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Old 29th November 2007, 15:33   #166
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Originally Posted by sathya_nars View Post
This is my opinion, others please correct me if I am wrong. For many cars, 1500 RPM is good to shift gear. This balances FE as well as engine's proper usage.

RPM tells how hard or soft engine is being worked at. Balancing it in right RPM optimizes the energy engine supposed to produce Vs actual. More strain put onto engine wastes fuel and hence FE reduces.
I'll put that as between 1500-1900 rpm since most cars deliver the tourque at higher rpms.


TurboSam: Will adding synthetic oil to the FIAT 1.6 engine help in omproved F.E figures. Which grade/brand do you suggest. Also is semi synthetic oil with changes every 15k km good enough as synthetic oil.

Last edited by gemithomas : 29th November 2007 at 15:35.
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Old 3rd December 2007, 09:17   #167
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Default hi gemi

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Originally Posted by gemithomas View Post
I'll put that as between 1500-1900 rpm since most cars deliver the tourque at higher rpms.


TurboSam: Will adding synthetic oil to the FIAT 1.6 engine help in omproved F.E figures. Which grade/brand do you suggest. Also is semi synthetic oil with changes every 15k km good enough as synthetic oil.
adding synthetic will definately help the best oil to use is mobil 1 -15w 50 not available in india second best will be 5w50 third best is 0 w 40 .. lower the first w no u go .. faster the light fractions evaporate from the oil.. in 1.6 engine around 500 ml will evaporate in 15000 kms .. if 5 w 50 is used in the same engine 1.5 lit of 0w40 evaporates in 15 k kms in hard driving..
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Old 18th December 2007, 21:04   #168
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Default pre heating the intake charge..

if we pre heat the charge<especially the fuel part ... the automisation will be greatly improved ... more power from the given amount of fuel...
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Old 19th December 2007, 13:35   #169
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1. While trying to stop the vehicle in known stops (speed brakers, lights, etc), what is advisable? Say, I am going in 80 Kmph in 5th gear, I try to shift down to 4th, 3rd and 2nd giving few sec's in each gear, without applying brake much - it works good but sometimes RPM goes upto 2500 to 3000. Will it affect engine in long run?
2. In such cases, what is advisable to keep good balance between engine life and FE (without applying brake much, trying to use engine braking)?
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Old 19th December 2007, 18:25   #170
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1. It definitely puts more stress on the engine and gear box however your brakes will last longer. However you lose fuel (if you drive a carb engine).
2. Since you are talking of known obstacles (lights etc), it is advisable to shift to neutral from 5th gear well in advance and slowly apply brakes. This will save a lot of stress on the engine and gearbox. But beware that your stopping capabilities are affected adversely upon shifting to neutral
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Old 14th January 2008, 18:11   #171
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Default please avoid the repetation of the contents

hi, dont want to point out anyone specific ... as far as possible ... avoid repetation of posts/ contents!
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Old 14th January 2008, 18:28   #172
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My friend lives in Calcutta. Drives an Aveo UVA. Normally in the city he gets 10-11 kmpl. Last Sunday, he participated in a mileage rally organised by GM for Chevy owners.

It was a 50 km circuit, with very light traffic. He drove non-stop, at 40-45kmph on the 5th gear and when they measured the fuel used, it worked out to 25+ kmpl. My friend was ecstatic.

In the evening, he went for the prize distribution sure to win a prize. The winner in the UVA class got over 30. This guy was devastated. 2nd and 3rd prize winners all got more than he had managed.

When he went up to the winner later and asked for some hints and strategies, the answer was such an anticlimax, he is yet to come to terms with it.

The winner's strategy was simple. Start the car, and quickly get to 60kmph. Then shut off the engine and coast till things get too slow.
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Old 14th January 2008, 18:42   #173
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Originally Posted by prabuddhadg View Post
The winner's strategy was simple. Start the car, and quickly get to 60kmph. Then shut off the engine and coast till things get too slow.
man ***!

All the power in car will loose power steering wont work, breaks wont work what if something comes in front ???

