Engine Theory, Build, Etc Discussion.

Discussion in 'Engine & Transmission Mods' started by BlkCurrantKord, Oct 15, 2007.

  1. sbanitt13

    sbanitt13 Member

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    Ive been searching and researching trying to find hp/tq specs for a boosted g23 (f23 block, h22 head) but all i can find are na. I plan on building a g23 and boosting it (around 20-25psi)

    Basically here's my question: is 450-500 whp a feasible goal while still being reliable for a boosted g23?
    I plan on forged internals and a built tranny, LSD etc. to support it but i was curious to find out. Also, i live in mn so i dont need to worry about emissions ;)
    Thanks in advance!

    Sent from my SM-G900P using Tapatalk
     
    Last edited: Oct 16, 2015
  2. #SOHCdeezenuttz

    #SOHCdeezenuttz New Member

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    Aloha,

    I been searching the forums for a few minutes. Is there anything that is TUNING SPECIFIC as to what ECU options are out there for boosted F23 accords?

    thanks in advance
     
  3. Bikes

    Bikes Member

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    I've been going over the thread and the other forums but haven't found anything on this:

    I'm going to replace my head gasket in the next little bit and I, having a machinist friend, was wondering if I could mill down the head a couple .001 to increase compression.
    Has anyone done this successfully?
    How much did they take off the head?

    (I've got a f23a1)
     
  4. 604ACCORD

    604ACCORD Well-Known Member

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    They would prolly have to do that any way to accept the new gasket
     
  5. SupraGuy

    SupraGuy Well-Known Member

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    Most of the time, when doing an engine build, there is a little bit of milling done to get a good gasket sealing surface.

    In order to determine your new compression ratio, first you get the combustion chamber size:

    First find the combustion chamber size. This can be calculated from the compression ratio, and displacement. It boils down to dividing the displacement by the compression ratio - 1. divide the result by the number of cylinders to get a per cylinder combustion chamber size.

    For the F23A1, that's a CR of 8.8:1 and a displacment of 2254cc, so a total combustion chamber size of 288.97cc or 72.24cc per cylinder.


    Now, change the combustion chamber by the volume you're milling off. Again, the F23A1 has a bore of 86mm, so that's an area of about 58.1 square cemtimeters for the bore. Multiply that by the amount bored from both the block and head. .001" = 0.00254 cm, so that's about 0.15cc per thou.

    So a .01" mill (10 thousands, or .005" each from the block and head -- pretty typical for block and head on a rebuild) on the head and block total would change the combustion chamber size to 70.74 cc. With the displacement (per cylinder) of 563.5cc, that would mean a compression ratio of 8.96:1. ((563.5+70.74)/70.74)

    Take .01" from both the block and head and you get a combustion chamber of 69.24cc, for a compression ratio of 9.14:1 ((563.5+69.24)/69.24)

    Often times, to keep compression rations lower, the Supra guys will go to a thicker head gasket, which increases the combustion chamber volume (particularly after having head and block milled) to allow more boost.

    Therefore, you also much factor in your head gasket thickness when calculating the final compression ratio, for any change from the stock thickness. Many aftermarket head gaskets will be thicker, in order to compensate for the milling of the block and head that will often happen when an engine is rebuilt.

    Anyway, that's how to calculate the change in compression ratio for a milled block and head.
     
    Last edited: Oct 6, 2016
  6. Bikes

    Bikes Member

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    sweet! Thanks man!
     
  7. Rodimus Prime

    Rodimus Prime New Member

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    Just heads up you better hot tank that engine. Any kind of carbon build up in the combustion chamber or valve seats can cause hot spots leading to pre ignition or burnt up pistons.
     
  8. Apzy6

    Apzy6 New Member

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    I have a 4dr f23 and I’m planning on swapping to a j series, j35 tbe. I was wondering what would be the best j35 to swap in.
     
  9. Remi

    Remi New Member

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    I have a 1999 Honda Accord Ex Sedan with a manual transmission, and it's a 2.3Liter, and I'm assuming it's a F23A1. I don't know too much about engines, but I do know that I want a 0-60 to be under 7 seconds for now, and be a tuner later lol. I want to build the engine but I don't know where to start. The car has 180k miles on it, but it has all been on the interstate and the guy never went over 4k rpms. Should I just buy the turbo kit for $600 and put it on? Should I tune it first? How do I tune it? How do I know the compressions and the air to fuel ratio? How do I beef up the transmission and the suspension? Should I do the axles? Heads? Add studs? Skunk 2 alpha connecting rods are $389.99, should I get them? How do I put them on? I have so many questions but no one to answer them.
     
  10. capsidx

    capsidx Well-Known Member

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    You should not be turboing a high mileage motor without understanding all the things you have questions about. The general consensus is these things can handle about 200 -250 hp on stock internals. You shouldn’t l assume you should get connecting rods and you’re set.

    The bearings should be replaced if you plan on beating on it. The timing belt should be inspected, the ecu needs to be swapped out for an obd1 ecu so you can run engine management therefore getting a tune. A tune will set the air fuel ratio so you don’t lean out. If you lean out on 1 hard pull you could blow the motor. My f23 when I had it was about an 8 second 0-60 motor and that was basically stock.

    So do the maintenance first and see where you stand. My suggestion is do a swap so you won’t have to turbo. In my opinion turbo is dangerous on an n/a motor because there are more things to go wrong, you don’t really get power until the turbo spools and they don’t really last that long depending on the setup. But you can get more out of a turbo setup than an na setup depending on your goals.

    Your suspension should be fine unless you start tracking it, your brakes should definitely be upgraded if you plan on doing highway pulls or just pulls in general. If I were you I’d rebuild the motor to do it right the first time so you’re not stuck on the side of the road with a wrecked engine.

    So here’s my recommended laundry list:

    (For low boost)

    Replace bearings
    Inspect crank clearances
    Inspect cylinder walls
    Replace head gasket
    Arp head studs
    New connecting rods
    Replace piston rings and pistons ( if needed)
    Oil pan with return line bung
    O2 wideband
    Better pads
    New rotors
    Obd1 ecu
    Engine management
    New injectors (depending on the duty cycle they’re at with the turbo, tuner will let you know)
    Intercooler
    Turbo
    Charge piping and oil feed/return lines
    Wastegate
    Downpipe
    Turbo manifold
    Missing link (depends on introduced psi)
    Vafc (optional)

    And there are probably some other things I’m forgetting to mention. Some of that stuff is optional. Of course you can just slap on a turbo and drive it but you probably won’t even make it to the corner. Also if you go through with it, drive it to the tuner while staying out of boost or the motor is gone. Overall should be more that 2,000 for a decent setup. I priced it once for my f23 and it was actually cheaper to swap out the motor and trans for something else. But to each his own. Good luck.
     

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