I want to fit an air/fuel gauge to my mk2 which is running a 2E conversion. Only the bottom end is from the 2E and head and all other parts, exhaust etc are all original mk2. I'm wondering what the best option is for getting a lambda boss in the exhaust. I wanted to leave the existing downpipe on if possible and I was wondering if there is anything that will replace the front silencer that has a lambda boss e.g. a corrado decat pipe or similar. Obviously it might need a bit of modification to fit. Alternatively I was wondering if stainless steel exhaust people such as powerflow etc can make up a through pipe with a lambda boss welded in to replace the front box... I Think it's worth having an A/F gauge as the 2L conversions seem to be renowned for running lean.
If you do decide you definately need an AFR gauge: lambda boss can be bought off ebay for 5 inc postage. This could be welded into your front exhaust pipe in this example. I would have thought there is enough pipe length to add sensor boss and still have room for the sleeve clamp. Make sure you don't put the sensor boss on the exhaust can. If there is not enough rom to add the boss then a stainless or mild steel replacement piece is what you need. If you take your front exhaust pipe to an exhaust company such as powerflow they can use it to make sure the stainless pipe they produce has same length and diameters where it joins the rest of the system. I looked into the range of AFR kits a few years ago and chose the AEM wideband, has been reliable & a great tuning aid for 2 years now. The cheapest I could find this kit was EFI parts .co.uk
if you keep your old dp then you cant use a cat bypass as these need a 3 bolt flange fitting. if you change downpipe for 2.0 8v/16v mk3 or corrado g60/2.0 16v then can get a miltek cat bypass which has 2 lambda bosses in it, that way future proofed if want to fit engine which needs a lambda plus have your afr gauge at same time. trouble with cat bypass pipe too is that it fits a 16v zaust so need to change that or fit a reducer. easier to get a boss welded in!
Not sure if there is any benefit on an engine you cannot map! However as per Ben's comments and yes I know the boss is a 5 mins job for powerflow on any competent welder once you indicate where you want it.
I might see if powerflow or similar can make me a bypass pipe up with a boss in then. Probably the cheapest and most convenient option. True you can't map it but it's nice to know what's going on. At least it will serve some purpose when the afm is doing it's bit and then there's the possibility of playing around with a fpr and perhaps different injectors. Either way it's cooler than a voltmeter in a set of 3 vdos
