9N3 Polo GTi boost issue
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
9N3 Polo GTi boost issue
Hey guys, hope you all well.
Have a very strange issue with my 9n polo gti. So I recently bought a complete turbo kit from a fellow member, which consisted of a t28 turbo (internally gated), manifold and adapter, turbo inlet pipe and downpipe. All the parts were in excellent condition and it worked perfectly in his car. Installed the turbo setup in my car and there arised my weird issue, the turbo will only start spooling at around 4500rpm (3rd gear) and reach its max boost of a measly 0.8 bar at 5500rpm which it will hold till redline. This is with the wastegate nipple disconnected (with it connected it's the exact same thing).
Now I really have tried everything to troubleshoot,
•Checked for boost leaks, none whatsoever. (At idle the car also sits perfectly at vacuum of -0.6.
•Checked cam timing.
•Checked for restrictions on the inlet side, charge side as well as the exhaust.
•Swopped out the turbo with another one and the boost curve is EXACTLY the same, so it's not the turbo.
•Removed the exhaust manifold and adapter to check for any warps, also remachined the adapter but it was exactly the same.
•Tighted the wastegate and also added a spring to the actuator, boost was still the same.
•Changed the tune on the car, also exactly the same.
The car was logged in detail and the map is requesting the correct boost level as well as N75/Wastegate duty cycle, the throttle body is fully open, fuelling and ignition timing are correct, but it is still extremely laggy and does not meet requested boost. So I'm now really out of ideas.
Any help would be greatly appreciated.
Sent from my iPhone using Tapatalk
Have a very strange issue with my 9n polo gti. So I recently bought a complete turbo kit from a fellow member, which consisted of a t28 turbo (internally gated), manifold and adapter, turbo inlet pipe and downpipe. All the parts were in excellent condition and it worked perfectly in his car. Installed the turbo setup in my car and there arised my weird issue, the turbo will only start spooling at around 4500rpm (3rd gear) and reach its max boost of a measly 0.8 bar at 5500rpm which it will hold till redline. This is with the wastegate nipple disconnected (with it connected it's the exact same thing).
Now I really have tried everything to troubleshoot,
•Checked for boost leaks, none whatsoever. (At idle the car also sits perfectly at vacuum of -0.6.
•Checked cam timing.
•Checked for restrictions on the inlet side, charge side as well as the exhaust.
•Swopped out the turbo with another one and the boost curve is EXACTLY the same, so it's not the turbo.
•Removed the exhaust manifold and adapter to check for any warps, also remachined the adapter but it was exactly the same.
•Tighted the wastegate and also added a spring to the actuator, boost was still the same.
•Changed the tune on the car, also exactly the same.
The car was logged in detail and the map is requesting the correct boost level as well as N75/Wastegate duty cycle, the throttle body is fully open, fuelling and ignition timing are correct, but it is still extremely laggy and does not meet requested boost. So I'm now really out of ideas.
Any help would be greatly appreciated.
Sent from my iPhone using Tapatalk
Last edited by madhoshival on Mon Nov 27, 2017 12:12 pm, edited 1 time in total.
- Carel040
- Cadet
- Posts: 206
- Registered for: 7 years 3 months
Re: 9N3 Polo GTi boost issue
Check n75 valve plumbing configuration could have swapped tubes
Sent from my ALE-L21 using Tapatalk
Sent from my ALE-L21 using Tapatalk
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Thanks for the reply, N75 is connected correct. I also left it plugged in and ran it with the vacuum going to wastegate opened which should make the car boost to infinity, but the boost never changed.Carel040 wrote:Check n75 valve plumbing configuration could have swapped tubes
Sent from my ALE-L21 using Tapatalk
Sent from my iPhone using Tapatalk
- Carel040
- Cadet
- Posts: 206
- Registered for: 7 years 3 months
Re: 9N3 Polo GTi boost issue
If I may ask did u scan with VCDS yet
Sent from my ALE-L21 using Tapatalk
Sent from my ALE-L21 using Tapatalk
- Dhir-DKR
- Cadet
- Posts: 418
- Registered for: 10 years 6 months
- Car Make: Audi
- Car Model: s3 - 8L 20v BT
- Location: Ballito
Re: 9N3 Polo GTi boost issue
Bro, did you check the fuses?
I had an issue where my car would only hit 0.3 Bar boost, nothing more. Traced it down to a blown fuse, changed it and voila, boosting again.
It's these small push-in fuses.
I had an issue where my car would only hit 0.3 Bar boost, nothing more. Traced it down to a blown fuse, changed it and voila, boosting again.
