OM606 Forged Connecting Rods – F-tune Performance IA Beam Rod Guide

OM606 forged connecting rods are one of the most important upgrades for any serious performance build. Today we cover the second generation F-tune Performance IA beam rods – what makes them different, which engines they fit and how to choose correctly for your application.

Why IA Beam Not X Beam or H Beam

The connecting rod market offers several beam configurations – I beam, H beam, X beam and various hybrid designs. X beam rods are typically the lightest strong option. H beam rods are widely used in performance applications. IA beam is a development of the traditional I beam with reinforced geometry.

The design choice comes from looking at what original high performance production engines use. Exotic sports cars, high power factory engines, motorsport applications at the highest level – they use I beam or IA beam rods. Not H beam. Not X beam. The manufacturers with unlimited engineering budgets and the highest performance requirements consistently choose this configuration.

If it is good enough for the highest levels of motorsport engineering it is good enough for an OM606 build. The IA beam design is incredibly strong in both directions of loading – compression and tension – and resists distortion under extreme forces.

Second Generation Rods – What Changed

The first generation F-tune Performance rods launched seven to eight years ago as traditional I beam design in two sizes – turbo specification and stroker specification. The second generation IA beam rods follow the same two size approach with improved geometry and materials.

Both generations are designed in-house and manufactured on the strongest available forged blanks. The manufacturing cost is significant which means profit margins are minimal. The goal is having strong rods in as many OM60x engines as possible – not maximising revenue.

Two Versions – Turbo and Stroker

Turbo specification rods: Designed for standard displacement builds. OM604, OM605 and OM606 at factory stroke lengths. Also fits OM602 and OM603 turbo engines as essentially a direct replacement – match the rod to the correct piston and it fits.

Stroker specification rods: Designed for increased displacement builds – OM604 to 2.3 litre, OM605 to 2.9 litre, OM606 to 3.5 litre. These are not applicable to OM601, OM602 and OM603 stroker applications.

Compatibility With Older Engines

OM602 and OM603 turbo engines – turbo specification rods are essentially direct fit. Match to correct pistons and install.

OM601 US specification – the 2.2 litre US engine has 89mm bore versus the standard 87mm bore of OM602 and OM603 turbo engines. This complicates the rod fitment. Options include bore and sleeve back to 87mm, source a standard 2.0 litre OM601, or contact specialists for alternative solutions.

Naturally aspirated OM601, OM602 and OM603 – these use 26mm wrist pins versus the 28mm wrist pin of turbo engines. Turbo specification rods require turbo pistons. On naturally aspirated engines with 26mm wrist pins this requires either sourcing correct pistons or using different rod specifications.

Bolts – Carrillo Recommended

Rods are sold without bolts. This is intentional. Local suppliers frequently offer bolts at prices that beat import pricing and there is no reason to force customers to pay more than necessary.

Carrillo bolts are the recommended choice – genuine original Carrillo hardware, not copies or clones. These are stronger than ARP in absolute terms though ARP is more widely available and more affordable. If you can source ARP locally at competitive prices they are perfectly adequate. If you want the absolute best bolt available use Carrillo.

Summary

• OM606 forged connecting rods: second generation IA beam design in turbo and stroker specifications
• IA beam chosen because highest level motorsport and exotic production engines consistently use this configuration
• Turbo rods: fit OM604 OM605 OM606 at standard displacement, also fit OM602 and OM603 turbo engines
• Stroker rods: for 2.3L OM604, 2.9L OM605, 3.5L OM606 builds
• OM601 US spec: 89mm bore complicates fitment – bore and sleeve or alternative solutions required
• NA engines with 26mm wrist pins need turbo pistons when fitting turbo specification rods
• Available through resellers worldwide to avoid high shipping and import costs
• Sold without bolts – Carrillo recommended, ARP acceptable

Stay tuned for supercharger and big block content. See you another day!