Hi, I don't know of any XF that has a temperature gauge, I think they are redundant on most cars now they rely on the ECU to trigger a warning. Phil

 

I think they are redundant on most cars now they rely on the ECU to trigger a warning. Phil

As an engineer, I must disagree with you, knowledge of engine temperature is essential to prevent damage. Just because the vast majority of people don't know how to use the information is no reason to remove it. Likewise the dipstick.

 

Jaguars don't have temp gauges any more. Haven't for a while actually.

If you want to get that type of information before the car is actually overheating you need to get yourself a wireless OBDII reader that will link to your phone.

 

deleted by choice

 

I don't mind the sender signals being smoothed out, I have had a few cars years ago where the petrol gauge altered every time you braked or went round a corner! Phil

We've all had those cars (Anyone that is old enough and I'm only 42.) I was really responding to GeoffR's comment. Nowadays all the gauge really says is when it's no longer cold and when it's overheating. It's so smoothed it's of no real use. People want a car that sits at a stable temperature throughout the driving cycle so that's what the gauge show. No fluctuations as the thermostat opens, closes or sits idling enough to set the fan off etc.

All the same information can easily be deciphered from no gauge. First 5 mins it's cold. Then if warning goes off its overheating.

Looks nice though.

 

Would this level of instrumentation suffice?

 

Would this level of instrumentation suffice?
View attachment 24004

I still look after a 727-200 so that looks nice and basic.

 

The dip stick is pretty pointless these days. You can check the oil anytime you want from the dash and it pops up with a warning if you need to add 1l rather than the old days when you'd get a warning (if you hadn't checked it manually as most people didn't) when it was so low the pressure had dropped and was causing damage.

The temp on the other hand, I like to know how warmed up the engine is. If the stat fails (I replaced the merc one due to poor warm up) I'll have no idea. Worse, it's unlikely to be found on a service and it could go undiagnosed for years.

Overheating I'm less concerned about as you'll still get a warning. Though it would still be better to see it coming.

 

The dip stick is pretty pointless these days. You can check the oil anytime you want from the dash and it pops up with a warning if you need to add 1l rather than the old days when you'd get a warning (if you hadn't checked it manually as most people didn't) when it was so low the pressure had dropped and was causing damage.

Without a dipstick you are completely stuck if the sensor fails. Good engineering practice would be to have both a gauge and a dip stick. Also note that unless you have a dipstick you can't see the state of the oil or whether it is contaminated.

 

No dipstick is a poor move for preventative maintenance.

 

I don't think I could tell contaminated oil by looking at a trace on the dipstick. Yes you're at the mercy of the sensor but on the flip side it's continuously monitored. My '05 merc didn't have a dipstick so it's not a jag or a new thing. But of course both would be better.

 

It's contamination with diesel I'm looking for, you can smell the diesel on the dipstick if it's present, you just have to explain to the neighbours why you are standing there sniffing a dipstick. Phil

 

I'm very 'old school' on this. While I appreciate a computer monitoring things and alerting me if I'm not looking at the dials at the time, I still like the dials as well.

I had a 1983 Audi Coupe that only had low and high temperature warning lights. While stuck in traffic on the way to work one morning the high temp warning came on, which I duly ignored because the sensor had failed on 2 previous occasions. It came on again later, followed by a lot of steam from under the bonnet. I then discovered I had dislodged the plug to the cooling fan while replacing a clutch cable the previous weekend. The engine survived, but I'm sure it didn't do it much good. If I'd had a gauge gradually increasing I would have taken more notice!

As for the dipstick, I still like to look at the colour of the oil over time and get some idea as to the basic condition of the engine.

 

Is it Concorde?

 

Yes it is, well done

 

How hard would it have been for Jaguar to include one page on the navscreen showing all those values that we like to see? I don't understand why they leave out vital information. I had an Alfa Romeo that did not get up to temperature very quickly anymore and it would drop temp when cruising at low speeds. Without the gauge I would never have spotted the issue. Guess I have to get myself an ODBII dongle for the iPhone and run the Torque app.

 

I suppose they don't see their target market would be that involved in their cars or interested in knowing the information.

 

I use something similar myself. They can also automatically record your 0-60 and give you a lot more information on the fly than any dials would ever give.
Things like battery voltage, g's, current HP, Torque, etc.

