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Old 18th June 2007, 10:39   #31
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ScarySkulls, I feel 5.5J are pretty big for Alto....U should not go over 5J...

Abhi
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Old 18th June 2007, 10:46   #32
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Surely will as soon as I have enough finances.
But still. Come to think of it. There is a limit to how much can fuel economy be ruined by increase in unsprung mass. (5J v/s 5.5J)

Anyways. Going to the MASS now.
Will update
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Old 18th June 2007, 11:13   #33
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Nah 5.5 wont make this much difference in fe its just .5 inch.. There is something else that is wrong with the car..

BTW did ya asked your bro. what FE he used to get ???
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Old 18th June 2007, 11:40   #34
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Quote:
Originally Posted by ScarySkulls View Post
There is a limit to how much can fuel economy be ruined by increase in unsprung mass. (5J v/s 5.5J)
The additional weight could be a factor, considering that you have gone from 4J to 5.5J, although alloys are lighter than steel rims. But the main reason for loss in FE would be the wider contact patch that would ensue with 5.5J rims. The reason is that with 5.5J rims, there will be appreciably less sidewall bulge as compared to the 4J rims, which in turn increases the width of the tyres in contact with the road. With grippy Michelin tyres, the increased contact patch could bring down FE due to additional rolling friction. I think 4.5J would be optimal for Alto with the 155/65 tyres.

I have the stock 155/70 R13 tyres with 5J alloys in my Santro and my tyres look as wide as those of a Santro with 165/65 R13 tyres on stock 4J rims (which leads to appreciable sidewall bulge). I have actually checked this out. In my case the FE seemed to come down by 0.5 km/lit after the switch to alloys. But after the recent engine tuneup + injector cleaning + engine carbon cleaning + AC service by Hyundai, the FE had gone up from 11 km/lit to 13. Pickup is also good.
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Old 18th June 2007, 11:46   #35
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Exactly rks, as you said your mileage is back to normal. Mileage will really not go down so much with the tyres.

The energy's aren't grippy performance tyres but comfort tyres. The rolling resistance doesn't depend on just the rubber. It is various other factors like the tread design. Also the XM1 are meant to increase mileage as they have a lower rolling resistance.
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Old 18th June 2007, 14:10   #36
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Something is wrong with the car i can say that

I have 185 65 r13 on my alto

the pick up has come down and the handling has improved i have been using this combination for almost 3.5 years

and the car is almost 5 years old and has done about 1.60lacs km

and the FE i get from the car in the city is about 15+ without a/c and i must say i have a heavy foot but my drivers have manage 18+ in city
and with a/c i get a constant 13 but if i drive normally i get around 14+ with a/c
and the highway figures are just plain impressive without a/c the car gives as much as 23 and the best ever is a 24 by my driver and with a/c it still manages to get around 20+

so in the end their is something wrong with the car

ps my rim are 5j and i maintain a constant 32 psi in my tyres

Last edited by manikjeet : 18th June 2007 at 14:11.
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Old 18th June 2007, 17:00   #37
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Back from the MASS.

Engine was checked using the OBD checker. All values normal. Airfilter was clean. Spark plugs showed sign of a perfect mixture with light brown colour.
Then the wheels were taken off and brakes cleaned and pads/shoes given a light rub with emery paper.
Rear drum was really very dusty and is was thoughly cleaned and spring inspected for proper play.

Then went to the petrol pump for a mileage run. Tanked up (which comparing with the last tankup means an Avg of 11kmpl in city WITHOUT a/c or heavy traffic and very light foot)

Then went on a highway run with the mechanic. 22kms run back and forth at constant 60kph in top gear.
Came back, and refilled from the same bunk. This time not even a complete litre went in. 0.66L to be exact.....lol. Even the mechanic was amazed now!

Damn! Could it be a sticky handbrake earlier?
And what to do with this preposterously odd mileage figure from the test run?

This is getting interesting by the day. Will keep updating you.

