All Things Mk5 > R-Tech Zone
Couple of questions....Dyno plots & KO4 compressor surge
Dan_FR:
Do you mean surge on boost under WOT, or the surge type flutter noise that K04's get on lift off (which sounds awesome)
I'm referring to the surging flutter noise you get under WOT with lots of boost below 4k rpm, where the valve should make no difference at all as it should be sealed/shut
No mapping will change the way the DV sounds on lift off, it'll be caused by a combination of the long thin pipes and the DV not releasing enough air pressure quickly enough. I can fully understand a Rev D reducing it, as if you look at the design of the G vs the D, once the D opens it will be able to flow a much larger volume of air which will reduce this noise.
flashp:
--- Quote from: Dan_FR on January 07, 2016, 09:12:29 am ---Do you mean surge on boost under WOT, or the surge type flutter noise that K04's get on lift off (which sounds awesome)
I'm referring to the surging flutter noise you get under WOT with lots of boost below 4k rpm, where the valve should make no difference at all as it should be sealed/shut
No mapping will change the way the DV sounds on lift off, it'll be caused by a combination of the long thin pipes and the DV not releasing enough air pressure quickly enough. I can fully understand a Rev D reducing it, as if you look at the design of the G vs the D, once the D opens it will be able to flow a much larger volume of air which will reduce this noise.
--- End quote ---
The best way I can describe it is if you're driving at say 2500rpm or thereabouts in 6th gear and you accelerate hard you hear a 'chuffing' noise (not the flutter) and it feels like the car is bogged down until sufficient revs can be developed and it clears. If you drop a couple gears there's no issue at all. This noise isn't that which is made by lifting off.
flashp:
Just checked with JKM and they confirm that I had a rev D valve in 2013 which was about 11,000 ago. So that kind of indicates what I need to do now then. I'll be giving R-Tech a ring to see what he says.
DANBOY66:
on my new turbo the cold size wheel has been changed i think its a lightweight wheel that has an extra blade
i have also had the hot side wheel clipped to aid better flow at the top end
with up rated bearing and seals
as previously said r-tech can't eliminate it but he can map around it
on my car i had a super chips map and it was mapped straight through it the cha cha cha went on forever before finally shutting up
after my first r-tech map it literally done it 3 times with bigger gaps in beetween before it was totaly gone
on Facebook beach buggy turbos a better description and pictures of my turbo :happy2:
GrayMK5GTI:
@flashp Niki maps around the compresser surge @MC71 mentioned after his Stage 2+ map that surge is only noticeable under a lot of load in a high gear (like foot to floor in 6th gear at low revs).
My mates REVO'd K1 with EVOMS intake is awful for surge in every gear, and the Dyno graph shows the drop in power as the turbo surges
Some graphs in here on Surrey RR's heartbreaker: http://www.mk5golfgti.co.uk/forum/index.php/topic,93698.0.html
Niki's traction control mapping makes a huge difference to getting power down, and the switchable mapping is also free :happy2:
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