[shrk_18]

Originally Posted by vellatechie

This is more than I get driving in and around NCR.

Colder air being denser, resulting in better burn giving that FE possibly ?

[Ad_J]

Originally Posted by shrk_18

Colder air being denser, resulting in better burn giving that FE possibly ?

Cold air is denser than hot air at the same altitude, more or less (i.e keeping the other variables unchanged). However, air density is inversely proportional to increase in the altitude. As we have studied in school, higher we go, less dense the air is. That's why some people experience breathing issues at higher altitudes, because the quantity of oxygen is less in the air.

AFAIK, an engine loses some power at high altitudes because of the thinner air. Can't say for sure how will it affect FE. In my observation, it decreases with altitude. I live in two places which differ more than 6500ft in altitude.

But, aerodynamic drag can also be an explanation in this case.

According to the drag equation, the drag (air drag in this case) depends upon the density of the fluid (air in this case).

Hence, it can be said that aerodynamics changes w.r.t the density of the air. Jispa is at 10,500ft above the sea level, the air is pretty much lense dense there.

Since, it has been almost half a decade I have switched fields (I have a Hons in physics btw, which I won't be using in my life anywhere in application ) and it is turning out to be a pretty good discussion, I wish someone enlighten us on this topic.

[vellatechie]

Originally Posted by NagaBond

.
This is very good news. I thought petrol engine will lose power at high alittude and AT will reduce the performnace further. How was the pick up at high altitude passes? At any point, did you feel loss of power? Thanks !

There were a few times (a couple if I try to remember) where I felt there was a quarter sec or half a second delay in power while overtaking, but frankly it was always more than enough.

Originally Posted by Ad_J

Cold air is denser than hot air at the same altitude, more or less (i.e keeping the other variables unchanged). However, air density is inversely proportional to increase in the altitude.

Yes exactly. I was also suggested that I should take two jerry cans because it's a 4x4 Petrol AT. But despite all of this physics even with broken roads (Between Nubra and Pangong, and Leh and Jispa roads were non existent for at least 50% of the trip) mileage was never an issue for me.

For anyone wondering, here is the DTE photo I took in Manali after filling up the tank till auto cut off kicked in. This went up to 775 after few KMs Because I guess I was going down hill after the fuel pump.

[wooka]

Originally Posted by shrk_18

Colder air being denser, resulting in better burn giving that FE possibly ?

Not at all. At 15k feet, air is 35% less dense, including the temperature difference, on average.


The turbo will accommodate the air pressure drop, so it will manage to sustain power. In fact, the petrol thar out performs the diesel in the hills, I feel. Throw in the fact that high altitude petrol doesn't freeze as easily as diesel, and at altitude diesels have DPF issues (any amount), you can spam that throttle all day on the petrol. The petrol also moves quicker. Is it (the engine, and the car) lighter? Seems to gain revs much sooner than the diesel. This matter in the hills, tremendously.

Lastly, the petrol always had better specs in terms of pulling power. 150 v/s 130 HP. In fact, I often wonder why the scorpioN diesel is so flat out underpowered. The Z8 4x4 diesel is some 172hp with all that additional weight, whilst the petrol is 201HP from the base model. What gives?

Wish I'd done my hons in Physics at Hindu after getting in, back in the day!

[zorori47]

Better fuel economy is because the engine is running lean due to less oxygen content. The ECU cuts back on the fuel being injected since there is not enough air/oxygen to maintain the stoichiometry as is done near sea levels. That is why you re-jet a carb at higher altitudes

While this reduces power output, it also increases the overall efficiency of the engine. Win win

[that_sedate_guy]

Originally Posted by Ad_J

Cold air is denser than hot air ...
However, air density is inversely proportional to increase in the altitude. ...
an engine loses some power at high altitudes because of the thinner air... aerodynamic drag can also be an explanation in this case.

