|
||
|
25th July 2015, 13:08 | #1 |
Posted a thing or two
75 facelift CDTi Connie SE Tourer. MGF 1.8 VVC Join Date: Jul 2014
Location: bristol
Posts: 1,424
Thanks: 176
Thanked 176 Times in 119 Posts
|
At what revs should the turbo kick in?
I am sure I read somewhere that driving a cdti below 1500 rpm is like driving an old lugger as the turbo cuts in a those revs. I been getting poor fuel returns (38-41mpg on a run) and I was advised to keep it above 1500 if possible. My engine really doesn't do anything until I hit 2000rpm and then it takes off like a rocket. When should it do this 1500 or 2000? I have been driving it very carefully in the past but now I am driving it harder to see if it makes a difference.
While on the subject I am really beginning to notice the difference between this manual and my old auto. Lots of strange noises one of which sounds like a thrust bearing issue, on deceleration, which is the opposite of what I would expect. I get a whining noise when I switch the AC on too but it works like a dream and has no leaks. I have just noticed all these things as I have done my first long run in traffic going to Cornwall and back. I may have to go back to an auto soon!
__________________
Onwards and upwards. MGZT-T MK1 front and rear ends fitted, specialist- components in line thermostat mod done, retro fitted cruise control, Mk1 real wood dash fitted, real walnut steering wheel fitted, Pioneer DAB radio fitted. |
25th July 2015, 13:20 | #2 |
This is my second home
75 CDT Auto Tourer , Rover 45 , Astra, Zaffira, Chev Captiva Join Date: Mar 2011
Location: Wilts
Posts: 3,342
Thanks: 203
Thanked 436 Times in 360 Posts
|
The turbo is turning all the time while the engine is running. The higher the engine revs, the more exhaust gases, the faster the turbo will turn, the higher the pressure will be.
What does change is the waste gate will open to exhaust some of the pressure to atmosphere. This is controlled by vacuum, which is in turn controlled by diaphragm. On these cars it is electronically controlled by the ECU using amongst others, readings from the boost pressure (MAP) as well as the engine revs. How, why and when it opens I have no idea. But driving any car within the appropriate torque range will always save fuel.
__________________
Chrome skull caps, EGR cleaned (original housing), Mondeo lower mounting, 12V outlets in the armrest and tourer boot, cat fixed, working FBH, Lidl plenum covers, DD with reverse camera.New speakesr/Tweeters with MDF rings. wood dash, Memory leather seats, wooden finished steering and handbrake, Xenon headlights. |
25th July 2015, 13:26 | #3 |
Posted a thing or two
75 facelift CDTi Connie SE Tourer. MGF 1.8 VVC Join Date: Jul 2014
Location: bristol
Posts: 1,424
Thanks: 176
Thanked 176 Times in 119 Posts
|
Thanks for that Spyder. I take it then that I should keep the revs up and not let it lug in too high a gear?
__________________
Onwards and upwards. MGZT-T MK1 front and rear ends fitted, specialist- components in line thermostat mod done, retro fitted cruise control, Mk1 real wood dash fitted, real walnut steering wheel fitted, Pioneer DAB radio fitted. |
25th July 2015, 13:54 | #4 |
This is my second home
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009
Location: Hampshire
Posts: 11,551
Thanks: 3,470
Thanked 3,119 Times in 2,247 Posts
|
Sluggish running below 2000 rpm is often a sign that the MAF is not working correctly. Try unplugging it and see if things improve.
|
25th July 2015, 17:46 | #5 |
Posted a thing or two
75 facelift CDTi Connie SE Tourer. MGF 1.8 VVC Join Date: Jul 2014
Location: bristol
Posts: 1,424
Thanks: 176
Thanked 176 Times in 119 Posts
|
I will Mike, thanks for the tip.
__________________
Onwards and upwards. MGZT-T MK1 front and rear ends fitted, specialist- components in line thermostat mod done, retro fitted cruise control, Mk1 real wood dash fitted, real walnut steering wheel fitted, Pioneer DAB radio fitted. |
25th July 2015, 18:01 | #6 |
I really should get out more.......
Rover 75 CDT Club Tourer Join Date: Nov 2006
Location: Milky Way
Posts: 2,381
Thanks: 105
Thanked 513 Times in 382 Posts
|
The symptoms you describe point to a MAF sensor that has had its day, what is the history of this sensor when was it last changed, as suggested elsewhere, disconnect it and go for a run if the car drives well and pulls well in all gears and well within the useful rev range, then there is your problem, buy a new GENUINE MAF sensor not which is aftermarket, better still get a Pierburg version and a digimafam from Roveron, and that is it you will not likely need to change it again.
Please remember to drive the car sensibly within the rev range appropriate to the driving conditions, no need to aim to keep revs at approx. 1500rps, you are not driving a racing car, but do please give the car a good run to get the engine really moving from time to time, once it is thoroughly warmed up, etc.. |
26th July 2015, 11:53 | #7 | |
Posted a thing or two
75 facelift CDTi Connie SE Tourer. MGF 1.8 VVC Join Date: Jul 2014
Location: bristol
Posts: 1,424
Thanks: 176
Thanked 176 Times in 119 Posts
|
Quote:
__________________
Onwards and upwards. MGZT-T MK1 front and rear ends fitted, specialist- components in line thermostat mod done, retro fitted cruise control, Mk1 real wood dash fitted, real walnut steering wheel fitted, Pioneer DAB radio fitted. |
|
26th July 2015, 15:14 | #8 |
Gets stuck in
R75 2.0 CDT Club SE Tourer Join Date: Oct 2013
Location: Manchester
Posts: 614
Thanks: 105
Thanked 101 Times in 89 Posts
|
What's the situation with your EGR Steve?
- by-passed? - cleaned? - never touched? If it's not been by-passed you might want to have a look at that before you spend serious dosh on a Maf. |
26th July 2015, 16:19 | #9 |
This is my second home
Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008
Location: Birmingham
Posts: 11,396
Thanks: 6,587
Thanked 2,262 Times in 1,729 Posts
|
Turbo starts to give the engine more power supposedly around 1760/1900 rpm.
__________________
Great Barr, Birmingham. |
26th July 2015, 17:25 | #10 |
This is my second home
75 CDT Auto Tourer , Rover 45 , Astra, Zaffira, Chev Captiva Join Date: Mar 2011
Location: Wilts
Posts: 3,342
Thanks: 203
Thanked 436 Times in 360 Posts
|
That is the start of the torque curve for the diesels, basically where the pressure available begins to exceed atmospheric pressure-in very simplistic terms that is.
__________________
Chrome skull caps, EGR cleaned (original housing), Mondeo lower mounting, 12V outlets in the armrest and tourer boot, cat fixed, working FBH, Lidl plenum covers, DD with reverse camera.New speakesr/Tweeters with MDF rings. wood dash, Memory leather seats, wooden finished steering and handbrake, Xenon headlights. |
|
|