My G35 I’ve had for about 8 months now and I’m ready to start modifications, I wanna add as much horsepower as possible without having to buy a super charge or a turbo charger. Any idea how I can do so what’s the best starter mods for the car and then once I have those what will really show me a difference in power?

 

5/16 plenum spacer for non-revup, 5/16 spacer and MREV2 lower intake if it IS a revup motor. HFC, rev-up airbox, tune.

Those are the biggest gains. Exhaust if you want it noisy and a little more power.

 

maybe things have changed?

IIRC, bread and butter bolt ons were IHCE...intake header cat exhaust.

that was good for about 40whp, right?

I know the plenum spacer helps as well. But there is no good acronym for 5 things.

IPHCE?

 

Headers were never extremely beneficial, they are mainly for sound. HFC's or straight pipes designed for scavenging and an unrestrictive exhaust will help. Most of the aftermarket intakes I've seen deal with heat soak issues so a good combination is a "Z" tube which eliminates the baffling and using a higher flow drop-in filter with the OEM air-box. The OEM velocity stack off of a Revup air-box will also help slightly. For the Revup, an MREV2 or the lower intake plenum from a DE will benefit mostly in the early part of the power curve. And yes, the spacer is a very good mod for those that don't want to go with an aftermarket plenum.

For those that want to machine out the inlet of the upper plenum and go with a larger throttle body, then a larger diameter intake would be best.

40+ gain with a tune is achievable on the Revup but would be much harder to get with a DE.