Hi from the UK
 

Just registered - this is the forum I've been looking for for some time!

I have a Citroen Xantia HDi, for the non-Europeans that's a hatchback with already very good aerodynamics, a class-leading (8 years ago) direct injection turbo-diesel with 110hp. I get up to 55mpg (UK) or 5.1 l/100km, measuring over 600 miles, but with fuel at over $2.50 a litre I would like to do better...

It looks to me like adding an undertray at the front and back will be worth doing - the car may well have had one at the front from the factory.

If anyone has fitted a mpg display to this car, I'd be very interested to hear how. It has a OBDII connector which apparently uses an ISO standard.

Simon

Scangauge II would be the ideal choice for an OBD II car.

Hi Simon - welcome to the forum.

The ScanGauge is an excellent tool, or you could build your own MPGuino, if you're the DIY sort.

Is this your car?

http://www.analogstereo.com/images/o...oen_xantia.jpg

Seems like they could have made the aerodynamics even better if they'd not gone for the "faux notchback" look!

I was just having a conversation about Citroens with my neighbour a couple of hours ago. (He's been stopping by regularly to chat, watching the progress on my Kammback construction.) There was one in town today for a bit car show - probably a 70's DS - and he commented on its apparently good aerodynamics.

Darin

$54 worth it? Probably not. But that's what coroplast election signs are for.

Depends on whether you like the candidate or not :thumbup:

Yes, that's the car - or at least the Mk1 version. Mine has a slightly different grille, A/C, more airbags - and more weight. They all feature hydropneumatic suspension - amazingly effective but it does mean engine-off coasting is not possible. Don't really want to lose suspension, brakes and steering...

What would be better than the faux notchback? Simply filling in the triangle between the top of the roof and the boot lip?

Just discovered the MPGuino - looks good. I know some have had no luck using ELM devices. At least I get something to play with if it won't work with my car...

Simon

Something like that, yes. There's an ideal rear angle/shape which simply drawing a line between those two points might not satisfy exactly, but a properly tapered roof/hatch transition at the rear would lead to a smaller trailing wake and would be better than the current shape. Air flow separates at the trailing edge of the roof in this notchback design with no chance of reattachment on the short "faux" deck lid.