370Z Forced Induction: Boost is not created equal

Many times a week I’ve been getting this question asked. What is the difference between a supercharger and turbo kit for the VQ37VHR? For starters most people get the misconception that a supercharger will produce boost faster than a turbocharger. There is much more to that answer. It all starts with properly piecing together a kit and its intended purposes. Turbochargers of today are much more reliable, use more advanced materials, and are manufactured in such a way that all improve the turbo’s quality\reliability and performance. This is why you see more auto manufacturer’s producing their vehicles with more turbos and the fact that gas mileage can be improved without sacrificing power.

The goal of this post is not to give you all the in’s and out’s of how a turbo or supercharger work but to clear up the biggest misconceptions and present to you the visual difference of what a supercharged and turbocharged engine in this case the VQ37VHR look like with two very popular kits out in the market.

TTvsSC

This dyno graph comparison plots both a SC’ed and TT’ed VQ37VHR against each other on 91 octane fuel. Red is supercharged and blue is turbocharged. This will definitely clear up the misconception that a supercharger can out spool a turbocharger. This particular supercharger is a centrifugal style which is known for its “lag” although people are unaware of it and differences between it and other supercharger styles. At 3500 RPMs you can see our plot. Boost on the SC’ed engine is 1.66 psi. Boost for the TT’ed engine is 8.5 psi. This correlates directly into power and torque of course! Let’s look at the differences there. We’re producing 274 torque on the SC’ed engine and 403 torque on the TT’ed engine. That’s a difference of 129 torque. I bet you can probably tell me which car would be funner to drive. Horsepower for the supercharged engine is 182 whp and 269 whp for the turbocharged engine. You can also see that peak power is also higher on the turbocharged engine.

A supercharger kit is cost effective to produce and install. There are less parts and much less labor involved to install it. The opposite is true for a turbocharger kit. However you can reap the benefits of turbocharging when you’re all done! It WILL put a bigger smile on your face, this is fact.

John’s 370Z TT+

Not your run of the mill TT 370Z.  John’s Z features a built engine, GTM Stage 3 TT Kit featuring the use of GT3071R (T25) turbochargers on .64 A\R turbine housings and T04B housings.  Swapping both the compressor and turbine housing would allow for less back pressure and more power.  However, we can’t complain with the results once we straightened this beast out!

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We modified a few things in the GTM kit.  For one we moved the placement of the BOVs.  They were located extremely close to the MAF sensors causing drivability and tuning issues.  We also removed the water injection system, improved fitment of a few pipes, and powdercoated the pipes black from their original polished look.  Silicone couplers were also all swapped out in favor of Vibrant brand couplers.  Fixes are pictures above.  Another thing you may or may not have noticed is this Z also sports an R35 GTR intake manifold made possible by GTM.

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The custom lower plenum that makes it possible to run a GTR intake manifold.  We removed it to weld up the holes (pictured) for the old water injection system.  No need to run water\meth now that we converted this Z to ethanol.

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GTM fuel rails feed Bosch 1000cc fuel injectors.

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Feeding the rails and injectors is the CJ Motorsports twin pump fuel assembly.  Two Walbro fuel pumps feed the system.  We swapped one of the 255s with a 485.

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One of our modified pipes finished in powdercoated black.

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The finished product.

Onto the fruits of ours and John’s labor:

91

Peak boost of 15 psi, average of 14 psi we managed 567 whp.  This is for 91 octane.  After this we began working on the ethanol tuning.

18psi

18 psi for 615 whp (ethanol fuel), we slowly worked our way up.

19psi

19 psi for 674 whp.

21psi

21 psi for 706 whp.

e85

Fully cranked up we managed a peak boost pressure of 25 psi, dropping past 5500 RPMs in part due to the compressor and turbine housings.  Just enough to make 800 whp and 700 pound feet of torque.

Josh’s 370Z TT

How’s that saying go?  A little more makes it better?  Well, what we have here is Josh’s beautiful black Nismo that has been transformed to be a killer.  A Fast Intentions Twin Turbo Kit.  This time its armed with HTA-68 Turbos covered by Alpha Compressor Housings.  The F.I. kit is all encompassing.  Should you need want the ultimate in power you can select from many different turbochargers to fit the bill.

