Forum » Link G4 Plus Software Tutorial » Link g4+ pnp rb25 closed loop knock control / closed loop lambda control.

Link g4+ pnp rb25 closed loop knock control / closed loop lambda control.

Link G4 Plus Software Tutorial

Discussion and questions related to the course Link G4 Software Tutorial

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My name is Kenny and I am new to tuning.

I have recently purchased a plug n play g4+ unit for my r33 rb25 to start learning.

I have a couple of questions that aren't very clear to me yet regarding my new ecu.

Question #1: The rb25 engine has 2 OEM knock sensors, when i look at the g4+ pin sheet i see that these 2 sensors are wired into the ecu. does this mean i can use these sensors to precisely monitor knock and use closed loop knock control? or do i need a link knock block?

Question #2: I have a Innovate MTX-L PLUS wideband gauge in my car, this gauge has a 0-5v analog output wire, can i wire this into my link g4+ analog input and use closed loop lambda control?

I hope any of you can answer these questions, thanks in advance.

Kind regards,

Kenny Spros

Hi Kenny,

Welcome to HPA.

The G4+ is essentially a Link G4+ Xtreme ECU, this means it has knock control built in so you can use the OE sensors in knock control, I would suggest changing these for a modern Bosch doughnut style sensor though but this does take some wiring adjustments.

Since the Innovate is a wide band controller you can use the 0-5v output and wire it into the OE narrow band wire, just cut and replace, and you will also need to add a signal earth into the ECU wiring too if the gauge has one

Thanks for responding Chris.

Are the OE knock sensors not accurate?

and i use the car as a daily and on roadtrips etc, different altitudes and temperaturs, can i rely on the closed loop lambda control / air temp correction to keep a steady AFR when in these conditions?

The RB OE knock sensors should be fine, as far as I know they are a wideband type. Note it is not just a matter of turning on knock control and it will work. You will need to fully tune the knock control system before you can rely on it for safety. You will likely need Audio knock detection equipment to tune it properly. There is a webinar here to give you an idea of the process:

CLL can be used to make minor trims but you dont want to rely on it to make corrections for a poorly tuned map. A properly tuned map should compensate for altitude and temperature reasonably well before any CL lambda feedback is needed.

i am aware of that yes, it just wasnt clear to me if these systems would work without the external control devices.

Thanks for all of your help.