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Don't know much about turbo. when I bought the car I took it on to a motorway and took it up to a 100 mph to see how the car was. Somewhere before 100 mph I felt a sudden rev increase and a speed boost.
This is the Turbo I guess. Can anyone tell me more about Turbo like what speed or revs it should engage at. many thanks.

A lot depends on which engine you have, and how you drive it. In normal driving mode, mine hardly ever kicks in as it is electrically adjusted, although if I floor it, the turbo comes in about 1500rpm. On my 1.9 DT, it would come in at about 2000rpm if I caned it, but if I accelerated gently, I could get up to 3000rpm without it ever kicking in. Cruising at any speed will see the turbo gently backing off to the point where it may be necessary only for the uphill gradients.

Hi mate, you didn't say what engine you have, a petrol turbo and a diesel will behave slightly differently but there aren't many turbo petrol 406's about.

A petrol has a wider more progressive band where the turbo is in operation compared to a diesel which can give you a big dollop of boost between 1800 and 3500 RPM (depending on the engine variant). The bigger the turbo the more likely it is to deliver full boost in a sudden neck snapping moment, smaller turbos are more even and progressive.
I can safely say whatever you have you are well into the boost range if you're approaching 100mph!
Some of the newer small capacity diesels behave more like a petrol and you don't really notice it boosting unless it stops working for some reason and you find you have a completely gutless car like the other halfs 307

In my 2.2 which has a fairly big turbo you feel the boost very nicely from about 1700 RPM in third gear, upshifting at just over 3000 and the needle on the speedo moves rather quickly to the right

Essentially if you gun it in third you'll feel it start to boost anywhere between 1500 and 1900 but be warned, once you get the hang of driving 'in the boost' it can be addictive and hazardous to your driving license!!!

Its a 1997cc 406 S HD (110) Estate Diesel. I have just taken it out for a test with the new information supplied by your good selves. No sign of Turbo even at 4000 revs + though its not slow.
When I bought the car I am fairly sure the Turbo would engage if I was quick on a roundabout say, however it did need a new Clutch so I had one fitted, Since then I have not felt the Turbo kick in at all.
Maybe the Garage have electrically adjusted it to be easy on the new Clutch and not mentioned it, I don't know.

If you're getting up to and over motorway speeds in a decent time you are getting boost. The engine would feel quite flat without it.
As you have the 110 pop the bonnet and rev the engine, you should feel the top intercooler hose firm up as it sucks air in through the turbo.

The turbo is not an on/off switch, it will start to boost gradually around 1500 rpm, and run out of puff around 3500 rpm. If you throttle off, the turbo will wind down to keep the revs even, and if you plant your foot down you should feel and hear the turbo.

As a test, drive up a steep'ish' hill in. say 3rd gear and put your foot down. If you go faster then the turbo is fine, if you slow down then the turbo is goosed....

Drive around with the windows down and enjoy the whistle from the turbo....

The Hdi is a very graceful engine, when compared to an older diesel that had no power until ' blam ' the turbo throws you back in the seat.

I mustard mitt when I first got my HDi 110 I was disappointed at the power delivery but soon got used to it. Full boost and torque are available from 1800 rpm to 2800 rpm, quite a narrow power band but very usable. 1st gear is a waste of time but I think you'll get the most boost/results in 3rd gear and to be fair the HDi should pull strongly within the power band.

Someone advised me early on that although the standard HDi doesn't feel that quick you only have to glance at the speedo to see you're actually pressing on quite nicely. Another thing is don't try too hard, don't floor the throttle, just let the engine do its work and learn where the power is. You have to sort of 'ride' with the torque wave it won't be pushed or hurried.

Well thanks, I have been for a test on a local steep hill and it pulled away in third gear quite well. Surly did not hear any Turbo Whistle and if there is a kick to it then its not very pronounced, subtle like.
It is a fast car so am guessing all I require is a return somehow to Turbo kick at 1500 or maybe 2000 revs.
Presently am thinking, as it has just passed MOT, therefor worth spending money on, to put it in for a Service and ask the Garage as well to advance the Turbo so it kicks in earlier. ?

Bearcat24 wrote:ask the Garage as well to advance the Turbo so it kicks in earlier. ?

It's not possible for the Turbo to be adjusted in that way, what you might want to check is the Vacuum system; there's a Vav pump on the RHS of the Camshaft and Electro-Solenoid Valves on the Bulkhead. Check all the Vacuum lines (small hoses) for signs of splits/leaks and check the Solenoids are working (some people swap them around I think?) all these things 'control' the Turbo output.

I remember once a member replaced the Vacuum pump itself and reported much stronger boost.

It will start to come on stream at around 1500 rpm, the acceleration will increase rapidly above that up to about 2000, after that you will not notice much difference. For optimum efficiency you need to keep in the 1500 - 2500 rpm range.

Peter

Another thing to note is that at 3200rpm, the fuel pump opens up a 3rd solenoid(?), which I believe delivers more fuel into the engine and gives a subtle acceleration boost. 100mph is about 3200rpm so that maybe what you are experiencing.

Some remappers keep this 3rd solenoid open at all times (amongst other things), which gives you more overall power.

What you want to do is have it re-maped mate, mines up from aprox 110bhp & 240Nm torque to 150ish bhp & 350ish Nm torque
You can really feel it 'kick' between 2000 rpm & 3500 rpm ,as others have said it starts to come on at 1500rpm.
There's nothing you can do to make it come on boost any sooner
Oh & the reason I state ish on my power figures is because I haven't had it dynoed yet to verify the figures, I'm quite happy with the performance though!