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Besides looking good, you’ll find this Z on road courses doing some time and kicking ass.

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There really isn’t much to see when the hood is open.  Looks better than something the factory could put out.

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One very important note to make is we converted the fuel system to a return style, similar to Norman’s Z.  In Josh’s Z we went with an Aeromotive 340 fuel pump.  We were impressed by its performance, as we ran only ethanol fuel.

9psi

9 psi of boost on ethanol.

10psi

10+ psi of boost, again on ethanol.

13psi

13 psi of boost, yes on ethanol, and also on a stock engine.  Could we have gone further?  Sure!  We have to control ourselves at some point however!  What’s that saying go??

Norman’s 370Z TT

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Norman’s Black Cherry Z may look docile but this Z packs a big punch.  The Z had a Fast Intentions “Stage 1” Twin Turbo Kit installed; consisting of Garrett GT2860RS Turbos.  The major difference between this one and the others we’ve done is the fueling.  The fuel system was converted to a return style fuel system with larger fuel rails provided by CJ Motorsports.  1000cc fuel injectors, Z32TT fuel pressure regulator, and a single Walbro 485 fuel pump finish off the fueling bits.  Beefed up for the sole purpose of running ethanol fuel and doing it on a stock engine.

 6psi

6 psi of boost, low timing for 457 whp and 411 torque.

9psi

9 psi for 509 whp and 475 torque.

10

10 psi for 537 whp and 508 torque.

11psi

11 psi for 552 whp and 523 torque.

12psi

12 psi for 580 whp and 543 torque.

13psi

And finally 13 psi for 632 whp and 589 torque.  Makes 500 torque by 3400 RPMs!  Most impressive response and drivability!  All done on a stock engine.

Anatoly’s 370Z TT

One of the first Fast Intentions TT kit for the 370Z happened to go on Anatoly’s Z.  This 2013 sleeper does not disappoint!  Armed with a pair of GT2860RS turbos utilizing Tial V-Band .86 turbine housings.  For fueling, we stuck with Bosch 650cc fuel injectors and Aeromotive 340lph fuel pump and keeping it a returnless system.  The factory returnless system has many bottlenecks.  Fuel upgrades for the 370Z are coming shortly to combat the shortcomings.

Video of how it sounds on the dyno.

91

91 Octane Results

100

100 Octane Results

Anthony’s 370Z TT

It’s been awhile since we last updated the blog. It’s been very busy at SZ thankfully. Thank you to all our great customers.

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Anthony brought over his GTM Stage 2 TT 370Z for some work and tuning. The heart of the kit makes use of Garrett GT2860RS turbos with an .86 turbine housing. The exhaust on Anthony’s Z was dual 2.5″ out of the turbos and necks back down to a single 2.75″ system which is really hurting the power and more importantly the efficiency. You’ll see that power is below average for a TT VHR even on 91 octane. Anthony has plans to “fix” and upgrade the entire exhaust system and make it dual 3″ throughout.

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Beautiful Work wheels complement the Z’s look and stance.

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This particular kit on Anthony’s Z was originally made for a G37 hence where the intake(s) sit.  The standard 370Z kit places the intakes forward close to the intercooler.

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91 octane for a max of 7 psi.  Once the exhaust gets squared away we should be able to make more power safely!  431 whp and 384 torque.

Bob’s NISMO 370Z TT

Bob came back to us after first having his Z34 tuned.  This time he came back for much more.  Bob, Fast Intentions, and Specialty-Z came together to formulate a plan to turbocharge the Z.  Fast Intentions has just recently began shipping their much anticipated twin turbo kit and we were the lucky ones to first install it.

