Xsara 'Overboost'! Anyone shed more light?

Overboost - as on many saabs, gives a short period of additional wallop - by keeping the wastegate shut for longer. Saabs are about 10s IIRC and so make for brilliant kick when overtaking.

Same as the Mondeo TDCI.

Pete.

I've got the same thing on a dispatch what happens is that when you put your foot to the floor, you get a little bit more boost before the wastegate opens up, therefore giving you more power for a brief period pressing and lifting off and then pressing the pedal again doesn't do s*it because it only does it once in a specified time period

which is why I think they are advertising it as having 110 bhp, it's probably the figure for the overboosted power

Just a bit misleading then.

There isn't any particular pressure. It varies from car to car. It's just more boost than whatever the engine is meant to run at continuously.

Colin.

Many thanks for the replies. I have a clearer picture now and didn't realise there were existing vehicles of other makes that have the same facility. I had never heard the term before and thought new and potentially hazardous ground was being broken.

Tony.

And the same as the Focus TDCI- which is allowed 1.2bar for 30 seconds with a fully depressed throttle- you wont get it unless the pedal is in this position.

Tim..

And the same as the Focus TDCI- which is allowed 1.2bar for 30 seconds with a fully depressed throttle- you wont get it unless the pedal is in this position.

Tim..

And the same as the Focus TDCI- which is allowed 1.2bar for 30 seconds with a fully depressed throttle- you wont get it unless the pedal is in this position.

Tim..

I still think that if the 110bhp is the overboost figure, they are taking the p**s calling it a 110bhp engine, what is the continuous rated figure?

You *think* it is? It's not for the Mondeo Di, and I don't see there being any difference with the other HDI / TDCi engines.

It's usually the quoted torque figure that's the overboost one, it doesn't overboost close to full RPM.

On the Mondeo Di, as I recall it makes around 10% of an increase in torque. The maximum torque figure is quoted as being 278 Nm, so perhaps the maximum non-overboost figure is around 250 Nm? It's in the brochure, but Charlie made me get rid of mine... :(

erm - is the Monnn Day - Oh a 1.6?

:)

Point taken, and "not yet." But it uses a similar engine with similar technology...

Tim S Kemp ( snipped-for-privacy@timkemp.karoo.co.uk) gurgled happily, sounding much like they were saying :

erm - is the Monnn Day - Oh a bit bigger than a Xsara?