I personally of the opinion that any B5 S4 build with bigger than K04 turbos it is requisite to run a wideband, and that it would be a wise investment for any custom-tuned stage 3 and on setup. A wideband sensor and monitoring hardware are just great insurance and useful for optimization (especially fine tuning a 'remote tune' on the street).
-Why Zeitronix, and why ZT-2?-
For Audi drivers I recommend the ZT-2 wideband over the other Zeitronix products and over the companies' widebands (I personally run a ZT-2 in my B5 S4 with a handful of Zeitronix accessories [EGT Sensor, Boost MAP Sensor, Fuel Pressure Sensor, ZAVT-1 Alarm Module]). The ZT-2 has the following advantages:
-- Painless RPM logging with no additional modules and an open OBD II port --
When logging actual air-fuel ratio with a wideband, it is important to simultaneously log other variables from the car's ECU (such as requested AFR, stock oxygen sensor voltages, MAF flow, etc) to fine tune or monitor a vehicle's tune. A wideband has to be able to log RPM in order to easily correlate and align the data from the wideband sensor with the car's ECU data. Some of the competing products (like the Innovate LC-1) require an additional RPM logging module for the Audi's, at additional cost and complexity. Other products (such as the Innovate OT-2) use the OBD II port to log RPM, making it impossible to log the ECU variables at the same time. The Zeitronix ZT-2, however, self-contains everything needed to painlessly log RPM out-of-the-box, and with the ZT-2 logging RPM it is as easy as splicing a single wire.
-- Future-proof and Versatile --
Though all of the hardware required to read wideband AFR's comes included in the ZT-2 package, there are however a plethora of add-on's that allow the ZT-2 to grow with your budget, or adapt to your needs as your build(s) progresses. Every ZT-2 comes equipped stock with the ability to simultaneously read 4 inputs (in addition to RPM and TPS), which can include:
-Exhaust Gas Temp- Most turbo Audi's are equipped with a stock EGT sensor, however the stock Audi EGT sensor is used as an upper-limit failsafe only. This means that the stock EGT sensor doesn't usually register a loggable reading below their failsafe threshold (which is usually a high value that you ideally wouldn't often be going above [945*C for the B5, for example]). So, the stock EGT sensors are good for their role as an ECU failsafe, but they are useless for monitoring the exhaust gas temperature where your car is going to be running 99% of the time. Exhaust gas temperature is an important tuning parameter and affects knock threshold and engine reliability. With the ZT-2 and Zeitronix's EGT probe, EGT's can easily be monitored and logged with high precision.
-Boost/Vacuum MAP Sensor- Similar to the EGT sensors, most turbo Audi's are also equipped with a stock boost MAP sensor for the stock ECU. However, like the stock EGT sensors, the stock MAP sensors also have hardware/software limitations with regards to loggable/readable values. The stock MAP sensor was originally implemented with stock boost pressure levels in mind (below 10 psi), and thus it is limited in it's ability to log values above a certain threshold (which is usually around 22 psi max boost on a B5 S4, for example). Many of the stage 3 and above turbo setups are boosting well above 22psi, and if they were to rely solely on the stock MAP sensor readings, they would be flying blind above ~22psi. An analog boost gauge in the cabin is better than nothing, but without a way to log/correlate the boost values with log data from the ECU and wideband, an analog boost gauge doesn't do a whole lot when trying to review logs or possibly have a 3rd party fine tune a 'remote tune'. Together with the ZT-2 and an in-cabin gauge (ZR-2, LCD or DashDAQ), a Zeitronix MAP sensor can also be used as an in-cabin boost gauge. I recommend the 5-bar MAP sensor over the 3-bar, as they both have similar accuracy (down to ~0.1psi), though the 5-bar has a larger range.
-Fuel/Oil Pressure Sensor- The stock B5 ECU doesn't have provisions to monitor fuel pressure. Whenever a turbo car is modified near the threshold of the stock fuel system and above, it is wise to monitor the system's fuel pressure, as a sub-par or faulty fuel system can cause lean AFR's and potentially lead to catastrophic engine failure. A standard analog fuel pressure gauge that people often install under the hood is good for setting a base fuel pressure at idle, but a weak or struggling fuel system usually manifests itself by not being able to keep up the fuel pressure at higher load/revs (not revving in neutral or idling). Similar to analog boost gauges, under-hood analog fuel pressure gauges lack the ability to log or monitor the fuel pressure throughout the rev-range, to later correlate with the rest of the log data. When utilizing an upgraded fuel system (possibly with multiple pumps and multiple potential failure points), it is wise to use a Zeitronix fuel pressure sensor during the tuning process to make sure your fuel system is up to snuff, and later to monitor the health of the fuel pumps/system as you daily drive.
- ZAVT-1 Audio-Visual Warning and Trigger Box- The ZAVT-1 is a innovation by Zeitronix that acts as an alarm, making a noise and igniting a red LED when certain user-defined thresholds are breached . The ZAVT-1 can also be set up to trigger a relay, as a system failsafe. For example, say you want a warning when the car is running leaner than 12.5:1 AFR above 4000RPM: you just set those warning parameters in the user-friendly software, and every time the car goes leaner than 12.5 above 4000RPM, an alarm will sound and a red LED will turn on (an output to trigger a relay for some sort of physical failsafe is also configurable). The ZAVT-1 can use the input data from many different sensors, including boost, AFR, RPM, fuel pressure, TPS, IAT, and EGT's.
- Black Box Data Logger- This is used in conjunction with the Zt-2 (or ZT-3) and essentially serves as a one-button logging trigger and memory card, so that you can log on the fly without a laptop.
- Easy Presentation and Analysis of Logs- The Zeitronix ZT-2 is one of very few widebands currently supported by Nyet's ECUxPlot, which is the de facto Audi B5 log plotting utility. ECUxPlot is a log graphing program that takes the logged data that you get from the ECU and automatically correlates it via RPM with the logged data from the Zeitronix ZT-2. ECUxPlot has automated correlation, filtering, graphing, and picture exporting features, which make analyzing the raw log data infinitely more palatable and easy. Example graphs from ECUxPlot can be seen HERE.
- User definable 0-5V inputs (log methanol injection flow for example)- The ZT-2 has 2 user definable inputs that can be logged simultaneously with AFR and RPM. Some people have been using it to monitor their methanol/alcolhol injection, for example, as seen HERE.
**Simply put, proper logging is some of the cheapest insurance you can get when working with thousands of dollars worth of hardware, and there is nothing like the peace of mind that comes from having hard data to verify that your car is running properly and not in danger. And that's not even mentioning the performance and optimization benefits that come with proper logging**
Example of an ECUxPlot graph of 2 3rd gear pulls, data logged simultaneously from the car's ECU (requested AFR [blue]) and the Zeitronix ZT-2 (actual AFR [red] and boost [purple])
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Originally Posted by trichard3000
. I wonder where such a thing could be found.
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