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Selin Dual Intake and Dual POP History

A little history first……
Way back in the day JWT was the only one making larger turbo bolt on solutions for the Z.
The Single factory MAF has a zero to five volt scale and JWT found that the single MAF voltage happened to correspond to about the same HP. So the 5 volt signal was good for about 500 HP.
The JWT solution was to remove the stock intake TEE and used a single MAF on one side and a dummy MAF on the other side…….this measured half the air going into the engine and by splitting the injector size in half in the chip, the ECU could measure 1000HP.
Because the Z32 has a idle air control system that pulls all the air at idle from the left side of the engine where the MAF was placed, It measured all the air at idle causing a rich condition at idle and low speed.
The JWT fix for this was adding, what they called the low speed drive-ability kit.
What this did was cut the idle air hose with a TEE and run the same size hose to the other side, Because the hose was longer going to the other side this was not perfect and JWT added a small restrictor to the driver side to try and provide a better balance.
Well that all worked, but was not perfect and just bolting them on did not always offer a great idle.
What is interesting and why I bring this up, is because the reason JWT developed the dual pop was because of the electronic limit of the MAF.
The limit was 5 volts and this was about 500 HP.
Because of this electronic limit of the meter being 500HP, that got miss-interpreted and people started saying you do not need a dual pop until over 500HP…….
Well, electronically that was true, but power wise it makes a difference completely stock. We found in testing over 11 years ago that getting rid of the stock TEE and completely separating the two sides of the air intake system made great gains…….The only thing we did not know was if some of the gains were in the tuning of the chip that was required to go to dual pop at that time.
Jim Selin came along and decided to create a better solution…….
The Selin translator does not require a low speed hose and it also does not require a chip change to split the ECU value if your under 500HP. The reason it does not need these extra items is because it still measures all the air, Jim’s translator simply takes any air coming into the engine from either side and adds it together and sends it back to the ECU as one signal just like 1 meter does stock.
The reason dual pops work is that stock, the 2 sides are fighting for air in the tee, both sides are pulling from the same center section causing the turbos to work much harder to suck air.
By completely separating the two sides it makes it much easy for air to get into the turbo and the results speak for themselves.
When going over 500HP the Selin translator can be switched to average and this still measures all the air, but adds both sides and sends exactly half of the total it measures back to the ECU. This setting requires a chip change to cut the injector size in half to allow measuring higher HP up to 1000hp.
Jim came to us with a few customers watching to have us help him perform a test before and after going not from stock, but from a single pop to Jim’s dual pop set up.
This was done while strapped to the dyno and no other changes were made except installing the Selin complete dual intake set up.
The car had 2.5″ exhaust and a JWT pop and JWT chip.
We made sure the car was stable before starting the tests.
We then made 3 pulls to make sure the reading was consistent…..We then added the Selin Elbows, a second MAF with second pop, and the Selin translator…..
We then made 3 more pulls.
I believe Jim only posted one before and one after of the dyno work.
I think showing all of them helps people to see that it was not some trick or strange anomaly.
I will show separate Horsepower charts from the torque charts make it easy to read and include Air fuel ratio and Boost readings.
Again, this was all the same chip and only adding the second pop.

Horsepower

Torque

Auto Dream Z32

Ken from Idaho brought over his Z32 for some tuning sometime last year.  Ken’s Z is absolutley beautiful inside and out.  This Z is equipped with an auto trans hence the title of this post.  Ken’s running a stock long-block with 2560R turbos, MS Manifolds, Selin Dual POP, SZ\300Degree 740cc Fuel Kit,  SZ 2.5″ DPs, TPs, and Catback, Stillen I\Cs, SZ Auto Trans, and Blitz Spec-R Boost Controller.

A cleanly executed engine bay.

The original charcoal grey paint was in immaculate condition.


Tuned for 91 Octane (Red Run) and 100 Octane (Blue Run).

Procharged Widebody Z33

Jesse’s mean looking Z has spent tremendous amount of time at the beauty shop but this Z also packs some heat under the hood.  After getting it back from the body shop Jesse brought it over to us to make sure his Z was “healthy” enough for some boost.  This Z sports ATI’s Pro-Charger air-cooled centrifugal supercharger.  It came to us with a UTEC piggyback EMS and we did a baseline pull to see where it baselined.  Z is still running a stock longblock with larger injectors and Walbro pump.

