Peugeot 407 SW - When are the rev's too low?

Honest John Back Room » Motoring discussion
View Threaded
Tue 8 Mar 2011 13:06
Peugeot 407 SW - When are the rev's too low? - fredthefifth

In his review HJ mentions "Reports of repeated EGR valve failure on 2.0HDI 136, possibly from trying to drive at too low revs." Well having bought a 407SW (but with the 140 HDI engine on which I assume the comment is still valid) I would like to understand more.

I am generally aware that letting an engine struggle at too low revs is not good, but that engine has so much torque that it is easy to let it struggle on sometimes without realising. I appreciate this is about feel and common sense but wondering if anyone has got any views or gudelines?

FTF

Reply | Report as offensive | Link
Wed 9 Mar 2011 10:18
Peugeot 407 SW - When are the rev's too low? - craig-pd130

My personal interpretation is to keep the engine in its peak torque band -- between around 1,750rpm and 2,500rpm -- and once a week or so, give it a burst up to 4,000 or so in 3rd and 4th gear.

My Mondeo IV has the same basic engine, and with the Ford gearing, it's obvious from the feel and sound that it does not like town speeds (30-ish mph) in 4th gear. At these speeds it's only at around 1,300rpm.

Sure, it will pull 4th gear and still accelerate hard from these speeds, but it doesn't feel happy doing it. So I use 3rd gear around town, which gives 1,800rpm at 30mph.

Pulling tall gears at low rpms isn't good for DMFs and drivetrain components, either.
Reply | Report as offensive | Link
Wed 9 Mar 2011 14:39
Peugeot 407 SW - When are the rev's too low? - ForumNeedsModerating

My Mondeo engine is the same (virtually) as yours too. Like the above poster, I don't follow that old nonsense about getting in a high a gear as possible, as soon as possible - as has been pointed out, the sheer willingless of the torquey diesel hides the strain it must take when pootling at less than 1500-1600 rpm in high gear - just listen for that 'clack-clack' sound - simply doesn't like it.

I also find the best economy when keeping revs at least 1750rpm - borne out by fill-ups & fuel computer. The engine around that figure always feels completely unstressed & smooth - good enough for me.

Edited by woodbines on 09/03/2011 at 14:40

Reply | Report as offensive | Link
Wed 9 Mar 2011 21:08
Peugeot 407 SW - When are the rev's too low? - fredthefifth

Ok thanks both.

Reply | Report as offensive | Link