Last edited by ScarySkulls : 18th June 2007 at 17:04.
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Old 18th June 2007, 17:24   #38
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Quote:
Originally Posted by ScarySkulls View Post
Then went on a highway run with the mechanic. 22kms run back and forth at constant 60kph in top gear.
Came back, and refilled from the same bunk. This time not even a complete litre went in. 0.66L to be exact.....lol. Even the mechanic was amazed now!
don't go by that figure at all

fill it upto the top. not till the auto cut, but till it visibly fills up to the neck. now run the car for around 200 kms and then again fill up to the neck from the same pump. now check the FE.

you should get some data after 4-5 days from now.
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Old 18th June 2007, 17:29   #39
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Quote:
Originally Posted by ScarySkulls View Post
Then went on a highway run with the mechanic. 22kms run back and forth at constant 60kph in top gear.
Came back, and refilled from the same bunk. This time not even a complete litre went in. 0.66L to be exact.....lol. Even the mechanic was amazed now!

Damn! Could it be a sticky handbrake earlier?
And what to do with this preposterously odd mileage figure from the test run?

This is getting interesting by the day. Will keep updating you.
Dont worry, drive for another 100-150km and check ur mileage...I am sure ur problem will be solved now... Probably the brakes were the culprit...

Abhi
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Old 18th June 2007, 18:22   #40
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Quote:
Originally Posted by ScarySkulls View Post
When about to start trip, Tank up. That means 35 Litres now in the tank. Set trip meter to Zero.
After the trip, tank up again and divide the no. of kms shown by the trip meter with the amount of fuel that goes in.

Fairly Simple. Isnt it?
I think you have to divide the tripmeter reading by ( 35litres - amount of fuel that goes in after the trip) to get the kmpl.
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Old 18th June 2007, 19:08   #41
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Quote:
Originally Posted by ScarySkulls View Post
Came back, and refilled from the same bunk. This time not even a complete litre went in. 0.66L to be exact.....lol. Even the mechanic was amazed now!

Damn! Could it be a sticky handbrake earlier?
And what to do with this preposterously odd mileage figure from the test run?
If it were a stuck handbrake your handbrake lining would have gone for a toss. If your handbrakes are still working, we can rule that out. Plus if the metallic grinding sound that you heard was from worn-out brake pads, that should have shown up during the check and you should have heard the sound whenever you applied the brakes.

As Zappo pointed out, you need to check the mileage with normal driving over a tank-full of fuel (filled up to exactly the same point; do not rely on auto cut-off). For example, if a slow puncture were to be the culprit, it would take effect only over a period of time, not in a short test drive.

Last edited by rks : 18th June 2007 at 19:11.
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Old 18th June 2007, 19:22   #42
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13.5 KMPL is too low for Alto. My Swift gives me around 16.3 KMPL with AC on for 75% of the time and fully loaded with 5 passengers and luggage
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Old 18th June 2007, 19:23   #43
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Quote:
Originally Posted by squarecut View Post
I think you have to divide the tripmeter reading by ( 35litres - amount of fuel that goes in after the trip) to get the kmpl.
The amount of fuel that goes in = amount of space left in the tank.

Where did that space come from? Obviously from the fuel used during the trip.

Makes sense? Or I need to review my method of calculation?
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Old 18th June 2007, 19:25   #44
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Quote:
Originally Posted by rks View Post
If it were a stuck handbrake your handbrake lining would have gone for a toss. If your handbrakes are still working, we can rule that out. Plus if the metallic grinding sound that you heard was from worn-out brake pads, that should have shown up during the check and you should have heard the sound whenever you applied the brakes.

As Zappo pointed out, you need to check the mileage with normal driving over a tank-full of fuel (filled up to exactly the same point; do not rely on auto cut-off). For example, if a slow puncture were to be the culprit, it would take effect only over a period of time, not in a short test drive.
Good point.


Anyways, Didnt rely on fuel cutoff this time and had filled up till the absolute max the pipe allows.
Lets see.
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Old 19th June 2007, 12:03   #45
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Post I too get 12.5

I too get 12.5 to 13.5 in the city in my 04 alto lxi.Ac is sluggish with the ac being on all the time.I drive in the traffic daily.
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