I'm pretty new to car "tuning". I've added bolt ons to my past few cars but never dove into fuel tuning like I have to with this car. I'm going to be doing a rebuild soon and I've heard alot about how you need a wideband to accurately read and tune A/F ratios. From what I've read it seems you need to weld an o2 bung on the downpipe and get a special O2 sensor to hook up to the wideband. Do you also need this with a Datalogger? I'm really confused about the differences between the two. I'd like to get a data logger since I could just buy a cheap pda and upload runs to my pc to look at later. It seems with a Datalogger you only need the special cable to hook it up, and the software which can be bought or found for free. Do you also need a special o2 sensor for this, if so where do you hook it up to, isn't it just the pda plugged into the OBDII plug?

If you don't need the o2 sensor for the datalogger then does it still measure the A/F like a wideband does?

Can someone explain each to me in simple terms what the difference is between the 2? I've read through so many posts about the different options and what they do I'm just confusing myself more with each post I read.

Okay I've read some more and think I'm going to be going with a pocketlogger (just need to figure out if I want to get a Palm m105 or IIIc). From what I understand this is not a wideband. Is the o2 reading it gets from the ECU the same as what my Apexi TT is getting, is it anymore accurate?

no.

To expound upon Dino's answer a little more, a datalogger and a wbo2 are two totally different things. The datalogger allows you to view different parameters of the engine such as timing, fuel trims, o2 voltage, throttle position, rpms, speed, and coolant temps. Any device used to monitor the srock o2 voltage should be similarly accurate. They are all just voltage meters.

A wbo2 sensor is a more accurate (resolute) version of the o2 sensor that comes in your car stock. The stock sensor operates with a volatge range of 0-1v, whereas a wideband sensor has a range of 0-5v. A wbo2 can give you a more accurate picture of your a/f ratio, but unless you are tuning very aggressively, the stock o2 is usually all you'll need. Most wbo2 kits come with some datalogging capabilities, but are usually restricted to only the wbo2 signal, rpms, and sometimes a couple of user definable inputs.

Neither of these devices will let you make any changes, but they are quite helpful in seeing how changes (made with a S-AFC for example) affect the different engine parameters. And hopefully that information keeps you from blowing up your engine. HTH.

Thanks for the explanation. I knew the datalogger read a bunch of parameters from the ecu, I was just confused about the accuracy of a dataloggers o2 reading versus a wideband's, and the Apexi, thanks for clearing it up. From what I've seen Widebands are a little pricey, the pocketlogger seems like a cool little toy. But really without an SAFC or e-manage (I just have a craptech FPR, soon to be a chillfactory unit) that's all the pocketlogger will be right...a toy to look at the different things that are going on. It will not actually help me tune with the FPR's right?

Yeah, you can tune for OK driveability with the A/F (stock sonsor) and the EGT gauge.

If you are messing with fuel, timming ( ignition), and other factors then yeah a datalogger would be essential. Its still a nice thing to have, but if you cant afford it right away it can wait a bit.