This car came to the shop a couple of weeks ago with the normal bolt-on mods and a shiny set of wheels to roll down the street with style.  This 2006 convertible with an automatic transmission entered our doorway with a Stillen cat-back exhaust system, Kinteix Velocity Manifold plenum, and a few other nice dress up pieces.  Then came the time to add some real power!!!

The basis of any real power addition with a VQ based drivetrain really needs to come by way of forced induction.  For this reason a Vortech supercharger kit was ordered as a starting point in this build.  Not wanting to stop there and be left wanting more, Rob and the the car’s owner went the full monte and also ordered a set of JWT camshafts, Stillen headers, and a set of high flow catalytic converters.  This isn’t going to be your everyday convertible after this transformation.

After the top half of the engine was taken apart and reassembled with the new bump sticks all of the new exterior power-adders were installed.  This car features the recently improved Kinetix Velocity Manifold and accompanying intake cover, and the new look with the supercharger left us wanting a bit more under hood bite, visually.  The decision was made to paint the engine cover to match the battery and brake master covers and off to paint it went!

While we were waiting its return, the final tune was performed and power numbers were recorded on our Dynojet dynamometer, but this isn’t where this story ends.  This car needed big brakes.  We knew it, the owner knew it, it had to be.  Rob made a call down to our good friends at StopTech Brakes to secure a four-wheel Big Brake Kit for the next day, and guess what… it was just what the doctor ordered.  The color-matched plenum cover went back on and the build was complete.  Wicked

From the dyno sheet you can see that the power gains are very impressive for a VQ35DE with an automatic transmission.  But wait you say, I said this was a 2006?  Yes, unfortunately Nissan did not put the improved “Rev-Up” engine in any of the convertibles for this year.  What’s even stranger is that this generation DE engine uses a few engine castings that are different from the first generation DE, strange.

Anyways, you can see the power is still climbing on the graph but the Nissan nannies step it to limit the fun at just under 6,500rpm.  There are software changes on the market that up the rev-limiter but they have shown to reduce the DE’s reliability down the line, and that is not an option.  We want this car to be enjoyed for as long as possible.

With the car now complete it was given a full detail before the owner came down one last time to take delivery.  This time he brought his son and a few of his friends to enjoy the occasion.  With all the test rides he gave that afternoon there is not a doubt in my mind that we will be seeing him for a set of rear tires very soon.  Enjoy the Z my friends, you have done well.

There are a few more photos after the ‘read more.’

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240Zs rule.  They are lightweight, handle amazingly well, and are easy to work on; but what do you do when the reliable L-series engine runs out of breath?   Simple, bring it to Z Car Garage and install a set of 44mm Mikuni carburetors, new header, and a slightly larger exhaust system…. and hold on!!

The amazing change in the dyno numbers only tell half the story.  The fun factor of this car is now light years ahead of where is was when the car first came to us.  The torque now stays strong through the entire rev-range and the increased breathing capacity now allows the engine to spin freely to six grand if you so desire.  There is an increase of FORTY horsepower and the same in torque through the last 1,500rpm.  This is a life changing difference.

One of the reasons this looks so drastic is the inefficiency of the semi-odd dual carb setup that this car came to us with, but the results prove that that this is one huge step in the right direction to making this car about as much fun that the owner can handle.  The car is now using three individual ITG filters to make sure that the newly found airflow is clean enough for government work so please don’t think that we sent this car on it’s way with no filtration.  Sorry that I don’t have any pictures.

On the horizon for this car is a possible camshaft change to get the last bit of power out of this engine so expect a post in the future if this comes to fruition.  The smile on the owner’s face hasn’t left since we gave the car back and it seems we have lit the fire under another early Z enthusiast, we are happy to help.  ZCG

There are a few more photos after the ‘read more.’

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What a busy day here at ZCG.  We went to William’s Autobody around lunch today and took a few photos of the first exterior paintwork to be done to the RB28 240z.  The paint looks amazing and there are still more coats to go with tons of color sanding in between to make sure the finish is perfect.  I’ll have more photos soon!

Rob and I were also out driving the ZCG 370z and a white 240z that is here to get triple Mikunis (see above photo) and we decided to stop by the scales and weigh the newly acquired 370z.  The car tipped the scales at 3,320 lbs with no passengers and almost a full tank of gas.  Not too shabby.  (For reference the ZCG G35 Twin Turbo came in at 3,600 lbs.)

More to come tomorrow.  Long Live the Z

Here are the results from this morning’s plenum swap.  The results are… ummm… about what we expected.

This car is a 02/06 350z with an automatic transmission.  There is an extensive list of aftermarket components on this car ranging from a carbon fiber diffuser to a custom painted roll cage, but this post has nothing to do with any of these mods, it is about the before and after dyno numbers.

The plenum install went off without a hitch and the car was back on the dyno in no time.  This mod was a straight plenum swap with no fuel or timing changes made (the owner did not want to install a Uni-Chip or other tuning hardware at this point.)

Run 003:  Stock Nissan Plenum (BLUE)
Run 005:  Cosworth Plenum (RED)

On to the dyno graph you can see that the Cosworth plenum LOST a healthy amount of horsepower and torque through the entire rev range except between 5,800-6,000 RPM where it gained two, yes two, horsepower.  The design of the plenum just doesn’t seem to work on lightly modified normally aspirated cars.  Unfortunately this is a loss that will really be felt when driving the car.  This plenum is so beautiful that we really wanted to make a ton of power with it so that we could improve the looks and performance of the engine.  At this point I would find it really hard to recommend this to a customer.

Mind you that this is the first normally aspirated car that we have installed the Cosworth on.  My full post with all of the boosted car tests is still to come this week.  That post will include all of the dyno results and all other pertinent test data.  Very, very interesting….

It’s Tuesday here at Z Car Garage (and everywhere I guess) and we have another busy day ahead of us.  We are still working on getting some ‘real world’ results on the Cosworth plenum and the full results post will be up in a couple of days once we finish testing and tuning on the dyno.  So far the results have been interesting…