 

Thinking I would get one of tehse readers myself (Cheap enough).
Anyone going to warn me off this?
http://www.ebay.co.uk/itm/ELM327-Bl...023?fits=Car+Make:Jaguar&epid=1279979173&hash=item1c6bc4f07f:g:zFQAAOSwtnpXnrt~

 

I ordered one of these to use with iPhone. I will post here if it works
https://nl.aliexpress.com/item/100-...b1-e45b-4ef2-b07f-0ebef07c1414-2&algo_pvid=7ef117b1-e45b-4ef2-b07f-0ebef07c1414

 

To be honest I don't think the lack of this information would or is stopping car nuts from buying these cars. I'm a car nut and I knew that Jaguars didn't have the gauges etc. before buying so just got what I needed to sort that out. Anyone who writes off the jaguar cars because of missing gauges isn't really into their cars because as far as I'm concerned they are some of the best cars performing in their classes.
Even if jags had the information visible I would have bought the reader anyway to see deeper into the systems as I like to know what's going on in my engine and beyond.

 

Hi, as you quite rightly say above, although I would imagine there are a lot of drivers who wouldn't understand what the gauges are telling them anyway. Phil

 

I promised I would post my results with the cheap Aliexpress OBD2 dongle ( https://www.aliexpress.com/item/100...t-Bluetooth-Work-On-Android-IOS-OBD-as-elm327-OBDII-Diagnostic/32799179200.html )
It sort of works in my XF 2.2 Diesel. It provides a number of gauges and readings. Some correct like engine temperature, speed, RPM, some wrong like the fuel consumption. The app does not allow much customization to fix this. One very annoying this is the app will give an error when the engine is stopped by the start-stop system. It will only continue after you clear the error message.
What struck me is the difference in speed between the dial and the app. The app reads the actual speed which is very close to the measured GPS speed. The dials and cruise control indicate roughly 6% higher. I would like those to be correct as well. Is that something the dealer can fix?
Also my engine temp does not go above 82 C during normal driving. Is that normal for a Jaguar Diesel? My previous car was around 90 degree.

 

Interesting on the speed. You would imagine the cluster reports whatever the computer tells it, after all, the cluster is just a computer readout based on the self same data. so if there's a discrepancy I would think it's deliberately programmed into the software. People generally drive with the expectation that the speedo overreads (so we truck along at '80' knowing it's really around 76 as this is how the old mechanical dials used to work. Sounds to me like they can get it pretty close to 100% these days so to protect the motorist, they're simulating the old mechanical inaccuracies!

 

Also remember a Speedo is allowed to over-read buy 10% but not allowed to Under-Read. If you were ensuring you were designing this system wouldn't you make it over-read by approx. 5%!

 

I think what GeoffR is saying, Daniel, is he wants a speedo that tells the truth. That's certainly what I'd like. My s-type tdv6 was only about 2mph over at any speed above 40 mph & below that it was pretty spot on. My xfs speedo is as inaccurate as all the rest out there.

 

The problem is, as Daniel350 points out, the only way to know the truth 100% in real time is to install a GPS speedo. The car can only tell how many wheel revolutions have occurred. Tyre wear results in a +/- 6.4mm to the diameter and hence distance travelled per wheel revolution, plus tyre pressures and temperatures and I imagine the overall diameter of the tyre is probably a tad variable too - then what about the overall differences between 18,19 and 20" wheels even with the appropriate tyre fitted?
So there is no practical way (unless you are prepared to have your speedo recalibrated every month) of having that level of accuracy. As over reading is legally acceptable and means you're immune to even the most over-zelous police force, they factor in a deliberate over read factor.
If you want 100%, attach a GPS speedo - much better (and more accurate) than a calibration card.

 

So it's down to manufacturers' costings and them taking the cheapest route. I know all that. They don't fit accurate speedos because they don't have to.

 

This certainly used to be the case with the old cable and gear setups but now?
Speed sensor pickups need to be very accurate for things like ABS and ESP so there is no additional cost for the speedo side of things - the computer knows exactly how fast each wheel is turning. that info is passed to the cluster and the cluster, being another basic computer can translate and display it with 100% accuracy. No cost implications whatsoever.
This is a deliberate decision with the customer in mind.
Most people are not petrol heads and aren't aware that their speedos are inaccurate and have got used to the idea that they can track along at an indicated 80. Sure we all know that's around 73-75 which is why the police don't prosecute but we're the minority, most are happy in their ignorance and given the way most of them drive, to be honest, so am I. Suddenly give them all a 100% accurate speedo and they'll all get tickets. I know I can cruise through an average 50 zone with an indicated 55, make progress through the traffic and not risk getting prosecuted. Now in truth I also know the cameras also allow a bit so possibly an indicated 60 would be ok but every time I eek out a bit more of the allowance I take myself closer to prosecution territory so I reduce my anxiety levels and relax.
So I have to ask, why do we care? I knew my merc speedo showed 75 at 70. All I achieved with this knowledge was getting frustrated stuck behind people driving at an indicated 70.
We are haggling here over 5 or 6 mph at 70+. Allowing for traffic, we're talking at less than 5 minutes progress over a 4 hour journey. It's that insignificant. Do we really care?

