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12:1 compression TUNING

Discussion in 'General Tech and Maintenance' started by khai_tuan_nguyen, Feb 8, 2004.

  1. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    I have another question that you might be able to help me with. Here is a little background. I have a 97 civic hx coupe. I installed a b20b with b16 head. I am running a p72 obd2 setup. I have 12:1 compression pistons. I plan on getting ahondata and going obd2-1 when i get the money. Anyhow my car was pinging so i had to retard the timing to about 14. It still pinged when it was cold. To stop the pinging I installe d an adjustable fpr. I had it set at about 40psi. IS that ok for my compression. Then a week later i installed the walbro 255 fuel pump and a new fuel filter. I adjusted my fpr as far as it would go and now it idles at 50 psi. I can not get it any lower. However now when i give it gas it accelerates and then seems like it boggs and gets sluggish and then picks up again. Is this because it is running rich? If so what can i do to avoid ping, have better throttle response and the psis? Do you think I should move the timing back to 16 degrees? Also is it possible through wrong timing adjustment to have a rod hit the piston or whatever its called?


    Cliff notes:
    High compression --> Ping + retard timing -> FPR + Fuel Pump
    -> FPR won't go under 50 psi -> Car may be running rich and bogs -> What to do ??? What psi should i be running?

    Thanks
     
  2. Slammed90Lude

    Slammed90Lude Senior Member

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    i think you mean a piston hit a valve- the rod is attached to the piston, which i'm sure you know- and yeah it's possible; it's not a real good idea to guess and check when it comes to stuff like this- get it on the dyno and get it tuned properly before the ping turns into a knock...knock...boom!
     
  3. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    So even though it is ok now, i can have a valve hit a piston by screwing with the timing?
     
  4. v8killer

    v8killer Member

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    @12.1 puttr at 40psi your rev will give you an extra 5psi , but w/255
    your gonna run rich on n/a its delivering more fuel.

    remember ...leaner is meaner
     
  5. pissedoffsol

    pissedoffsol RETIRED

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    i think you're confusing CAM timing with IGNITION timing.

    without adjusting the cam gear, and using stock settings, and assmuing that the timing belt was installed properly and not a tooth too high or back, there is no way on stock b16 cams that your valves are hitting a 12:1 piston. 12:1
    s aren't THAT tall... and morover, b16 cams don't have that big of a lift.

    pinging is a result of shitty gas. if you're only feeding it 91 octane, thats probably why its pinging. Unfortunately, quantity can only make up for so much in terms of quality- and feeding it extra gas to make up for octane simply won't work.

    running rich doesn't make the car feel sluggish. it will be slower, and you will have a greater exahust smell, but the motor will still run fine.

    as for your igition timing- what did you do? move the distributor? if so- put it back to stock, or even retard it, to make up for the shitty gas.
     
  6. ek9r

    ek9r Senior Member

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    :werd: :withstupid: great info
     
  7. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    You are absolutely right i am mixing ignition timing on the dist. Ok so my question is this. With the fpr i could adjust it fine below 40 even, now that i put that fuel pump on it will not go below 50. And what i meant earlier was that with the 12:1 compression i had the dist timing at 14, instead of stock 16 so that it didn't ping, but now that i am running more gas can i put it back to 16. Also sincei put the fuel pump in when i give it gas it runs sluggish then before i had it. That is what i meant by sluggish and it does feel like i bogs, because it picks up then you feel it bog then starts to pick up again.

    SO what do you guys think.

    Also does that mean i can turn my dist timing w/o hitting a valve into a piston as long as it is not hitting now? The only prob with dist timing is pinging. So where i have to worry about valves into pistons is the cam timing? Is this correct?

    Khai
     
  8. jamesA

    jamesA Well known pissed off telephone guy VIP

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    I'd keep the distributor timing at 14 btdc. If it isn't pinging, don't try to fuck with it... aka the old addage...if it ain't broke, don't fix it.
     
