1.8t Boost fluctuation

Post Reply
User avatar
SoDub
Chairman
Chairman
Posts: 3875
Registered for: 15 years 1 month
Car Make: Seat
Car Model: Seat Ibiza Cupra 20VT
Membership No: 1998

1.8t Boost fluctuation

Post by SoDub »

Hi Petrol Turbo peeps. I seem to be having a tiny bit of fluctuation. Now that I think of it it has probably been there since I bought the car.
But after hooking up a boost gauge and reverting to a stock DV I can see it happening in the higher gears. Load the car in 4th and 5th and boost climbs to 1.2 but drops to between 1.05 and 1.1 for a millisecond then back up again.
Sometimes it will hold once back up to 1.2 but occasionally will drop sliiiightly again and return to 1.2.

We suspect the car has a leak of some sort as it is reading -0.6 on idle. We checked all the DV piping and the DV seems fine but it could be on it's way? Could it be the n75 is starting to die? PCV faulty?
Anyone else had this issue?
Current
El Toro
2009 Seat Ibiza Cupra 1.8T(El Toro)

Blossom
2007 Seat Ibiza Cupra 1.9TDi(Blossom)





Ex
Turbo Killer Sportline
2007 - Polo TDI Sportline
"I live my life 1 turbo at a time."
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

Sounds like the Actuator spring that has gone weak causing it to open and close under boost.
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
User avatar
SoDub
Chairman
Chairman
Posts: 3875
Registered for: 15 years 1 month
Car Make: Seat
Car Model: Seat Ibiza Cupra 20VT
Membership No: 1998

Re: 1.8t Boost fluctuation

Post by SoDub »

I'm hoping its something not as drastic! That leak we heard with James and Mig could be the bastard causing this.
Maybe I swing passed this weekend to find it quick and then see from there if the issue persists?
Car still makes required boost and does not overboost at al - will not go over 1.2 bar and runs well. It's just that little fluctuation.
Mig picked it up when he drove my car when I first got it and we thought it might be the TC kicking in a bit.

Vortex has quite a list of things it could be but the main cause is usually leak or a DV on it's way.
The actuator spring being weakened should result in irratic boost and won't hold peak boost at all - But who knows :(
Current
El Toro
2009 Seat Ibiza Cupra 1.8T(El Toro)

Blossom
2007 Seat Ibiza Cupra 1.9TDi(Blossom)





Ex
Turbo Killer Sportline
2007 - Polo TDI Sportline
"I live my life 1 turbo at a time."
User avatar
dazza
Field Marshal
Posts: 12139
Registered for: 16 years 2 months
Car Make: VW and VW
Car Model: Amarok and Citi Sport
Membership No: 1327
Location: Roodepoort

Re: 1.8t Boost fluctuation

Post by dazza »

Sounds bad maybe you should just sell the car to me :troll:
Darryn Van Rooyen
Current: 17 Amarok V6 D/C 4Motion H/L Auto
Current: 1987 Citi Sport 1.6
Current: 91 Citi Sport 1.3
Current: 05 Kawasaki 200KDX, 16 KTM 300 EXC
Previous:
14 Amarok BITDI D/C 4Motion H/L Auto
12' MKVI GTI Manual
2009 Audi TT 2.0TFSI S-Tronic
2008 Honda CBX250 Twister - Crashed!
2011 Amarok BiTDI D/C Highline 4Motion
08 RS MKV GTI DSG
09 ZG Ibiza Cupra TDI
06 CW Sportline
01 Citi 1.4i
01 Yamaha YZ125
99 Toyota Tazz
94 Fox 1.8 Sport
User avatar
SoDub
Chairman
Chairman
Posts: 3875
Registered for: 15 years 1 month
Car Make: Seat
Car Model: Seat Ibiza Cupra 20VT
Membership No: 1998

Re: 1.8t Boost fluctuation

Post by SoDub »

dazza wrote:Sounds bad maybe you should just sell the car to me :troll:
Deal! Put monies in my account and let's do this :troll:
Current
El Toro
2009 Seat Ibiza Cupra 1.8T(El Toro)

Blossom
2007 Seat Ibiza Cupra 1.9TDi(Blossom)





Ex
Turbo Killer Sportline
2007 - Polo TDI Sportline
"I live my life 1 turbo at a time."
Nikz_tsc
Cadet
Posts: 831
Registered for: 11 years 4 months
Car Make: Volkswagen
Car Model: Mk7 GTi
Membership No: 2093
Location: Durban

Re: 1.8t Boost fluctuation

Post by Nikz_tsc »

Stompie wrote:Sounds like the Actuator spring that has gone weak causing it to open and close under boost.
+1 with what Stompie said. Had this issue on my 9n3 and it got progressively worse. Swapped out the actuator for another oem one and the fault went away.
Current: Mk7 Gti

Previous: Ibiza Cupra 20vT; Polo GTi 20vt

TSC Garage
Performance Tuning Solutions
info@tscgarage.co.za
0619955604
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

Nikz where did you manage to get another actuator...flip i cant find one anywhere so just did the external spring mod on mine and has been working 100% for the last 3 years.

