I've heard it come up a few times when talking about re-sleeving my block, but what does FMR mean Thanks

 

Its FRM I, it means you can't put aluminum pistons with FRM sleeves.

 

And what exactly are FRM sleeves? Thanks and sorry about the FMR part.

 

I always thought it was ------- RandomStrike's Mom....guess you learn somehting new everyday

j/k

 

Thanks.

 

FRM = Fiber Reinforced Metal

The B21 and some of the H22 blocks had FRM sleeves. These sleeves were extremely strong, but the piston rings need to be made out of aluminum in order to withstand the sleeves. Using regular rings will wear them out really fast. Using these type allow the sleeves to be thinner than normal steel sleeves.

As for using aluminum pistons, oh wait! The stock ones are aluminum.

 

DOH!

 

Fiber Reinforced Material, it has aluminum in the sleeves

 

And are stock pistons on an H22 made out of aluminium?? Because I'm looking for pistons with a lower compression so I can boost, but I want to try and avoid re-sleeving if at all possible. Mahle claims that you don't need to re-sleeve, they coat their pistons with different material so it won't damage the sleeves. back to the original question are stock H22 pistons made from aluminium, I know someone already said they were, but is that true?

 

The stock pistons are cast. The S2000 has FRM sleeves and aluminum pistons stock and yes they are coated to prevent them from tearing up the sleeves. So yes Mahle probably is selling the same thing