[Ricci]

Originally Posted by Sutripta

^^^
Was talking of pad contact area, not pistons.

Regards
Sutripta

Yes, and I thought my post did cover that bit about increase in area.

Originally Posted by Jeroen

I'm not so sure that increasing the size of the pads will increase braking. I'm pretty sure it doesn't actually. With disk brakes it is all about clamping force. As the clamping force remains the same the braking action will remain roughly the same.

To your earlier point, you need to increase the calliper dimension pistons or find a way to increase the pressure (in a hydraulic brake system) e.g. booster, multi piston or just push the brake pedal harder.

Quite correct, I should have mentioned that. Keeping the master cylinder same, the same force gets distributed over a wider area, resulting in less pressure. Net improvement in braking is minor but it's rare to only increase the number of pistons/pad area without changing rest of the apparatus, mainly the master cylinder.

[supremeBaleno]

Originally Posted by SS-Traveller

The oil change interval published by manufacturers is not sacrosanct, but is an advisory for maximum interval when driving under ideal conditions - which is impossible to achieve in real life.

What constitutes "ideal conditions" ? In the manual of my car (Baleno 1.6), it just says replace oil every 10K kms - no mention of any driving conditions (ideal or otherwise).

Originally Posted by SS-Traveller

...just remember to change the engine oil sooner than your car's manufacturer recommends.

How sooner ? And what would happen if we stick to the manufacturer recommended interval ?

Originally Posted by sanjeevgpc

I am sure that auto companies consider all the aspects before they recommend an oil change interval. They should be keeping some buffer and suggesting an oil change much before its actually required to cover instances where people forget a oil change in time.

Indeed. Since they make the car, I would think they would be the best person to know how long the oil would hold.

Originally Posted by sanjeevgpc

I think many of us change oil more frequently than actually required just because we have some kind of fear.

Fear, if any, is misplaced, from my experience. We usually keep our cars (and bikes) for atleast the minimum govt. stipulated life of 15 years, if not more. And always do oil (& filter) changes only at the manufacturer recommended intervals - used to be every 5K kms for the M800 and now every 10K for the Baleno, AStar, Swift. Even after 15 years or more, we have never faced any issue with the engine of any of our cars.

Originally Posted by sanjeevgpc

Sadly we have started considering just the monetary cost of oil change and not the overall cost of damage to environment which is caused due to spent oils.

This is another crucial factor that we need to take into account. Thanks for bringing this up.

[Jeroen]

Originally Posted by Samfromindia

Well filling nitrogen is like using premium fuel. You dont get the real world benefits for which you pay for. It costs nothing to fill normal air, maybe max 10rs tip, while it costs around 200rs to fill 5 tyres. But are you even getting twice the benefit for 20 times of what you pay for ? Normally the nitrogen filling stations claim pressure will hold much longer than normal air, also some even say better ride and handling but in real world at least i never felt any difference. Coming to the teflon coating, i believe its one of the dealership money making tactic for charging a huge premium for polishing. I believe we even have a thread to stay away from it. But most of the times customers fall for that trap and end up losing money.
]

I have used nitrogen for about a year in the USA on my Jaguar XJR. Cant say I noticed any difference, no matter what I keep checking my tires on a regular basis never the less.

My thoughts are that nitrogen for ordinary car use makes not much sense. But say in racing or on aircraft it makes a lot of sense and it could be a legal requirement (e.g. aircraft tires)

I cant really comment on the "Indian Teflon" experience, but I do have European Teflon experience. There is what is known as 'Protech" treatment available. I have it on some of my classic cars. Essentially it is a Teflon based additional layer that is put on the car's paint. It is not something like a DIY job. It takes special machines, to prepare the car's surface and to apply the Teflon coating. It is also applied to (aluminium) wheels.

For instance my Alfa Romeo Spider had such a treatment. The results are phenomenal and absolutely long lasting. After the car has been treated is look absolutely gorgeous as if polished and waxed to the nth degree. You never need to polish and or wax again. All you do is hose down the car and it will look as new, polished and wax and shiny! In Europe in many place there are DIY wash boxes where for a few euro's you can use a high pressure hose with de mineralised water. So you don't even need to shammy down the car after hosing it down.

How long it last depends mainly on whether your car is kept in a garage, or sits 24/7 outside. I had my Spider treated about 15 - 17 years ago and only lately I have been thinking of maybe getting it redone.

But it is not cheap. An average saloon car will take a full day of work and will cost Euro 1200-1500 (say well over INR 100.000)

There are a few other Teflon treatments (under other brand names) available as well. From what I have seen and heard the consensus seems to be that the Protech is the best and the most expensive.

Jeroen

[DHABHAR.BEHRAM]

Dear SS-Traveller - hello to you. Thank you very much for starting this very important and relevant, also fantastic discussion on this thread. I saw it just now, so I am posting. Do you have a post on "vehicle life under RWUP condition"? (RWUP means Real World Usage Pattern). If no, please start, if yes, I will go through the first 5 pages to get the information and give comments.

Best regards,

Behram Dhabhar

[Crazy_cars_guy]

Thank-you so much for this thread. So informative. And:

Originally Posted by SS-Traveller

No harm done whatsoever. One can use engine braking to retain control over the car over an infinite distance. Much more sense doing this, than using brakes!

Thank-you a million times for confirming this one. Seriously.

[Sutripta]

@SST: Next topic - DOHC engines => hitech racing engines.

[Lobogris]

Originally Posted by sanjeevgpc

I am sure that auto companies consider all the aspects before they recommend an oil change interval. They should be keeping some buffer and suggesting an oil change much before its actually required to cover instances where people forget a oil change in time.

Big engines, like used in aircraft and ships do not change their oil as often and most actually take a sample of oil and check that in labs to see if the oil has really gone bad. One such lab is http://www.blackstone-labs.com/

I think many of us change oil more frequently than actually required just because we have some kind of fear. Not sure taxi drivers who drive much more than us also do such so often changes and use the highest quality oils available.

Sadly we have started considering just the monetary cost of oil change and not the overall cost of damage to environment which is caused due to spent oils. A large portion of such oils actually goes down the drain and comes back to us in drinking water.

Hope some oil company will come out with a detailed report and article on how to really know if my car really needs an oil change.

I agree with you. There is bound to be some tolerance built in to the recommended intervals. At least 25% of the people are bound to forget the oil change interval and could go over by a few weeks or a few thousand kms. It is mostly fear factor that makes many people change their oil earlier than necessary. I would have no worries in exceeding the manufacturer recommended interval by 20% if my car is not suffering from some issue like burning or leaking oil. I am not suggesting that this should be made in to regular practice but there is no need to worry if one exceeded the interval once in a while.

[harikrishna.te]

Originally Posted by Aroy

Each start of the IC engine consumes some fuel. How much is that in equivalent minutes of idling is debated, but the general consensus is that stops more than a minute benefit from engine stop.

I have seen this measured on a turbo-charged diesel engine (a 16 T truck) and the results are fascinating. The experiment was done to convince truck drivers to switch off their engines when they stop for tea. Generally, they keep (or used to) the engine running for the 10-15 minutes they stop.

To quash the misconception, a fuel meter was fixed and different scenarios were simulated.

If the stop is more than 60 secs, shutting the engine off saves a lot of fuel. It took only a couple of milliliters of fuel to start the engine back again, but almost 30 milliliters to keep the engine running for one full minute. This will increase if there is additional load (and higher idling RPM).

As far as I have seen, turbo failures don't occur because of start-stop situations. They occur when the driver raises the engine RPM suddenly before he switches the engine off. The turbo reaches 150000 RPM but is starved of oil and consequently fails.