2007 G35 Intake Project

[Fast355]

Finished up my air intake setup on my G35 this afternoon after replacing the a/c compressor this morning. A/C clutch coil failed on it after 215K.

I was already running the HPS silicone intake hoses. I ordered a cheap intake setup from Amazon about a year ago but did not like the aluminum tubing and the way they heat soaked. They had terrible transitions and necked down the MAF sensor openings to about 2.25" which is smaller than the factory MAF housing. Car ran well but ran rich on the stock tune. I had pulled them off and put the stock air boxes on with K&Ns. I finally got the itch to let the VQ V6 have that awesome intake howl they have. I ordered a pair of 2.75" MAF housings about 3 months ago that were finally delivered this morning. I used the heat shields and filters from the cheap intake kit. I fitted it all up. Have a little tuning to do on the MAF tables but it runs very well. Fuel trims are running about +10 to +14 at the moment. Have not been WOT but the car accelerates much more smoothly now. I love the way this little high reving 6 sounds. It has equal length headers, high flow cats, 2.5" custom built exhaust with a X-pipe and 4 magnaflow mufflers into 4" tips. Quiet when you are cruising along but really opens up when you get into the throttle. Cruising around town checking out the a/c repair this evening it was knocking on 20 mpg. I even ran it up to 5,000 rpm a couple of times in 1st and 2nd gear at about 1/2 throttle leaving a couple of traffic lights. Not bad for a ~380 hp V6 with a 5spd auto and 3.91 gears in a heavy 4 door sedan.

A/C repair was a complete success. With an Oreilly's Murray reman compressor and charged with R152a it is cooling down to 34°F with the a/c fan on high speed and the climate control temp set to 60°F. It will freeze you out of the car after 5-10 minutes. Compressor is running quietly too. Much quieter than the 215K mile one even though it too was still blowing ice cold up until the clutch coil failed. Thats with a 25% underdrive crank pulley as well.

[Fast355]

This was the air intake tube setup the way they shipped. It was a $124 system. Great buy for the heat shields and filters. The piping bumped to 3" after the 2.25" MAF section and those flimsy thin silicone couplers reduced it back to 2.70" at the throttle body. The HPS hoses are 2.70" ID and the new maf housings are 2.75" OD. They fit perfectly and the air flows smoothly through the system now. The MAF reading has never been very smooth at idle on this car. I am thinking of ordering a pair of 6:1 MAF screens for it to see if it will run more smoothly with them in place.

[Fast355]

Amazon kit installed on a G37. I like my install with the heat resistant silicone intake hoses better. Much less flashy under the hood and much less heat soak. Intake air temps stayed under 110°F rolling around town this afternoon. With ceramic coated headers and around town driving those metal tubes would nearly scald your hand after 30 minutes of driving around town.

[Fast355]

This is the exhaust setup I am running. 2.5" dual on a 3.5L engine because it spins 7,800 rpm on the big end and likes to breathe. Car was instantly far more responsive after the exhaust and high flow cats went on. OEM cats may have been partially plugged after ~200K as the catalyst beds were rattling around in the housings.

[Fast355]

And the equal length, merge collector shorty headers. These alone after the exhaust setup added 20 ft/lbs in places of the powerband in the low-midrange. Did not gain alot of peak power (9 hp wheel), but I am not spinning the thing 7,000+ all the time. These gained torque across the whole powerband from 2,000 rpm and on compared to stock. Give me the torque gains any day. Compared to the stock un-equal length tubular manifolds these make the engine sound much smoother to my ears. These were another amazon buy, open box special for $200 to my door and a reputable brand.

Car made 296 RWHP and 270 RWTQ untuned with the HPS Intake hoses, K&N filters, headers and 2.5" exhaust. Air/Fuel ratio in the low to mid 12s. Gains of 26 HP and 28TQ. There were a few areas it made as much as 40 ft/lbs more in the midrange.

[Fast355]

These are the stock manifolds. I think the longer equal length primary tubes and the nicely designed merge collector are responsible for the torque gains. A couple of small changes that make a huge difference. At first glance they look alot alike. Not until you put a tape measure up to the primary and realize it is 50% longer than stock and the stock ones have up to 2" of variation in length between shortest and longest although the short one and long one are on opposite banks.