6MT.net Infiniti G35/G37/GTR Community - Where does the '05 hp increase come from?

struan87 · 03-09-2005, 10:00 AM

Oh
Oh hey guys
How ya been

Did we ever figure out for sure what caused the 37hp increase from the '04 sedan to the '05? As far as I know, the engine/drivetrain/exhaust/intake are all the same, so I imagine it must be in the computer (ie, the '03s and '04s were detuned). If that's the case, then a ECU reflash should be able to add all that hp to a pre-'05 sedan. Which makes the technosquare ECU about $10/hp, quite a deal.

Does anyone know if there are different parts in the '05 that contribute to this? I've only heard rumors before, so I'm looking for real data. I'll ask the dealer next time I'm there, but they seldom know this stuff.

**GZire** · 03-09-2005, 11:58 AM

Hey Stru was wondering where you've been.

Here's what I know for certain;
1. Peak hp is up & torque is lower.
2. The lower intake manifold is revised on the 05's, been seeing this advertised for sale. Supposedly gives more kick on the high end, but you will loose something off the bottom (sounds exactly like the 05's in general).
http://infinitipa.zoovy.com/category...eupgrades/?p=3
3. The exhaust valve timing has been changed.
5. Rev limiter has been raised 500 rpms.
6. Peak hp is rated at or near rev limit.

Here's what I think;
The extra hp has come at the top end due to exhaust valve timing, intake modifications, & raising the rev limiter. There may actually be a loss in overall performance due to the loss of torque on the low end (but peak hp sells cars). Also I think there was a revision to the exhaust also, but don't remember for sure.

struan87 · 03-09-2005, 01:33 PM

Okay, cool. So the lower intake is the only mechanical difference. Valve timing is computer-controlled, right?

It seems like modding for the extra hp wouldn't be worth it (to me) since I care more about the low end anyway.

**GZire** · 03-09-2005, 05:28 PM

As far as I know only the intake has been messed around with, but I wouldn't put it past the engineers to have also done some work on the sedan's exhaust since it seemed to be the most restrictive part of the system.

Exhaust valve timing would be adjusted through using a different cam profile for the valves.