Hello guys

I have a question regarding rod selection for my current build.

I’m in the middle of a fairly serious engine project: a high-revving NA6CE 1.6 with ITBs.
The base engine is the stock 115 hp unit, and I’ve already gathered most of the internal components.

Current build overview:

• Block / displacement
  • NA6CE 1.6
  • 81 mm overbore (approx. 1720 cc)
• Bottom end
  • ACL Race bearings
  • Fluidampr crank damper
  • Boundary Stage 1 oil pump
  • 1.0 mm head gasket
  • Target compression: ~11.3–11.4:1
  • Toda 3.5 kg flywheel)
• Head / valvetrain
  • Toda forged pistons 81mm
  • Toda 272° / 10.3 mm lift camshafts
  • Toda adjustable cam gears + timing belt
  • Supertech +1.0 mm intake & exhaust valves
  • Supertech valve guides
  • Supertech dual valve springs
  • Supertech valve stem seals
  • Shim-under-bucket conversion
  • Head skimmed 0.55 mm
• Induction
  • Jenvey individual throttle bodies (ITBs)
• RPM target
  • ~9000 rpm max

My question:

I’m currently deciding on connecting rods and wanted some input from people who have built similar high-rev NA BP engines.

I’ve been looking at:

• Carrillo rods (~432 g) – very light, excellent reputation
• Maruha rods (~460 g) – slightly heavier, also well-regarded

My main concern is:

• Are Carrillo rods too light for a 9000 rpm NA build like this?
• Or is that weight actually ideal given the goal of reducing reciprocating mass?
• Would you personally go with something else entirely for this kind of setup?

I understand that lighter is generally better for high RPM response, but I also don’t want to sacrifice long-term reliability or introduce issues with harmonics / fatigue margin.

If anyone has experience with similar builds (especially high-rev NA 1.6–1.8 BP engines revving near 9k), I’d really appreciate your input.

Also, if you have any general comments about the build, feel free to let me know, this is my first big engine project and I’m trying to make sure I’m not missing anything obvious before I assemble it.
Important Note:The car will be used as a weekend car, mainly for spirited driving, with occasional track and drift days.

Because of that, I’m not building a pure race engine, but something fun and responsive that can still handle occasional abuse.

 

then ditch any ideas of running to 9000rpm. This is no Honda motor.
quickest way to wear out a motor, even if built with all the best bits is to rev it to the moon.

 

Yes, that is clear to me that it is not a Honda engine 😄

And yes, I know it’s not ideal to use “high-rev” and “reliable” in the same sentence, but I want to make the best of it.

I’m fully aware it won’t last another 200,000 km, so don’t worry 🙂

 

Stock ports and valve dimensions with those cams, the B6 won't flow nearly enough to get to 9k and make any power. I'd expect more like peak power at 7700 and running out of breath by about 8000, assuming you get the runner lengths correct (math). In any case, light rods are a good idea for a build like that. Good luck with it. Post dyno plot.

 

There will be complete head and block work done, including ports for the oversized valves 🙂Okay, I understand. I hope I will still get some good power nevertheless.

Would you pick Carrillo or Maruha rods?

 

Whichever is lightest. It won't rev high or make too much power so you don't need monster rods.

 

I agree with Emilio. Not enough cylinder head. I wouldn’t expect more than 150hp NA on gas. A turbo build would be less expensive and make twice the HP.

The CP ProA rod at 416gr would be the best option with a lightened piston and a taper wall pin. The ProSA rod is 431gr which is basically the same rod with a thicker center web. I’m running a set in a turbo build that runs to 7500rpm with no issues after 5kmi.









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