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Calculated Build

Discussion in 'Engine Building' started by KingBacis, Jul 8, 2009.

  1. KingBacis

    KingBacis New Member

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    Ok, so i'm tyring to wrap my mind around how exactly i'm going to build my setup. Going with a b20 block and pr3-3 head(b16) and gsr tranny as the 'main components' so to speak. This is going to be a boosted setup in my crx, but i have a spare ls block that i'll probably incorporate to get the chains moving in the swap while the b20 is being built. Haven't picked a turbo yet, maybe a gt35. I plan on sleeving it, forged internals,PnP the head/Tb and IM, balanced, ect to make sure i have a reliable setup. I'm doind a da suspension swap first, and planning on getting a quaife lsd for the tranny. My questions are, What comp pistons to go with? I'm thinking 9:1 With that tranny/block/head going boost, anybody know what the ideal powerband range is? I know its probably going to be mid range, and that its too early to tell without more info but i just want a *rough* idea from somebody with a sim setup. I have the tranny gearing specs and the formulas for calculating where the rpms are gonna fall ect so i just wanted to like i said get a rough idea from somebody who knows before i blow money on bolt-ons for the wrong powerband.

    Anybody have a 3000+ powerband boosted b20 with tips? Also what camgear to go with that would give the ideal lift duration to extend my powerband?

    I've done tons of research before coming to you with my questions which i feel can be answered here, thanks in advance, -KB

    PS, Before you ask what my power goals are, as in horsepower, as in *peak* horsepower, don't have one. My goals are at the track, not the dyno, 12's or less 1/4m ww not dd;)
     
  2. KingBacis

    KingBacis New Member

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    Okay, so here are some calculations i came up with for the gsr tranny to try to determine my powerband. According to wiki, the b20b/b20z reach peak hp @ 5400 and peak torque @ 4300, with the redline being 6300.

    That said, the standard gearing for a usdm gsr is as follows:

    1st -3.230
    2nd-1.90
    3rd-1.360
    4th-1.034
    5th-0.787
    FD-4.4

    Now lets assume that the headwork is done and you can rev to say, 7.8-8K safely. When you shift, in theory, you want your rpms to drop to the begining of your powerband (or for some a lil earlier for traction issues) in order to reap the most benefits from your setup, correct? That being the case, I've calculated two possible shifting scenarios, assuming that one would like to start from peak torque, which in this case is 4300. One will shift at 7300 (3k powerband) the other at 7800rpm(3.5k powerband). Remember, these are assuming that your still making power up to where i pointed out the shift points to be.

    Shifting at 7800rpm

    Gear RPM Drops Speed (mph)
    1st N/A 35.184
    2nd 4588 63.910
    3rd 5583 89.286
    4th 5930 117.436
    5th 5936 154.29

    Shifting at 7300rpm

    Gear RPM Drops Speed (mph)
    1st N/A 35.184
    2nd 4294 58.813
    3rd 5225 83.562
    4th 5550 109.908
    5th 5556 142.424

    You'll notice that the 7.3rpm shift starts me slightly lower in my powerband, so i can 'scrape the plate' so to speak, but i'd be losing 500 rpm worth of power, or do these things cancel each other out? I know building a motor is about compromising a little bit of this for a little bit of that to gain the right amounts of blah.

    The gear speeds were calculated using the formula (Rpm/gear/Fd) x60x0.000585x3.14=?/1.609 (To convert to mph)
    Then you plug it back in with the advancing gear to determine what your rpms will fall to.
    Example: (7800(rpm)/3.230(Gsr 1st)/4.4(Gsr Fd)x60x0.000585x3.14=60.488kmh/1.609=37.594mph
    THEN, with that number, turn it back to kmh(60.488) and do the equasion backwards now, but use 2nd gear where you used first to determine where your rpms will fall to when shifting at 7.8k. So (60.488/3.14/0.000585/60)x4.4x1.900=4588.
    Oh, and the 0.000585 represents your tire diameter, assuming its 58.5 cm (1inch equals 2.54cm)
    Sorry if i am confusing you all but feedback is much appreciated, thanks again, KB
     
  3. CAFROG

    CAFROG Honda Minion VIP

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    small turbo: quick spool up

    big turbo: strong spool up

    LS transmission IMO is best for your set up

    Stage 2 cams from a variety of companies

    Stage 2 Drag clutch

    This whole venture of yours will be a minimum $5000-6000
     
  4. KingBacis

    KingBacis New Member

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    Thanks for the feedback. Unfortunately, you might be right about the ls tranny, because it seems that the gsr is more suited for N/A and or low-mid turbo builds (say up to maybe 250-300ish, just throwing up a number) but i think it might lose in the end to the ls turbo with higher numbers (say 400-600) because of tracktion issues. Ls tranny's are suited for low end power, just like the b18 and especially b20 blocks. Mismatching the transmissions might not be the best idea i'm starting to see. My only fear with switching to the ls is being wrong, as in being beaten lol.

    Anyone else wanna chime in?
     
  5. KingBacis

    KingBacis New Member

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    By the way, which ls were you refering to? did you mean;
    B18B1
    1st 3.230 (Same as gsr 1st)
    2nd 1.900 (Same as gsr 2nd)
    3rd 1.269
    4th 0.966
    5th 0.714
    FD 4.266

    Or the B18A1
    1st 3.166
    2nd 1.857
    3rd 1.259
    4th 0.935
    5th 0.742
    FD 4.4 (Same Fd as gsr)
     
  6. BrutalB83

    BrutalB83 Brutal Moderator Moderator VIP

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    "Tracktion" issues should be resolved via proper performance enhancements (tires, suspension, traction bars, etc.), not by using an inferior gearbox that was built mostly for fuel economy. Don't slow yourself down in hopes of going faster...
     
  7. KingBacis

    KingBacis New Member

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    lol @ my sp mistake, thanks for the imput though.
     
  8. Gnarphantom

    Gnarphantom New Member

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    lmao "imput"
     
  9. awptickes

    awptickes unimpressed by you VIP

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    Great idea btw, but do you think that Honda didn't already do this?

    Also, your logic is flawed, because you're going to be using a b20/b16 hybrid, your power and torque curves are going to be different.
     
  10. KingBacis

    KingBacis New Member

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    Can you explain this? I'm guessing you mean because the motors have two diff redlines?
     
  11. awptickes

    awptickes unimpressed by you VIP

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    No.

    I'm saying that you need to build up the motor, tune it, dyno it, then build your gearbox.

    What you're doing now is akin to buying the cart before you have even know what breed of horse you want.


    An important thing to keep in mind is the adage "a rock-solid tune for one engine is a basemap on another." Meaning that your setup will make different numbers that anyone elses. Similar, yes, but very rarely the same numbers. Especially with a 10 year old engine.
     
  12. KingBacis

    KingBacis New Member

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  13. Matts96HB

    Matts96HB . Moderator VIP

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    If your car is setup to put the power to the pavement efficiently, traction will not be an issue with a GSR or even B16 transmission.
     
  14. KingBacis

    KingBacis New Member

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    By that do you mean suspension wise and or clutch/flywheel?

    and I do know what i want, i'm just trying to figure what tranny is best for me. People keep saying go with this or that (nobody in particular) but are not showing me why. I think o'll go with the gsr, thanks to all that gave constructive feedback.
     
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