[NIP]

Originally Posted by SDP

Spent some quality time with the Duma...you understand your car better and you bond well.

Totally agree. Washing and detailing your car definitely bonds you with your vehicle.

[SDP]

Originally Posted by SDP

Adjusted the tyre-pressure to the correct recommended levels after last time. Same usage like last time, 100% office commute, 0% AC.

Filled up today morning. The tank took 22.46 liters and its been 261kms since last top-up. This works out to be 11.62kmpl. Decent. I was expecting lower than last time because of the lowered tyre-pressure.

...
-------------------- What next? ----------------------
I will take one more snapshot of the FE 2 weeks from now after another 250 odd kms - this time with 100% AC. You must have noticed, I am changing one variable at a time. Let's see how the next experiment pans out.
...

Driving on 32-30psi and with almost 100% AC. 100% office commute. Had planned a top-up after 250-260kms. Instead I did 674kms and refuelled today. The tank gobbled up 64.69 liters of diesel. So the FE is 10.42kmpl. This is the second lowest FE I got ever. But the number is inline with my expectation that with almost 100% AC, the FE would drop by 1-1.5kmpl as compared to 0%AC. So its OK.

So here's my understanding of my XUV's FE:
1. 100% city usage, 32-30PSI and 100% AC -> 10.5kmpl
2. FE improves by 1.25-1.5kmpl with 0%AC usage
3. FE improves by 0.75-1kmpl with 38psi
4. FE decreases by 1.5-2 kmpl at full load

[Heavy Horse]

Originally Posted by SDP

Driving on 32-30psi and with almost 100% AC. 100% office commute. Had planned a top-up after 250-260kms. Instead I did 674kms and refuelled today. The tank gobbled up 64.69 liters of diesel. So the FE is 10.42kmpl. This is the second lowest FE I got ever. But the number is inline with my expectation that with almost 100% AC, the FE would drop by 1-1.5kmpl as compared to 0%AC. So its OK.

So here's my understanding of my XUV's FE:
1. 100% city usage, 32-30PSI and 100% AC -> 10.5kmpl
2. FE improves by 1.25-1.5kmpl with 0%AC usage
3. FE improves by 0.75-1kmpl with 38psi
4. FE decreases by 1.5-2 kmpl at full load

Hey SDP, fantastic stuff. Only one question. What's the logic for FE improving with higher than recommended tyre pressure. That seems a little anomalous to me. Rest of your data is highly logical.

[SDP]

Originally Posted by Heavy Horse

Hey SDP, fantastic stuff. Only one question. What's the logic for FE improving with higher than recommended tyre pressure. That seems a little anomalous to me. Rest of your data is highly logical.

That's a very good point Heavy_Horse! The fact that under-inflation has a severe negative impact on FE is well known. So I guess I assumed that the reverse would also be true. Did a quick search on internet and could not find any reliable source which claims increase in efficiency with 10-15% overinflated tyres.

Thanks for bringing it to my notice!

[anandtheleo]

Originally Posted by SDP

That's a very good point Heavy_Horse! The fact that under-inflation has a severe negative impact on FE is well known. So I guess I assumed that the reverse would also be true. Did a quick search on internet and could not find any reliable source which claims increase in efficiency with 10-15% overinflated tyres.

Thanks for bringing it to my notice!

The reason I think is because of the reduced contact patch of the tyre on the road due to increased air pressure. But this in turn will increase the uneven wear of the tyres, it will wear more in the center than in the shoulder of the tyre.

[SDP]

Originally Posted by anandtheleo

The reason I think is because of the reduced contact patch of the tyre on the road due to increased air pressure. But this in turn will increase the uneven wear of the tyres, it will wear more in the center than in the shoulder of the tyre.

Contact patch reduction is imaginable. Shoulder uneven wearing is also imaginable in a bike tyre. But for a car-tyre, that too something as broad as a XUV's, I doubt. Anyways, let me read up a little bit more. If you come across any other sources, please do share.