All of these are massive contributing factors to both engine power and fuel efficiency. In terms of a summary:

Air density: Lower at high altitude --> Lower power delivery and hence lower FE because lower power output necessitates the driver to put in more throttle to get the desired acceleration and speed. @zorori47 explained that the ECU alters the fuel ratio but it doesn't take away from the fact that the engine now has to work a lot harder to cover a given distance at a given speed. A lean running engine running for longer on lower power is not more efficient than a rich running engine running for a shorter duration with higher power on tap.

Air temperature: Lower at high altitude --> When the temperatures go sub-zero, fluids in the car will get more viscous. This includes the coolant, Engine oil, Transmission fluid, differential oil and more. Pumps, gears, bearings which are involved with these fluids will need to work harder to displace the same volume of fluid as under normal conditions. The energy for this work done comes from the engine which results in fuel being burnt for such auxiliary activities apart from moving the car. This contributes to a lower fuel efficiency.

Also Air density: Higher at low temperature --> Cold air of course is denser but this increase in density is negligible compared to the massive drop caused by the altitude increase. Hence, if at all this contributes to anything, it'll only reduce the adverse effects of high altitudes to a certain extent.

Aerodynamic drag: The drag forces on a vehicle, while directly dependent on the density of air, is majorly dependent on the speed of the vehicle because the equation calculates drag with the velocity squared. Hence every km/hr added modifies the drag force to a higher extent than the changes in air density. Hence, at ghat speeds, the drag forces have a much lesser hold on FE than at highway speeds or crosswinds. This, combined with the lower density translates to a similar, sometimes even better fuel efficiency.

While turbochargers aid in combating the lesser oxygen availability, the benefit is at the expense of the engine maintaining the turbo spooled up and hence requires a certain rpm range to be effective. Superchargers if at all present, will induce air at all rpms but again, at the expense of valuable engine power. So forced air induction does not translate to better fuel efficiency, only to better power delivery. This serves to mitigate the power loss effects of lower air density.

The other contributors are gravitational forces and inertial forces acting on the car which the engine has to burn fuel to overcome. A continuous uphill will destroy the fuel efficiency but as we know, no mountain roadways are continuous uphills due to valleys and other geographic considerations. Hence the engine will not always work towards pushing the car against an incline. While this seems like a small factor, let's not forget that the force is dependent on the mass, acceleration and the incline angle.
Further, this force works hand-in-hand with inertia which is also dependent on mass and acceleration. Hence at a decline, however miniscule, the mass and inertia of the car works on its own to cover distance at little or no throttle input.
Furthermore, braking on hilly areas is done comparatively lesser than on plains and cities because in an uphill section, you seldom come across situations to brake hard and lose momentum completely. In downhill sections, unless you coast on very high gears (not an option in automatics) or in neutral (very dangerous BTW), the engine braking will take care of slowing down anyway.
These above points contribute to a big difference in fuel efficiency because these are conditions at which one would normally cover two metres at most in city traffic before slamming on the brakes for an auto guy. While not straightforward, the lesser interruptions to the inertial forces on the car contribute a lot to better FE which might have given these better figures.

P.S: I am a Mechanical Engineer (or was/ studied/whatever ) but really, these above points are more from personal experiences than from theory.

[asingh1977]

So it has been almost a month and half since we purchased the Thar. Wanted to put in some pointers and observations, for the Thar Petrol AT HT 4x4 option we picked:

3 door SUV -- really:

Since the time of the Mahindra Classic, and then the original Thar a "jeep" has been an aspirational vehicle for me. The initial two offerings had a lot of short-comings, specially in terms of safety and daily family usage for urban settings. Then came the Thar 2020, and it just ticked all the boxes. Living in Gurgaon it is either an SUV or only an SUV. With the bad roads and SUVs adding an aesthetic fashion sense, we were on the lookout for another SUV. (Already had a 5 year old Creta). Did not want to go the Seltos way, since it is too similar in nature and design language to the Creta. TATA, is a no go, due to bad service, and just not comfortable with the brand as of now. We tried the Jimny before the Thar and were ready to go ahead. Once we saw live versions on the road, realization hit: that it is just too small to be classified as an "indian SUV", if you know what I mean. Also it seemed over priced, metal to money. Still love that Japanese rocket, and would pick it up if we need to change cars again, immense practicality, 4 doors, and 4x4 kit.

