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Compound Turbo Thread

Posted by RWD4G63, Oct 31, 2012

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  1. KeelesKustome

    KeelesKustome Proven Member

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    What intake manifold is that?
     
  2. XLR8

    XLR8 Proven Member

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    Looks like a stock evo IM, it is most likely ported.
     
  3. RWD4G63

    RWD4G63 Proven Member

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    Yes, it's an Evo intake with the injector bosses cut off and a DSM intake flange welded on.
     
  4. Sp1kE

    Sp1kE Proven Member

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    Bringing this back.
    I just got my setup running maybe a month ago. And while tuning I am seeing crazy high intake temps. (peaking at 140 with a small water to air setup.)
    What are you guys seeing for temps or doing to combat them?

    I am going to build a resivoir first and check my pump is flowing correctly.
    Then maybe some insulation/heat shields... and if I have to, a meth nozzel in between stages....
     
  5. caged

    caged Proven Member

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    When I first took mine to the track I had problems with it picking up heat from the manifold, I logged 170F at the top of 4th. I put a longer air intake on and it dropped down to 120F with a track temp of 90F and a front mount intercooler. I think I may of been in an un efficient part of the comp map though. On my new setup I plan on running pre turbo e85 injection which should drop it down alot. I also have secondary injectors 5inchs up the runners and they make a huge difference to cooling because I had to adjust my temp correction a huge amount to stop it leaning out.

    And put some pics of your setup on here.
     
  6. Sp1kE

    Sp1kE Proven Member

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    Oh nice, glad to see i am not the only one.
    There are pics of my setup in the second post of this thread. Air intake does a 90 at the big turbo and the filter is right behind the bumper on the drivers side. (no picture of it)
    I only have the stock headshield. Everything else is kind of "open".
     
  7. RWD4G63

    RWD4G63 Proven Member

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    What boost pressures are you running?

    Air-to-water setups have to be designed quite well to keep temps down for any length of time, but I really don't think 140 is any big deal if you're running E85.

    Meth in between stages might bring temps down, but I doubt it will help with power much.

    Tyler did some experimentation with pre-turbo methanol injection on his 16G car. It always made less power everywhere with it on. And his intake temps probaby hit 400* (no that's not a typo).
     
  8. Sp1kE

    Sp1kE Proven Member

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    My tuner and I stopped at 20psi. There is no e85 up here in Canada... well its not popular.
    I am running 94oct.
    I was just talking to some local guys and they were reporting around 78-90*F post intercooler on a cool night at 15+psi.

    My intake temps cruising are not dropping much below 90* on those same nights...
     
  9. RWD4G63

    RWD4G63 Proven Member

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    Yeah I'm thinking you're rather tight exhaust setup and your small water to air setup are causing that. Do you have a heat exchanger somewhere?

    EDIT: I'm blind. Yeah the heat exchanger looks adequate, but the water to air is really small.
     
  10. Sp1kE

    Sp1kE Proven Member

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    Ya, I have one inplace of a front mount. There are some pics on the first page of it.

    I guess I will start with the basics and see if I can get it to drop.
     
  11. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    You need to insulate your hotside, especially on a compound setup with all that surface area. Not only are you losing energy to power the turbines, but you are negatively impacting other systems with radiant waste.

    You need to run more boost, at 20psi combined between two compressors.. its extremely unlikely that they are operating in areas of the map that are remotely efficient. That you only have 94oct available (IIRC) makes this a tough predicament.

    If pre-compressor injection does not cool your IATs, you need to look at a bigger nozzle, different orientation or both.

    What air/water core are you using? It looks very small in the picture from post #3. I don't know that I would run that for a 16G by its self.

    Think about the amount of heat energy you need to remove to reach your desired intake air temperature under worst case scenario and scale everything proportionately.. this includes coolant water capacity and heat exchanger. You are looking at a removing the equivalent amount of energy that was able to heat up a fluid mass on the order of dozens of pounds/minute to several hundred degrees above ambient.

    That is a lot of energy, and the heat sink needs to be up to the job.
     

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  12. RWD4G63

    RWD4G63 Proven Member

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    Woah! I forgot you had a 2.4. The amount of restriction you have built into the exhaust system with a 16G and HY35 coupled with the cast iron manifold and I bet you have a CRAZY hot bay.
     
  13. Sp1kE

    Sp1kE Proven Member

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    Sigh... ya a bigger hotside turbo is in the plans.
    Should I just start with the insulation of the turbos? or will I be wasting my time?
     
  14. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    Whether you coat them or wrap them, it's worth it.

