How to reduce the Idle RPM

15th February 2005, 10:48

Hi,

Is any body reduced/changed the Idle RPM of diesel cars -- Indica,Indigo.

What are implications of reducing the rpm arounf 5% --apart from reduced fuel usage.

I observed with idle rpm , I can move the car on a horizontal road(without pressing the accelarator). So I think the Idle RPM is
high. Do the manufacturers, deliberately keep the Idle RPM little
high -- so that initial start would be easier.

Suryam

tabrez02 · 15th February 2005, 10:59

Dear Suryam

I would recomend NOT to change this setting. This is however called the timming adjustment in deisel indica. Whatever they set it in the service would be the ideal for indica as it depends on the various aspects. like when you switch on the A/C (if u have DLS and above) the RPM would reduce little cause of the load. So they always keep it on the higher side. This is what i have noticed in my X V2 Indica. Even sometimes when you switch on the headlights the rpm changes.

15th February 2005, 16:31

Quote:

Originally Posted by tabrez02

Dear Suryam

I would recomend NOT to change this setting. This is however called the timming adjustment in deisel indica. Whatever they set it in the service would be the ideal for indica as it depends on the various aspects. like when you switch on the A/C (if u have DLS and above) the RPM would reduce little cause of the load. So they always keep it on the higher side. This is what i have noticed in my X V2 Indica. Even sometimes when you switch on the headlights the rpm changes.

I do agree manufacturer will set higher limit to accomodate headlights, AC,etc(I have even observed if I swerve steering wheel, I do observe the rpm change).

My observation are:
If any of these are kept-on -- AC, headlight, steering wheel, rpm goes down(obviously because of higher load)

If any of these are kept-off -- AC, headlight, steering wheel, rpm goes up(obviously because of lower load)

The Idle rpm also goes up when temperature goes up -- as viscocity of oil is less at higher temps. When enigine is started from cold conditions, the rpm is lower(as oil visocity is higher)

So I was wondering, is there anybosy done some research on this area.

Rehaan · 18th February 2005, 10:56

Quote:

Originally Posted by Suryam

(I have even observed if I swerve steering wheel, I do observe the rpm change).

This is due to the powersteering pump running off the crankshaft.

R

Deeps · 19th February 2005, 17:16

Most of the reasons why not to reduce the rpm have been mentioned. Also, if u decide to lower the idle rate 5%, its possible that the technician may screw up and reduce it further than 5%. This could be very bad for the engine. Another thing is that even the manufacturers set the idle rate at the minimum while considering the extra load that the engine will have to tolerate. So it makes absolutely no sense to reduce it even further!

15th February 2005, 10:48	#1
Suryam Posts: n/a	How to reduce the Idle RPM Hi, Is any body reduced/changed the Idle RPM of diesel cars -- Indica,Indigo. What are implications of reducing the rpm arounf 5% --apart from reduced fuel usage. I observed with idle rpm , I can move the car on a horizontal road(without pressing the accelarator). So I think the Idle RPM is high. Do the manufacturers, deliberately keep the Idle RPM little high -- so that initial start would be easier. Suryam
	() Thanks

15th February 2005, 10:59	#2
tabrez02 BHPian Join Date: Nov 2004 Location: Bangalore Posts: 286 Thanked: 6 Times View My Garage	Dear Suryam I would recomend NOT to change this setting. This is however called the timming adjustment in deisel indica. Whatever they set it in the service would be the ideal for indica as it depends on the various aspects. like when you switch on the A/C (if u have DLS and above) the RPM would reduce little cause of the load. So they always keep it on the higher side. This is what i have noticed in my X V2 Indica. Even sometimes when you switch on the headlights the rpm changes. Last edited by tabrez02 : 15th February 2005 at 11:01.
	() Thanks

19th February 2005, 17:16	#5
Deeps Senior - BHPian Join Date: May 2004 Location: Delhi/Noida Posts: 1,119 Thanked: 170 Times	Most of the reasons why not to reduce the rpm have been mentioned. Also, if u decide to lower the idle rate 5%, its possible that the technician may screw up and reduce it further than 5%. This could be very bad for the engine. Another thing is that even the manufacturers set the idle rate at the minimum while considering the extra load that the engine will have to tolerate. So it makes absolutely no sense to reduce it even further!
	() Thanks