The VQ35HR engine in the ’07-’08 350z just continues to impress us here at Z Car Garage.  This last generation of the VQ35 responds so well to bolt on modifications that the sky is the limit when it comes to producing normally aspirated horsepower.  Yesterday we bolted on another Injen intake system and an Unorthodox Racing pulley to accompany the Nismo exhaust that was already installed on this customer’s car.

The Injen intake now grabs air from in front of the radiator almost directly in the high pressure air stream.  The quality and appearance of the intake is top notch and fit and finish is up to the standards of a company that has been around as long as Injen.  The pulley from Unorthodox Racing is a high quality piece machined out of aluminum and is supposed to weigh around seven pounds less than the stock piece (8.25 vs 1.32lbs.)  We actually weighed both pieces and found the stock pulley on this HR to weigh only 4.8lbs, go figure.  Maybe they had two on the scale?  Anyways, the pulley is the stock diameter so all benefits come from reduced rotational mass rather than an under-drive system.

They dyno results were right were we expected them to be, but that doesn’t make them any less amazing!  While the main horsepower gain comes on the top-end, there are notable gains throughout the mid-rage on the torque side of the equation.  From looking at the graph you will also notice that the modifications cause the torque curve to not drop off as quickly past 5,500 rpm.  The car now makes twelve more foot-pounds of tourqe at peak horsepower, you will certainly feel that in your butt dyno!

Since the two modifications were carried out at the same time I can’t say for sure how much of a difference the crank pulley alone made, but if you look back at the first Injen intake we did on an HR you will see what the intakes did by themselves on that car.  I know, different day, different car,  but can be used as some sort of a comparison.

We are patiently waiting to see more aftermarket suppoort for the HR engines to see what sort of power we can extract.  I want to see cams, intakes, new headers, and more ideas that I’m going to save for our shop to make.  Hopefully more is on the horizon.

I know that we have been putting up a ton of GT-R related posts lately so here is one for the 350z owners.

Now… Back to your regularly scheduled Z programming.  The 3.8L GReddy TT engine is back in the chassis and all mechanical connections have been made.  Next on the the agenda is to re-install the inter cooler and all the the intake piping that goes with it.  At the same time the all electrical connections will be made and then gone over again to make sure that we don’t have to go back into the engine bay after we are done.  This car also runs a Haltech engine management system that uses a MAP (Manifold Absolute Pressure) sensor instead of the factory MAF (Mass Air Flow) equipment so the final tune should be fairly straight forward.

Wikipedia will do a better job at explaining the differences:  CLICK HERE FOR MAP vs. MAF Wiki

This car should be close to being buttoned up near the end of the day and running on the dyno early next week.  This car will be tested extensively by us to make sure that the customer is entire satisfied with the end result.  We may even make a trip to Infineon Raceway for their infamous Wednesday Night drag race series.  With drag slicks or wrinkle wall tires the quarter mile time should be able to meet or best our GT-R.  Seriously.  Z Car out!

We finished the relatively easy task of putting a modified 350z back to stock for starters last week.  This car came to us from another shop with a massive oil burning and smoking issue.  The car was running a built engine, GReddy TT, full fuel system, and so on.  It turns out that the other place believed that the turbos were the issue so the original set was trashed and two new sets were installed before the owner decided to bring the car to Z Car Garage.

The engine was disassembled and the inspection discovered that it had been subjected to massive detonation and was no good.  It was torn down and all good parts were saved for later use.  A stock engine with low miles was sourced and was installed.  The car ran great when delivered and most importantly the owner was happy.  The car went from being on the lift with no engine, trans, etc. to being a runner in less than a day.  Nice job Fred.

As for the turbo kit, it will be going on a built 3.8L VQ in a customer’s car that is from Tennessee.  It formerly had a custom built supercharger but we knew from the beginning that it would be getting turbos.  The car now features a fully built automatic transmission, rear end, and axles to accompany the rest of the drive train.  It was meant to be a brutal daily driver that will stand up to the abuse of back to back runs down the drag strip and it already features a nice set of Volk Racing SF Challenges for street duty and a four-wheel Rotora big brake kit.

The first two pictures below are of the car with the old supercharger setup.  The last one is of the engine running normally aspirated this morning before it was taken apart for the GRreddy twin turbo system.

…and finally this “morning”….

We should also be receiving the carbon fiber hatch back from our paint shop back today for a really trick twin turbo 350Z that we work on.  This car, seen above, was featured in D Sport magazine last year and it is truly something special.  Look for a full rundown on this car once this stage is completed.

More updates to come today.  I have a lot more to write about.  ZCG

We had this beautiful twin-turbo 350z leaving today and the rain was nice enough to stop for a few minutes so that I could get a few pictures.  This car features an APS twin turbo kit with JWT cams and a custom 3″ down-pipes made by us.  It has full Tein coil-overs, Stop-Tech big brake kit up front, and beautiful Volk Racing TE37 wheels.  On street fuel (91 octane here in CA) this car makes over 450hp to the rear wheels.  Awesome.

Baseline dyno and stock pictures:

We are all aware that the HR version is at the top of the hill as far as the 3.5L engines go.  But now we have some hardcore proof of how strong this engine is with just a few bolt-ons.  This car belongs to a good friend and customer of ours and it is now starting to put down some serious power.

Earlier this year Z Car Garage installed a Bassani cat-back exhaust system with cross-over pipe.  The baseline dyno for the new mods (high flow cats and intake) was done with the exhaust system installed.  The Bassani exhaust post on My350z.com can be found HERE.

The Stillen high-flow catalytic were first on the list to be installed after today’s baseline dyno.  They installed in about a half hour with no real complications.  Then our Innovate wide band O2 sensor was then installed to monitor the air/fuel ratio.  Off to the dyno!  The gains we saw were a pleasant surprise and we are very happy with the overall result.  This mod also brought out some more roar in the Bassani system.  It sounds mean…

Next on the list for this morning was the new Injen Intake System for the VQ35HR engines.  This new system uses twin POP style filters and drastically moves the location of the filters all the way down and into the front radiator opening in the front bumper.  This move ensures that tons of fresh, high pressure, air will be crammed into the filters.

As you can see form the graph above we also picked up some massive whp gains from the intake as well!  In uncorrected form this car put down over 300hp to the rear tires, WITH ONLY A FEW BOLT ONS!!  All of the dyno graphs listed here are SAE corrected to even things out.

This post should brighten the days of more than a few HR owners who cringed when they heard of the imminent release of the new 3.7L engine.  Only time will tell how much more normally aspirated horsepower we will make with this engine but you better believe that we have more HR parts on order as I write this.  Can you say experimental ECU tuning?  Ummm… I love the smell of power in the morning.

All three runs below: (click for larger)

More Photos After the Read More

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