Im thinking of making an upgrade to my R56S wngine with forged pistons. Seems that the piston rings are in bad shape (consuming too much oil) so i probably have to open the engine and replace them, but once i do so why not put forged pistons in there. Friends have advised me for those two brands, Mahle and CPS but i have no idea which of the two is best! Any help on this and where from can i get them as cheap as possible?

 

Talk to Jan at RMW. He also now has a big valve head for the R56.

 

Also look at Supertech, best Bang for your buck, IMHO. BUT, if you are burning oil, and you did a leak down test, and a compression test, and everything points to rings, it might be wise to tear down before you order any parts to determine if cylinder walls are out of tolerance (out of round, conicity, scored???).

 

We've had good luck with the Mahle pistons. We are restocking them next week if you need a set.

 

If it's a daily, I wouldn't run forged.....

 

What fo you mean by daily? If i use the car every day you mean? And if so, why not run forged?

 

Do some research on "piston slap".....as I understand it, in a very basic way, your "new and improved forged pistons" will have different propties than the ones you pull out...expands at a different rate....
Result....while you can do great and amazing thing boostwise, engine life is still pretty short...

 

Forged are stronger than cast. So thats good. As the guy above me stated, do a little research on forged pistons before you go with them.

Expansion rates of forged pistons are a lot slower, meaning you have to let the car warm up 100% before driving it. (Call it 20 minutes of idle time). If you don't, you run the potential of having a TON of blowby and damage to your rings/cylinder walls. If you're going to run forged, you need forged rods as well. The different strengths between cast and forged will mean your rods are the weaker point (if you use cast rods).

Really, for the price, and the fact that your car won't be making 500+ hp (an arbitrary number) you won't need a forged piston.

Not trying to say that forged are out of the question, but you should ask yourself, what is the point?

 

The stock Mahle pistons are forged...

 

Unless you're tuning to make a beast of a car and do an engine build, I would stick with OEM piston. Even if you were doing an engine build the pistons aren't the weak spot in the motor. The con rods are the weak spot in these engines...

What was the cause of the piston rings failing? What does the cylinder look like at this point? Have you had any predetonation issues?

I would def address what exactly kind of shape the cylinders are in. Are the pistons themselves good and just the rings messed-up? What caused the piston ring issue? I would hate to spend money on nice pistons only to have the same issue occur again. Like others have said, go OEM to save engine/piston longevity.

 

Please share where you have found this info. As far as I have ever been able to find, the Peugeot motor (the one in our cars) has cast pistons. All of the spec sheets on the web show this as well.

 

I am no technician, so any research i do will probably be pointless cause i don't understand any tech stuff!

A friend was telling me that if i go over 200hp i will need forged pistons. And to come to think of it, Isn't the JCW using forged pistons?

 

Depends on the boost you run...
SOME oem pistons do crack and fail around the skirt at higher boost levels.
This is where a relationship with a vendor pays off...
You can tell them what you expect from the motor...what you needs, wants and desires are...and they can suggest a product to meet your goals.
Forged pistons are right for some...overkill for others...even not "right" for some.
Talk to vendor...see what they offer...and let them explain it to you.
I would PLEAD with you to PLEASE BUY your product from them when it is time if you do go that route...
Sometimes a JEG's or other big box parts store that lists THOUSANDS of different part numbers can beat them $$ wise..but expertise is very valuable...especially if you do not understand the differences in different products!!

 

For the research, you will be able to learn a tad about the applications and the differences between the two. You at least won't be completely ignorant about it. Its best to know something about what you're buying/doing, so you don't get shafted by anyone who is selling it to you or installing it.


I've seen cars with high compression and turbo make well over 200 HP without forged internals. For example, a 11:1 compression ratio, with a decent turbo setup can make 500+ hp without forged internals. You're not going to make 300+ on a mini, so I don't think you'll have an issue.

 

+1 . Unless you have about $20k or more to spend on an engine build and a tuner that is 100% sure he can tune for all those mods then I would save your money and not waste it on forged pistons. A nice suspension set up goes a long way on the MINIs.

 

Go with super tech... if you go mahl or CP you need rods too... so if your just going to do pistons go with super tech, factory compression...