Auxiliary Gauges... January 25, 2021, 11:30:22 AM Been swotting up on gauges but thought I'd start a thread where I can check over the ins and outs of fitting them with those who've already done it.Before that... Scherni was asking about brackets so here's a few images of a VDO one that you can use to make your own from as the bought ones are vastly overpriced for what they are. I get aluminium off-cuts on eBay for small money, its easy to drill / cut and bend. There's plenty of sellers and you can often get pieces very close to the dimensions you'r after which saves on some work.The genuine one below is for a long bodied gauge such as some clocks and the out-side temperature gauge, most others will be short bodied but you can simply adapt the arm length to fit your particular gauge depth, all the other details are the same.I'm using a plastic ruler, so please allow for it being a little imprecise!56mm across -38mm hole center, to hole center - holes themselves are 5mm.13mm width -Arm length 60mm (NB - For the long bodied gauge, standard gauges are approx 1/3 shorter)
Re: Auxiliary Gauges... Reply #1 – January 25, 2021, 11:50:18 AM Question of my owm -I've picked up a new, genuine VDO oil pressure sender for a fraction of the price it should be.The downside (of sorts) is that I've had to allow for the thread being 1/8 NPT whereas the receiving hole on the MK2 is M10x1- which is no big deal as an adapter would've been needed to connect both it and the existing sender anyway and it was just a case of getting one with both types of thread instead of each being M10x1.This particular VDO sender is also the 2 x pole version (single pole are available), with that additional pole intended to feed a low pressure warning light.I can see no reason why it'd make any difference to the operation of the gauge regardless of the number of poles you have?The second pole is soley to fit a warning light, if present and used it'll be independant of the cars own warning light - so in effect you'll have 2 x warning lights.The VDO sender operates its low pressure warning at 1.25 Bar.Have I understood correctly that the standard VW sender activates the cars own warning light at 1.8 Bar (on 8v GTI's)?
Re: Auxiliary Gauges... Reply #2 – January 25, 2021, 12:49:32 PM Quote from: L90E on January 25, 2021, 11:50:18 AMThis particular VDO sender is also the 2 x pole version (single pole are available)The second pole is soley to fit a warning light, if present and used it'll be independant of the cars own warning light - so in effect you'll have 2 x warning lights.Unless you had to remove the factory sensor to fit the VDO sensor.
Re: Auxiliary Gauges... Reply #3 – January 25, 2021, 02:42:46 PM You know, I could 3D print some plastic ones from the information you've given me... 1 Likes
Re: Auxiliary Gauges... Reply #4 – January 25, 2021, 02:49:49 PM My understanding, I'm yet to fit my set. I have TIM gauges rather than VDO (I just liked the name on the gauge).The 2 pole sender goes in place of the current pressure sender that does the warning light/buzzer. So 1 pole feed the original function the other pol feeds your new gauge.If you only have a single pole sender you would have to keep your original sender too, this would mean a T piece of some kind. Now if you intend to fit oil temp as well as pressure you can either use the oil temp sender location that feeds the MFA oil temp (where present) but this means you'll no longer have oil temp in the MFA. If you want to keep the MFA and add a gauge again you'll need a splitter. This is the route most people seem to take, which is a good reason to have a 2 pole sender otherwise you'll need 2x splitters.The next thing that comes into question is the location in the block. I gather the pressure gauge can give slightly different readings depending on it's location and more so if you have to use T piece or a remote pipe. Some oil temp senders can run off an adapted sump plug, I assume the temp can vary in different parts of the engine. Another reason to keep the MFA gauge if you're readings are taken from 2 parts of the engine.As for M10 vs NPT, most of the T pieces seem to be some combination of NPT so having a sender with that thread will most likely make life easier. The T pieces that have 1 make and 2 female M10 threads tend to be much more expensive and less readily available. Last Edit: January 25, 2021, 02:51:41 PM by Eddypeck
Re: Auxiliary Gauges... Reply #5 – January 25, 2021, 07:10:22 PM A 3D print would likely work perfectly, there's no real force used by the metal clamp as very little effort is needed to hold the gauge in place... infact over tightening would probably cause damage.The rear housings on some ages / styles of VDO gauge are already entirely plastic, including the threaded bars the clamp slides ontoThis is a great site for VDO technical specs and numbers if you're looking for the correct senders to match your specific gauge- VDO Webshop NLI'd thought perhaps the second warning light pole could be connected to the existing sensor wire but it's the difference in Bar as to when the warning is activated that may be a problem.The VDO is at quite a lower level than the VW one if I've understood correctly, may be coming on too late after any damage has begun?As much as I like the look of additional gauges in their own right I'd also want them to be as accurate as possible, hence also going for a genuine sender rather than the one of the compatible (read that as fake) Chinese ones you see.This is an old post from 'Club GTI'... if it's yours apologies in advance but it seems to indicate theres 2 x oil pressure warning sensors on the 8v engine - read it for yourself rather than me try to explain as I'm still trying to get to grasps with this myself and have maybe misunderstood something -Club GTIThe pics below are of the sensor / adapter and old sensor I've got.Because the VDO sensor is the wrong thread to fit the block I can't check this for sure, but it definitely looks like an extremely tight fit even I could... infact it may not screw completely down due to the angle of the spar on the engines bracket. If that's the case an adapter, to act as an extension would be needed regardless to take it way from the block and stop it fouling on anything.