The kit is offered in different options dependent mainly on turbo size selection.  All turbos used in the kit feature Tial .86 turbine housings made from SS cast for improved flow and heat enthalpy.  This allows faster spool from the turbine.  The base kit starts off with a pair of GT2860RS turbos.  Followed by the Garrett GTX compressor wheel upgrades.  Finally the Tial Alpha series (HTA) turbo as the creme de le creme for those looking past stock shortblock power handling capabilities.

before

The NISMO as it sat before its twinturbo adventure.

disassembly

The VHR ready to leave its cozy engine bay.

engine_removed

Now its time to start disassembly to make way for our twinturbo parts!

stockfuelinjectorsinrail

With the intake manifold removed the stock fuel injectors and rails come out.  We’ll be moving more air so we’ll need larger injectors.

fuelinjectors

Stock injector on the left and our new higher flowing 650 cc injector on the right.  Appropriate adapters for the electrical connection are provided to make it simple plug n’ play affair.

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Rails, injectors, and adapters installed.

sparkplugs

With the intake manifold removed for the injectors install, we also replaced the factory DENSO spark plugs in favor of HKS Racing spark plugs.

stock_clutch

The stock Nissan clutch (disc shown on top of pressure plate).  Since we’re going to be making more power and especially torque we removed the stock system and upgraded to the SZ Max Street Clutch & Flywheel Kit.

stock_flywheel

The heavy factory Nissan dual mass flywheel also gets ditched.

rearmainseal

We took the opportunity to replace the rear engine main seal.  This would also be the time to replace the pilot bushing that is included in our clutch and flywheel kit.

stock_slave

The factory cheesy Nissan slave cylinder & bearing get upgraded with our own piece also included in our kit.

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Our upgraded slave & bearing assembly that includes SS lines and easy bolt in adapter plate.

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Our piece installed, ready to go.

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Our lightweight aluminum segmented flywheel bolted down.

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The Max Street kit uses a modified organic clutch disc for smooth engagements.  Those looking to do more aggressive driving like drag launching and slipping will want to use our 6-Puck or 5-Puck options.

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Our Max pressure plate bolted down.

exhuastmanifolds

The Fast Intentions casted V-band exhaust manifolds for both the turbos and wastegates.  Beautiful merge of all 3 cylinders as one can see.

turbos

The two stars of the show, Garrett GT2860RS turbos.  Measuring 60mm on the exducer portion of the compressor wheel.  The kits also ship with the oil drain fittings installed for less guessing.  The fittings use an o-ring for sealing against the center section drain.  Notice the elegant taper used on the Tial turbine housing.  All this helps power and spool.

tial_wastegate

A good view of the Tial wastegate(s) used on the kit.

passengersideview

Passenger side of the kit installed.

driversideview

Driver side of the kit installed.

intakefrontview

Ready to go back to its engine bay.

oilpan

The kit makes use of the Greddy oil pan with the turbo oil drain fittings also already installed when one receives it.  Also pictured is the engine oil filter relocation which is also part of the kit.

stock_diff_bushing

A must for any Z34 is removing the terrible squishy liquid filled differential bushings.  Only one horizontal mount is used on the Z33s and Z34s which also makes things worse for movement and wheel hop.

whiteline_diffbushing

Whiteline bushing in place ready to get pressed in further into the subframe.

intercoolerfrontview

Intercooler looking mighty mean.  The Tial BOVs are also easily mounted to the end tanks of the intercooler.  This intercooler is actually separated in the middle and makes use of a divider plate to make sure all of the core(s) is used.  Behind the intercooler is the Fast Intentions 34 Row Setrab oil cooler.

intercooler_sideview

Here’s another view of the intercooler (not an actual picture of Bob’s NISMO).  The intercooler brackets included in the kit are also already painted!  Love that.  Ready to bolt in and go, less install time, and more GO time!

side_view_exterior

A beautiful twinturbo kit for a beautiful Z.

szdyno91

Last but not least our final power and torque numbers for 91 octane.  We installed a Blitz sbc-iD Spec-R boost controller that works also as a boost gauge.  An Innovate MTX Digital Wideband was also installed to monitor AFRs.

Jeff’s 370Z

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Jeff came to us from LV so we can tune his beautiful Z.

Armed with the standard bolt-ons like a Stillen Gen 3 Intake, HFCs, and catback exhaust.  Stock exhaust manifolds.

