NefMoto

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.

(https://img-comment-fun.9cache.com/media/azVzObj/ajGk59px_700w_0.jpg)

So i'm wasting my time and this turbo spools normal? I thougt 0.64 AR T25 should spool faster...

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

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

yep

Thanks for answers

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?

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!

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