Z32 Turbo / Injector Question

Discussion in 'Technical' started by Cliff, Mar 1, 2020.

  1. Cliff

    Cliff Member

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    Hi everyone.

    It's been a while since I've posted in here (moving / building a new house / baby...) life, sigh...

    I am finally near a point where I will have a space to work on my Z again and I am looking to upgrade my stock turbos. Over the years I have dreamed of what kinds of upgrades I would go for with my Z, power vs lag; street vs drag... A few years ago when I first began my latest build I had decided about 500 whp would be a nice fun car to drive around. These days it seems every kid has access to a 800 hp Mustang or a 700 hp SUV off the showroom floor so I wanted to get a little bit more ambitious with my power goals and bump it up to 600 - 650 hp.

    I have an extensively modified turbo Z32 engine which was done in anticipation of new turbos later down the road. Well today's the day (actually 2 months will be the day....) and I seem to be more confused than ever.

    Now, to the reason for this post. I would like to have around 600-650whp with minimal lag so I have been looking at ConceptZ's "G6 GTX" turbo kit (Garrett 2560 ball bearing turbo w/ billet wheel) which they state is good for up to 650+ whp. I have also been looking at their "G7" turbo kit (Garrett 2860 ball bearing turbo NO billet wheel) which they state is good for approx. 700 whp; both estimates presume appropriate supporting mods). Each of these turbos should have the ability to reach my power goals but I wonder if my NISMO 740cc injectors will be my limiting factor. A quick list of some of my more pertinent supporting mods:

    Dual intake w/ dual pop filters
    Z1 upgraded intercoolers
    3" downpipes
    3" to 2.5" test pipes
    2.5" HKS exhaust
    Walbro 485 fuel pump
    Tomei type-L FPR
    Haltech flexfuel sensor
    NISMO 740cc injectors "new style"
    Haltech boost control solenoid
    Haltech Platinum Pro ecu tuned via MAP sensor
    3bar MAP sensor


    Now, here are my latest thoughts. In a perfect world I would choose the G6 GTX (Garrett 2560 ball bearing billet wheel) turbos and run some high test race fuel like VP 110 to support my high turbo psi goals. However, in addition to that stuff being ridiculously expensive, it just isn't practical because it is so hard to find where I live (middle of nowhere south Georgia, USA). I can MAYBE find 93 octane within a 20 miles radius of my new house but I can't really say for sure because I haven't been here long enough to find such. I know there is one e85 gas pump in town so that would be available and allow me to run slightly higher boost pressures but then I believe injector size may start to limit my hp goals since e85 takes roughly 3x as much fuel compared to high test unleaded.

    So, if running high boost pressures (say 21psi and up) would require either high test fuel or high volumes of e85, would I need to be looking at a larger turbo to achieve my goal of 600 whp? Obviously this would equate to more turbo lag, but a larger turbo would flow more air at 14 psi than a smaller turbo at 14psi no? Would this allow me to find more hp without needing high test fuel or upgrading to even larger injectors?

    Thanks in advance for sharing your thoughts!
     
  2. Cliff

    Cliff Member

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    This thread has given me some more to think about: https://forums.nicoclub.com/injector-sizing-for-e85-t427891.html

    While the OP there isn't referring to a Z32, or even a V6, the conversation regarding injector flow rate for e85 as it relates to relative AFR vs actual AFR sheds some light into the professional ecu tuners' world. Specifically:

    "Please people, when you dont know DONT answer ...

    750cc injectors are WAY enough, i know a 430+HP e85 CA18DET with these and they are far from being maxed ...

    e85 does NOT allow you to run leaner ... you need to run a lot RICHER, stoich is around 9 for e85, where it is 14.7 for standard fuel, and you should aim for 6.5 when on full load. When you see an AFR of 12 using e85, you are in fact at "stoeich minus 2.7" . A wideband AFR sensor is linear and does not care about the fuel used; it measures lambda. Lambda is then multiplied by 14.7, so using e85, you will have the same kind of numbers as with standard fuel.

    It does allow you to get rid of knock, and setting very agressive ignition timing, as it has 105 octane, it will cool the engine better as you inject more. The problem is, if you take advantage of what it allows, you risk overheating your engine without knowing it (you would get knock with standard fuel to tell you), so monitor your EGT.

    Simply put, a turbo engine tuned to use e85 (with bigger injectors and fuel pump) can pump 10 to 20% more HP, without upping the boost. And it DOES allow to up the boost, too
    " - by croustibat

    and

    "You just beat me to what I was going to say.

    EVERYONE NOTE THIS!

    When you stick a car converted to E85 on a wideband, it is going to read like it is running on gasoline, but those AFR's are not correct!. As croustibat said, widebands actually output a Lambda signal. If you don't know what that means then let me explain.

    Lambda is actually the output that all oxygen sensors output. When we speak about AFR's it is specific to the fuel that we are using. For example, If our wideband sensors outputs 2.5v at a stoichiometric, then our gauge will show 14.7 if the gauge was calibrated for gasoline. Now if we instead run the motor at stoichiometric on propane, the wideband will still output 2.5v, and the gauge will still show 14.7, but our ACTUAL AFR is 15.5, OR if we do this with methanol, our ACTUAL AFR is 6.4. The gauge still shows 14.7 because it was calibrated for gasoline.

    So this being said, you DO need bigger injectors, but because of ethanol's properties, you can run leaner mixtures than you would with gasoline, but you're still much richer than you are with gasoline, regardless of what the gauge says.

