What are the best turbo pistons now?

[325isBimmer]

I cracked my S52 block and it is pressurized the cooling system. Time for a new build and looking for input on the best pistons for a M52 with 135mm rods and S52 crank. Any advise on rod and main bearings also? Are coated worth it?

I was looking at getting these: https://store.vacmotorsports.com/mob...s52-p4967.aspx

[wgknestrick]

I cracked my S52 block and it is pressurized the cooling system. Time for a new build and looking for input on the best pistons for a M52 with 135mm rods and S52 crank. Any advise on rod and main bearings also? Are coated worth it?

I was looking at getting these: https://store.vacmotorsports.com/mob...s52-p4967.aspx

M50s make the best turbo engines IMO.

[325isBimmer]

Why are the M50 engines better? I was getting the M52 just for the crank sensor in the block

[digger]

smaller bore is less likely to crack

[milKt]

If your M52, S50 or S52 blocks are cracking,
you're doing something wrong.

The original reason some BMW heavy hitters were using the m50/m52 was because they believed their busted HG's due to too little meat between cylinders and/or cooling jackets.
All that changed with proper block & head prep...and O-ringed or cut ring head gaskets "holding their own".

CP are good, yes.
Advantages of "coating"?
or is that another piece of metal we can "pretty up", before they get dirty/beat up.

[325isBimmer]

If your M52, S50 or S52 blocks are cracking,
you're doing something wrong.

The original reason some BMW heavy hitters were using the m50/m52 was because they believed their busted HG's due to too little meat between cylinders and/or cooling jackets.
All that changed with proper block & head prep...and O-ringed or cut ring head gaskets "holding their own".

CP are good, yes.
Advantages of "coating"?
or is that another piece of metal we can "pretty up", before they get dirty/beat up.

I have had this motor turbo/built since 2006 so it has lasted a long time. It ran lean after a long right turn road racing and it had some detonation or preignition. I have cp pistons and arrow rods but I'm just wondering what people are running today since it has been a long time since I built my motor. Just looking for some honest opinions on coatings and pistons in real world use. I also just want the M52 block because I want it as strong as possible. I switched to cut ring and had zero gasket issues when they came out.

[TheJuggernaut]

I have Ross pistons and I'm really happy with them but I really dig the options available from CP, if I didn't already have a profile figured out with Ross, I'd get CP for my next order, with the X forging style.

For coatings, I have no data to back this up but I'm a fan of the hard anodizing, I'd definitely do that again, gives the piston that much more resilience (plus if you run ethanol, hard anodizing protects the alu from corrosion). The coating I'm not sold on, I'd still do it again because I'm an idiot but from what I've seen, it doesn't stay on the piston all that long.

rejected-4-300.jpg

[dominator293]

With regards to blocks, i'm not sure about US variants, but in Australia the M52's are alloy block and the M50's use an iron block. Hence why the M50's iron block can handle boost a lot better than the M52 alloy block. Certainly correct me if I'm wrong, but turboing an M52 alloy block over here is seen as risky and not good for high boost pressures. Just my 2 cents.

[wgknestrick]

With regards to blocks, i'm not sure about US variants, but in Australia the M52's are alloy block and the M50's use an iron block. Hence why the M50's iron block can handle boost a lot better than the M52 alloy block. Certainly correct me if I'm wrong, but turboing an M52 alloy block over here is seen as risky and not good for high boost pressures. Just my 2 cents.

Correct, but doesn't mean you can't make power with S52s, or M52s. M50s are universally accepted to handle the most HP and boost of the 3, while also being the most reliable long term.

CPs are also generally considered a top tier piston that has many good results. I don't know of many people besides tuners that have multiple long term experiences with all the pistons available.

[325isBimmer]

Thanks for the input. I was just checking to see because it has been awhile since I built my last motor and checking for any tested setups that are working good. I will probably go with CP again. I was just confused when somebody said the M50 was stronger than the M52 because I thought they were both made from the same block. The blocks I use are cast iron, not the aluminum versions. I will post up what I order. I am just waiting for my block so I can measure the bores and see if I need 84mm or 84.5mm.

Thanks
-Mike

[dominator293]

Must be an M50 block if it's cast iron, M52's don't come in cast iron. But pretty sure they are same same besides the material they are made of.

[someguy2800]

US single vanos M52’s are all cast iron except for Z3’s. It’s the same casting as used to build S52’s. It’s a different casting than an M50 but I don’t know of anything that makes one casting stronger than the other.

[dominator293]

Ahh good to know!

[Nutzy]

Nice to see another boosted BM in Canberra!