4thgearbaselinevstune

The blue run is our baseline which was pretty high already!  310whp, not bad for just a baseline!  However after some tuning we were able to get up to 320 whp.  19 whp gain at 5700 RPMs!  Both runs above were performed in 4th gear.

5thgear

Finally, our 5th gear run for a very impressive 332 whp and 272 torque!  Congrats Jeff!

 

SZ ECUTek Tuned Nismo 370Z


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We took this 2011 Nismo for some testing on ECUTek’s tuning suite and also some comparisons on the stock Nismo tune, ECUTek tuning, and adding the Stillen Gen 3 Intake.   The Nismo came to us with only K&N drop-ins in the factory air boxes.  We were curious to see how much more could be extracted from the Nismo since they come with more aggressive tunes from the factory which includes leaner AFRs and higher ignition timing.

ECUTek is a new comer to the tuning world for the 370Z & G37s.  Since its had a fresh start it currently only offers one RaceRom option of simplified ignition timing.  This nice feature overwrites Nissan’s complicated ignition timing strategy for a more simplified version that uses “normal” (BTDC values) values in its map.  There currently is no setting changes for fan control, fuel cranking enrichment, and the ability to have multiple maps.  ECUTek plans to release more RaceRom features soon like launch control, flat foot shifting, and map switching.

baseline_ecutektuned

The graph above shows our baseline (blue) against our SZ ECUTek tuning (Red).  Performed in 4th gear, our final pull was performed in 5th gear coming up later.  Only mods are the K&N drop-ins in factory air boxes for both runs.  298 whp and 242 torque for peak numbers from our baseline.  Tuned peak numbers were 310 whp and 258 torque.  Peak numbers increased 12 whp and 16 torque.  However the peak numbers don’t tell the only story.  Our entire powerband had even better gains.  On the cursor of the above graph, 5500 RPMs we gained 20 whp and 19 torque.

apart

After our initial pulls performed, we began to take the Nismo apart to install the Stillen Gen 3 Intake and GTM 34 Row Oil Cooler.  We wanted to see how the Nismo would perform when adding the intake after its been tuned.  Would it make more power?

installed

Ready to go back together.  The placement of the air filter’s in Stillen’s kit is one of the best out in the market.  It keeps the open air element filters away from the engine bay heat and high up away from water.

intakedyno

It is hard to distinguish the two runs above, but red was our tuned run with stock air boxes and K&N drop ins.  Blue was after we installed the Stillen Gen 3 Intake AND tuning.  Throwing the intake kit on the car without tuning we lost power.  It leaned out the tune enough that we had a drop in power all over the power band.  This is why on a stock Z, you can add the intake kit and it will make power, it leans out the rich factory tune on the non-Nismo cars to make power.  However on a tuned car, you will most likely have the results we experienced.  This isn’t the first time we’ve performed this test and we get the same results each time.  So on the blue intake tuned run we gained 4 whp and 3 torque at 7000 RPMs.  We lost some from 5200 to 6000 and then again from 6100 to 6600.  Again, the above runs were performed in 4th gear.

5thgearfinal

Our final pass in 5th gear 1:1, with SZ ECUTek tuning and Stillen Gen 3 Intake.  Almost 323 whp and 268 torque.

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Nismo 370Z Greddy TT

Mark’s Nismo is not the average run of the mill, even with a TT kit on it, this Z has a built motor to go along with it.

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The VQVHR engine now has 8.5:1 compression pistons and forged rods to make more power on higher boost levels.

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It has a prototype Kinetix intake manifold on it, when we did a smoke leak test, almost every runner on the collector was leaking.  Not acceptable, so we pulled it off and tig welded around every single runner.  Besides losing boost pressure to the cylinders, tuning would be off and inconsistent.

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Our clean repair performed on the outside of the runner\collector.  Its hard to see so it is circled in red.

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fite370tt_91sztune

Our results on 91 octane fuel.  Peak of 16 psi, tapering to 15 psi at peak power.  Fantastic torque for a VHR engine.