Least expanding forged piston?

[RipperXX]

Looking at after market piston choices, and what I am wondering (been looking but can't find numbers on every piston choice) is, IS there a lighter than stock piston that doesn't expand a crap load but proven? I know all forged pistons expand and require something like 3-4x the stock piston to wall clearance but the less the better to me.



Anyone know? I know Mahle has a light piston, I think it's cause they use a shorter skirt, which i'm not sure if thats a good idea for a street engine or not. Nor do I have any idea of the recommended PW clearance for them. Can anyone help with the choice?

 

[delta448]

This post may help:
http://www.dsmtuners.com/forums/cylinder-head-short-block/306392-piston-rod-recommendation-700-900hp.html#post151612511

In my opinion Mahle makes a damn fine 4032 alloy piston with excellent low thermal expansion and awesome weight savings, but I've not used their stuff before. They would be my choice right now for a 4G63 build though.

 

[RipperXX]

Thanks, i'll go threw and read all that. I have read up on Mahle pistons before and apparently they also manufacture pistons for some exotic car manufactures if I recall correctly. And there the lightest ones I have found.

Did you read somewhere in the linked thread about a low expansion on them?

 

[donniekak]

Out of the aftermarket pistons companies, wiseco's run the tightest ptw clearances.

 

[RipperXX]

Well stock is something like .015 right? and the norm for Wiseco is a minimum of what, .045" Seems like a lot to me, your telling me no one else has a tighter spec? Because that seems like a LOT to me. I know once there warmed up they expand and fit tight but I just don't like the idea of that. If there is a less expanding piston made out of the 4032 material like the Mahle then i'd like to know the specs. So far it does look like the Mahle is offering what I am looking for. So i'm pretty sure there what I will go with, although I do NOT know the PTW clearance for them yet.

 

[pneumo]

Wiseco recomends .0025" PTW clearance.

 

[RipperXX]

I guess that other 0 makes a big difference. But I would have sworn I read about people cracking blocks running PTW clearances that tight with the Wiseco pistons, and that most people were running .004x did they change the alloy, or am I just crazy?

 

[viperlp01]

What but so does Mahle. There "recommended" PTW is exactly the same as the wiseco. I had to do a ton of research and finally decided on the Mahle strokers over the wisecos. They are by far the lightest piston on the market and i also like how the oil ring stays inside the piston unlike the wiseco which is exposed on both sides by the wrist pin hole. I just talked to the machinest that we go through and we decided on a .0030 ptw for my power goal/boost levels. Also that recommended PTW is a bunch of bullshit. You need to fit the PTW to the power goals of the car. It isn't much but it does matter.

 

[herms99gst]

i have a set of arias forged pistons im installing in my car as we speak. I know my ptw was set at .045...The weight of the piston itself is 340g. I also called arias and for the boost level im going for they told me to set up the top ring at .023 and the secound at .019...is their a way to calculate the expansion of a piston by the ptw and ring gap?

 

[pneumo]

That's odd, usually the second ring has a larger gap than the top ring.

 

[draculia]

I have read up on Mahle pistons before and apparently they also manufacture pistons for some exotic car manufactures if I recall correctly.

Mahle is an OE manufacturer for many European companies. I had some euro spec high comp OE Mahle pistons in my old E30.

 

[herms99gst]

yeah, the new 2011 toyota camary v6 run mahle pistons....which is a beast of a lil grocery getter ....to bad i had to go with the 4cyl.....damn gas prices

 

[viperlp01]

Mahle makes the evo 10 pistons. The stroker piston weighs somewhere around 270 grams. They are rediculously light when you hold them compared to the wiseco. THe engine is almost done. I also did my PTW different. I did top ring .018 and bottom ring .020.

 

[RipperXX]

Anyone have any good info on filing your rings?

 

[JayRolla]

I know Jacktransmissions here has used wiseco religously in almost all there builds and have worked out great. There is always going to be expansion on alluminum pistons and you have to live with it. Just remember to let the car warm up before driving and getting into boost or high rpms. The one reason I like OEM builds over forged alluminum setups.

 

[viperlp01]

I have talked to a few people about filing rings. What I ended up doing was put a fine file on vise and only filed one side of the ring and made sure that I filed it straight by pushing the ends together and having them line up straight. The most I had to file off was .002.