Rotating Assembly Weight: Stock Vs. Aftermarket

[NateDogg]

Can anyone comment on this? Any significant differences between brands/ piston CRs/alloys/designs etc?

[KATwo40]

I don't have any hard data for you, but I used Arias slugs, AMS sportsman rods, a 12lb flywheel and had the entire assembly lightened/balanced.

The engine revs much more freely and the revs drop more quickly because there's less rotating mass.

Additionally, I require more braking into the corners because there's not as much engine braking from the loss of weight.

Whether this is good or bad, I couldn't tell ya'. All I know is Wednesday I pulled a 944 Turbo by about 3-4 cars in 3rd gear, so I'm happy.

[NateDogg]

Sounds fun. I suppose that flywheel is the biggest benefit..

Im wondering if Ivan or Chris from AMS can comment on this?

[nissanfanatic]

http://www.importbuilders.com/....html

Looks like Wisecos tend to be the lightest as far as pistons..

[9sec240]

I did weigh stock, Pauters, Crowers, AMS Sportsmans, and AMS Pro series rods and posted that info somwhere. I hate to say this but try searching. From what I remember, the Pauters were about the same as stock at just over 700 grams. Crowers were next in line at about 700. Our Pro series rods are just under 700 and our Sportsman rods weigh in at about 600 grams.

We got 5 sets of Eagle rods in which weighed a bit more than our Sportsman rods but we ended up returning them due to quality issues.

I have not weighed pistons. I will try to do that tomorrow. I have stock pistons, Arias and a set of JE that a customer sent in to use in his engine build.

In the past 10 years I have used just about every brand of piston and have yet to find a better quality, better functioning, more cost effective piston than the Arias.

[NateDogg]

Thanks for the info, Ivan.

One of the reasons I'm curious about piston weight is to see whether or not there would be an increased load on the stock rods if aftermarket pistons were used.

[nissanfanatic]

Orion weighed JEs and they the same as stock pistons. That was one of mine and his thoughts as well..

[NateDogg]

Well I've looked up the following pistons at .020" overbore and as close to 9:1 CR as possible:

Wiseco 9:1 CR : 358gArias 8.8:1 CR: 360gJE 9:1 CR: 355gRoss 8.5:1 CR: 362gCP 9:1 CR: N/A

Doesnt seem like there's much in it as far as weight savings goes for these piston designs.