[chetanhanda]

Originally Posted by TURBOSAM

yes , many car manufacturers do provide either heated air intakes-- uno carb version has a thermostat which enables the engine to suck hot air from around exaust manifold automatically when the ambient temp is low! ----or heated throttle bodies_----palio 1.2 has heated throttle body

I think the concept of having heated throttlebody in fuel injection system is to prevent freezing of the TB and not for increasing the mileage.The manufacturers need to also consider the people living in colder parts of the world where it snows, they cant have ice forming on the bore of the TB due to chilled + hi velocity air being sucked in. Even Honda's have heated TB's but the main aim is to prevent ice forming inside the surface, the temp which we have in places where it snows + the combined effect of the cold air rushing thru the intakes will chill it further and cause ice to form, this will definately preven the butterfly valve etc in the TB from operating correctly.
In case of carb engines I think it maybe something do with the air and fuel to mix correctly as the both the air+fuel comes via the TB, hot air helps mix the fuel better.

In case of MPFI the injectors add the fuel later on in the intake runner so the effect of heated TB will not be felt unless the TB is heated red hot to make a diff. The air is anyway rushing in at such high speeds , it will be in contact of TB for a very short period of time ..few milliseconds before proceeding to the intake plenum, if the TB needs to heat the air to a decent level to make a diff it needs to be super red hot or make the air travel in the TB for a longer loop to make a diff. And anyways the engine coolant is not that hot to indirectly heat the TB which will then heat the air within a few milliseconds and keep it hot enough till it reaches the injectors. Plus the injectors will be spraying atomised fuel which will then totaly canel out the effect of the "coolant heated TB".

The only reason they have heated TB's is to prevent the icing in the bore of the TB which will affect moving of the butterfly valve in cold weathers...

(Some people , if they want more power will ask why not remove the coolant line to the TB for having cooler air, I think it will be hardly noticeable even on a dyno as the "heat soak" of the engine will be good enough to cancel out effects of the coolant bypass, it will be tough to have repeatable runs to even notice this mod)

[chetanhanda]

Originally Posted by anupmathur

Very difficult for a lay person to decide.

The person is not a lay person anymore as the person is on TBHP who is genuinely interested and has done some amount of reseach into this- he is inspired enough to join a forum and ask the questions, his intention is pretty clear , he doesn't want to be an average Joe.So definately if he gets some suggestions Im sure he will get it, its a matter of experience

Originally Posted by anupmathur

Too many people are driving at too low rpms in too high a gear and getting bad FE figures. The engine is being operated in it's 'inefficient' range from the FE viewpoint/specific fuel consumption viewpoint. Solution? For the Average Joe: the middle path, courtesy Gautam Buddha!

If they get bad FE with low rev+tall gear combo the problem is with the engine not with the driving style.If the engine is fine the mileage will be better with this style.
You dont vary the parameters by bringing in stuff like bad engine, punctured tyres, pulling a trailer etc.

Obviously if the wheels have fallen of and he is using this drving style he will not get a good mileage.
Now my question to you is : Should he take the middle path or the sensible TBHp path - repair his car and drive with low rev+tall gear possible without straining the engine ?

[anupmathur]

Originally Posted by chetanhanda

without straining the engine ?

IMHO, this IS the tough part for people to figure out.

[musicmanaman]

I get lower mileage driving the Maruti recommended way, that is shifting at 10,20,30,40 etc, and get a higher mileage when I rip a little, this has left me a little confused.
These are my observations on my 99 carb zen. So now I try and enjoy driving as I get better mileage if not the same, then when I was driving in the economy mode.

[anupmathur]

Originally Posted by musicmanaman

I get lower mileage driving the Maruti recommended way, that is shifting at 10,20,30,40 etc, and get a higher mileage when I rip a little, this has left me a little confused.
These are my observations on my 99 carb zen. So now I try and enjoy driving as I get better mileage if not the same, then when I was driving in the economy mode.

Exactly! Which I why I had put up this post earlier:

Originally Posted by anupmathur

Too many people are driving at too low rpms in too high a gear and getting bad FE figures. The engine is being operated in it's 'inefficient' range from the FE viewpoint/specific fuel consumption viewpoint.

[gemithomas]

Just found thse specifications for the FIAT Adventure 1.6

Gear km/h
1 7.7
2 13.95
3 20.34
4 26.85
5 33.55


5th Gear at 33km/hr!!! Isnt that a little too low?

[anupmathur]

Gemi, why, may I ask, are you suddenly posting in Greek?
Please translate and post this one back in English!

[TURBOSAM]

Originally Posted by chetanhanda

To get best mileage u need to drive with the lowest rpm in the tallest gear possible.

I dont know why everyone is searching for torque curves ? You dont need to see a torque curve chart in order to understand when to shift gear for best mileage... Just see how low you can allow the speed to drop without stressing the engine, after a few minutes of experimenting u get the feel of the engine as to how low the gearing will allow u to go.

Even if u are driving the car for the 1st time - shift to 4th and leave the throttle, let the revs drops, then try to see how comfortably the engine picks up with mild throttle just enough to keep the car cruising along... then just stick to that throttle input.

For long flat stretches/freeways try it with your overdrive and for city try with everything apart from overdrive.simple.

