Well I have the dreaded exploded piston from running the Alta stage 3 tune in a can on my car instead of having the car properly dyno tuned for fueling/boost etc. (NOT blaming Alta, just pointing out what helped cause the problem)

My question is now that there are a few piston options out there who has gone with what? I'm not doing any head work for now just building up the bottom end to be nice and stout while running slightly more power than stock. Eventually i'll get another head to have done up to bolt on the car. For now i'm just running a stock upgraded turbo, turbo back catless exhaust, W2A intercooler setup and true cold air intake.

I'm trying to decide between the Carrillo(CP) and the Mahle pistons. Carrillo has the advantage of being able to choose from 2 different compression ratio's but the Mahle pistons have a stock dome instead of the the generic dome the Carrillo pistons seem to have.

 

Well, if you want to build the bottom end up properly you will also need rods. Carillo is really the only option for them. Any good machine shop can make them match the pistons you want. Go with the stock compression ratio. I would get the mahle pistons because they are made out of a metal more suited for daily driving.

 

Yeah I'm going with rods for sure. I'm not sure I follow when you say the Mahle pistons are better metal for a daily driver... they are forged aluminum just like the CP pistons.

 

Different types of aluminum.

 

Here are 2 choices you have.
Choice one the cheap way,
Just buy another engine for $3k call it a day and waiting for the next time this happens
Choice 2 the more expensive and might possibly last longer way,
Build the bottom end of the engine with money easily shooting up into the $10k range.

 

I wouldn't blame it on bad AFR from the Stage 3, running so much boost on the known weak pistons is probably the cause. But anyways, that's my 2 cents.

i would just buy a reman engine. The amount of time and money you're going to spend is not worth how little power gains are to be had on this engine. I've though about this a lot, and when my engine gets weak, I will just buy a reman engine, send my cylinder head to Thumper, and get a remote tune again from Evolve.

 

Reman engine is not an option. Sorry to be so direct but I don't want it to turn into one of those threads. I understand the financial implications of the road i'm taking here.

I'd rather rebuild stronger than stock for a couple thousand more. Labor cost is a non-issue since i'm doing it at a friends shop. Machine shop work is a non-issue since i'm a machinist.

I'm more interested in the metallurgical differences between the CP and Mahle pistons now that that has come up, and the piston dome design and whatnot.

I was leaning towards the Mahle anyways based on their reputation and the similar to stock dome design. I've tried researching to see which are made of what kind of aluminum alloys and can't find it anywhere. MNIPWR what information are you basing this on? I'm not being argumentative I want to genuinely know so please don't confuse my questioning for that.

Also on a side note, this is my summer only fun car now. I have a Subaru Legacy for the winter and any time the weather is real crappy out. So not quite a daily driver and not quite a track only car. Somewhere in between.

 

From other engine types, the common forgings for pistons are from 2618 and 4032 aluminum alloys. There are several different metals and quantities that are different between the two alloys. If I remember correctly, one of the alloys expands more than the other, and there were slight differences in toughness. I'm no expert, but have done a bunch of reading in the past.

I would presume that either alloy used in a forged piston will be a signficant strength and toughness improvement over the factory cast piston.

Mike

 

I did a lot of research before I bought my pistons. Mahle and CP have both E-Mailed me in response to that question. You can buy CP pistons with the stock dome design. You would just have to call or e mail them and ask them if they have any left. I have the part number somewhere if you want it. I would not but any piston that does not have the teardrop shape. It is vital for the itemization of the fuel. CP pistons are made out of 2618 alloy and the Mahle are made out of 4032. Im not going to explain the difference but here. http://en.wikipedia.org/wiki/Hypereutectic_piston

 

Sorry to hear about your current issue, but whichever piston you decide on going with, make an investment on an Oil Cooler Kit. Aside from from running the higher boost with your stage 3, the stock pistons will crack because of this strain being put on them. IMO, with these cars, we should all slap on an oil cooler kit once we get a tune done, especially for track days or drag. The constant increase of temps with no oil to compensate will eventually have mini owners run into this issue.

 

Wossner now have pistons available for the r56. Another good brand

http://item.mobileweb.ebay.co.uk/vie...d=310594797402