And for those that really do, well every mobile phone and tomtom has a gps based speedo these days. Drive to a real 70, glance at the dash readout and then you know where your 'real' limit is. It's as simple as that.

 

IIRC JLR set all speedos to read 5% plus 2 mph (3 km/h) optimistic.
In theory this over-read can be removed by tweaking the CCF using SDD.
I had it removed on my old XFR but it didn't quite work, only the extra 3 km/h went away but the 5% remained.
I'm with GeoffR, I would much rather have an accurate speedo than one I know is overly optimistic, on the F-Type I get a bit fed up with having to constantly do a mental calculation to work out my real speed as opposed to what the speedo is reading.
I find that the majority of drivers in Adelaide have "speeding phobia" and they sit precisely on the speed limit as indicated by their speedo, and they obviously have no idea that their actual speed is significantly less than what the speedo says. This can be very annoying at times, such as on a clear dual lane road where a pair of these muppets sit exactly side by side at 10 km/h under the already painfully low speed limit.

 

Hi All

Why would Jag be paying less for an inaccurate speedo. As per OzJagXFS they actively set them to be 5% out as it is in the middle of the limits they are provided by law. If you manufacture something why would you actively set it to be right on the end of a set of limits not in the middle.

GeoffR as a B2 i'm sure you are aware that Pitot/Static systems are still the main driver for Speed with a GPS correction. You are well aware of the costs that go into these systems. Is this what you are pushing for with costs associated. A 737 Classic E and E bay total is worth about 1 or 2 of the boxes in a Max or NEO so obviously the £150k XF is an acceptable cost to you.

Really it comes back to my first point though. If you have Limits of 0% Under-Read and 10% Over-Read why would you push hard against one of the limits and not go in the middle! If they aim for 5% plus 3kmh then 6% sounds like they are 100% on manufacturer target!

 

GeoffR as a B2 i'm sure you are aware that Pitot/Static systems are still the main driver for Speed with a GPS correction. You are well aware of the costs that go into these systems. Is this what you are pushing for with costs associated. A 737 Classic E and E bay total is worth about 1 or 2 of the boxes in a Max or NEO so obviously the £150k XF is an acceptable cost to you.

As a B2 I am also well aware that the Pitot/Static system measures Airspeed, required for aerodynamic reasons and GPS measures Ground Speed which the passengers like because it tells them how long it will take to get there. The errors inherent in such systems are now quite small and are acceptable.

I don't know of a Pitot/Static system that is "corrected" by GPS because indicated airspeed is so vital in knowing what the wing is doing. What you might have is a correction, based on GPS altitude data to get True Airspeed (TAS) but it is IAS that appears on the pilots ASI. Lets not go into position error here.

None of which is relevant in this case because the errors between wheel speed and GPS ground speed are, in comparison, minimal. In the vast majority of cases the average of the wheel speeds is going to be very close to the actual ground speed, certainly much closer than -0% +10%. As others have pointed out the error, in a modern car, is almost entirely artificially introduced. So to give the XF a speedometer error of, say, +2 MPH at 70 should be cost neutral because they wouldn't be artificially adding 5% +3 KPH in software. As an engineer I find the idea of a deliberate 10% error unacceptable. Also, please consider that my Saab, which cost less than an XF in 2011 has an error against a GPS of +1 MPH at 30 and +2MPH at 70, I consider this acceptable but only because I know the magnitude of the error. I would actually be satisfied if JLR simply published the fact that their speedometers overread by 5% +3KPH and if other manufacturers were required to do likewise.

In the meantime I will tell you that the Saab 9-5 had a capability for the speedometer to be calibrated to match the wheels and tyres fitted, if you wanted greater accuracy you could calibrate to a narrower tyre, of the same wheel diameter and aspect ratio. Thus if you had 235/45R17 tyres, calibrating for 225/45R17 tyres gave an error of around +1 MPH at 70.

 

I had an x type that over read on the mileage. The sat nav said 4.5 miles but the car said it had travelling 4.9. I took it back to the dealer several times who came back with the usual 'no problem could be found' and finally said Tough, but very nicely. My concern was that the service intervals could be reduced unnecessarily but that was that.

My XF appears to have a pretty accurate speedo because every time I go past one of those things that tell you your speed it seems to match pretty closely.

 

Hi, I have a Nextbase 512G dash cam and the screen on it always shows 5mph less than the speedo whatever speed I am doing. Phil

 

Have any of you actually opened up the console. The speedometer needle is just pushed on to the shaft of the motor. It has no key point to lock it in place so it can be moved. That in itself removes any chance of accuracy.

 

It is two and a half years since I disposed of my XF so I may be misremembering this but isn't there an option to display the speed digitally between the Tacho and the Speedometer? If so I would think that could be accurate.