It's these small push-in fuses.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Scanned and no errors.Carel040 wrote:If I may ask did u scan with VCDS yet
Sent from my ALE-L21 using Tapatalk
Sent from my iPhone using Tapatalk
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Nope, not getting any limp mode bro. Throttle is opened 100% and getting 100% wastegate duty cycle.Dhir-DKR wrote:Bro, did you check the fuses?
I had an issue where my car would only hit 0.3 Bar boost, nothing more. Traced it down to a blown fuse, changed it and voila, boosting again.
It's these small push-in fuses.
Sent from my iPhone using Tapatalk
- Carel040
- Cadet
- Posts: 206
- Registered for: 7 years 3 months
Re: 9N3 Polo GTi boost issue
Did u find the fault yet
Sent from my ALE-L21 using Tapatalk
Sent from my ALE-L21 using Tapatalk
- dcmk4
- Lieutenant
- Posts: 1741
- Registered for: 9 years 11 months
- Car Make: VW
- Car Model: MK7 GTi
- Location: Cape Town
Re: 9N3 Polo GTi boost issue
Have you done a compression test on the car?
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Not as yet.Carel040 wrote:Did u find the fault yet
Sent from my ALE-L21 using Tapatalk
Sent from my iPhone using Tapatalk
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Motor has been rebuilt.DCmk3 wrote:Have you done a compression test on the car?
Problem has been there before the rebuild and it's the exactly the same now.
Did a compression test before and all was perfect.
Sent from my iPhone using Tapatalk
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Hi guys.. just an update.. thought it was the head.. so I got a head off a running car.. also changed the turbo with a brand new one and the boost is EXACTLY the same. Any thought?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
Ever tried swopping out the dump valve?. or blocking it off as a test?
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Did a complete boost leak test.. and switched between my stock 710N and forge splitter.panic-mechanic wrote:Ever tried swopping out the dump valve?. or blocking it off as a test?
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
can't go back to stock turbo to test? Perhaps it's simply that turbo.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Tested a stock ko3.. and from logs it does look like it takes a while to spool even the ko3.. only reaches peak boost around 4000 rpm.panic-mechanic wrote:can't go back to stock turbo to test? Perhaps it's simply that turbo.
Sent from my iPhone using Tapatalk
- dcmk4
- Lieutenant
- Posts: 1741
- Registered for: 9 years 11 months
- Car Make: VW
- Car Model: MK7 GTi
- Location: Cape Town
Re: 9N3 Polo GTi boost issue
Just for testing purposes bypass/replace the lines between the WG, n75 and TIP and see if there's any difference.
Perhaps by some chance a line has a blockage or is slightly leaking.
Perhaps by some chance a line has a blockage or is slightly leaking.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
I tried running it with the wastegate line completely off.. but that doesn't seem to make a difference.DCmk3 wrote:Just for testing purposes bypass/replace the lines between the WG, n75 and TIP and see if there's any difference.
Perhaps by some chance a line has a blockage or is slightly leaking.
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
No then you have a cam timing issue or something like that. Engine mechanical
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
Also thought this.. and so I changed the head.. but the problem is exactly the same.panic-mechanic wrote:No then you have a cam timing issue or something like that. Engine mechanical
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
Changing the head does not guarantee that you also did not set the cam timing incorrectly. Show pictures with the engine tdc markings and cam timing markings you are using. Are you sure the crank trigger wheel is original and correct.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
panic-mechanic wrote:Changing the head does not guarantee that you also did not set the cam timing incorrectly. Show pictures with the engine tdc markings and cam timing markings you are using. Are you sure the crank trigger wheel is original and correct.
All markings are lining up and the car is not throwing any codes.
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
no show the other side of the cams. Tappet cover off. Did you check if the crank tdc marking is correct. I have seen the pulley key break off and the crank move.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
- madhoshival
- Cadet
- Posts: 182
- Registered for: 8 years 7 months
- Car Make: VW
- Car Model: 9N3 GTi
Re: 9N3 Polo GTi boost issue
panic-mechanic wrote:no show the other side of the cams. Tappet cover off. Did you check if the crank tdc marking is correct. I have seen the pulley key break off and the crank move.
I have removed the crank pulley like twice so far.. everything is intact there.
Sent from my iPhone using Tapatalk
- panic-mechanic
- Panic's Place
- Posts: 26715
- Registered for: 21 years 8 months
- Membership No: 79
- Location: Benoni, putfontein.
Re: 9N3 Polo GTi boost issue
No I give up. Burn it.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
Perfect Power dealer. I do dyno tuning.