Re: ARTICLE: Mechanical Empathy | Preserving the Car While Driving Quote:
Originally Posted by a4anurag Good to see the practice put in place to save the brakes. IIRC you drive a Beat D. Right?!The engines which we drive have been put to much higher stresses and load conditions before they are actually produced for the mass market. Though FE will drop slightly but wear and tear will not be a problem but it depends on the frequency you do this and also the gear:speed relation that witnesses the RPM blip.
I did try the downshift in my Swift ZDi after reading your query.
80kmph @ 5th gear was at 2000 so downshift to 4th gear yob the RPM to 2500 which is fine. When I downshift near 1500 - 1600 RPM, the resultant RPM is near 2100 which is in the peak turbo range anyway.
I advise you to downshift when the RPM drops near 1500, so the resultant RPM will be near 2100 - 2200 which is fine. 3500 - 4000 RPM is harmful but anything near 3000 is fine. Not alarming at all but it all depends how frequently you do it. Load wise no problem but FE will drop slightly.
Apologies for not understanding your real question.
Slowing down from 50 kmph to 5 kmph in 4th gear will kill the engine. Every gear has a designated speed in which it will be comfortable to drive on.
I am giving the gear and speed for my car - Swift ZDi:
0 - 20 kmph = 1st to 2nd
20 - 35 kmph = 2nd to 3rd
35 - 50 kmph = 3rd to 4th
50 - 60 kmph = 4th to 5th
All of the above are we've the RPM is at 2000 where I upshift. Coming to downshifting, I do when the RPM drops to 1600.
Follow the above and you shouldn't be in a problem.
Hope it helps. |
Thanks for the tip Anurag !! I drive a Beat Petrol.
Will see if I can reduce the RPM to the 1500 range.
The idling of my car is ~900. It pulls ahead without Acc input at 900.
So at 1500 it can still pull in 5th gear. Infact today I slotted into 5th gear at 1000 and it went smooth.
The issue is while slowing down. I will see if I can get to 1500 before I hit the brake or get near the hump. May be my braking distance calculation has to be improved. Quote:
Originally Posted by SS-Traveller No harm to engine, even if revved to the redline for a few seconds. The shock is being taken up by the clutch - so clutch wear is likely. Letting out the clutch hard may damage the clutch otherwise than simple wear. In any case, why downshift at 1800 rpm? You are in the "rev band" of the engine, and it'll pull out well from that rpm. Allow the rpm to drop below 1500 as Anurag said... |
Thanks SST for the inputs. The clutch wire, plate, etc (the entire mechanism) is in good condition for my car.
In Feb this year, I had a problem of a ring sound coming whenever I accelerated.
The Chevy A.S.S people diagnosed a lot and tried a lot to adjust the clutch but it didn't go. They said that the clutch plates may have gone, so wanted to replace it. So when they opened up, they saw the clutch plate was perfectly fine for my 24k driven Beat. So they replaced the entire mechanism under warranty. So now I have a new clutch mechanism and the ring sound has also gone. So now I can say that the clutch is new and should behave well with the engine praking practice. Have to see in the long run if it gets affected. Quote:
Originally Posted by a4anurag I guess the lowest RPM should be between 1200 - 1300 to prevent lugging.Anurag. |
My Beat Petrol moves ahead without Acc input in 1st gear at 900. Quote:
Originally Posted by thoma This is called downshift, you up-shift to a higher gear not lower.
As SST rightly pointed out, downshifting to a very high RPM is going stress your clutch. FE is not an issue as most cars now have a cut-off. It is specifically mentioned in my Micra Owners's Manual not to over-rev while shifting to a lower gear to avoid engine damage. |
Err, my bad. Got confused with the terms upshift and downshift.
Makes me little relived to get to know that FE wont be impacted much due to the fuel auto cut off mechanism. |