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Author Topic: 1,8T GT2871 AR0,64 slow spool  (Read 2539 times)
nupustas
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« on: September 13, 2021, 07:26:38 AM »

Hi,
I'm stuck with slow spool,About 0,5bar/3500rpm; 1bar/4300rpm; 1,5bar/5100rpm.
Let's not talk about pre-turbo exhaust / intake leaking, everything tested several times. I have no leaks, new oem DV (also tested),intake pressure test at 2,0bar was done.
  • New assembled 1,8t engine, high ported head/manifold and stronger rods - every other parts stock. 9,0CR, new OEM VVT.
    Pre-intercooler 63mm, post-intercooler 65mm intake system.
    Exhaust: Downpipe 76mm, and 65mm post downpipe (no cats). Downpipe "snaky" shape, and has almost 90°angle after turbo.
    New ball bearing GT2871 AR0,64 turbo (also tried to replace with china GT28 0,64-almost identical spool).
    Long term fuel trims about 1-2perc. LAMFA while spooling 0,82 (after all runs, best results reached). 550cc injectors. 83mm maf (rescaled)
    Timing - stock 165kw maps (exept last row at high load).
    VVT - tried with on, tried with off. Tried on in different areas. Only noticed gain - better torque in very low rpm with advanced intake cam. Would be helpful more info about "right" VVT tuning to help spool.
    Wastegate internal - spooling slow also with stucked wg arm(tested with absolutely clogget out wastegate flapper)
    KFVPDKSD axis rescaled as S4 wiki says, doesnt noticed any difference
    When it fully spools - till redline holds pressure and car runs great. In this area everythink ok
P.S. Intake manifold presure in photo black, requested pink



All ideas are welcome. I have no longer anything to check.
« Last Edit: September 13, 2021, 07:28:21 AM by nupustas » Logged
fknbrkn
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mk4 1.8T AUM


« Reply #1 on: September 13, 2021, 07:36:01 AM »



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nupustas
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« Reply #2 on: September 13, 2021, 07:42:45 AM »



So i'm wasting my time and this turbo spools normal? I thougt 0.64 AR T25 should spool faster...
« Last Edit: September 13, 2021, 07:45:32 AM by nupustas » Logged
Blazius
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« Reply #3 on: September 13, 2021, 08:02:04 AM »

Stop logging with vcds... get normal logs, go enable cwmdapp 8, set wgdc map to 95% and you will see where you spool, you will not beat that. But I dont know what you are expecting.
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nupustas
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« Reply #4 on: September 13, 2021, 08:16:29 AM »

Stop logging with vcds... get normal logs, go enable cwmdapp 8, set wgdc map to 95% and you will see where you spool, you will not beat that. But I dont know what you are expecting.
I'm not at home at the moment, logging with what I have... As i said, i mechanicaly clogged out wg arm (just testing one idea, if 95% doesnt work due to weak spring). With 95% and machanicaly clogged-out was same spooling result. About CWMDAPP I hear the first time, will search info about it
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sonique
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« Reply #5 on: September 13, 2021, 10:20:45 AM »

gt2871 old laggy turbo not good
too small turbine side and very big compressor
not possible  better spool
3071r  same spool and better topend
3067r better spool
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fknbrkn
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mk4 1.8T AUM


« Reply #6 on: September 13, 2021, 01:34:38 PM »

So i'm wasting my time and this turbo spools normal? I thougt 0.64 AR T25 should spool faster...
yep
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nupustas
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« Reply #7 on: September 13, 2021, 10:27:46 PM »

Thanks for answers
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tao13
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« Reply #8 on: September 14, 2021, 07:48:50 AM »

Many people talk only from what they think or calculate........without real example.
You can do better.
Mine is a GT2871r but genuine Garrette and i have 0.63 at 3500 , 1.45 at 4300 and 2.3 (limited by me ) at 5000 and can keep it to the red line!
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nupustas
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« Reply #9 on: September 14, 2021, 10:32:59 AM »

Many people talk only from what they think or calculate........without real example.
You can do better.
Mine is a GT2871r but genuine Garrette and i have 0.63 at 3500 , 1.45 at 4300 and 2.3 (limited by me ) at 5000 and can keep it to the red line!


Interesting. This is T3 (if 0,63?), so should spool latter than t25 0,64. Maybe you bottom-end stroked to 2,0-2,1l? Can you post more info about you hardware?
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tao13
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« Reply #10 on: September 14, 2021, 12:09:43 PM »

1.8 normal dimmensions
gt2871r with t25 flange with iron exhaust manifold (short) with internal wastagate 1 bar spring
head is stock with stock camshafts
big intercooler 550mm X 350x 55mm
long line on 63mm between turbo and throttle
nothing else!
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nupustas
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« Reply #11 on: September 14, 2021, 10:03:08 PM »

I didn't see main diferences in hardware than mine. But your log looks great.
Do you have timing/AR/maf logs while spooling?
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