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Old 14th January 2008, 18:46   #174
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Default the valve timing & its effect on engine efficiency..

the valve timing and its effects on engine cycle..
1>some deg of valve overlapping reduces the pumping losses..(lesser negative work)--but if designed wrongly then the fresh charge is lost through exhaust valve
opening the exhaust valves later(extended power stroke.. more +ve work ) help extract more power from the same fuel---increased fuel economy--
3>opening inlet valves earlier reduces pumping losses...(lesser negative work)--- increased fuel economy--
4>closing inlet valve later while still maintaining the final compression perssure...( its atkinson cycle...expansion stroke is longer than compression stroke)... gives more power in the amount of fuel used.. though the total power output is lesser..) ---increased fuel economy--
5> when max power is demanded ..high engine speeds+high loads..intake valve closing timing is retarded to synchronize the intake pulsation for larger intake volume..(more power from the same engine)..increased volumetric efficiency..
6> under hi load +low speed conditions.optimum torque delivery will be assured by intake valve closing timing advanced to ensure sufficient air volume(higher volumetric efficiency) at the same time ex valve opening timing retarded to to provide higher expansion ratio(higher mechanical efficiency)
7> at idling valve over lapping should be eliminated to super stable idling by stabalizing the combustion..
complicated.?. right..? . so unless we have a variable valve lift+variable valve duration + variable valve event<phasing> mechanism controlled by e.c.u. +ignition curves plotted for each of the 7 above mentioned working conditions + knock sensor to assist the e.c.u. to have a mechanical feed back+a wide band 4 wire lambda sensor to provide a chemical closed loop feed back... WE WILL BE LEFT WITH THE COMPROMISES!!!
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Old 14th January 2008, 20:08   #175
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Default yes! its as per the rules!!

in milage marathon following things are to be followed
1>u are given x amount of rated, tested and measured fuel ..
2>engine can me running or stalled.. car has to clock max kmpl in given fuel .. AVERAGE SPEED SHOULD BE MORE THAN 28-35 KMPH depends upon the organiser..
in std cars people have achived more than 250 kmpl...
  • Did you know that the current European Shell Eco-marathon record for a combustion engine entry was set in 2004 by the team from Lyce La Joliverie (France) at 3,410 km on the equivalent of a single litre of fuel.For prototype vehicles using fuel cells, the record is even more impressive. In 2005, the hydrogen-powered vehicle built by Swiss team ETH Zurich achieved a projected 3,836 km on the equivalent of a single litre of fuel. This is the equivalent of driving from Paris to Moscow
i personally have achived following figures without cutting off the engine, without coasting in neutral or without coasting while clutch is pressed.
speeds were @80-110 kmph.while customer is sitting next to me !
to and fro on the same roads to even out the road slope effects including ghats!
1>palio 1.2<72 bhp> non NV 2 kmpl without a/c .. 2 people on board
2>palio 1.6 gtx<100 bhp >18 kmpl in a/c .. 2 people on board
3>petra 1.9 d 30.63 kmpl in non a/c 5 people+50 kg dead weight in trunk
4>petra 1.6 16kmpl in a/c 2 people on board.
5>palio stile 1.1 21.4 kmpl in a/c speed not to be dropped below100kmph 2 people on board.
6> m 800 mpfi 5 speed 28 kmpl ina/c 2 people on board+ some traffic too





Quote:
Originally Posted by prabuddhadg View Post
My friend lives in Calcutta. Drives an Aveo UVA. Normally in the city he gets 10-11 kmpl. Last Sunday, he participated in a mileage rally organised by GM for Chevy owners.

It was a 50 km circuit, with very light traffic. He drove non-stop, at 40-45kmph on the 5th gear and when they measured the fuel used, it worked out to 25+ kmpl. My friend was ecstatic.

In the evening, he went for the prize distribution sure to win a prize. The winner in the UVA class got over 30. This guy was devastated. 2nd and 3rd prize winners all got more than he had managed.

When he went up to the winner later and asked for some hints and strategies, the answer was such an anticlimax, he is yet to come to terms with it.

The winner's strategy was simple. Start the car, and quickly get to 60kmph. Then shut off the engine and coast till things get too slow.
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Old 14th January 2008, 21:32   #176
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Quote:
Originally Posted by TURBOSAM View Post
adding synthetic will definately help the best oil to use is mobil 1 -15w 50 not available in india second best will be 5w50 third best is 0 w 40 .. lower the first w no u go .. faster the light fractions evaporate from the oil.. in 1.6 engine around 500 ml will evaporate in 15000 kms .. if 5 w 50 is used in the same engine 1.5 lit of 0w40 evaporates in 15 k kms in hard driving..

Just a few doubts. FIAT recommends 15W40. What will be the adverse effects and advantages of shifting to
1)5W40
2)5W50 (is it actually advisable to shift from the recommended '40' value to a '50'??)
3)0W40

WOuld really appreciate your help on this.
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Old 15th January 2008, 09:58   #177
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MODS: SLightly Out of topic for this thread but just wanted to have the continuation.