PS and OT: When I removed the spare wheel/tyre over the weekend, I was overwhelmed by the sheer size and weight of it. I know that it is exactly the same size as the other 4, but on the car, the wheels don't look too big. But in isolation, they are more than a handful.

[SDP]

During the cleaning and waxing session on Sunday, I noticed that the right front tyre seemed underinflated. When I checked the pressure, it showed 22psi!

I got the air topped up yesterday in all tyres and this particular tyre hasn't shown any leakage till today morning. So I doubt if there is a punture.

The SUV was at the service center on 2nd and 3rd Mar. The work included steering center-alignment and resolving vehicle-pulling-to-left issue. Unfortunately I had not checked tyre-pressure when I got the vehicle back. Now I have a doubt: did the service-center lowered the pressure in my front-right tyre as they could not solve the vehicle-pulling-to-left issue any other way?

Is that possible? There are a few posts on the niggles thread which hint at a design issue because of which the camber can not be adjusted beyond a limit. Could this be related to that? Am I being too paranoid?

[Heavy Horse]

Originally Posted by SDP

During the cleaning and waxing session on Sunday, I noticed that the right front tyre seemed underinflated. When I checked the pressure, it showed 22psi!

I got the air topped up yesterday in all tyres and this particular tyre hasn't shown any leakage till today morning. So I doubt if there is a punture.

The SUV was at the service center on 2nd and 3rd Mar. The work included steering center-alignment and resolving vehicle-pulling-to-left issue. Unfortunately I had not checked tyre-pressure when I got the vehicle back.

Hi SDP, I've developed this habit that whenever I get my vehicle back from the ASS, I make it a point to immediately check the tyre pressure at my favourite fuel station. This habit has grown with my Honda City where invariably I would find that the tyres were hugely over inflated. In fact I'm convinced that those guys just pump in the air and never bother to check the exact readings.

I must say that with M&M has NEVER happened though there have been only 2 occasions, once during delivery, and today after the first service. On both occasions pressure has been spot on. But I still retain my old habit, since tyre pressure is one of the a key determinants to a good FE.

Just my 2 cents !

[SDP]

^^ A valuable lesson leart, Heavy_Horse!

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Yesterday night, I was heading home from work. I was about half a KM from my office and was just getting warmed up to the 12-13km drive. Typical half-lit street in Mumbai and then out of nowhere a loud DHAAAP!

My heart sinks! I was aware of my sourrounding, so the possbility of a car bumping into me was remote. But, same could not be said about a bike. A moments survey through all mirrors and a quick glance over shoulder revealed that there is nobody around. My mind is racing through all sort of worst-case-scenarios. I am in the middle of the road, can't stop there. So I slowly move to the left and stop some 50-60 feet ahead. While I pull the car to the side and get out of the car to investigate, mind is still in turbo mode.

Was it a rock? Unlikely, I have had hits from rocks earlier, the contact area is small so the noise is different ..more like a clang than a DHAAP. Does that mean this rock was much bigger? I hope not.

Did my tyre burst? Unlikely, its cold. Also the vehicle did not feel any different in the 50-60feet after the sound.

Did anythying fall off? Oh boy! Did the exhaust pipe came off and is now being dragged behind the car? That would be a disaster! Its almost 8pm. Support from RM and Mahindra-Roadside-Assistance might not be fast enough at this hour.

With my mind still juggling a thousand posibilities, I got off the car. First thing, tyres. Looked at all of them, they were fine. A sigh of relief. Next: visual inspection of the panels, hoping not to find a huge dent. Its dark, visibility is limited especially on the footpath side of the car. I use the reflection on the panels to figure out if there is a dent or a noticeable ding anywhere. Nope! Another sigh of relief. I get down on my knees and peek under the car. Nothing stuck, nothing noticeable missing, nothing dangling, nothing leaking. All is well!