Reluctantly we decided to take the test drive of a Thar. Any model available. A new Dee Emm showroom had opened close to our abode. Called up the center, and requested for an at-home test drive. Surprisingly, next morning the sales personnel turned up with a Diesel 4x4 automatic. (I was in the mind to purchase the RWD, honestly). Having practically no experience with automatic transmissions, I took the jeep out for a drive. Was slightly hesitant with a h-u-g-e bonnet in front, which seemed to have a mind of its own. Immediately I realized: the steering is so weird. Just weird. It totally felt like from the 80s in design, finish, and did not spring back. Once on the main road, the sales guy told me to pedal it, "bhiya race do". That is when it hit me! What brute force has been mated to the motor. The car picks up, and just continues to do so. Linear. I did not even think there was a turbo there. Once you get comfortable with a huge bonnet, and slow steering adaption to the wheels, the Thar is a breeze to drive. We were quite impressed. My wife drove after me, and took the jeep back to our house parking. Her views were same as mine! I quickly coined it: a modern classic Oh yes!

It would be the 4x4 Red, Petrol Auto HT. Smile.

Booked and bespoked:

We went ahead with the booking, and decided on the following accessories:

1. Rear-view camera: There is absolutely no visibility when backing up.
2. OEM seat covers: Did not like the gray native color option. Also seemed too soft for an off road appeal.
3. Radiator guard: Seemed logical, in place of what was given by the factory. i.e. more secure and robust.
4. Steering leather grip: The original steering is too old school, and felt over plastic.
5. Arm rest with storage: Found it awkward driving without a place to rest the left arm.
6. Back seat arm rests with storage and live USB connectors: Just to add more storage to the limited space available.
7. Stepney Wheel cover: For security and ease of parking on road.

Augmentations added as post delivery purchases (all from Amazon, links in bold):
1. Rubber key cover -- to save from water and accidental drops
2. Mats -- the showroom ones did not have red accents/stitching
3. Back seat hooks -- for hanging bags and caps
4. Long USB cable -- the phone holder area is too dark, I like the phone to be visible

The dealership told us that Petrol AT 4x4 variants have minimal waiting periods, and we should get the jeep soon. Well we did. In 10 days. I was quite surprised. Was advised to go ahead with the payments, and get the VIN allocated.

Delivery / Initial Impact:

The delivery time was pre-set, and all pending formalities were completed. In between we also bid adieu to our 13 year old i20 (54K running) to make way for a the new red. We reached the showroom, and the Thar was hidden with the customary cloth, so could not tell much. I just lost patience and asked the sales guy to remove it. That is when the shock hit. Seeing a demo vehicle, seeing a new vehicle on the road, BUT nothing beats seeing your own vehicle for the first time, fresh off the assembly line. The red just popped like crazy, and the most striking feature. Those huge wheels. People not well versed with the Jeep (or teamBHP), honestly gape at the wheels when close up. Signed all the paper work, did the photos, and took possession of the new metal. Loved it. Since we were taxed for time, fueled up the tank, and parked it home. Realized within a few km of driving, that the mStallion is a gem of an engine. Straight and well timed power delivery. The automatic is smooth, and the ease of driving 2T equipment is hardly felt. The Thar honestly is not that much of an attention magnetic in Gurgaon -- since so many are around. But still at times people stare (specially pedestrians, with a smile), and people really make way. Like they yield. No need for honking or acting aggressive, cars part their lane, and also pause to let the Thar cross if they are about to make a turn from the median. I have always been a meek driver, and drive quite sedate. It is shocking to see the look on people faces, when a Thar stops to let them pass, or gives side. Part of life!

