piston decision

[superR]

I am currently in the market for a set of forged pistons and rods for my turbo R , mainly because im now addicted to boost! ;)
there are many varieties and brands out there but i have narrowed it down to the following due to there resonable price and brand recongition i have of them. It's between CP's , weisco's , JE's and Mahle pistons.
Which are good and which are bad...they cant all be reliable.
What CR ratio do i want in a turbo type R i was thinking along the lines of a 9.8 OR a 10.5 CR ....the aim is to run around 15-18psi.
Also another question , stock bore size pistons or overbore size........ i know if i overbore the sleeve become slightly thinner thus weaker and suseptable to cracking , but i also know that aftermarket pistons may not be right for my current bore size ( the clearences may not be spot on). is this statement true or fales?
If any one has done somthing simular or has any sort of imput, it is all wecome as it is a hard choice to make cause once they are in they will be in for a very long time!

james

[Weq]

Weisco's at .5mm over. IMO.

Stay away from JE as they have 2 much silicon content.

u need to go overbore on ur stock sleeves to get a good seal and give the pistons the correct clearance. This wont make the sleeves anymore suseptable. If u are going to crack a sleeve, its becuase ur tune sucks or u over-rev.

[superR]

lol i knew what you think weq......i agre je are not the best of choices.im liking the Mahle pistons , they have some sort of thermal/friction coating thats sounds really good but how can i take a munufacturers word for it. As for the overbore that makes good sence. My tuner is defitly upto standard so there wont be a problem there.
im also a little worried about piston rattle , so i need a piston with good expansion/contraction properties.

james

[pornstar]

already wanting more? lol :) nice james

[Slow96GSR]

All those are good choices. JE is back ordered on most of their pistons so stay away from them. We run CP and Wiseco in our cars and JE too. I personally run CP. I also coat mine. Wiseco comes with the skirts coated already so just the tops would need to be done. I would go .020 over and about 9.0:1 to 9.5:1 cr. ARP head studs and main studs couldn't hurt and are only $350USD extra. Also a good head gasket should be done. Fo the expansion and contraction read this (http://www.strathlan.com/CMS/docs/ThermalConsiderations.pdf). For rods a set of Eagle H-beams will do. If you are looking to spend $1500-$2000 on this just get a rotating assembly from eagle, that's rods, pistons, crank, rings, and pins.

Then since you order from the U.S., I bet, you can ship them to a coater then they can ship to you. Coatings are well worth it on a boosted motor. I noticed a 30-40% drop in temp before the turbo was installed and with it I run 5-10% cooler than stock. The cost for coating the crank is $110USD, pistons are $40 each, and rods are like $30 each. It also helps you get up in speed by reducing drag off the crankshaft.

That's my $.02USD and I know you all hate spending money on coatings and shipping but it's worth it. Good luck with the build and I am glad to see you like the boost!

[todaek9]

cosworth...

[superR]

slow96gsr , yer i am thing the weiscos have a great skirt coating but it is worth spending the extra to get the crown coated too.....the egal H beams were my first choice all along.
I got another question..if i get pistons that are 9.8CR for a B18C1 engine and i have a b18c7....would the CR be the same...i think it would be less with these pistons wouldnt it.....
I have never heard of cosworth pistons but i will look into the all the same.

james

[Slow96GSR]

I'll have to look up the specs on the c7 so give me some time on that. As for coating the tops, it is worth every penny! It keeps the heat in the combustion chamber. It also allows the pistons to handle a little more heat before breakdown although I bet you won't get that hot. It will be a little less for coatings if you already have the skirts coated like with the Wisecos. If you want a quote on the coating pm me and I'll put a call in for you. I bet it would be about $25USD each instead of the $40USD each with skirts.

Cosworth makes great pistons too. We haven't used them much but not to many people ask for them.