Would love for you guys to chime in.

I'm wondering if the Mahle -31cc piston which is a 2618 Alloy according to Mahle (called them) and their online chart, I just wanted to know if anyone bought them and has a picture of this piston, see if it is a proper inverted dome with proper quench, here is the part number:

SBC425030I31

Thanks guys, planning on running about 17psi.

 

You didn't ask Mahle when you called them? I would guess they're full round as opposed to D shaped.
What do you mean by proper quench? D shaped to match the head chamber?

 

Yes I called they said they are D shaped which is great, I'll go for them on my next setup, wen with JE's this time, I just couldn't find enough info of others using them, but I also haven't found any negatives, in the end was my buddie's decision, but I must say the customer service from Mahle is extremely good, I couldn't believe it, their tech guy is awesome and two days in a row answered within 1 minute.

 

I run -28cc JE forged 2618 blower pistons (4.030) in a 383 LT1. D shape. I have read that it is important to have a full circular raised feature to squish the fuel/ air mixture to the ignitor plug as the piston travels up on the compression stroke.

My forged assembly (Callies/ Eagle H-beam 6") has been working great for 7+ years with about 14 psi of boost. Runnung a 9.5:1 static compression. -31cc piston should be a good choice. Fluid flow is the most important criteria on a FI engine.

Also, blow-by was a concern/ problem of mine as I experimented. I ended up with an external vac pump (gzms 103). This solved all of my problems, and, a great power adder.
B.

 

I bought them for my build but they dropped right to the builder, so im unsure of what they look like yet, but anything made by mahle is going to be top quality, and yes they are indeed 2618 alloy as well as the -26 and -28 stuff. I plan on about 15 psi myself from a D1SC for the 383 build.

 

You'll be fine with those, I'm running the Mahle -26cc Powerpack pistons, which aren't as tough as what you're getting, and my engine makes 15# peak boost without any issues.

 

Been traveling way too much lately, sorry I missed this for so long.

Several pics of mine:

https://www.camaroz28.com/forums/sho...d.php?t=738817

 

I've run both the SRP D-shaped dish and a Ross O-shaped dish. At first, I thought I liked the D-shaped dish better for better quench characteristics.

Later (after breaking more SRP pistons than I care to remember), I went with Ross because they could offer an oddball bore size. When I received them, I was surprised to find a O-shaped dish. After taking a closer look, I noticed a big advantage of the O-shaped dish. Since the dish is spread out over a larger area, it doesn't have to be as deep or close to the ring groove. This leaves a LOT more material in this area, thus preventing the lip from breaking off. I never broke a Ross O-shaped dish piston. On top of that, I've heard several experts comment that quench isn't nearly as important on forced induction.

Mike