After some weeks of taking it to office (what a 4x4 waste), these are my happy-moments:

1. King of the road: The high perched seating takes a while to get used to. Literally 90% of roof-tops can be seen. Totally commanding, and confidence inspiring. Gives better control of the vehicle and external environment variables get dialed in perfect, as soon as one gets in to the Thar.
2. Chariot mount: Getting into the Thar for the driver is, well: a fun task. There is no grab handle. Since I am quite lean I manage it easy. I like to step on the foot board, while holding onto the top of the open door. And literally climb-on. It just feels so old-school, historic, and maybe the closest I will get to being a knight (or a Highlander).
3. Full visibility: A lot has been mentioned about this on TBHP, so not to say much. Basically: flatland. On a side note, it is quite easy to reverse, looking back from the side window. The Thar is a small vehicle in terms of length, so the back corner is easy to judge, when reversing onto a pillar side, or adjacent car. Simple.
4. Automatic: After 20 years of manual gears, the AT is such a breeze. This is the prime reason the THAR AT is so popular with urban dwellers. Like 50% of the road worries are over with an automatic. The gearbox on the Thar is smooth, and changes at appropriate times. The surge is immediate, if one peddles down, and is propelled forward immediately. Knock-downs are timed, if you let go of the throttle. Well rounded gearbox, and engine combination.
5. Jeep: Enough DNA has been retained to call it one. How many choose this. Only a select view. Just love the feeling. Somehow people who rode these "general purpose" vehicles as children/youngsters (tea estates, hill stations, rural transport, armed forces, school ambulances) will feel a pining or long-lost-hope when they see the Thar. It certainly has an attraction and pull. Sweet but hard to describe!

Overall the Thar meshes well in the urban jungle, and is not out of place. OK, not in its jungle element, but can prove its worth in the city.

The Long drive:

We planned a trip to Corbett National Park, to my home state. Sans Garhwal, but into the heartland of Kumaon via UP. Overall impressions would be:

Bounce and roll: The vehicle is quite bouncy over speed breakers and bumps or holes. No damage will come to the under body, but people will be thrown around, specially at the back. One cannot gun over road undulations, but need to articulate and manage the nose of the jeep. I was comfortable taking it to 100 km/per hour, but did not push it beyond that. The jeep runs planted, but any small bump causes minuscule swerves, which can be unsettling. Highway proficient drivers will not have issues with this. I am an urban driver. So will not push my luck!
Brakes: Quite scary, till you get used to them. Feel mushy, and the Thar takes a while to stop. One has to pre-judge traffic and anticipate when to slow down, or stop. Again it is just getting used to driving heavy machinery, with a bit sub-par brakes. Better brakes (or maybe 4 discs) could have been provided.
Seating: I guess it is just for 2 adults, and 2 youngsters. Adults in the back will really not be happy. Ingress is also not easy for the well built!
Highway manners: The Thar is a decent mile muncher. After 900 km, I am getting around 10.5 km/liter. Which I think is decent enough. One can drive the jeep all day for long journey's and should not be uncomfortable. The high top driving stance takes a while to get used to. The drive is fluid enough and overtakes are fast, if timed well. Just remember the braking is a bit latent. But the road presence is wide, and vehicles provide passing lanes immediately. One can drive confident, and no need to feel wary or scared of the stupidity which happens on Indian roads.

Parting shot:

I am extremely happy with the decision we made for the Thar. It is a unique vehicle, and nothing on Indian roads is remotely even close. Have no qualms about the build quality and body form-factor. One knows what they are signing up for, purchasing a three door, high chassis mounted car. Also from the bottom of my heart. Would want to thank this forum and all the members providing insights, reviews, and experiences. It goes a long way. If not for teamBHP, we would never have purchased the Thar. Never. The essence of 20+ years of threads/posts here on teambhp related to the Mahindra Thar/CJ & MM series (and god bless Behram ji), bears the fruit of this post. Thanks again to all members and forum staff.

It just brings a smile to my face, when I park, and turn back once, while walking away!