You need minimum the torque if u want max mileage, in terms of gear ..think of it as higher/taller gears with lowest rpm give best mileage..

its so simple.
just keep in mind , if u are driving better programmed ecu equipped car ,then dont press the accelerator more than 30-40% of the full range. other wise it will go in open loop <no cross checking the fuel strength by ecu with the help of lambda reading>and then u end up with considerably rich mode<power mode>
if u are driving a carb version then there is no close loop possibility , so wider the throttle more the ventury opening . easier the breathing for the engine-higher the VOLUMETRIC efficiency at the same rpm<+lesser parasitic pumping losses too>

[gemithomas]

Originally Posted by anupmathur

Gemi, why, may I ask, are you suddenly posting in Greek?
Please translate and post this one back in English!

So sorry. Did not notice that the alignment had gone haywire.

THis is the Speed at each gear that is recommended. GOt it from an old website when the adventure 1.6 was launched.

Gear_________ km/h
1 _____________ 7.7
2 _____________ 13.95
3 _____________ 20.34
4 _____________ 26.85
5 _____________ 33.55

I tried this out. And guess what you would be changing gears just below the 1500 rpm mark. And you wont feel that the engine is strained unless you are fully laden or you are going up a slope. Guess thats how turbosam manages to get these astonishing figures from the FIAT 1.6-es. But its quite difficult. You need to get used to such sedate driving. Turbo SAm. Is this your secret style of Driving?

On the other part. I read another thread where it is suggested that you zoom up in full speed till you reach the 5th gear. THe claim was that by doing so you are in the lower F.E mode for the least time and thus efficiency figures can be maximised. For example if you shift ot 5th at this 33.55 kmhr. You will be pressing the accelerator for much more time till you reach around 60km/hr and then only you might be driving with minimal acceleration. But in the other case we just zoom to 60 in seconds and then use minimum acceleration. Well That too seems sensible

[chetanhanda]

Originally Posted by gemithomas

So sorry. Did not notice that the alignment had gone haywire.

THis is the Speed at each gear that is recommended. GOt it from an old website when the adventure 1.6 was launched.

Gear_________ km/h
1 _____________ 7.7
2 _____________ 13.95
3 _____________ 20.34
4 _____________ 26.85
5 _____________ 33.55

I tried this out. And guess what you would be changing gears just below the 1500 rpm mark. And you wont feel that the engine is strained unless you are fully laden or you are going up a slope. Guess thats how turbosam manages to get these astonishing figures from the FIAT 1.6-es. But its quite difficult. You need to get used to such sedate driving. Turbo SAm. Is this your secret style of Driving?

On the other part. I read another thread where it is suggested that you zoom up in full speed till you reach the 5th gear. THe claim was that by doing so you are in the lower F.E mode for the least time and thus efficiency figures can be maximised. For example if you shift ot 5th at this 33.55 kmhr. You will be pressing the accelerator for much more time till you reach around 60km/hr and then only you might be driving with minimal acceleration. But in the other case we just zoom to 60 in seconds and then use minimum acceleration. Well That too seems sensible

5 gear _____________ 33.55 kmh
is this realistic ? is this possible ?

[chetanhanda]

Originally Posted by TURBOSAM

its so simple.

right ..exactly what Im saying.. its so simple
just learn to listen to ur engine
people should just have patience and try to practice instead of going for torque curves..

[vivekiny2k]

Originally Posted by abhibh

Now i am confused. Check this
http://www.team-bhp.com/forum/226145-post32.html

and http://www.team-bhp.com/forum/techni...l-right-5.html

no need to be confused. we are discussing two different points.

make up your mind whether you want to squeze last bit of mileage from the car, or have a regard for your safety.

EDIT: if you are very good at undrstanding, and listening to your machines, you can actually strike a fine balance.

[chetanhanda]

Originally Posted by anupmathur

IMHO, this IS the tough part for people to figure out.

Originally Posted by gemithomas

THis is the Speed at each gear that is recommended. GOt it from an old website when the adventure 1.6 was launched.

Gear_________ km/h
1 _____________ 7.7
2 _____________ 13.95
3 _____________ 20.34
4 _____________ 26.85
5 _____________ 33.55

Thats where the problem lies.
1st step is try and figure it out and not look at charts/tables from some websites on when to change gears.
Without even trying to learn to hear/feel the engine people want mileage by following torque charts which is again going in wrong direction.
(here we go again anupmathur .. Im going in loop again )

People want to follow charts from some website but not try and hit the road and understand their engine.

they will need multiple tables on when to shift gears at what speed for the following :
just a list of tables they should require instead of just one ..
1] going up a slope +good fuel
2] going up a slope +bad fuel
3] going down a slope +good fuel
4] going down a slope +bad fuel
5] straight road +good fuel
6] straight road +bad fuel
7] going up a slope +good fuel +very hot temperature
8] going up a slope +bad fuel +very hot temperature
9] going down a slope +good fuel +very hot temperature
10] going down a slope +bad fuel +very hot temperature
11] straight road +good fuel +very hot temperature
12] straight road +bad fuel +very hot temperature
13]..
14] straight road +bad fuel +very hot temperature + no passengers+no luggage etc etc etc..
...
.....
10012212]..
10012213]..
10012214]...
.....

I can just keep going on and on

[anupmathur]

Originally Posted by anupmathur

Yes, it would be good to judge by the sound. Try to develop a sense for where the engine sounds 'happy' or is 'singing'! Engines actually almost 'talk' to you.

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[chetanhanda]

Originally Posted by anupmathur

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