First off we would like to congratulate the owner of this car on it’s (now not so recent) purchase!  He traded in his ’05 35th Anniversary edition with the VQ35DE engine for this ’08, it turns out he just couldn’t resist the call of the HR!!

This build started off some time ago when it came into Z Car Garage fully stock with plans for a simple Injen intake system, a new-to-the-market ARK cat-back exhaust system, and a set of high flow catalytic converters.  It turns out that we saw nearly zero gain from the ARK exhaust (we tested it on it’s own with no other modifications) and the fitment was beyond terrible so it was packed up and sent back immediately.  Bummer I know.

Not willing to accept defeat we decided to go with the tried and true Bassani cat-back system in search of actual power.  The new exhaust came right back at us with a nice gain and the Bassani exhaust note can only be described as GLORIOUS!

Now that the car had a little bit of get-up-and-go the owner decided to upgrade the rolling stock, and with a set of VOLK wheels it is hard to go wrong.  A hard to find, and very expensive, set of VOLK GTS wheels (with a killer looking matte black center) was chosen and wrapped in Toyo Proxes rubber which I’m pretty sure are 255’s in the front and 285’s in the rear.

This list of mods was able to hold him over for awhile-ish.  Actually the need for more power and a killer stance on the Z33 was eating away at him… as it does all of us.  Now a set of Stillen headers were ordered and added to the mix.  More exhaust flow means more power… within reason of course in a normally aspirated engine.  To up the ante one more level we also contacted UPREV and decided to do a computer re-flash so that we could form the timing and ignition maps to a higher level.

All of the hardware changes without the re-tune netted us 18 horsepower and 12 ft/lbs of torque at the rear wheels.  From here on out we started to play with the UPREV re-flash system.  You will see from the dyno graph that it took us quite a few runs to get the tune to where we were happy with it.  We were able to gain 8hp and 1 ft/lb of torque and we still think that there may be a little more in the Z.  We have the software to re-tune the car anytime we wish now so we will be taking another crack at it in the near future.  Plus I have a feeling that there will be a few more modifications done which will require further tuning magic.

Now to obtain the proper stance for the car a set of PSS10 Bilstien coil-overs were delivered to the shop.  It even says on the shock that they are tested on the Nurburgring, how cool is that? (see photos after the jump)  The issue here with a Z or G is that camber becomes an issue when the lowering gets aggressive.  Once again a preemptive strike was made before any problems arose with by installing front and read adjustable control arms from SPL Parts.  One look at the pictures of these parts and you understand why they are so special.  Furthermore we also installed a new set of Hotchkis swaybars just so that we left no suspension stone unturned.  Looks and awesome handling should always go hand in hand.

You can see from the final picture here that the car now has that killer stance and a good amount of new found power to go along with it.  But, like the title says, I’m pretty sure this car will continue to be built up in the constant pursuit of the perfect Z.  Will the owner ever reach it?  Only time will tell, and we are certainly willing to help.

There are quite a few more photos after the ‘read more’ at the bottom so check them out!!

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We have done a couple of these modifications before to other HR equipped 350Zs with great results.  This round of upgrades differs in two areas.  First off, this is the first set of headers that we have done on an HR car, and secondly, this car is an automatic.

The other changes we made to the car were the tried and true Injen intake system and a pair of Stillen high-flow catalytic converters, both of which we have installed on numerous cars that have come through the shop.  Both of these parts have made nice gains in the past so we pretty much knew what to expect here.

Looking at the dyno graph you can see that the automatic transmission is certainly using up a little more power than in the manual cars but the power gains are more than noticeable.  The car is now more powerful throughout the entire rev range and the torque curve in the middle is now gonna give that push in the back that we all love when you stab the throttle.

I have a feeling that we will be seeing this car again for another round of modifications.  Now that we are an Up-Rev software retailer maybe we will get the chance to play with the fuel and timing tables to get the car where it needs to be.  We can’t wait to get the chance.

Yesterday we installed a set of Stillen high-flow catalytic converters (HFCs) onto the 350z that received the Injen Intake system and the Unorthodox Racing lightweight pulley last week.  We’ve seen how these HFCs have improved the power band in the past on other cars but it’s always nice to back up good results.  Again, this car is equipped with a Nismo exhaust system, unlike the other car with these mods which has a Bassani exhaust.

The Stillen high flow cats are a high quality piece but as with all exhaust modifications where the stock catalytic converters are removed we were interested to see if there would be any increase in exhaust rasp.  As you remember this was a small issue that we had to resolve on the red HR car that had the Bassani true dual system with an x-pipe.  The Nismo system is much different, it comes from the cats into a 2.5″ to 3″ Y-pipe (stock is 2″ to 2.5″.)  From there is a single 3″ pipe, with resonator, back to a factory style (but larger diameter) rear muffler.

This car with the HFCs installed exhibited almost none of the rasp that has become associated with the dual exhaust cars.  While the exhaust note was very nice, you can see from the dyno graphs that this car was a few horsepower short of the Bassani 350z.  The cars were dyno’d on different days but all the results are SAE corrected to get them on as even a playing field as possible.  In their uncorrected forms, both of these cars are putting down over 300hp to the wheels. Very impressive.

Below you can see the run comparison with and without the HFCs.  The Stillen cats gain around 10hp and 10lb/ft of torque at the wheels throughout the rev range.  That’s certainly power you will feel on the road which makes this change almost mandatory from a performance aspect.

Here are the graphs that show this customer’s entire power gains over the past week or so and the comparison between the this car and the earlier Bassani equipped car.

We are trying to get the ball rolling with a header and camshaft comparison for the HR engines and maybe an turbo install in the near future to show all of you what is really possible with all available modifications.  We can’t wait to make more “RELIABLE” power from the HR series.

Link:  Other HR related posts

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.

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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