Re: Auxiliary Gauges... Reply #6 – January 26, 2021, 12:15:32 AM Famous last words, but I think I'm getting my head around this - maybe someone can double check my thinking?As per the above link - On a standard 8v GTI there are 2 x oil pressure senders.One is sited above the oil filter area and the other is sited at the end of the cylinder head (on the passenger side.)The one at the oil filter operates the low pressure light and buzzer if the pressure should fall below 1.8 bar while the engine is running at around the 2000 rpm mark. The one sited on the cylinder head only operates the warning light, but unlike the other sender it will activate the light at any time the pressure is below 0.3 Bar. This will happen regardless of whether or not the engine is running, so includes when the engine is off, but the ignition is at the 'accessory on' point.This is where it gets a bit grey for me -It's looking like VDO no longer manufacture (if the ever did) an aftermarket pressure sender where the warning light feature activates at either of the 1.8 or 0.3 bar points the standard VW senders do.I think this'll mean if you use the second pole on any of their senders to connect the wiring from the VW sender it'll not follow the correct activation points.Mine is 1.25 Bar so doesn't really suit replacing either VW one and would likely either give false alerts or worse still not activate when it's needed? Interestingly if you check out VWHeritage's VDO stock there's only one twin pole pressure sender available for the MK2 8v and they go to the trouble of highlighting that it activates the warning light at a higher pressure than the standard sender. The 6 - 9 PSI quoted by Heritage as their gauges warning point equates to 0.4 - 0.6 Bar... remember the upper mounted VW sender activates at 0.3 Bar.That makes me think they intend the VDO sender to be fitted into the upper cylinder head point?At the moment that's where I'm going with mine - Not bothering with the VDO warning lamp... either as a stand alone one of its own or connecting the existing sender wires to.There's just no need for the VDO's own warning light to be wired up... apart from kicking in at 1.25 Bar which is at odds with the VW settings its only duplicating a warning feature that's already there. Using the cylinder head position also does away with any space issues there would've been if the lower point were usedInstead I'll be leaving the filter top sender as is and using the adapter to allow the original cylinder head sender to remain along side the VDO, retaining it's original warning of 0.3 bar.What do you think? Last Edit: January 26, 2021, 01:14:56 AM by L90E 1 Likes
Re: Auxiliary Gauges... Reply #7 – January 26, 2021, 09:56:45 AM Sounds like you have a handle on it. The 2 pole sender I have I lifted from an Audi in a scrap yard. I need to take a look at what markings are on it.
Re: Auxiliary Gauges... Reply #8 – January 26, 2021, 03:56:02 PM Read elsewhere since that the upper sensor point will result in the pressure under reading on a standard gauge, needs to be the lower one that's used. Will wait to the engine's able to safely run and try the variables then. Or I could just f*** it all in the bin and go for these?(USB looks the part.)Digifizmini.de 1 Likes
Re: Auxiliary Gauges... Reply #9 – January 26, 2021, 04:34:46 PM Have to admit, I quite like the USB one
Re: Auxiliary Gauges... Reply #10 – January 26, 2021, 10:13:14 PM This is a great read! Thanks for this @L90E Also, don't bin the idea.. stay with it and then we can get the answers and then once I've got my gauges in and working then go ahead to Digifiz haha Also @Monkey what would the cost be on a 3d printed gauge bracket?I would need 3...
Re: Auxiliary Gauges... Reply #11 – January 27, 2021, 01:41:29 AM Just venting... too much invested in the current set up!Someones had the same idea about making the brackets - are you able to download the file from here?https://www.thingiverse.com/thing:176764#Instructions
Re: Auxiliary Gauges... Reply #12 – January 27, 2021, 07:56:29 AM Yep, I can print them out. Thingiverse is brilliant for stuff like that.It's where I got my centre console one from.I'm actually planning to upload my switch blank up there when I get time too.By the time I've printed and posted, it would probably be about £10 for a set. Last Edit: January 27, 2021, 08:00:09 AM by Monkey 1 Likes
Re: Auxiliary Gauges... Reply #13 – January 27, 2021, 10:00:19 AM Quote from: Monkey on January 27, 2021, 07:56:29 AMYep, I can print them out. Thingiverse is brilliant for stuff like that.It's where I got my centre console one from.I'm actually planning to upload my switch blank up there when I get time too.By the time I've printed and posted, it would probably be about £10 for a set.i'd go for those at that price - my metal bending would be awful, and happy to pay for someone else to do the work haha
Re: Auxiliary Gauges... Reply #14 – January 27, 2021, 11:53:36 AM Here's one for thought -As a vague rule most after market temperature gauges seem to either state what they're measuring - 'water'', 'oil' etc or have a little emblem on the face - an oil can or thermometer in water for example.I've however seen some gauges that simply say Cels / °C or °F if in Fahrenheit.The upper and lower levels on gauges that are marked as being for oil seem to commonly be between 50° to 150° and 40° to 120° for those marked for water, but you'll find plenty of variations on this, so it doesn't seem to be a firm rule.I'm guessing it's to give you the scope to fit a gauge with a range that covers most engine types - diesel / petrol, big and small.The question is - if you've a gauge that doesn't state what it's specifically measuring and it's range suits you're engines oil or coolant temperature ranges can it be used for either (with the correct sender of course) meaning the wording or symbols simply help show at a glance what's being monitored if you've more than one gauge and are effectively the same otherwise? Last Edit: January 27, 2021, 11:55:14 AM by L90E 1 Likes
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