Replacing PCs

[930LDR]

Need to replace the P&Cs in my 930 as part of my rebuild. Have access to a new set of 3.3 Mahles as well as 3.4 Nickies and JE Pistons. Pricing for the 3.4 setup is right about 2x the 3.3s (killer deal on the 3.3s)

Would appreciate some opinions. I'm leaning towards the 3.3s based on price and Mahle reliability. The fully finned 3.4 setup up though is great in theory but can't quite wrap my mind around the $$$

[nocarrier]

I have the exact same problem. However, after reading about how another pelican on the 930 forum was pushing over 700hp on a stock set of half finned cylinders, I am seriously thinking about going with the stock p&c's.

I wonder how much hp is gained by going from 3.3 to 3.4

[930LDR]

I would think that without anything else done you'd be looking at a pretty de minimus gain given the 3% change in displacement.

[JFairman]

The new 3.3 mahle's would be the best choice if staying 7:1
With the others you can go 7.5:1 or 8:1 for better acceleration in city driving.

Another lower cost option is look for used 3.2 fully finned cylinders. They often go for around $3-400 a set.
Then send one piston and the cylinders to Cylinder Repair, Head Repair, Cylinder Replating Services by Millennium Technologies or Cylinder Plating | Cylinder Honing | Cylinder Repair | Cylinder Re-Plating| US Chrome Inc Cylinder Repair Company so they can bore and plate the cylinders to perfectly match your pistons.

You can usually do everything for around $2500 or less that way.

[HelmetHead]

Originally Posted by JFairman

The new 3.3 mahle's would be the best choice if staying 7:1
With the others you can go 7.5:1 or 8:1 for better acceleration in city driving.

Another lower cost option is look for used 3.2 fully finned cylinders. They often go for around $3-400 a set.
Then send one piston and the cylinders to Cylinder Repair, Head Repair, Cylinder Replating Services by Millennium Technologies or Cylinder Plating | Cylinder Honing | Cylinder Repair | Cylinder Re-Plating| US Chrome Inc Cylinder Repair Company so they can bore and plate the cylinders to perfectly match your pistons.

You can usually do everything for around $2500 or less that way.

+1 This is the route I went...3.2 cylinders worst case 500 a set..then punch them to 3.4

[930LDR]

Any concerns on the longevity of boring out those 3.2s?

[JohnJL]

I've had 2 sets of JE and perfectbores now, happy with both sets. First was 10.5:1 cr 3.0L naturally aspirated. The second are 98mm 3.2L SS 8.5:1 compression with ceramic domes and coated skirts in the supercharged car.

[gsxrken]

They really do have woeful pre-boost torque. I've been commuting with mine a bit and have been day-dreaming of a a set of 8:1 Nickies to pick it up some. Based on that, if I was you, I would be looking for an improvement if I was going to lay out the cash.

What I haven't researched is the fueling requirements of 8:1 to avoid detonation. I run a 7006 at 1 bar and am OK according to my LM-1 wide-band, but I don't know if AFR is the only thing that will hold off pinging. 8:1 mechanical with another atmosphere stuffed in there may ping anyway... I don't know so do your homework first. (And then post it here )