Now I am confused. The sound was loud and came somewhere very near my car. There was no other car around at that moment. What was it? I decide to trace back the path to the appoximate point where I heard the sound. Brain still in overdrive. One possibility, a bottle! A empty plastic bottle- let's say Pepsi 600ml - with the cap secured would explode if I drive on top of it. With no cap, it would just get crushed. With a cap, it would puncture/rupture somewhere and make a loud sound. While I am walking back looking for any clues, I am getting more and more certain that it must be a pet bottle.

I reach the place. I can see 50 feet on either side and there is no mangled remains of a bottle. The street lighting is poor, but the road and the surrounding is clean. I am still trying to figure out what the hell happened. And then I notice water on the floor - almost half a liter - and a torn plastic bag just next to it! I heave a HUGE sigh of relief! Time to go back and verify my conclusion. I hurry back to the car and check for water on the car. Below the front left door, the black cladding, I see some water drops. Still not too visible. I open that door and hold it open so that the puddle lamp provides the much needed light in that area. Its confirmed, there were good amount of water drops on the black plastic cladding. I run my fingers on the entire cladding and notice that the water was loacalized just on the front part.

So that's it! Some kid might have thrown a plastic-bag water-filled baloon at the car .. or might have left it on the road and being transparent I did not notice it. Happy holi to that kid and happy holi to you guys!

[carzone]

Originally Posted by SDP

Happy holi to that kid and happy holi to you guys!

thats undoubtedly the best way to wish holi to fellow BHPians I have seen till date. You had my heart racing the way you narrated it. At the end, it was LOL.

Glad that your car is safe and happy holi to you as well.

[M35]

Originally Posted by SDP

Happy holi to that kid and happy holi to you guys!

You had me tossed up all the way, only to realise that you were kind of crying wolf

"Life is like a box of chocolates, you never know what you're going to get."

Happy holi to you too.Keep revving and do drive safe.

[SDP]

In IT, one of my favourite quotes is "Bugs that go away by themselves, would come back by themselves". Applying Murphy's law to that quote, that bug that you could not reproduce, will resurface at the worst possible time.

I dread such bugs/niggles.

Sunday, after a waxing session, I long-pressed the unlock button on the key just to check if the siren/hooter is working. No sound

Monday morning, security alarm still not working. Reverse alarm also not working. (My conclusion - They use the same physical hardware, so hardware issue.)

Monday night, security alarm started working, BUT reverse alarm still not working. (My conclusion - Hardware seems ok. Software/configuration might have a bug).

Tuesday morning, security alarm and reverse-alarm BOTH are working! (My conclusion - Salute to M&M for inventing self-healing hardware and software! )

[n.devdath]

Originally Posted by SDP

Salute to M&M for inventing self-healing hardware and software!

Welcome to the tribe of self healing M&M vehicles...!!

Scorpios are known for this quality for a long time now and I m glad that the same genes are carried over to the XUV as well.

[Mudhalaipatti]

:-), You had my heart racing.
What a way to wish Holi.

And on the software, yeah it has built in AI and reprograms itself. Welcome to The Matrix.

[tachobells]

Originally Posted by SDP

In IT, one of my favourite quotes is "Bugs that go away by themselves, would come back by themselves". Applying Murphy's law to that quote, that bug that you could not reproduce, will resurface at the worst possible time.

I dread such bugs/niggles.

Sunday, after a waxing session, I long-pressed the unlock button on the key just to check if the siren/hooter is working. No sound

Monday morning, security alarm still not working. Reverse alarm also not working. (My conclusion - They use the same physical hardware, so hardware issue.)

Monday night, security alarm started working, BUT reverse alarm still not working. (My conclusion - Hardware seems ok. Software/configuration might have a bug).

Tuesday morning, security alarm and reverse-alarm BOTH are working! (My conclusion - Salute to M&M for inventing self-healing hardware and software! )

In IT, one of the golden rules to resolve a bug is to "restart the system".
I guess that works for automobiles too..