Thank you for reaching till here!

[Crosscountryman]

Don't worry about the brake bite. It will settle down in couple of 1000kms and then you'll be on the other side of the spectrum... overbite 😀. Every time you brake hard, you'll be watching your Thar's backside.
Here's wishing you lakhs of happy jeep miles.

[jimmzbond]

Originally Posted by vellatechie

I just completed my first Leh circuit in my Thar Petrol AT and it was a wonderful experience. I did Delhi - Pathankot - Srinagar - Kargil - Leh - Nubra - Pangong - Hanle - Leh - Jispa - Rupnagar - Delhi. I did about 15 days of travel followed by 10 days of Vipasana in Leh before heading home.

Thar is a beast and surprisingly my jerry can was not required (it wasn't even close). According to the car, I consistently got over 10.5kmpl between Srinagar and Jispa. This is more than I get driving in and around NCR. When I did my refill in Manali, it showed DTE of 760km. I firmly believe during the last service a small electric engine was added to my car and was upgraded to mild hybrid.

This circuit has been posted multiple times so I won't create a new thread but if anyone has any question, I'll be happy to answer.

This is my Thar at Khardungla.

Thanks a ton for sharing this, i too have a Petrol RWD AT and i was wondering if i can do this trip ever. I have few queries - Did you use 4WD on the trip or one can complete in 2WD mode. Any specific reason why you did the trip clockwise and not manali - Leh-srinagar as most people use this path.

[vellatechie]

Originally Posted by jimmzbond

Thanks a ton for sharing this, i too have a Petrol RWD AT and i was wondering if i can do this trip ever. I have few queries - Did you use 4WD on the trip or one can complete in 2WD mode. Any specific reason why you did the trip clockwise and not manali - Leh-srinagar as most people use this path.

Yes there are 4 instances when I used 4x4. In Hundar there were loads of sand next to the road and my Thar got stuck when I stopped at 2 restaurants for Tea. Also while going for the Sand Dunes location l, I took a wrong turn and had to go through bit of sand for about 100m. Lastly, there was a 50m stretch after Khardungla where road was just mud due to melting snow. I used 4x4 in these places, other than these, 4x4 wasn't really required anywhere.
Also, yes you can very easily do the circuit in RWD Thar if youre careful.

The road elevation from Srinagar is not as Sharp as it's from Manali. If you're worried about AMS or just want to be little cautious, entry from the Srinagar route is the best way to do the Leh Circuit. I frankly lost count on the number of sick people I saw who were coming via Manali when I stopped for Tea.

[arunpools]

Originally Posted by vellatechie

For anyone wondering, here is the DTE photo I took in Manali after filling up the tank till auto cut off kicked in. This went up to 775 after few KMs Because I guess I was going down hill after the fuel pump.

I experience terrible fuel mileage when forced to drive dead slow in the city and have also seen the car doing better on the hill roads. Mine is also a P AT.

I reckon this is mostly due to that Torque convertor AT under the hood. The lockup clutch in the Torque Convertor does not close until about 1500 RPM (+/-). So, if you are in the city in first and second gear in D mode, the lock-up clutch will remain open a lot of the time especially if you are in thick stop go traffic. A lot of power is wasted in the TC unit when you drive with the lockup clutch disengaged. A disengaged lockup clutch gives you a smooth ride with minimum harshness from the transmission but at the expense of fuel efficiency.

It only takes the gear to go to 3rd once for the lockup clutch to hold below 1500 RPM. After that, it remains closed for RPM below 1500 even in 2 and 1st unless you come to very low speeds. You can observe this when you start moving from a complete stop. Accelerate moderately after stopping and release the A pedal. Observe the Tacho needle dropping dead to about 1000 mark as if there is no connection between the engine and the wheels. The TC lockup clutch is not engaged in this situation. The same would happen even in the 2nd gear. So, if you were continuously moving even at reasonable low speeds and not stopping, you should get better fuel economy.

