Boost level with mods

Discussion in 'Generation 4 - Performance Upgrades' started by skyshadow07, May 25, 2020.

  1. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    So I was told by Torrie the 15psi is as high as he would suggest I go with my mods (mods in signature). I guess I was under the ASSUMPTION that I could run 17-18 on stock turbos and HPFP. Am I wrong? generalizations welcomed...
    What PSI are you guys running and married with what mods?
     
  2. yaycandy

    yaycandy Florida is too damn hot

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    18psi, my drive yesterday on my x4 shows 17 and a half psi but its been over 18psi a few times.
    Lsm catless downpipes, msd coils, roush intake, lower temp thermostat, straight pipe, ajp tuned. No fuel mods
     
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  3. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    commanded 18? I see 18 as well but as a spike during a shift. So no turbo or fuel upgrades?
     
  4. yaycandy

    yaycandy Florida is too damn hot

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    New stock turbos when new engine was installed. My old turbos have billet turbines but i havent installed them yet. No fuel upgrades. Maybe one day. I did ask for a high psi tune and had to sign saying its track use only for his safety. I see around 17 looking at the guage when i stomp it, it has spiked over 18 but i just redid my datalog on it yesterday and didnt really push the car since.
    17.11psi max from “normal” driving yesterday. My usual driving is stupid with abs fuse pulled and high rpm launches and burning tires.
    5389521D-A2A5-45AA-91AF-89B1FAE0EF61.jpeg
     
    Last edited: May 25, 2020
  5. Jordan_R

    Jordan_R Stock Block Ready To Knock...er..Rock

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    15 psi maintained. Spikes don't count. Prehpfp that's about right. Once you have upgraded fueling you can command 18 but it tapers in the top end. Still a huge difference though.
     
    Last edited: May 25, 2020
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  6. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    yaycandy, you can see what the desired or commanded is from your logs. It's labelled TCBP_DSD(psi). I think your's is 15 like me because I see 17psi spikes.
     
  7. High on Ethanol

    High on Ethanol SHO Member

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    Look at the curve on your log. You should see it taper as Jordan said.
    Mine peaks at 22 or 23 spikes but only actually maintains about 19 steady until around 6k where its around 17.
     
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  8. SM105K

    SM105K Streetlight Grand Prix Champ/ IG @egocheckersho

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    Yep, one spikes to 18 and then tapers to 14.
     
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  9. Jordan_R

    Jordan_R Stock Block Ready To Knock...er..Rock

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    When you have the fueling you ride the boost spikes as much as you can it seems. It's all extremely hard on these turbos and commanding 18.5psi my turbos only lasted 10k miles before they kicked the shit. Basically was at 100% wgdc most of third and into fourth. Going upgraded turbos actually I would say increases the life of the turbos because they don't have to work as hard to produce the same results. Luckily mine were warrantiable then I sold them to recoup some upgraded turbos cost lol
     
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  10. yaycandy

    yaycandy Florida is too damn hot

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    Now im sad
     
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  11. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    Jordan, So you were tuned at 18.5 on stock turbos? Was it a stock HPFP as well?
     
  12. Jordan_R

    Jordan_R Stock Block Ready To Knock...er..Rock

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    No, that was with an xdi35 like I said commanding 15 is about right prehpfp upgrade.
     
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  13. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    Has anyone done the Turbosmart internal wastegate actuator upgrade?
     
  14. High on Ethanol

    High on Ethanol SHO Member

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    Can't see it being worth the cost. Probably be better looking at intake/exhaust upgrades.
    Maybe ask Gearheads Matt about wastegate questions. He's done the research im sure.
     
  15. Joshw0000

    Joshw0000 SHO Member

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    I have a CAI, colder plugs, thermostat, 3 bar MAP, noise maker delete, and Unleashed tuned for 93 octane. I regularly see spikes of 19 PSI.

    I recently installed exhaust cut-outs and it seems like I get less boost with them open. I need to do a comparison between open and closed to confirm.

    Sent from my SM-N960U using Tapatalk
     
  16. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    You can see your commanded boost level in your logs, It's labeled TCBP_DSD(psi). That's most likely a boost spike. If you're tuned to 15psi, the 19psi spike is the highest I've seen. Boost spikes are fickle in the turbo world, they are seen as bad by some and good by others. Some tuners allow them to help with a mid-range RPM surge. It can make the engine feel more responsive and powerful in the mid-range. If you open a wastegate right as the boost spikes, the gate's latency to open makes it too late. But if you open it too soon, you can increase turbo lag. A wastegate needs to be given time to “catch” the boost curve. To eliminate a boost spike, the wastegate must begin to open before the target boost by a certain amount of time depending on the turbo system. If the wastegate begins to open at the target boost, a boost spike will occur as the wastegate will need some time to open to the right valve height to divert enough exhaust gas to maintain the desired boost level.
     
  17. FiveLeeter918

    FiveLeeter918 Ortiz Performance Sales Sponsoring Vendor Supporting Member

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    I bought a test for testing to try to alleviate the boost drop Jordan was talking about, but have yet to have time to install and dial them in.
     
  18. 802SHO

    802SHO FULL SEND

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    I had a 19 psi "race tune" for the track that I left on the car. I ran a 12.06 full interior (trunk stuff gone, low fuel)stock turbo, stock IC, 93 octane, Alky 100% meth 1500cc, sp534 plugs actually, stock coils, Airaid intake, 3bar, stock trans mounts, lowering springs, catch can, stock IC plastic plumbing. DA was about 900ft I think. September track day back in 2018. Best was last run. Oh yeah, catless downpipes, same exhaust now except 3rd cat still there...then xpipe no mufflers. And PP trans cooler. Fricken A...forget my mods...stock HPFP and Stock LPFP, no nitrous yet. Jeeezzzzzzz
     
    Last edited: May 26, 2020
  19. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    You wouldn't happen to have logs from back then would you?
    I would like a 'turn it to 11' tune at like 17-18psi commanded without having to get the upgraded HPFP or turbos. Not a every day tune, just a tune for looking good at the track.

    By the way, that white truck was shitting and getting!
     
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  20. skyshadow07

    skyshadow07 On a mission to get below 4000lbs

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    I'm considering the billet wheels and thought I could throw those on with it for boost drop.
     

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