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NA vs FI

Discussion in 'Engine Building' started by MadEgo, Apr 26, 2004.

  1. MadEgo

    MadEgo Member

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    I am not quite sure which way I want to go. I was wondering what some of the pros and cons are for going forced induction Vs. naturally aspirated. Tell me your opinions. (This is a serious topic please don't lock it) :locked2:
     
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Simple response:

    NA:

    + power curve
    + instant response on gas pedal
    - not as much power

    FI:

    + tons of power potential
    + can be more streetable than a crazy all motor build
    - power curve isn't very linear on a big turbo setup

    There you go. What you pick really depends on your budget and on how you want to use your car.
     
  3. MadEgo

    MadEgo Member

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    I just needed a little clarification. Thank you for breaking it down simple.
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Sure thing- there's a LOT more to it than that, but that at least gets you started..
     
  5. JDMilan

    JDMilan Senior Member

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    cost of going NA is cheap from the get go only, in the long run it can get very very expensive, but in the honda world it's my personal favority route. NA

    FI, tough to beat with the bang for the buck of say a bolt on turbo kit at a standard 7psi, but once again, it's not linear.

    just make sure you consider other factors, such as reliability, $$ issues, what type of racing you'll be doing also.
     
  6. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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  7. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    You can have a near-instant response on the gas with a turbo if, as Calesta hinted, you run a smaller turbo, in addition to having a free-flowing exhaust (this includes the uppipe to the turbo).

    The WRX (non-STi) comes equipped with a smaller turbo, which is both a blessing and a hindrance. It allows for a quick spool-up (especially once you get the restrictive factory uppipe replaced). It's at full boost now by 3000 rpm (as opposed to around 4500 bone stock).

    However, it doesn't allow for much higher psi levels than stock, given its relatively small size. For road/track racing, it's a well-engineered system. For the dragstrip or higher-horsepower numbers, it's undersized.
     
  8. StyleTEG

    StyleTEG Senior Member

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    I would say one major disadvantage of FI on our specific engines, is they were not built or designed to handle the kind of cylinder pressures FI can create. They are alluminum block, open deck.

    I honestly wouldn't feel safe running much more than 6-7psi on a stock honda block.
     
  9. b16ahatch

    b16ahatch Senior Member

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    A lot of people feel the same way about boosting a stock block, but my buddy ran 15psi all day on his b16 for over a year and the car still reads perfect compression. Me personally, i wouldint do 15psi. I would keep it below 10psi. 10psi should be fine on a stock block.
     
  10. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    It's all about proper tuning. Using a dyno along with a wideband O2 sensor, EGT gauge and the like, setting proper timing and fuel curves will allow for higher boost levels on a stock Honda block, as b16ahatch noted.
     
  11. JDMilan

    JDMilan Senior Member

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    true true, proper tuning is key when having a stock internal honda motor with FI on top of it.
     
  12. StyleTEG

    StyleTEG Senior Member

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    Its not uncommon for people to run 15psi on a stock block, or someone to know someone who has. But thats hard to say for direct evidence. First not all engines are created equal, the quality of the break in, the casting process, etc all can make some engines stronger than others. Further how a car is driven and how well it is taken care of can make a huge difference.

    I knew a friend boosting 12psi daily on his stock block, but he drove it like he was a grandma because he was afraid of blowing it up. (which happened to his first two boosted engines).

    I wouldn't put myself in a situation where I could cause enough damage and be SOL.
     
  13. beerbongskickass

    beerbongskickass Senior Member

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    At 10 psi I am making 216whp/181tq on my completely stock d16z6. It was tuned with Uberdata and I have been running it this way for a little over 2 months and almost 3000 miles. I redline this thing daily and have raced it quite a few times. Compression is 195 in all 4 cylinders. Realiabilty is all about tuning and fuel management. I don't think NA even compares to FI... once you go turbo you will never go back. B)
     
  14. StyleTEG

    StyleTEG Senior Member

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    I still dont' agree on a block built for the forces generated by a NA engine.

    Like I said its still an alluminum open deck block, the internals are still relatively weak.

    You said you raced it quite a few times, what is that 5-10?

    With our NA build ups, my friends and I spend 20minutes + at or near redline at road cources. Is that something you would feel safe with on your turbo car? My brothers GSR is turbo, and I think if he did it would have to come back in a trailor.
     
  15. beerbongskickass

    beerbongskickass Senior Member

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    Here is a stock internal b18c1 for ya making 354whp and I would bet money his motor will last... http://www.boosted-hybrid.com/viewtopic.php?t=82

    I have only been out to the street races once since I have been boosted, but I probably raced at least 20-30 times that night. A lot of times back to back and I never had one problem. I am actually going out street racing again this week and next week so I can beat on my car some more.

    I would like to spend a little more time tuning until my car it's perfect, but other than that I would have no problem taking my car on a road course. It's only been tuned for WOT and we only got about 5 dyno runs in, but the A/F is in the 12's and the timing is pretty conservative. I'm sure a lot of people with turbo hondas do auto-x and road racing. With proper tuning and fuel management I see no reason why you couldn't.

    I will admit I am pretty much maxing my motor out though (I hear the d-series rods are good to about 220whp?). I know a lot of people have run around 200whp on d-series motors for a long time without problems so I am not too worried.
     
  16. StyleTEG

    StyleTEG Senior Member

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    Maybe I am just paranoid :)

    Although RR probably is the most stressfull on the engine itself out of the three (drag, autox, rr) as drag and autox last from 10 second to one minute. Road racing is at or near redline of 20minutes at a time (or more).

    But I am probably just paranoid. I don't like hondas oem design when it comes to boost, but that doesn't mean it doesn't work.
     
  17. beerbongskickass

    beerbongskickass Senior Member

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    Well, I would be paranoid about driving my car if it was NA or FI at or near redline for 20 minutes non-stop... :unsure:
     
  18. MadEgo

    MadEgo Member

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    I am looking to do something like that to my 94 coupe. Does anyone know of any reputable places in AZ where I can get hooked up?
     
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