It looks like 60 to 80kmph is the range that gives the best fuel economy. So, if you were doing those speeds on the hills with a light foot 10.5kmpl fuel economy seems to be okay in my opinion. BTW your engine performance should worsen with altitude mostly because of lack of oxygen. Cars nowadays have mass flow sensor at the air intake and oxygen sensor in the exhaust to detect precisely how much air is getting sucked and how much of the air fuel mixture is getting burnt and the fuel is injected accordingly. So, lack of oxygen at altitude is compensated by the ECU. You would definitely feel a pinch in power and throttle response but I'm not sure about the efficiency.

P.S. The clutch will remain closed more aggressively to very low RPM if you select the Manual mode. This is how you can take advantage of engine braking on the downward slopes.

[vellatechie]

Originally Posted by arunpools

It looks like 60 to 80kmph is the range that gives the best fuel economy. So, if you were doing those speeds on the hills with a light foot 10.5kmpl fuel economy seems to be okay in my opinion. slopes.

Apart from just a couple of stretches during my trip I almost never hit 80kmph. Between Spiti and Leh, almost 120km of the road is just non existent where speed rarely crossed 40kmph. The mountain tunnels have a speed limit of 50kmph.

But u agree with your assessment. When I am on the highways, I set 80kmph via cruise control to get the best mileage-performance balance in my Thar.

[josetom89]

I second that. 80 km/hr is the ideal speed for the Thar. For me the main deterrent is the Wind noise which is excessive post 80km/hr.

Did few mods on my Red guy. This is the first time I am fiddling with a car prior to first service. I got that confidence predominantly due to the infinite number of modded thars I see every day.

Works were done at AJ Alterpit, Kottayam. They are official dealer for Bimbra products. Mods are as follows.
1. Stedi homage head lamps. Got my uncle to carry it from Australia. Cost. Approx 23k
2. Dechromed all the badges using 3M wrap cost 4.5k
3. Alloys painted Matt Black cost 10k
4. It was AJ's idea to modify the OE grill slightly to enhance the aesthetic. He claims to be the inventor of that Mod. They removed the horizontal bars behind the vertical one's and installed a thicker, denser mesh behind the verticals. Looked good for me as I really didn't want to go for Wrangler grills. Cost 4.5k
5. Installed some other basic stuff like Proman handle bars, steering wheel cover, Under body coating etc.
To sum up the works were near and professional. The Thar is truly a looker now.

[wooka]

Originally Posted by Malhi

Hello everyone,

This is just an informational post. I sent my Thar for periodic service at 80,000 kms to Koncept Mahindra, New Delhi. The cost estimate sent to me was a whopping 14k+ gst. I immediately called the supervisor and informed him that I had never paid more than 10k for a regular service back in my hometown in U.P., but he was adamant.
Regards.

Known problem lot, this dealership. Keep the CSM's number handy and email customer support with the quote anytime you have doubts. Stick to your scheduled services
. What is ESP / ESC and ABS doing if not braking in a straight line? Unless you have a history of driving downhill, having braked very hard, and using the brakes as your primary braking mechanism, I don't see why the rotors should warp, esp when they're as chunky on this car as any.

Skim your rotors only if they show significant reason.
Do so with smoothing out the pads else you're back to square 1 in no time I reckon.

Here's an excellent guide by Shashi on the topic.
https://www.team-bhp.com/forum/techn...ml#post5016636 (When do brake discs require replacement?)

[s4ch]

Originally Posted by josetom89

5. Installed some other basic stuff like Proman handle bars, steering wheel cover, Under body coating etc.
To sum up the works were near and professional. The Thar is truly a looker now.

Agreed on the looker part. The grill mod is an interesting mod, not really seen it before. Gives it a nice blacked out look - nice one!

Regarding the Proman handles, wouldn't they be extremely dangerous in an accident? As in, if your head hit that in a collision it could be fatal, even when wearing a seatbelt and having the airbags go off? Looks lethal to me!