Ive heard that the Forge actuator is a pain in the ass to set up perfectly and causes **** or something,
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
Bev0_tsc
Lieutenant
Posts: 1990
Registered for: 11 years 7 months
Car Make: Vw
Car Model: '08 Polo Gti
Membership No: 2087
Location: Midrand

Re: 1.8t Boost fluctuation

Post by Bev0_tsc »

Stompie wrote:Nikz where did you manage to get another actuator...flip i cant find one anywhere so just did the external spring mod on mine and has been working 100% for the last 3 years.

Ive heard that the Forge actuator is a pain in the ass to set up perfectly and causes **** or something,
Forge is life.
Bagged '12 Edition 35
Bagged '08 Polo Gti

IR Tuned
My CW PGTI
My CSG ED35
User avatar
Killerwatt
VWCSA Member
Posts: 4819
Registered for: 15 years 10 months
Car Make: AUDI
Car Model: S3
Membership No: missing
Location: Brakenhurst

Re: 1.8t Boost fluctuation

Post by Killerwatt »

Hard to say from your description. I don't think its the actuator being weak.

Any logs of the car?
How does the requested boost, actual boost and n75 duty compare?
Is the actual load exceeding the specified load and the throttle closing?
User avatar
Killerwatt
VWCSA Member
Posts: 4819
Registered for: 15 years 10 months
Car Make: AUDI
Car Model: S3
Membership No: missing
Location: Brakenhurst

Re: 1.8t Boost fluctuation

Post by Killerwatt »

Also what are fuel trims sitting at? To check for a weak actuator, just unplug the n75 electrical connection and check that the boost is around 0.3bar under full throttle.
User avatar
dazza
Field Marshal
Posts: 12139
Registered for: 16 years 2 months
Car Make: VW and VW
Car Model: Amarok and Citi Sport
Membership No: 1327
Location: Roodepoort

Re: 1.8t Boost fluctuation

Post by dazza »

VeeDubbed wrote:
dazza wrote:Sounds bad maybe you should just sell the car to me :troll:
Deal! Put monies in my account and let's do this :troll:
How much dollar :lol:
Darryn Van Rooyen
Current: 17 Amarok V6 D/C 4Motion H/L Auto
Current: 1987 Citi Sport 1.6
Current: 91 Citi Sport 1.3
Current: 05 Kawasaki 200KDX, 16 KTM 300 EXC
Previous:
14 Amarok BITDI D/C 4Motion H/L Auto
12' MKVI GTI Manual
2009 Audi TT 2.0TFSI S-Tronic
2008 Honda CBX250 Twister - Crashed!
2011 Amarok BiTDI D/C Highline 4Motion
08 RS MKV GTI DSG
09 ZG Ibiza Cupra TDI
06 CW Sportline
01 Citi 1.4i
01 Yamaha YZ125
99 Toyota Tazz
94 Fox 1.8 Sport
User avatar
SoDub
Chairman
Chairman
Posts: 3875
Registered for: 15 years 1 month
Car Make: Seat
Car Model: Seat Ibiza Cupra 20VT
Membership No: 1998

Re: 1.8t Boost fluctuation

Post by SoDub »

dazza wrote:
VeeDubbed wrote:
dazza wrote:Sounds bad maybe you should just sell the car to me :troll:
Deal! Put monies in my account and let's do this :troll:
How much dollar :lol:
So much dollar I can't even say! :troll:

I need to keep this cab for the next year or 2 at least. Not having to pay installments is boss!
Current
El Toro
2009 Seat Ibiza Cupra 1.8T(El Toro)

Blossom
2007 Seat Ibiza Cupra 1.9TDi(Blossom)





Ex
Turbo Killer Sportline
2007 - Polo TDI Sportline
"I live my life 1 turbo at a time."
The Snail
Cadet
Posts: 82
Registered for: 11 years 4 months
Car Make: vw
Car Model: MK4 GTi

Re: 1.8t Boost fluctuation

Post by The Snail »

Exactly what killerwatt said :iagree:
ex. Golf 4 GTi AGU/AUQ

t3/t4 50 trim .48ar
260kW and 390nm
Eurodyne maestro software

Audi 3.2 vr6 Turbo
323Kw and 660nm @ 0.7 bar
Nikz_tsc
Cadet
Posts: 831
Registered for: 11 years 4 months
Car Make: Volkswagen
Car Model: Mk7 GTi
Membership No: 2093
Location: Durban

Re: 1.8t Boost fluctuation

Post by Nikz_tsc »

Stompie wrote:Nikz where did you manage to get another actuator...flip i cant find one anywhere so just did the external spring mod on mine and has been working 100% for the last 3 years.

