my question...what do OEM pistons weigh?
 

Rausch

Well-known member
Joined
Dec 21, 2004
Messages
12,049
Location
Cleveland, OH
I know there are a few fellas with accurate scales and some stock and aftermarket parts laying around that should be able to get you some numbers.


I don't think the relation is direct however. The issue, as you noted, is peak speed. The rod angle also plays a part, but sticking with this particular for the moment may shed some light.

The piston peaks in terms of speed just as it changes direction. TDC and BDC. The concern here is that speed is the limiting factor to the engines reasonable redline. Reducing that weight being accelerated/decelerated would most definitely help the situation, but I think there are other things that would need to be addressed as well. The rods are taking more abuse, the wrist pins, piston pin area/skirts, etc.. Granted reduction of mass would definitely led itself to taking that redline up, as well as allowing for a greater operating load, but I think it's more logarithmic than a direct correlation.

I have an interesting write up (looks like a term paper) on the computer somewhere. The math seems solid though Shoot me your email and I'll be more than happy to pass it along.
 

I have some stock pistons and Arias pistons down at the shop i can get you a weight tomorrow. With the 1.5 rod ratio of the 2.3 i would not try stock rods unless you plan on keeping your rpm around 7000 . Even with a light weight piston like a Mahle you would be playing with fire trying to calculate, since there is no definitive point at which a stock rod will fail. We have seen around 500 being the limit but there have been failures at 450 and i have seen over 550 so there is just too much tolerance to get an math formula out of this one. I too have racked my brain about the 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 4G63 and 4G64 variants. I plan on taking my 2.3 up to 9000 rpm+ just hope it will stay together : )
 

GVR-4

Well-known member
Joined
Apr 22, 2002
Messages
2,610
Location
Asheville, NC USA
I've got some brand new Wiseco 2.3 stroker pistons that have the weight written on them with a Sharpie. They range between 289.6 and 290.6 (I'm assuming grams). They're stock bore (85mm).
 
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