  9. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    that is true, but what i am saying is that was before yhe fuel pump, fpr, now it bogs so if i increase timing would itr make it not bog.

    i appreciate it
    khai
     
  10. 9sech22civic

    9sech22civic Senior Member

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    from my experience in tuning. you need to run higher octane fuel and turn your timing back to 16. by retarding timing you can increase engine temperatures also. By running 12:1 compression thats a lot of heat being created in the combustion chamber and with a fuel that doesn't burn as easy as ...let say 100 octane. Using 91 you will create enough heat to cause self combustion before your plugs actually fire, like a diesel for an example they run as low as 15:1 without a spark source. so i would recommend what pissed of sol stated>> get a hondata or stand alone. and have some professionals tune it for you. try throwing in good octane booster and watch what happens.
     
  11. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    i am going to get a hondata when the budget allows, but for now what should i do anout the bogging and the fuel pressure not going below 50psi?

    Thanks
    Khai
     
  12. tab

    tab Super Moderator

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    Like he said. Retard the timing a tad to keep detonation down. As soon as you have the money, get it tuned. Dumping in too much gas in is probably making you bog.
     
  13. pissedoffsol

    pissedoffsol RETIRED

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    Honestly, i wouln't wory about it. stock is in the mid-low 40's anyway, and a couple psi more won't kill you.



    Again, see what I said above. Quantity cannont make up for quality.


    Perhaps a return line is colgged?
    I see no reason why adding the large pump should make your motor run ANY different at all. It will put more fuel to the rail, but if it's not used, it will be returned to the tank.



    right- you are dealing with INGITION timing- the time of when the spark happens. not CAM timing- which could cause "hitting".



    Not at all. "pinging" is the best case scenioro. Poor timing leads to pre and/or post detonation. Detonation = boom. i highly suggest you retard it... maybe even less than 13 or 12. if you are pining at all, its bad. cut some timing.

    Moral of the story is, Cali sucks. :) 94 at the pump, 3 min from my house. But seriously, you can't make good clean power off shit gas. That's all there is too it.
     
  14. pissedoffsol

    pissedoffsol RETIRED

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    really? Please explain more please.



    (also known as pre-detonation as i said above)



    hey now, i never said that :p
     
  15. 97hatch

    97hatch ?

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    on the temp note with timing i just wanted to make a correction.

    advanced timing means it wil run hotter/cause detonation
    retarded means that it will run cooler/prevent detonation
     
  16. 9sech22civic

    9sech22civic Senior Member

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    what i meant what you mentioned was having it tuned and dynoed by some proffesionals.

    As for retarding timing for increases in temperature. is for higher rpm range. sometimes your getting the spark before 100% fuel /air is disbursed into the combustion chamber. you can also create 2 flame fronts which will cause preignition the opposite of detonation. if its a stock motor with stock internals i wouldn't be too much worried, but with 12:1 and shitty fuel you have somewhat of a risk but then again your at risk anyway when your up above 8000 rpm's. but then again 16 isn't that bad even 15 your probably ok.

    while we were tuning my car the race mode i have a idle timing of 19 and above 2000 rpm it starts to advance. well when we tuned the street mode to 18 and not to advance the ignition mapping till around 3300. so i can run 94 on the street without pinging. brent from pfi was worried about increases of engine temperature, due to retarded timing. he stated increase in coolant temperature was caused by retarded timing.
     
  17. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    Thanks everyone especially sol i am truly learning a lot about fuel and timing. Ok so 50 psi is ok and my timing i will keep. However i need to figure out the fuel bogging me. When i changed the fpr it was fine. Then i changed the fuel filter and the fuel pump and now it boggs. I also installed a fuel gage on the fuel filter? It leaks a little, could that cause the bog? When i feel around the fuel filter i can see gasoline on my fingers also when the car sits it cranks to prime the fuel and then starts up. What else could I have done to cause the bogging if all i changed was the fuel pump and the fuel filter?

    Thanks in advance
    Khai
     
  18. pissedoffsol

    pissedoffsol RETIRED

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    That's no good. you don't want a fuel leak in your bay. fix that at once.

    It could also be causing a leak in the vacuum system, which could lead to the FPR getting a poor reading, and thus, causing your bogging.
     
  19. khai_tuan_nguyen

    khai_tuan_nguyen Senior Member

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    So the bogging and the high fpr is probably because of the leak huh. Alright I will check that out and see if that fixes anything. Any other things for me to check?
    If there was a leak wouldn't the fpr gage go down instead of up though?

    KHai
     
  20. StyleTEG

    StyleTEG Senior Member

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    What cams are you running?

    Another source for the bog could be you seriously undercamming your engine.
     
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