R33 Gtst

[Nasti]

CAN ANYONE PROVIDE ANY SUGGESTIONS/THOUGHTS ON THE FOLLOWING

Mods

• Fuel pump (Walbro 500hp, 250l/h), I/C(Blitz LM kit), turbo (Garrett GT3040), injectors (555cc Nismo), coils (Spitfire), Apexi PowerFC computer, exhaust (Nismo 3.5”), EBC (Greddy Profec B).

Problem Description

• Knocks under load and especially on high boost

• Doesn’t seem to produce power quickly enough – very lathargic

Work Completed

• Replaced upper O2 sensor – improved fuel efficiency but no change in knock

• Removed and inspected all pieces of exhaust for problems. Ran/drove car with exhaust disconnected from dump pipe back – no change in knock.

• Removed piping on inlet and outlet of intercooler for inspection for excessive oil and/or rag left in piping – intercooler and piping both extremely clean, no signs of any oil at all.

• Performed pressure test using smoke machine from just before throttle body to just after AFM – no leaks and held pressure above 1bar.

• Checked PowerFC hand controller coolant temperature sensor reading from cold to operating temperature – nothing seemed unusual.

• Completed compression test on all cylinders – all cylinders +/-3psi.

• Spark plugs changed 3 times – Iridium then copper then copper. No change in knock.

• Fuel pressure has been checked on a dyno run very recently – nothing unusual. Fuel filter replaced anyway.

• AFM – originally installed Z32 replaced with seemingly working Z32 (both purchased brand new).

• Turbosmart BOV (kit for Skyline) – purchased recently just in case it was the standard BOV resulting in the lack of power / lethargic build of power.

Edited March 13, 2008 by Nasti

[tridentt150v]

Maybe check the voltage at the injectors? and/or the fuel pump, Walbro's are known to drop voltage.

What power are you making and have you had your afr's checked?

[R31Nismoid]

What does the workshop think?

Sounds to me like its the tune.

That would answer poor power response and the knock.

[_Sawyer_]

Hope ur running at least 95 octaine fuel through it, otherwise thats why ur car would be knocking

[R31Nismoid]

Fuel has little to do with it if its tuned for the fuel its using

[paulr33]

learn how to debug and troubleshoot knocking - its covered in the powerfc faq in my signature

[Devils_Advocate21]

knock a degree of timing out and see if it improves

[_Sawyer_]

Fuel has little to do with it if its tuned for the fuel its using

thanks for stating the obvious, if its tuned for 98 octane and hes got 91 in it........................................KNOCKING............................

[R31Nismoid]

Considering his detailed post and testing - i would highly doubt something that simple is being overlooked here.