Mahle Piston Help
 

I am looking for some more information on the Mahle "Max Moritz" type Piston for a '89 3.2. Below is a picture of the Piston.

http://img.tapatalk.com/d/14/05/08/7uje4e2a.jpg

They are 98mm and came in two dome heights providing different Compression Ratios. They are from the 98P11 forging.

Is anyone familiar enough with these to explain their differences and why you would select one over the other? How much of a CR difference should you expect? The effect it would have etc.

Thanks!

Wow, Crickets........

Original build was going to use 98mm 9.8cr Mahle P&C on a 1989 3.2 Engine with a 964 cam and SW chip. SSI's or another exhaust would also be used if they were worth it.

It turns out my P&C are 98mm, but a lower 8.9 or so CR. Now I am wondering how this will affect my original plan and if I should make some changes.

What effects will I have with lower CR? Should I select different cam profile etc.

Thanks for any info!

The two sets differ by compression height and pin diameters: one set is for 3.0 SC engines and the other is for 3.2 Carrera motors.

These are not interchangeable without different rods.

Both are for a 3.2
 

Hi Steve,

Thanks for the reply. According to many emails with MAHLE, they are both for a 3.2 Motronic. The pins measure at 23mm. The dome heights were made at 9.3mm and 10.0mm. Their volumes are 28.3cc net volume and 35.4cc net volume.

Have I mixed something up here? I sent them pictures of all the markings and they were ID'd as the 9.3mm Dome Height set yielding a lower CR.