Ive heard that the Forge actuator is a pain in the ass to set up perfectly and causes **** or something,
Friend had a blown k03s which i pulled the actuator off. I think i still have it lying around though. Will look for it.
Current: Mk7 Gti

Previous: Ibiza Cupra 20vT; Polo GTi 20vt

TSC Garage
Performance Tuning Solutions
info@tscgarage.co.za
0619955604
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

Nikz_tsc wrote:
Stompie wrote:Nikz where did you manage to get another actuator...flip i cant find one anywhere so just did the external spring mod on mine and has been working 100% for the last 3 years.

Ive heard that the Forge actuator is a pain in the ass to set up perfectly and causes **** or something,
Friend had a blown k03s which i pulled the actuator off. I think i still have it lying around though. Will look for it.
Yeah cos i know you cant really buy them new, ive tried looking
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
User avatar
Hobbs
Cadet
Posts: 667
Registered for: 11 years 11 months
Car Make: VW
Car Model: GTI MK5 - 248kw 530nm - KO4
Membership No: 1848
Location: Boksburg

Re: 1.8t Boost fluctuation

Post by Hobbs »

Ko3s love to surge with stock actuator, get a forge actuator and issue will be resolved.

Sent From my POS.

I.G - Hobbs_ZA
MK5 GTI
GTX30
Forged motor
power uknown
User avatar
Killerwatt
VWCSA Member
Posts: 4819
Registered for: 15 years 10 months
Car Make: AUDI
Car Model: S3
Membership No: missing
Location: Brakenhurst

Re: 1.8t Boost fluctuation

Post by Killerwatt »

How on earth will an actuator with a higher spring rate make a turbo less likely to surge?

Stompie, what's your actuator at now?
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

Killerwatt wrote:How on earth will an actuator with a higher spring rate make a turbo less likely to surge?

Stompie, what's your actuator at now?
My actuator is set to two turns in as per what yosh told me to do cause it was opening up too soon.
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
User avatar
SoDub
Chairman
Chairman
Posts: 3875
Registered for: 15 years 1 month
Car Make: Seat
Car Model: Seat Ibiza Cupra 20VT
Membership No: 1998

Re: 1.8t Boost fluctuation

Post by SoDub »

Hi guys, better later then never, issue got slightly worse and I could hear turbo flutter. Bypassed the n249 after doing some Vortex reading and everything returned to normal.
Current
El Toro
2009 Seat Ibiza Cupra 1.8T(El Toro)

Blossom
2007 Seat Ibiza Cupra 1.9TDi(Blossom)





Ex
Turbo Killer Sportline
2007 - Polo TDI Sportline
"I live my life 1 turbo at a time."
User avatar
P1LAYA-ZN
Cadet
Posts: 263
Registered for: 9 years 10 months
Car Make: Audi, VW and Toyota
Car Model: S3 8L 20VT & Mk 1 Jetta GLi
Location: Durban

Re: 1.8t Boost fluctuation

Post by P1LAYA-ZN »

What should be the boost reading on the boost guage @ idle, mines is also around - 0.6 / 0.7 Bar ?
#Builtnotbought
Image
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

P1LAYA-ZN wrote: Wed May 02, 2018 12:34 pm What should be the boost reading on the boost guage @ idle, mines is also around - 0.6 / 0.7 Bar ?
-0.7bar on idle -0.6bar should also be good.
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
User avatar
P1LAYA-ZN
Cadet
Posts: 263
Registered for: 9 years 10 months
Car Make: Audi, VW and Toyota
Car Model: S3 8L 20VT & Mk 1 Jetta GLi
Location: Durban

Re: 1.8t Boost fluctuation

Post by P1LAYA-ZN »

Cool, also how would you know there is a boost leak if you have a guage fitted ?
My S3 8L is stock and peaks @ 0.8Bar, but gradually drops and car feels lazy, although these cars are slow in stock form.
Should it peak @ 0.8Bar and stay there ?
What is the stock boost for this car, and when doing Software, what is the max safe level of boost for pump fuel ?
#Builtnotbought
Image
User avatar
Stompie
Boostleak Guru
Posts: 20203
Registered for: 12 years 9 months
Car Make: BMW
Car Model: 2006 120D
Membership No: 1843
Location: East Rand

Re: 1.8t Boost fluctuation

Post by Stompie »

To find a boost leak, you will need to pressurize the system.
0.8bar from what i remember is stock boost, Should peak at 0.8bar and taper off as revs climb.
Stage 2 software saw me hitting 1.4bar boost, thats usually the norm with a stock turbo and is safe. not sure if you can go higher.
Image
BMW 120D E87
Ex: 07' Polo GTI 1.8T Rides Thread Here
User avatar
P1LAYA-ZN
Cadet
Posts: 263
Registered for: 9 years 10 months
Car Make: Audi, VW and Toyota
Car Model: S3 8L 20VT & Mk 1 Jetta GLi
Location: Durban

Re: 1.8t Boost fluctuation

Post by P1LAYA-ZN »

Thanks, just what I needed to know.
#Builtnotbought
Image
Post Reply