Cold weather PSI

Discussion in 'General Community' started by fast shadow, Oct 24, 2006.

  1. fast shadow

    fast shadow Member

    So on my way to work at around 9 this morning I had an open stretch of road on 400 before the ramp onto 285E. After dodging a couple of stray bales of hay lying on the edge of the road (WTF?) I laid into it in 5th gear to see how much boost I'd picked up in the cold weather. When my car first got tuned it was on a hot as hell afternoon in Orlando and the most boost we saw was a little over 23psi. This morning I hit 24.7 and probably would have hit 25 if I'd started at a different RPM. :eek:hnoes: Time to start datalogging on the way to work to make sure I'm not getting any knock with the extra boost. Anybody else notice the difference?
  2. miloman

    miloman Retired Admin

    my boost has been right around 19.1 so far...

    do u have meth injection?
  3. fast shadow

    fast shadow Member

    no meth yet, next on the list along w/ stepping up to 28psi.
  4. miloman

    miloman Retired Admin

    evo can run 23 psi on pump?!?!?:bowdown:
  5. LazyGun

    LazyGun Member

    I was about to post something about the cold weather and how my car now feels especially zippy these last couple of days.
    No idea what my boost is (lack of boost gauge being the problem there ;) ), but the car does feel much more 'peppy'. Shame that cold sometimes = ice. Nice having the extra power, but not much fun not using it on the back roads I take to work in the morning. :)
  6. fast shadow

    fast shadow Member

    yes sir, on 93 octane the evo9 is good for 23-24psi spikes tapering down to just under 18psi at redline. personally, I'd rather have the extra 500cc of displacement of a 2.5L motor.. but the ability to run a relatively high amount of boost is nice. But now that it's so cold I don't want to overboost too badly.
  7. miloman

    miloman Retired Admin

    23 psi on pump must be nice... but my limited knowledge of tuning always told me that safe boost and timing are directly related to octane and compression... whats the compression on an EVO?
  8. 1ll-WRX

    1ll-WRX Active Member

    yeah cold weather boosting is very nice.....
  9. fast shadow

    fast shadow Member

    8.8:1 CR

    I hit 25psi even on my way to work today. I did a fourth gear pull and my AFRs were a steady 12.0-12.1. I do believe she's running too lean, captain. I guess I'll do some logging on the way home to see if I'm picking up any knock counts. Last week I was seeing 11.7-11.9 AFRs and I wasn't knocking.. but I get the feeling I'm pushing my luck now! I'm starting to have second thoughts about running a manual boost controller, but frankly I know more people who've gotten headaches than happiness from EBCs.
    Last edited: Oct 24, 2006
  10. miloman

    miloman Retired Admin


    stupid strong motor

    jokes aside, im pretty impressed... u guys have more compression, leaner AFR, and can run more boost on pump... must be sweet... can anyone explain how that works?
  11. crashtke

    crashtke Member Supporting Member

    Wow, that is kina scary lean at 12:1
  12. longfury

    longfury Active Member

    Even with forged internals and a cast iron block, it can't run that lean long term. Everyone I have talked too thought it was nuts.
  13. Alex

    Alex Community Founder Staff Member

    its also nice because its been relatively humid.

    cold + damn = winnAr
  14. fast shadow

    fast shadow Member

    Yeah, I'm gonna d-log it a couple of times and then probably back down the boost. Damn you good weather! :rofl:
  15. fast shadow

    fast shadow Member

    Ok so I did a few pulls. I'm no expert tuner but I could see what was happening. With more boost and cold, dense air I was reaching a higher set of load cells and more fuel was needed. I sent the ROM file out to the guy that did my tune and he made some changes. It was pretty cool to see that the changes he made were exactly what I expected to see, it confirms I'm getting the right idea of how to tune.

    The good news is that even my worst pull only yielded peak knock counts of 7, which isn't bad. It's enough knock to require attention but not enough to burn up anything. So now that I have my original flash file from when I first got tuned and now this updated file - I basically have a "cold weather" and a "warm weather" tune I can switch between depending on the climate.

    By the way if you have a modified turbo car I can't recommend the Zeitronix wideband enough. With the addition of the Kavlico precision MAP sensor and the LCD display it's invaluable. I don't have the optional EGT probe yet but as soon as I go alky/meth I'll add that as well. You can even get an alarm module that will sound off a siren if you go too lean, EGTs go too high, etc.

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    Last edited: Oct 25, 2006
  16. crashtke

    crashtke Member Supporting Member

    I like street tuner myself! It can monitor anything and everything that the ecu sees.
  17. keevo54

    keevo54 New Member

    Turn your MBC back down to 23 psi if u want your car to last, as that is the highest boost most tuners recommend
  18. fast shadow

    fast shadow Member

    Did some retuning last night and got the AFRs back where they should be.
  19. fast shadow

    fast shadow Member

    Doug retuned my car on Nov 4, fixed the AFRs and the final numbers were 348whp/351tq at around 23psi on pump. Thank you, TopSpeed and thank you cool air.
  20. miloman

    miloman Retired Admin

    very nice :)
  21. Cool_____

    Cool_____ Banned

    Man sometimes I miss my old 1g and the old 4g63.
  22. mckenzietj

    mckenzietj Member

    Last edited: Nov 21, 2006

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