    Any amount of that heat energy you can pipe out vs radiate is beneficial on a few levels.
     

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  15. Sp1kE

    Sp1kE Proven Member

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    2 turbo blankets ordered :) I will post my results.


    Also should I look at upgrading to one of those 8cm housings for my 16g to free up some of the exhaust restriction? Or would it be ineffictive once the wastegate opens up?
     
  16. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    Good stuff. :thumb: Some wrap on the wastegate and inter-stage pipe would go a long way as well. If you can swing it, wrapping the pipes for the LP turbine and wastegate would be a good idea too.

    Yes an 8cm housing for your 16G is a good idea. Ideally you would've ran the T3 10cm housing, but that would require too much of a change to your existing hardware.

    You could even go so far as to use the stock heatshield bolt holes to hang a piece of reflective foil or sheet metal between the 16G's compressor housing/J pipe and the HP wastegate.
     

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  17. RWD4G63

    RWD4G63 Proven Member

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    An 8cm would be good yes, but I think something bigger than the HY's 9cm housing would be of most benefit to the system overall.
     
  18. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    I agree with that completely. The drive pressure of the LP and the backpressure downstream of that in the pipe to atmosphere will be multiplied across the HP turbine and additive to the drive pressure required by the HP turbine. Would make a considerable difference.

    But I am not aware of any other options for the HY35 at this time.
     

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  19. Sp1kE

    Sp1kE Proven Member

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    Ya I was just working with what I had...
    I will put that on the list of things to change out. I am sure the backpressure is unreal.
     
  20. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    Upgrading down the road to something like an open T4 19cm HX40 could prove especially beneficial on a pump gas setup in terms of the amount of boost you can run and how aggressive the tune can get, with little or even negligible overall penalty in response as the HP stage will breathe better (read: spool quicker) with less resistance downstream.

    Clever waste-gating could help light the LP stage faster as well, taking advantage of the unmolested energy from the motor by-passing the HP turbine.
     

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  21. RWD4G63

    RWD4G63 Proven Member

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    I'd just stick a HX35 with a 14/16/22cm turbine housing on it.
     
  22. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    A larger unit, like the 60mm HX40 map, being wider at low PRs (dictated by fuel in this case) may allow him more room before running off the right hand side.

    The HX40 is seeing the system of the 16G and the motor as basically just one large motor, and it will have demand flow like a larger motor when you plot it out on the LP stage map.

    The bigger turbine would also help with being on pump gas.
     

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  23. RWD4G63

    RWD4G63 Proven Member

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    I'm just saying as an easy way to reduce backpressure. Regardless of turbo you'll be able to max the flow out. An HX40 would definitely be a much better choice in large turbo.

    I personally think the "math" side of compound turbo systems is overrated. Find a turbo that spools fast, and one that makes the power you want. Put them together and figure out what combo of boost pressures work best. Just don't size them too close together.
     
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  24. LandSpeed-DSM

    LandSpeed-DSM Proven Member

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    Well, when your PR is too low and you have more motor than turbo what happens? Same goes for a compound system when you run a low Primary stage PR and engine demand puts you into the choke below what the turbo would be capable of on a smaller motor at a higher PR.

    Math is never over-rated.. thats just how the world works.

    There are countless examples of this.

    How much power do you think you'd get out of an LS7 running a single HX35 at 7psi?

    You will have a heck of a time pushing even 40lbs/min and the motor would fall on its face well before stock redline.

    A DSM example is Kevin's car, 90lbs/min out of a 67mm at 4.0PR as a single, can barely make that much out of a 75mm at 2.0PR on the primary stage.

    The primary stage is what dictates how much air the system will flow. If you don't or can't run it at a PR where it moves the most air, you are going to fall short.
     

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  25. RWD4G63

    RWD4G63 Proven Member

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    Your example is extreme.

    Johns car makes 650whp through an auto (That's 750whp on a manual car) with the H1C at 18psi and 27psi on the HX52. What you're saying is that if the boost is turned up on the 52, it won't make more power because of mass flow?

    If what you're saying is true, there there is no advantage to a compound setup in the power making aspect besides area under the curve.

    This also means that someone needs to come up with "progressive wastegates" Where we can constantly vary the amount of boost through each turbo. Punch the small charger up, then fade it out when the big turbo comes on to make top end power. Essentially making a sequential turbo system.

    OR that any compound setup needs a MUCH larger charger for the larger turbo.

    I'm also willing to bet that we've all been doing it wrong and you don't need to recirculate the wastegates from the smaller charger, as now they're adding mass flow and limiting power by increasing exhaust backpressure.

    Sorry for all the rambling.
     

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