Here is what i have understood about engine oils. I now doubt why our manufacturers specify certain grades. I think it has got more to do with the ability of the seal ad plastics used to deal with low viscosity oils. From what i have read i understand that the lower the viscosity the better for the engine since oil flows much more faster. I mean, a 0W20 oil would lead to much lesser wear and tear than a 5W40 oil. I think another disadvantage would be that the lower viscosity might lead to much higher levels of oil loss and thus leading to more frequent top up requirements. Probably this could be another reason for manufacturers specifying grades which might be also bassed on the servive intervals recommended by them.

FIAT recommends 15W40 for the 1.6 engines. My question is would it be best for our engines if we fill 5W30 and top it up more frequently based on the oil loss. WOuldnt the low viscosity reduce the stain on the engine and this should also help in impriving F.E figures along with keeping the engine lesser prone to wear and tear.

Why do you recommend a 5W50 rather than a 5W40??

Please go through the article below.
"Viscosity of an engine oil represents its resistance to flow. The higher the resistance the higher the viscosity. In other words, given a specific opening, the lesser time a given quantity of oil takes to flow through the lower is its viscosity and vice versa. This would mean that a 10W oil would flow faster than a 40W oil It is common sense that temperature has an effect on the thickness and viscosity of oil. Thus considering the high temperature variations in operating an engine we all use multi grade oils. [/FONT][FONT=Verdana]Multigrade oils work by having a polymer added to a light base oil which prevents the oil from thinning too much as it warms up. At low temperatures, the polymers are coiled up and allow the oil to flow as it's low number (W number) indicates. As the oil heats up, the polymers unwind into long chains which prevent the oil from thinning as much as it normally would. The result is that at 100C, the oil has thinned only as much as it's higher rating. Think of it like this: a 10W30 oil is a 10-weight oil that will not thin more than a 30-weight oil when it gets hot. The higher the viscosity index, the less an oil will thin at a specified temperature.

The API/SAE designation for multi-grade oils includes two grade numbers; for example, 10W-30 designates a common multi-grade oil. Historically, the first number associated with the W (again 'W' is for Winter, not Weight) is not rated at any single temperature. The "10W" means that this oil can be pumped by your engine as well as a single-grade SAE 10 oil can be pumped. "5W" can be pumped at a lower temperature than "10W". "0W" can be pumped at a lower temperature than "5W", and thins less at temperatures above 99C (210F). The second number, 30, means that the viscosity of this multi-grade oil at 100C (212F) operating temperature corresponds to the viscosity of a single-grade 30 oil at same temperature. The governing SAE standard is called SAE J300. This "classic" method of defining the "W" rating has since been replaced with a more technical test where a "cold crank simulator" is used at increasingly lowered temps. A 0W oil is tested at -30F, a 5W at -25F and a 10W is tested at -20F. The real-world ability of an oil to crank in the cold is diminished soon after put into service. The motor oil grade and viscosity to be used in a given vehicle is specified by the manufacturer of the vehicle (although some modern European cars now make no viscosity requirement), but can vary from country to country when climatic or mpg constraints come into play. Oil circulates through the piston oil rings to cool and lubricate the compression rings. Inside gasoline engines, the top compression ring is exposed to temperatures as high as 500F. "

Hoping to get some good insights.

Last edited by gemithomas : 15th January 2008 at 10:03.
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Old 18th January 2008, 20:54   #178
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Quote:
Originally Posted by TURBOSAM View Post
in milage marathon following things are to be followed
1>u are given x amount of rated, tested and measured fuel ..
2>engine can me running or stalled.. car has to clock max kmpl in given fuel .. AVERAGE SPEED SHOULD BE MORE THAN 28-35 KMPH depends upon the organiser..
in std cars people have achived more than 250 kmpl...
  • Did you know that the current European Shell Eco-marathon record for a combustion engine entry was set in 2004 by the team from Lyce La Joliverie (France) at 3,410 km on the equivalent of a single litre of fuel.For prototype vehicles using fuel cells, the record is even more impressive. In 2005, the hydrogen-powered vehicle built by Swiss team ETH Zurich achieved a projected 3,836 km on the equivalent of a single litre of fuel. This is the equivalent of driving from Paris to Moscow
i personally have achived following figures without cutting off the engine, without coasting in neutral or without coasting while clutch is pressed.
speeds were @80-110 kmph.while customer is sitting next to me !
to and fro on the same roads to even out the road slope effects including ghats!
1>palio 1.2<72 bhp> non NV 2 kmpl without a/c .. 2 people on board
2>palio 1.6 gtx<100 bhp >18 kmpl in a/c .. 2 people on board
3>petra 1.9 d 30.63 kmpl in non a/c 5 people+50 kg dead weight in trunk
4>petra 1.6 16kmpl in a/c 2 people on board.
5>palio stile 1.1 21.4 kmpl in a/c speed not to be dropped below100kmph 2 people on board.
6> m 800 mpfi 5 speed 28 kmpl ina/c 2 people on board+ some traffic too


