Engine Braking

[Grecian VTR]

Hi all,

 

New to the forum and to Citroens!

 

Had my C4 HDi Coupe for a month and a half now and very happy with it, seem to have been very lucky and don't have any squeaks or rattles!

 

Just the one query though, had several cars before this one with the last being a 206 HDi. All of my previous cars have had quite a bit of engine braking when going downhill.

 

My C4 has very little if any and i am constantly on the brakes. Thought i would test it tonight on the way home from work. Travelling down a hill which is approximately 150yards long the car picked up in speed by 9mph with no help from the right foot (it is not a massive gradient by any stroke of the imagination and a 40mph zone).

 

Recently been back to the dealer for the 1000 mile check and they said they couldn't re-enact the fault on a road test (possibly because they only drove it around the industrial estate which is flat!).

 

Is this a common thing with the C4 or just my engine?

 

Piccie of car for any one interested:

http://img2.freeimagehosting.net/uploads/th.a2782b68f6.jpg

 

Thanks for any help

Andrew

[kfk]

had customers ask about this mainly in C3.

 

If your aproaching a roundabout and slowing down without braking all goes well untill your nearly on top of it, and then you feel the car start to pick up speed.

 

You will find in that instance its a characteristic of being in the wrong gear at too slow a speed and the engine reacting to the low engine revs and that its likely to stall.

 

The instances i have had this it has been in 2nd and 3rd gear. I guess thats why they give us a clutch and 1st gear & brakes

 

Basically, if your in gear and try to drive the engine below a certain engine speed it wont let you.

[wozza]

Not got the diesel i have the petrol but i find my engine braking fine 2nd or 3rd down steep hills will happily sit at 30. Unsure of the diesel maybe need to try a lower gear? It should not be much different to the 206 apart from the car weighing a bit more thus going down hill will want to pick up more speed.

 

Car looks good.

[C4VTS]

Hi Grecian VTR, and.... nice car by the way from your pic. :rolleyes:

 

I think the gearing in the C4 is much higher than some other cars, which may explain why engine braking is less efficient.

 

Also I am led to believe that the current driving test encourages use of the brakes rather than changing down as we used to do back in the 70's.

 

It may also be something to do with the PSI engines, to make them more efficient?

[wozza]

I only did my test 20 months ago but i was told to use engine braking as well as my brakes. But the general thing is most people should use the brakes because there cheaper to replace than a gearbox if you screw it up.

 

I make use of both if im slowing quickly i down shift as i brake as well as a couple other things just helps the car a bit more i find it doesnt seem as jittery.

 

But as i said 3rd at 30 down steep hills is fine in my car wont get much quicker 32 is the most it seems to go to.

[LeoTheHamster]

You could always use the Speed Limiter if you're that scared about going over the limit :rolleyes:

[Mat]

You could always use the Speed Limiter if you're that scared about going over the limit :rolleyes:

The speed limiter only limits the throttle, so going down a hill wont apply the breaks if the engine doesnt keep it at the max speed.

[Grecian VTR]

Definitely not in a gear where the car is trying to keep the engine running and pushing it along that way, normally in 4th or 5th at about 2k revs.

 

Tried the limiter but that doesn't work, will cut the fuel supply when you hit 40 but doesn't stop the natural momentum of the car so it just picks up speed and starts beeping that i am going over the limiter speed!

 

More worried about the police that quite often sit in the petrol station at the bottom of the hill with their speed gun :rolleyes:

 

I was taught more to use the natural engine braking to slow rather than heavy braking as well, guess it's just going to take a bit of getting used to and using lower gears on the hills.

 

Will give it a proper test soon, don't know if anyone knows Telegraph/Haldon Hill (two very steep hills) by Exeter where the A38 turns into the M5, used to be able to go down there in the 206 in 5th with the engine keeping the car at 70 (ish!) not needing any manual braking, shall see what the results are with the C4

[ham's c4vts]

there maybe an unseen force acting on your car call gravity :P . when ive gone down to cornwall i rarely use the throttle as it all down hill to cornwall, just a bugger coming up hill on the way back! :P :P

 

welcome to the forums and have fun :D

[Johndouglas]

The lack of engine braking is one of the differences between diesel and petrol engines. In diesel engines there is very little engine braking because even when the fuel is cut off by lifting the pedal, large amounts of air is still taken into the cylinders and the compression is still taking place. Truck diesel engines cope with the lack of engine braking by using a Jake brake.

[Grecian VTR]

The lack of engine braking is one of the differences between diesel and petrol engines.

Correct me if i'm wrong but don't Peugeot and Citroen use the same engines with their relevant badge on it? My 206 was a '02 plate 1.4HDi and that had loads of engine braking, my C4 is the 1.6 92bhp HDi model.

[kfk]

Personally i wouldnt expect to get much engine braking at 2000rpm in 4th or 5th.....you need to change down the box.....just out of interest what speed are you doing in 4th at 2000 rpm?