You can see his blue baseline run was way too lean the way it came in.  We yanked the UTEC out, performed a voodoo ritual & tune up (spark plugs, fluids, etc..), and lovingly tuned this Z.  We ended up with a much safer tune and more power & torque throughout the entire powerband (red run).

Z32- GT2860RS Mild Street Build

Another mild street build we did earlier this year.

  • Factory Nissan Longblock
  • JWT Sport 700 Turbos (GT2860RS)
  • MS Manifolds
  • SZ 3″ 5-Bolt Down Pipes
  • SZ 3″ to 2.5″ Hi-Flow Cats
  • B&B 2.5″ Catback
  • Nismo 740cc Injectors
  • Selin Dual POP Kit
  • CZP 2.5″ I\C Piping
  • ASH Massive SMICs
  • SZ Flywheel & SZ Max Street Clutch
  • Blitz i-Color Spec-R Boost Controller

456 whp & 418 torque on 91 Octane.  No data gathered on higher octane fuels since the owner has no plans for running higher octane fuel.

370Z TT…..the way it should be

Back in June I picked up a Z34 with intentions that if I bought one it would HAVE to be twin turbo’ed shortly thereafter.  When the new gen Z first came out I wasn’t completely sold on its looks.  I hoped at the least the engine and interior were further improved upon than the Z33.  As time progressed I began to liken the fish hook head lights, although the fangs on the bumper were still undesirable.  In any case, I had the burning desire to feel, drive, and interact with the new generation of Z car.  Having played with some at the shop I was pleasantly surprised as to how much better quality was up over the 350Z.  Handling is superb while retaining a very comfortable ride that doesn’t bring discomfort to  my body.  Having owned various high power Zs the added power of the new Z34 was a benefit, but I was spoiled.  This is why it just had to be turbo’ed.

Older brother Z32 gets to share his bedroom and share stories.  Looking at the rear of the Z34, the only thing I didn’t like was the rear fog light.  Painting the lower portion of the bumper black helped detract attention from it.

It’s almost a shame the front bumper has to hide such a beautiful kit produced by GTM.

The kit selected to power the Z is a high quality GTM Stage 2.  The turbos used are Garrett GT2860RS’ utilizing the .86 turbine housing and Tial external wastegates.  A GTM competition oil cooler was added to combat the already (factory) problematic oil temps.

Engine cover painted to match.

Since the car was to see some drag strip use we selected our flywheel and High 5 Clutch.

6 psi of boost (Boost Controller Off), good for over 400 whp.

9 psi for 488whp.

12 psi (100 octane) for 557 whp.  This is efficiency!  Less boost than a comparable Z32 and making more power for the given boost level.  The one thing lacking versus its older brother Z32 is the torque output.  The VG30DETT is good for matching HP & Torque values.

The blue run was the car BONE Stock compared to the red run force fed by 12 psi of boost from the GT2860RS’.

Power comes on very smoothly unlike a Z32 which can be violent.  Due to in part by the flat torque output.  It feels like the car could have come equipped force fed from the factory, its that good.  The VQ37VHR engine acts as if nothing were different with this amount of power running through its veins.  Something the old VQ35DE could not accomplish on a factory engine.  The bone stock VQ35DE could really only safely muster under 400whp.  Anymore and you risk certain catastrophe on the VQDE engine.

[http://www.youtube.com/watch?v=8MFxWUu6U3U]

On its first maiden voyage down the 1320 the Z and I (CAR #7293) were able to break into the 11s.  Prior to this it had been over 5 years since I last banged the gears down the track.  I can say this car is limited mainly by my driving and with some practice it should see low to mid 11 E.T.s.

