Fox Turbo Guys.....i Need Your Help

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by madmike1157, Oct 20, 2013.


  1. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    Alright.

    I am going to make a hotside for my combo, now that I have a mocked up engine to work with. That will require that I have a turbo to work up to.
    Compressor maps are waaay too much like college level trig for me,...( and I hate math) so, I am at a loss.
    You'd think that with all the science out there that there would be a turbo size calculator where you could just plug that junk in, and it would spit out the recommended A/R, hot side/cold side wheel size and frame size.....but no.

    I found this one was recommended by several http://www.squirrelpf.com/turbocalc/, and I used it to confuse myself further. I plugged in my specifics, and it did recommend a bazillion different makes along w/ their respective maps.

    I read, and read some more ( I may need to do even more of that)
    I do know that I'm gonna buy a Chinese turbo from the plethora of ebay suppliers out there I found this:
    http://www.godspeednet.com/media/10/a20791712487ec77bb2b2d_m.jpg

    From what I'm seeing I want a big A/R (towards 1.0) To tell the truth IDK what I want. But if this is a good one, It will be what I buy.

    I'm also gonna use an A2W intercooler,..and will use a separate little radiator w/ a pump circulating the water.
    I don't need the I/C yet, so it isn't as important as the primary.
    #1
  2. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Is this planned for the Futura?? If so, I'd guess you'll want something a bit smaller for faster spoolup
    #2
  3. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    It is, Keep in mind that the turbo has got to be good for 500+ FWHP.
    #3
  4. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Has anyone ever seen a NO2 /fuel injection into the hot side inlet of a turbo? It would provide an extra surge of hot gas to spin up the turbo.

    Or is the spool up delay really due to the inertia of the turbine/compressor rotating assembly?

    Edit: see https://engineering.purdue.edu/~propulsi/propulsion/jets/basics/water.html Check out the description on the bottom half of the page...
    Last edited: Oct 20, 2013
    #4
  5. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    nitrous port into a 1200 degree housing, not for me!
    #5
  6. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Last edited: Oct 20, 2013
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  7. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    Dude, that is the exact same turbo I linked.
    #7
  8. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Sorry man, your link was only to a pic of a turbo. Cant tell too much from that. o_O
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  9. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    NO2 by itself will not spontaneously ignite or explode: it is a oxygen provider, and needs fuel to combine with to burn.

    If the NO2 frightens you there still is water injection to consider.

    Read a little further and you'll find that they also use water injected into the hot gas stream just before the turbine wheel. The water instantly vaporizes into steam and the increase of gas volume spins the turbine faster. That's a technique that's been used for over 50 years in jet engines.
    Last edited: Oct 21, 2013
    #9
  10. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    Well, I figured it out.Calculations came out to where I should use an equivalent turbo to a Garrett 60-1.

    I bought this one:
    http://www.ebay.com/itm/HUGE-GT35-T...Parts_Accessories&hash=item1e7fbdeba3&vxp=mtr

    It's so cheap,...if it ain't right I can buy a different one (or, an actual Garrett 60-1, for 4 times that.)

    I'll buy my J-bends tomorrow, I have to cut out the six individual flanges this week, and be ready to build by weeks end.
    #10
  11. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    that should work!
    #11
  12. f8tlfiveo

    f8tlfiveo My wife likes my spool and blow-off valve.

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    I bought a gt45 turbo for my bone stock motor. A lot of people are using these making good power on sbf and sbc. I would recommend taking the turbo cold side apart and deburring everything. The castings on the Chinese turbos seem pretty good but they do not deburr the parts. This will help just in case there are any metal chips from the machining process. There are reviews on the turbo forums of people finding foreign matter in the turbo. If you don't clean it out you know where it will end up
    #12
  13. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    Good advice, I read that somewhere too, that their final Q/C leaves potential dirt/debris inside. I'll look when I get it here. Thanks.
    #13
  14. f8tlfiveo

    f8tlfiveo My wife likes my spool and blow-off valve.

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    I bought mine a month after my son was born.. It is not installed yet. He turned 2 in July, but I did take it apart and clean it up a little bit. No debris but burrs were there. Hopefully get it on the car soon. I have all the major stuff to do it but I am in my last semester then graduate in December. And my house is for sale at the moment, don't really want the car in pieces when I move. Maybe I should mock up everything on my spare motor. That might be a good idea.
    #14
  15. HotFox

    HotFox Active Member

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    whats the plans for the header? three feeding one half of the turbo split will be most efficent. if firing 1-5-3-6-2-4. 1-3-2 should be one side, 5-6-4 other half. there is a program called pipemax that can help with dia. and length It can be bought for like $30 I think. I would also refer u over to speedtalk.com for tech engine design questions.
    #15
  16. FastDriver

    FastDriver Mod Dude

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    You know, the compressor map is only one half of the equation. The turbine efficiency map is the other. I went through compressor maps and learned how to apply the math. I picked the turbo that would work best for me, but there wasn't a compressor map to look at on it, because Precision doesn't believe in them, according to a tech I spoke to just a couple weeks ago. It turns out that I wish I'd had the maps to look at, because my exhaust back-pressure is way too high, about a 3:1 exhaust pressure to boost ratio. Unfortunately, turbine maps are even harder to come by than compressor maps. So it seems that with turbo-charging, you either have to follow in someone's footsteps, take your best guess, or get some sensors and to with the trial and error method until something works the way you want it to.

    As a general rule of thumb for me, I look at the size of a modern compressor and figure that it can support that much RWHP or more. That's not necessarily where they would be most efficient, though. So to quickly get you in the ballpark, I would have put you at a 55-60mm compressor.

    Choosing the right compressor is a balancing act between spool RPM, compressor surge, efficiency, and power goals. On the turbine side, it's a balancing act between spool RPM, and back pressure at your power goal.

    Choosing the frame is the next most important question. I feel my motor is on the border line between choosing a big frame (T6), and a medium frame (T4). I can't see why you would ever need more than a T4 frame for your V6 at those power levels.

    Finally, A/R can be used as more a fine-tuning adjustment. On the exhaust the larger the A/R, the slower the spool, but the lower the back pressure. The smaller the A/R the quicker the spool, but the higher the back pressure. The rule of thumb here is to shoot for 2:1 exhaust pressure:boost or less. If you pick the wrong compressor or turbine, the A/R won't matter enough to make a big enough difference.

    That's not an answer to your question. I'm just giving a little insight based on my understanding of turbo sizing. I can help with the calculations, but I'm still not confident enough that compressor and turbine maps will nail it every time. In the end, I would call a reputable turbo engine builder and listen to their advice.
    #16

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