    What I did with my car was to simply get a cheap Autometer gauge that doesn't have a digital readout. The color of the LED's are still appropriate because it's simply a Lambda gauge. I was able to do this because of the Innovate LC-1 wideband I use has a programmable output that I configured to run that gauge. And if I change fuels I can see the effect because it changes the lambda output and shows up on the gauge.
    " - by float_6969

    While I can't say I know exactly which turbo setup is going to maximize my smiles per gallon, it does seem to make sense in my head that differences in timing and actual AFR's would allow a good tuner to recapture some of the horsepower that would potentially be lost when comparing say 93 octane at 100% injector duty cycle vs e85 at 100% injector duty cycle. By itself this still doesn't help me find my answer on which turbo I want to upgrade to however, since Z1 bundles their 600 and 700 hp power packages with the NISMO 740cc injectors I figure I can't be too far off in my ambitions to deliver 600 whp to my Z. So I guess I am still at the Garrett GTX 2560 billet ball bearing vs Garrett GT 2860 ball bearing turbo crossroad.

    I will say I am still leaning towards the 2860's since they are slightly smaller and thus should have a bit less lag, but the question is how much? From a well written article by the ConceptZ team, they say the 2560 has about the same amount of lag as a 2860... If that's true, wouldn't it make sense to go with the larger turbo so I could run it at a slightly lower pressure? Article here: https://conceptzperformance.com/blog/whats-in-a-name-garrett-turbo-nomenclature-more/

    Sorry if I got a little long winded here, just hoping that consolidating this info might help someone else in the future. Let me know if you have any thoughts!
     
  3. ProckyZ89

    ProckyZ89 Senior Member

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    Firstly, you’ll need GT2860 or GTX2860/63/67

    650rwhp isn’t a easy goal (not as easy as the murican happy dyno make it seem)

    Secondly
    You’ll need a second fuel pump

    Thirdly
    Injectors will not cut it.
    Even if flowing 1:1 that’s 740
    Take out the expected manual driveline loss you’ll be at 100% duty.

    Can you not run e85?

    Recipe
    Gtx2860 gen2 turbos
    1300cc injectors
    Top feed rails
    Twin in tank walbro 485 or 525
    600rwhp @25psi

    I’ve made 500rwkw area on 2863’s
    Others have made over that on same turbos (600-700rwhp area)

    Hope that helps
     
  4. Cliff

    Cliff Member

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    Thanks ProckyZ89.

    My tuner managed to squeeze out 420 hp on a Mustang dyno with all my above stated mods yet still stock turbos so I was thinking the 600 to 650 hp goal wasn't too ambitious. Looking back at the dyno sheet and it looks like it says "engine power" so I guess I misinterpreted it as being whp. I do have some upgrades to help a little with drivetrain loss such as a pulley kit, lightweight flywheel, and Ray's LMGT4 wheels (hoping for a new driveshaft somewhere in my future) but I do get what you're saying .

    I'm surprised you said I would need a second walbro 485 just because I haven't heard that before in regards to hitting the 650 or even 700 hp goals for our Z's. Maybe that would only be necessary for an e85 tune using 1,300 cc injectors as you recommended? Bigger injectors may be required for me to hit my hp goals but I'm not ready to go there since my 740's are less than 2 years old (unless I could sell mine for a decent price which I think would be a bit unlikely).

    Do you have any input on 14psi with bigger turbos vs 14 psi on smaller turbos? I'm thinking the 2860's and 2560's wouldn't really have that much of a difference at the same psi but I'm not a tuner and could be totally wrong.

    Have you happened to ride or drive in similar Z's with each of those setups? I'm trying to get an idea of what the lag difference would be, noticeable vs negligible.
     
  5. beaver

    beaver southern zeds

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    I have 2560's and I can say.. there is no lag.
     
  6. SRB-2NV

    SRB-2NV #TEAMROB

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    "Do you have any input on 14psi with bigger turbos vs 14 psi on smaller turbos?"


    You are confusing boost pressure and potential power output. Boost pressure is changing the atmospheric pressure the engine sees so 15psi out of stock turbos is the same as 15psi on a gt45.

    The power difference from different turbos comes down to turbine back pressure and compressor efficiency. In a perfect world doubling the atmospheric pressure will double power aslong as fuel is in check, however we dont live in a perfect world and compressing air heats it up and turbines arent without backpressure.

    Example(numbers pulled out of thin air):
    A VG30DE makes 220crank HP and flows 22lb/min at say 25°C ambient temperature

    Now on stock DETT turbos it may make 15psi of boost however backpressure may be 30psi and the plenum inlet temperature may be 50 or 60°C. Engine flows 44lb/min but only makes 350hp.

    Change to GTX3071s at 15psi and the back pressure may be 5psi and plenum inlet temperature may be 35°C. Engine flows 44lb/min and makes 440hp.

    Both setups technically "flow" the same however one is much more efficient in its operation. Boost psi numbers are irrelevant.


    Remember this is just an example and the actual hp numbers i put above are pulled out of thin air.
     
  7. Cliff

    Cliff Member

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    Thanks for the detailed response SRB-2NV. It helps but I still feel very newb on the matter lol.

    Another thing I am contemplating buying is the CZP fuel rail. Mostly I want it because I would prefer to run AN fuel lines (just a little peace of mind regarding fuel leaks). This newest upgrade project is pushing my budget so I am wondering if that would be $500 worth placing somewhere else. Are there any real benefits with the upgraded fuel rails? I dont think my fuel system is extreme enough to see a performance gain.

    Walbro 485 fuel pump
    Tomei type-L FPR
    NISMO 740cc injectors
     
  8. rob260

    rob260 Moderator Staff Member

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    Not really they are the same internal diameter as stock.
     

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