After hearing the news that the ZCG 370z made some pretty nice power gains, a new customer came in and wanted to do the same for his blue 370z.  To up the ante a bit he also ordered a set of Berk high flow catalytic converters (HFC’s) to replace the stock units and hopefully make some more power, let’s find out.

We knew exactly what to expect from the install and everything went off without a hitch.  We obviously had to perform a few minor tweaks with the Stillen pieces just like we did on our shop car to get the fitment to be acceptable.  After all parts were installed the car was strapped to the dyno and we went about our business to get some numbers.  After all was said and done the car picked up 27whp and 14wtq for a total of 302whp and 247 ft/lbs of torque.  Which means the Berk HFC’s add roughly five to six horsepower when you compare the numbers of the ZCG 370 which goes without the HFC’s, for now….

The really nice thing about these simple bolt-on modifications is that the performance of the engine is increased over the entire power band.  I don’t know of anyone in their right mind who would turn these gains down for the price.  300+ whp with THREE bolt-ons, not too shabby for a couple hours work.

Special thanks to Ken at Roost Billet Products for making those killer ZCG plates for all of our show cars and cars without plates.  You rule Ken.

If you have been keeping up on our 370z exploits, good for you.  If you haven’t then HERE is some mandatory reading.

We were planning on taking the car to the Motorsport Auto Show (MSA) from the beginning and if you know us then you are aware that there was NO WAY that we were going to take a stock car.  We made a few phone calls to the people that can make things happen and the ZCG 370z turned into a monster overnight.

We decided that the first change to the car needed to be in the suspension department.  Eibach springs was a first choice because of their pedigree in the industry and we shortly had a couple of boxes at our door.  They are advertised to lower the car 0.9″ in the front and 0.8″ in the rear.  The springs are a progressive rate set-up front and rear to help with ride quality and in the handling department.  The looks are vastly improved as the photos show and I’m happy to report that there is a noticeable decrease in body roll and mid corner stability seems to be improved; it’s a nice improvement considering that the ride quality is not any more harsh than before.

The next call we made was to our friends down at StopTech Brakes, and we went for the big boy of brake kits.  You can remember that we ran into problems with the stock brake system after a few sessions on the track so we felt the need to step up here.  It was the week of the MSA show so we needed to request overnight delivery if we were to finish everything that week and when we unwrapped the boxes we were overjoyed.

Before our eyes lay the latest and largest kit that StopTech has to offer for the 370z.  It includes 6 piston front calipers with 380mm rotors in the front and 4 piston calipers and 355mm rotors in the rear.  The rotors are a slotted two piece design to aid in performance and replacement.  I don’t even know where to begin to describe the feeling these brakes give when you slam on the “stop” pedal, it’s not worth testing the limits on the street so we will be heading back to the track with haste very soon.  Bummer, I know, more track days for work.  Where will it end.  Haha

Now comes the time for improved power.  We ordered the Stillen cat-back exhaust and the new Gen-3 intake system to help our car breathe better on both sides of the engine.  Before I even get to any sort of dyno results I need to say that everyone here at Z Car Garage was let down by the fit and finish on these two products.  The exhaust rubs and hits in at least two or three places, its painfully annoying.  The intake system comes with no brackets of any sort and the front part is left to bounce around to rub on and destroy anything it pleases (see video below.)  We have made our own brackets and changes to the intake to prevent any sort of serious damage, we were even forced to wrap the air conditioning lines on the driver’s side to prevent the intake from inevitably rubbing through.  Stillen is a huge company with tons of R&D time in these products, I don’t understand how they could ship a part like this and expect owners to be satisfied.

As far as power numbers are concerned, it is an improvement.  On the graphs the blue line is the car returned to its totally stock form for a baseline.  The red line is after the intake only.  The final green line is with the intake and exhaust.  Each change gains around ten wheel horsepower and a moderate torque increase as well.  Too bad horsepower poor fit and finish.  I have heard from our sources that they have made improvements to the exhaust fitment, and not to defend Stillen, but these were some of the first parts on the market for the 370z.  We here at Z Car Garage just want our customer base to get the the best product they can, and the product that you deserve.

As far as future upgrades to the ZCG 370z are concerned, I will be posting the solution to our other track event failure sometime next week with test data to follow as soon as we get back to the track.

Here is the video of the intake that is supplied without any brackets.  We ended up making our own.  Enjoy the random music in the background.

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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