You did a 16 in a Petra 1.6?! Man you are amazing! I once did a 15+ in my Petra on the highway, but then I discovered the roar at 4000rpm and have never done over 13.
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Old 18th January 2008, 22:06   #179
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Hi TURBOSAM,

Its so good and pleasure to read your detailed posts...

Now about increasing FE we have hot air intake and/or fuel preheating methods available which also increases power as most of fuels gets vapourized & gives useful mechanical output which is against the conventional thinking of having colder air giving more power & FE....I remember many of our members never agreed on that part...

Will you please share your ideas how hot air/pre heated fuel increases the efficiency of an IC engine?

Does using hot air intake for more FE is against the low of physics and themodynamics?

Complete vapourization of fuel is the key to improve FE together with many other techniques...
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Old 26th January 2008, 12:53   #180
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Default welcome ,fine tuning!

heating the intake charge has many benifits.
when the charge travels at speed at low pressure ,
the temperature drops drastically.. this ..cold/chilled charge when enters the combustion chamber ,
it absorbs a lot of heat from the cylinder walls,and the cumbustion chember.
still the temperature is much lower than the ideal.when the charge is compressed it gets hot but not much... then the spark occurs!
the pressure starts to rise and this pressure <force on the piston multiplied by the surface area of the piston >pushes the piston down .
hotter the in coming charge.. BEFORE COMPRESSING... higher/ earlier the pressure will rise after the combustion.
as we are pre heating the intake charge by utilizing the otherwise wasted exhaust heat .. we are in a way re cycling some of the heat,
when the incoming charge absorbs the heat from the cylinder walls and combustion chember it over cools the components..
and lot of thermal energy .. produced by the combustion is used to re heat it ....MAKING THE EXPANSION STROKE LESS EFFICIENT THERMODYNAMICALLY.
WE ALREADY LOOSE @ 33 to 40 % of heat energy in exhaust gases and additionally @33 to 40 %heat energy in cooling .
that too in very good engines running at oprating temperatures , at wide open throttles and at full load.
so at normal oprating conditions we hardly get @ 15% of the thermal energy comverted in useful energy.
hotter the charge, lesser the heat it will be absorbing from the engine components,coolent and engine oils.
so faster the optimum temp achived..
leading to lesser frictional losses ,lesser mechanical wear and tear.
hotter the air fuel mixture better the chemical environment
<more the successful marriages between fual atoms and o2 atoms>
leading to more complete combustion
leading to more energy FROM THE SAME AMOUNT OF AIR AND FUEL!
some additional tech jorgon..
even though the expansion stroke of the crank is to be 180 degrees.
the cam opens the ex valve @ 30-40 deg before the bottom dead centre .
so resulting expansion stroke becomes 180-40=140 degrees only
its the torque which ruens the wheel,,
torque is force on the piston multimlied by the perpendicular distence
< between the centre lines of crank chaft and the crank throw- big end>
the angle is 10 deg when the pressure wave strikes the piston rises to 90 deg and then comes back to 180 at bottom dead centre.
more the linear pressure build up in the upper range of the stroke .. more the torque..
as when piston decends , the pressure drops but the angle is increasing lengthening the distences between the centrelines!
this helps increase the torque.
warmer the in coming charge. lesser the initial time it will take to build up the pressure required to move the piston IN THE EARLY STAGE OF THE EXPANSION STROKE >

this will help gain in BRAKE MEAN EFFECTIVE PRESSURE<the rea indicator of engine >and gain more power in lesser fuel
added bonus is longer engine component lofe..
Quote:
Originally Posted by finetuning View Post
Hi TURBOSAM,

Its so good and pleasure to read your detailed posts...

Now about increasing FE we have hot air intake and/or fuel preheating methods available which also increases power as most of fuels gets vapourized & gives useful mechanical output which is against the conventional thinking of having colder air giving more power & FE....I remember many of our members never agreed on that part...

Will you please share your ideas how hot air/pre heated fuel increases the efficiency of an IC engine?

Does using hot air intake for more FE is against the low of physics and themodynamics?

Complete vapourization of fuel is the key to improve FE together with many other techniques...
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