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#251: 01-02-2012, 08:03 PM
Scooby2.5's Avatar
Title: Truth [Search All Things]
Location: Kansas City MO Area
Car: 05 Outback STI E85 385/425 6 Speed DCCD
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AVO380 with FMIC tuned by Calvin Dotson/Tim Bailey on a Mustang Dyno.

I might add that Cobb Plano talked me out of ACL bearings and Gates Racing timing belt.
They also recommended the STI gasket kit.

Cobb plano guys used to run the Dallas Subaru Dealer parts and service and race cars and they claimed they had never had a failure with above mentioned parts.

I did have a gates racing timing belt on my car from 108k-158k

I just decided since they were providing the warranty, I would do their recommends.

Cobb no longer sells their Cobb rods that were made by crower but here is a link where you can purchase the same ones from Crower. If you do look at the crower Rods be sure you get the correct ones, some are longer than others and if you get the longer ones you need custom pistons.
Some rods are 5.187 in length and some are 5.135 or 5.141

I have the longer rods with custom pistons.

NO I did not pay $900 for them I got a preassembled short block cheap and tore it down and had Watt and Cobb build it back due to wrong 2.0l pistons.
Sold the 2.0L pistons and purchased new 2618 JE's.

They also like I said use the Mahle 4032 pistons, you could call and talk to Chris Flemming at Cobb plano and he could tell you for sure.
I would go with the Mahles if doing it again as I said above.

The 2618 alloy is stronger and what most use for turbo race cars but like I said they are noisy.

Here is a snippet from the NASIOC stickied Piston FAQ and a link to it:

4032 pistons will have quieter cold start operations due to their tighter piston to wall clearances compared to 2618 pistons. This is due to the 15% greater thermal expansion seen in the 2618 alloy. 15% may seem like a lot, but do the math. Considering a piston to bore clearance of 2/1000's of an inch, 15% is only .0003". Once the pistons have reached their operating temperature, the noise (piston slap) differences should be nearly identical in volume between the two alloys. 4032 pistons will have reduced oil consumption and longer ring life compared to their 2618 cousins due to their better cold start tolerances. While to many these physical comparisons point towards 4032, you must understand that 2618 pistons, for their slight “defects”, are clearly superior in terms of tensile strength and fatigue endurance to 4032. This is why most piston manufacturers specify the 2618 alloy for use in Subaru (turbocharged) pistons.

Last edited by Scooby2.5; 01-02-2012 at 08:14 PM..
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