Z32 NA Power

By far one of the highest NA Z32s we’ve seen.  John’s Z has lots done to it.  Something we’d like to see is a change of cams after looking at his power delivery.  It has regrind cams in it now.  To remedy some of this we installed a set of adjustable exhaust cam gears which gained more power and smoother power & torque delivery.  We also added a Selin Dual POP, fixed his VTC, and tuned it.  A before and after is shown below.  A list of some power mods John has are:

  • Factory 120+k Miles Engine
  • Stillen Headers
  • SZ Hi-Flow Cat Pipes
  • SZ Single Oval Catback
  • Regrind Cams
  • Tomei Adj Exhaust Cam Gears
  • SZ Flywheel & Sport Street Clutch
  • Electric Cooling Fans
  • Selin Dual POP & Translator
  • UD Underdrive Pulley
  • SZ Tuning

The red run was with a single POP filter untuned.  The blue run is with the Selin Kit, VTC fix, and tuning.  A peak gain of 10 whp & 12 torque.  The  most impressive gains to be found were at the mid-range (20 to 25 whp & torque).

SZ Z32 Turbo Outlet Pipes

We are proud to release our own Z32 turbo outlet pipes.  These pipes allow for the smoothest transition to 2.5″.  This will make more power and make it easier to install 2.5″ intercooler piping.  Typical transitions made in the silicone hose (2″ to 2.5″) are too dramatic and turbulent.  Our pipes come in raw aluminum form and can be painted or powdercoated to suit your looks and needs.  These pipes also retain the use of the factory outlet hoses for an easy upgrade.  For a limited time only you can pick up a set for $149 + Shipping.

40th Anniversary Z34

Andrew brought us his pretty 2010 40th Anniversary 370Z for some tuning.  Andrew has the Injen CAI and Fast Intentions C.F. Catback.

Nice solid gains.

“FMIC Ed”

Ed’s been a good customer of ours for quite some time.  We’ve always come to know him as “Ed with the Front Mount”.  Ed was sporting the Apollo FMIC kit which in our opinion sucks balls.  I’d like to add as I was reading on another forum that FMICs CAN work on a Z32 when designed properly.  The only one to our knowledge is the TDM FMIC Kit.  We run it on our blue drag Z32.  It has less bends and a very high quality core.  The (Apollo) kit increases piping length and also adds more bends.  This in turns adds to restrictions and loss of power, along with blocking airflow to the radiator.  Slowly Ed fixed maintenance issues and did small upgrades along the way.  Recently he finally decided to have us ditch his FMIC setup in favor of larger 2.5″ I\C Piping, Ash Massives, and Z1 T.B.s to round out the combo.

Ed’s current mods:

  • Stock Turbos & Manifolds
  • Stock Engine
  • SZ 2.5″ Downpipes & Test Pipes
  • HKS Hyper Catback
  • RPS Twin Carbon Clutch
  • Selin Dual POP Kit
  • Nismo 740cc Injectors & 300Degree Rails

This is a before and after from just changing out to the old FMIC to the larger I\C piping, Massives, and T.B.s.  Red run was the old FMIC, Blue run the new setup.  Some gains down low and impressive gains up top.  Almost 50 ft\lbs and 60 whp gain at 6500 RPMs.  Efficiency is key, more power on same boost levels.

Track Duty Z31

The Deal Family’s Track Warrior Z31 Turbo

A few weeks back we got a call about Z31 needing some dyno time.  Owner’s Todd and Tyler Deal were battling misfiring and poor running performance out at the track.  This Z has an impressive list of parts one is a wickedly built SOHC VG30 that makes use of a VG30DETT crankshaft.  The car and its parts don’t look impressive but this car does surprise once it finally was fixed.  I don’t have all the details on the car but it obviously has a healthy sized T3 framed turbocharger, JWT Cams, 2.5″ I\C Piping,Greddy Recirc Valve, Tial W\G, Greddy Profec B B.C., and AEM Water\Meth Injection.  The water injection does an excellent job in keeping engine coolant temps down believe it or not.  This Z also makes use of a transmission cooler & pump to combat unwanted heat in the gear box.  This 1984 Z depends on the use of JWT’s ECU conversion that uses an 88-89′ NA ECU, Ford Cobra MAF, and Bosch 420cc Injectors for engine control.

Resting after a hard day’s work.  The I\C can easily be seen along with beat up brake ducting.

After a few attempts to make a clean pass on our dyno due to tremendous misfiring, we took over tuning and fixing any mechanical\electrical issues.  A shout out to Clark Steppler from JWT for fixing the ECU quickly.

The blue run was the way it came in.  Really bad misfiring, so much a complete run could not be made.  After some time of tuning you can see where ended up on the red run.  See how torque happy these SOHC engines are.  401 whp & 429 Torque.