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CDTI - Which gear at what speed

Chriseybaby

Chriseybaby

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Cambridge
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Accord 2.0 i-Vtec Ex
After reading another post about driving styles it seems that some people go for a high gear as soon as possible to save fuel. The petrol guys really seem to shoot up the gears to a point that I would be worried about my clutch.

My lowest speeds are

1st gear - 0mph (Unless its rolling down a hill)
2nd gear - 10mph
3rd gear- 21mph
4th gear - 30mph
5th gear - 45mph
6th gear 52mph

This seems to go fairly easy on my clutch (bar possibly 30mph in 4th) and return good fuel economy.

What does everyone else do?
 
Never looked at it in that level of detail Chris, but I do know the sweet spot for economy/reasonable speed is circa 1900RPM
 
I'm still learning mine. I'm changing gear a bit later now as I was changing so the revs dropped to about 1100 in the next gear, but this does seem to labour the engine a bit too much.
 
Changing at 2k rpm sounds like a good rule, but what does that drop the rpm to after the change? It seems that 1200rpm is around the min for me. Im sure I read a post on here saying the petrol guys are doing 30mph in 6th!
 
I often do 30 in 6th...
 
The recommended shift points, as per the manual, are:

1st to 2nd 9 mph
2nd to 3rd 22 mph
3rd to 4th 34 mph
4th to 5th 44 mph
5th to 6th 53 mph

ps these figures are for the 6 speed diesel, petrol figure are different.
 
Does the six speed diesel rev lower in top gear compared to a five speed for a given speed?
 
Doc said:
The recommended shift points, as per the manual, are:

1st to 2nd 9 mph
2nd to 3rd 22 mph
3rd to 4th 34 mph
4th to 5th 44 mph
5th to 6th 53 mph

ps these figures are for the 6 speed diesel, petrol figure are different.
Click to expand...

I change at those speeds; anything lower and the engine labours.
 
How well is the clutch, and DMF for that matter, gonna last if your in 6th at 30? Surely that takes the rpm down well below 1k?

Interesting to see what the manual states, seems my changes aren't too far off
 
It's on tick over...800 ish.
 
Matt said:
Does the six speed diesel rev lower in top gear compared to a five speed for a given speed?
Click to expand...

Meant to add, on my 5 speed 'box in top gear 1800rpm gives me 60mph, and 2050rpm gives me 70mph.

If sixth gear runs at a lower rpm, I'll look out for one next time.
 
Matt said:
Does the six speed diesel rev lower in top gear compared to a five speed for a given speed?
Click to expand...

Yes mate it does.. somone posted the ratios a while ago and from what I can recall only 1st and 2nd were the same on both 5 and 6 speed boxes. After that the 6 speed box had slightly shorter rations and long 6th.
 
ChrisG said:
How well is the clutch, and DMF for that matter, gonna last if your in 6th at 30? Surely that takes the rpm down well below 1k?

Interesting to see what the manual states, seems my changes aren't too far off
Click to expand...

I don't see that it would affect the clutch or DMF if the engine is not being made to labour or excessive gear changes are being made.
 
30 in 6th? WOW, that surely is hurting the engine...? I do 3rd because it feels right for the optimum mpg and torque. Seriously, 6th gear at 30???
 
Yeah baby - engine is perfectly happy on the flat - it really is just ticking over.
 
TheJamMod said:
30 in 6th? WOW, that surely is hurting the engine...? I do 3rd because it feels right for the optimum mpg and torque. Seriously, 6th gear at 30???
Click to expand...

I have to agree with you on this, I'm not an expert on car engines, but used to own and race karts (with 2 Honda GX160 engines) We used centrifugal clutches so this is where my knowledge comes from so may be flawed. As far as I can see if your asking your clutch to pull you along, in a high gear, your more likely to wear the pads or plate, even more so if you ask it to accelerate from there
 
Premature clutch wear is not the problem on the iCTDI, it's a premature adjustment of the pressure plate self adjusting mechanism.. in all the cases of clutch failure I've seen posted on TA, I can't ever recall seeing a worn friction disc yet.
 
F6HAD said:
Premature clutch wear is not the problem on the iCTDI, it's a premature adjustment of the pressure plate self adjusting mechanism.. in all the cases of clutch failure I've seen posted on TA, I can't ever recall seeing a worn friction disc yet.
Click to expand...

Is the adjustment of the clutch pedal cruise switch easy to check?
 
I usually err on the side of revs, changing up at about 2.3->2.5k on the flat, or 2.5->3k on hills. My theory is not to overheat the DMF. Whether this is borne out in practice, I don't know.
 
Matt said:
Is the adjustment of the clutch pedal cruise switch easy to check?
Click to expand...

I've never checked myself Matt, so maybe have a go and let us know?
 
ChrisG said:
I have to agree with you on this, I'm not an expert on car engines, but used to own and race karts (with 2 Honda GX160 engines) We used centrifugal clutches so this is where my knowledge comes from so may be flawed. As far as I can see if your asking your clutch to pull you along, in a high gear, your more likely to wear the pads or plate, even more so if you ask it to accelerate from there
Click to expand...
I don't see how it would hurt the clutch if it is not engaged. The clutch plate is only in use if the pedal is engaged. I never labour the engine at 30 mph and if faster acceleration is needed I change down to the appropriate gear.
 
when the engine is cold I'm trying to change gears before engine reach 1.8k after when it's warmed up I'm changing gears at 2-2.2k.I think that is optimal balance between fuel consuption and torque. but you know if someone is seating on my **s , well...gear down,foot down and 3,5 - 4k and a he disappears in fumes. B)
 
I've found that when the engine is cold the car needs a few more revs in order not to be labouring.
 
I tend to use the instant mpg as a guide to engine load, and agree it feels wrong changing at low revs on a cold engine. Obviously don't thrash it though!
 
I agree, but it depends what you mean by low revs? Is it 1100 or 1800? Because as we all know that rev limit for diesels is lower then for petrols.
 
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