I read recently that the '05s have a change that was made to them. Can someone explain what the change was?

Is it a change that would keep me from needing to get an aftermarket plenum?

I just didn't know if it was a significant upgrade that was made by the factory.

Thanks,

Jeff

 

There are two parts to the Plenum....an upper part and a lower part. Significant changes were made to the lower Plenum on the '05's.....shortening the intake runner sections among other things.

The jury is still out as to whether any Plenum mods (new upper Plenum or Plenum Spacers) improve hp/torque on the '05's. On My350Z, a member with a '05 Anniversary Edition seemed to dyno with improved numbers with upper Plenum mods while here on G35driver, a member with a '05 G35 6MT seemed to have no significant performance gains with his upper Plenum mod.

 

Is it a fact that the 05's have different lower plenum ?? does this apply to both 6 Speed and Automatic ??

 

Good point.....it is just the 6MT '05 G35C that has the different lower plenum. This motor also has different pistons and has variable valve timing on the exhaust as well.

 

The MT6 Sedan as well.