How to properly run in a new diesel engine?

Discussion in 'T&AA - Travel and Anything Automotive' started by Acroback, Dec 5, 2012.

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  1. Acroback

    Acroback RAID Rookie

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    I have a Diesel Duster 85 PS.
    So here is the deal.
    1. I upshift at 2K RPM most of the times.
    2. I drive at 80kmph in 5th gear mostly, but I keep varying the RPM till 2.5k rpm to reach 100 and then come down to 80.
    3. Also, I noticed a strange phenomenon post 500km mark on ODO. Earlier I saw engine doing 80kmph in 5th gear at 2k rpm, but now after 500Kms it does the same speed at same gear at 1850 rpm.
    Is this normal? Should be worried about this? Similar drop in rpm can be seen in lower gears too, except 1st I think. Will this speed gear rpm combo change further? Till when?
    4. Also, when I stop at signals, I do not switch off the engine because I do not want to bring down the temp of the engine. Is this the right way? When should I switch off engine in stop go traffic? Any handy tips?
    5. Another thing, when I move the gear in neutral waiting at a Red Signal, I noticed that during idling time there is rhythmic action engine takes and perhaps send tiny, very tiny amount of vibration to cabin. Mind you nothing moves an iota inside.
    Just that I can feel the feather light vibration while resting my hands on steering. This super minuscule vibration is rhythmic at interval of about 1.3 secs. is this normal? During driving this vibration goes away and I do not sense of feel any goddamn vibration inside.
    Please share your experiences.
     
  2. JD666

    JD666 RAID Leader Staff Member

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    I have a Diesel Duster 85 PS.
    So here is the deal.
    1. I upshift at 2K RPM most of the times.

    Ideal upshift points would be best given in the owner's manual, or if you have a power/torque curve of the engine. Upshift at such a point, that it drops your rpm in the higher gear, to the meaty band of the torque, so that you get maximum pull from the engine.

    2. I drive at 80kmph in 5th gear mostly, but I keep varying the RPM till 2.5k rpm to reach 100 and then come down to 80.

    Needed for the first 500-600 kms, after that drive it as you like.

    3. Also, I noticed a strange phenomenon post 500km mark on ODO. Earlier I saw engine doing 80kmph in 5th gear at 2k rpm, but now after 500Kms it does the same speed at same gear at 1850 rpm.

    That could be the clutch bedding in. Earlier there could have been a slight slippage since it was new, but now its gripping properly. Or it could just be an intermittent issue with the meter.

    Is this normal? Should be worried about this? Similar drop in rpm can be seen in lower gears too, except 1st I think. Will this speed gear rpm combo change further? Till when?

    Is normal, though will not change further. if it does, then needs to be looked into.

    4. Also, when I stop at signals, I do not switch off the engine because I do not want to bring down the temp of the engine. Is this the right way? When should I switch off engine in stop go traffic? Any handy tips?

    There are 2 conditions for this, One is optimum operating temperature and the other is keeping the engine within range. You can switch off at a traffic light which is 60 seconds or longer. However for a turbo engine, for the first few hundred kms, avoid doing this so that the turbo shaft beds in properly ( there are no bearings, only oil which acts as a fluid bearing ). Upon restarting make sure you don't gun the engine ( again if turbo ), and increase power gradually.

    5. Another thing, when I move the gear in neutral waiting at a Red Signal, I noticed that during idling time there is rhythmic action engine takes and perhaps send tiny, very tiny amount of vibration to cabin. Mind you nothing moves an iota inside.

    Joys of living with a diesel ( pun intended )

    Just that I can feel the feather light vibration while resting my hands on steering. This super minuscule vibration is rhythmic at interval of about 1.3 secs. is this normal? During driving this vibration goes away and I do not sense of feel any goddamn vibration inside.
    Please share your experiences.

    It's the vibration due to the low engine rpm at idling. Absolutely normal. Not felt in a petrol because of the lower compression ratio, there is lesser jerk to the piston, hence lower the vibration. Moreover a Diesel engine is inherently heavier than a petrol, so such vibes are amplified greatly.



    Also refer to this thread -

    How to maximize the fuel efficiency of your vehicle. Must read! Petrol is 75 bucks!! | RAID101[/quote]
     
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  3. Acroback

    Acroback RAID Rookie

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    Thanks JD666

    I have a query - What is the RPM range one should aim for during initial few kms? How do I know what RPM range to keep and the way to keep that range? Should I always aim for that rev range or it is ok if I occasionally reach upper echelons of the RPM range.

    e.g on highway drives, I avoid reaching 3K RPM( because my car does 100kmph at around 2.5K rpm and I do not go beyond 100kmph). But during empty stretches in city, I rev the engine to 3.5k RPM in 4th gear for a second or two and then bring it back to sane levels of 1500RPM-2000RPM.

    What is the right way to do it?
     
  4. JD666

    JD666 RAID Leader Staff Member

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    For this we need information like at what rpm is max power produced, and max torque. They are the first indications for shift points.

    for eg if you want maximum acceleration, your shift point would be around the max power produced mark, so that your vehicle gathers speed the fastest.

    if you want maximum pulling ability, and in return improving your fuel efficiency slightly, best point would be around the max torque mark, since a higher gear will put more load/strain on the engine, so if its in the optimum rpm, it will be able to pull better.

    Generically speaking, manufacturers keep this around the 2000 rpm mark ( good enough to upshift or downshift ), but when you drive practically sticking to it, you will find that it makes for really sedate driving.

    My suggestion would be first to tape a sticker over the tachometer, and see what feels right ( you are not over revving the car, or pulling it in a high gear at a low speed that makes the engine shudder ). Then remove the sticker and see your shift points. Go with instinct. If still you feel confused, then look for the power/torque values and then base your shift points on that information.
     
  5. Acroback

    Acroback RAID Rookie

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    JD666, sorry for external link.
    Here is the power to torque ratio for 85 ps model.
    Renault Duster : Official Launch Report - Page 51 - Team-BHP , look at post number 753.

    Surprisingly, the torque is available at lower gears too, no wonder there is nil turbo lag in 85 PS engine. It feels just like driving a Petrol :).

    if I understand the graph correctly, 3.5K RPM looks like the limit I should be aiming at.

    But still the question is HOW? What is the right way to do it? I am more interested in that.
     
  6. JD666

    JD666 RAID Leader Staff Member

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    Thats an impressive curve. You have most of the torque present between 1500-3000 rpm. So you could shift around 2000-2500 rpm and enjoy the power output, while keeping the engine revs in check, allowing for good mileage.

    How I would see it -

    When accelerating and having adequate open space to speed up, to rev till about 3000 rpm tops and upshift around that mark.

    If not enough space, and in traffic, 2200-2500 would be a a good mark to keep the acceleration steady.

    You could up shift the lower gears ( 1-2-3 ) at a lower mark ( 2200-2500 ), and then pull out 4th to upshit around 2700-2800.

    See it also depends on one's driving traits. I started learning on Suzuki engines and petrol only, so for me my habit is to pull each gear and enjoy the power build up. Then switched to Hyundai, and shifting became slightly sedate, since the engine offered ample torque towards the lower end.

    When I drive a diesel, my habit is to enjoy the torque ( shift early, hold onto the taller gear like 3rd or 4th and then shift into 5th once around a decent cruising speed )
     
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  7. turbo99i

    turbo99i RAID Rookie

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    JD very good explanation.


    Sent from my iPhone using Tapatalk
     
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  8. JD666

    JD666 RAID Leader Staff Member

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    thanks bhai!
     

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