My new project; Fiat Scudo (1.9TD XUD9)

[Hauki]

Ok, I was meant to be getting something more aero than this as I have to do like 3000 mile trip about once a month (Finland - UK - Finland). But it was a great deal and the 1.9 TD should be a great platform to build on.



So, if anyone has any tips for the XUD9 or diesel engine tricks in general please share. I have read decat plus bigger airbox can help?

Few questions I have;

1) The main priority is the height, its sits way too high this thing. Lowering springs are quite expensive for it so I was thinking if I add an airdam at this height, it will be huge, will that help or hinder FE?

2) Wheels are 14", I can get Michelin energy savers at this size, but would it be better to take the wheel size up to 15" or even 16". Do I increase the rolling radius or keep it the same?

3) Trailers. If an aerodynamic trailer reduced drag, how much would it need to reduce it by to overcome the tyre rolling resistance and added weight.

This van will be on highway for 90% of the time, so weight is not so much of an issue if it is sat at 60mph/100kmh is it?

[jtbo]

I have XUD9TE in my ZX.

Replacing thermostat made it stay better warm, but that is about it, haven't done anything else to engine that I could think affecting economy.

My best experience has came from aerodynamic improvements, also I have boost gauge so that I know to stay off boost most of the time.

Tires I use are Continental Viking Contact 5 winter tires, great tires even at summer, 175-65-14 size, also a lot lower rolling resistance than summer tires.

Cut plastic foam from some mattress or use old washing sponge under throttle pedal, makes it lot more comfortable at longer trips as I suspect Fiat has also too light throttle pedal as most cars.

Front air dam and wheel arches blocked (rear is easier to do at least) + smooth wheel covers at least to front should help a lot.

If you can get full belly pan that is really smooth, then perhaps airdam is not good as air running under the car would not cause much of drag.

Check Audi A2 post from Aerodynamics section that Vekke posted, latest version of thing that they made to back might work for you too?

Trailers I have read can be really helpful, especially if there are no hills, but if you go to UK, there might be additional costs from trailer at some point, so that is better to check out first.

One mod I would love to do for my car is engine kill switch, for longer coasting starting up would not then cause glow plug cycle to run.

If you can get cheap solar panels (most likely those would be thing to buy from UK, we finns have lot of extra in their price here) then you could bypass alternator as you have roof surface available, you could put solar panels and some aerodynamic fairings to make added height to work as improvement to shape, solar panels could load battery, engine does not need much electricity and replacing lights with LEDs would make electric needed quite small, so it might be possible to keep alternator from charging most of the time.

Removing it is not very easy at least with my version of engine as there are lot of stuff on same belt.

[Hauki]

Thanks jtbo, yes the throttle is crazy light so great idea with sponge or something, I will look into that.

What l/100 are you getting out of the ZX?

There is a connection under the steering wheel to plug something in, but I don't know what format it is, I would really like a scangauge so I can get accurate readouts instantly but I am not sure a 1998 diesel will be OBDII compliant. But the Peugeot 806 and Ullyses are basically the same platform and they have factory fuel computer installed so it must be possible. I wonder if I can fit the driving clocks out of one of those...

My engine stays around 81°C, what temp are these engines supposed to run? I am going to do some grille blocking because there are lots of open spaces on the front of this van. I think I only need the top grille open where the air inlet is and a bit of radiator is visible.

It coasts ok this van, almost as good as my Volvo 240, but you can really feel the drag at 60kmh and above, it is really strong. So I think aero is where my problems lie here. The underneath is quite messy and is causing a lot of drag so I will try and get the airdam sorted.

I will do some testing on each modification. I live on an island in turun saaristo so roads are empty! I have a couple hills I can test on. I am going to mark in chalk a line at the top of the hill, and I will coast down and mark a line with chalk where I stop. I will do this with each mod and draw a new line the further I go.

[jtbo]

Here is my fuel log, my nemesis are wet and snowy roads.
1997 Citroen ZX Monaco Gas Mileage (ZX) - EcoModder.com

Your car has no OBDII afaik, they probably are not plugging anything to plug that is under steering wheel at inspection either? They test OBDII cars there so that is one way to tell.

Boost gauge is from my experience quite helpful, it is also quite easy to install as there is tube coming from intercooler to pump, you can easily put T-piece there.

Every downhill my temps are falling at this weather, I might put some blocking to upper grille too.

Wiki (link is at top of this page, black small words menu that is easy to miss) has explanation of testing method how to get cd and rolling resistance tested, level road is needed for that.

There is also another method posted at here by tarksu:
Ilmanvastuksen että vierintävaskuksen mittailua

I think that your car was also sold as Citroen, some small changes perhaps?

With testing, weather variable, especially wind can have lot of effect, so comparision between the runs is always bit of challenge with road testing. More test should give more accurate results however, so I recommend to do many runs and work out average from those.

With Peugeot they might have used newer model engine in those? I remember 306 did move to electronically controlled engine at some point while ZX never got those, only after Xsara replaced ZX they got newer model engine, HDi.

I have Volvo 240 too, diesel version, has been off the road few years. With serviced brakes and new Nokia summer tires it did coast a lot worse than my ZX, I think it was because of tires, but aerodynamics probably did play part in equation too.

Oh yes temps, well my temp meter is not made for easy reading, but normal is just needle thickness away from 90C. Motonet does sell only 82C thermostat, I bought mine from Citroen stealership, was not expensive and I think this is 86-88C more engine temp should be better for economy I have read.

Before that it was just bit above 75C lower when coasting, now it is that 86-88C, but when I coast down a hill it can drop close to 75C.

Genuine Citroen thermostat is good in there that it stays closed until temperature is reached and opens then fully, I can observe this from temperature meter, it goes close to 90 first, then drops all of sudden from there, it does make car heat up lot faster, old one was not such type.

My efan is broken, so summer I have to keep eye of temperatures, but as I don't drive at city it really is not bothering me, fan is not really needed, especially when I turn engine off at traffic lights.

Air filter in mine is foam that needs to be oiled, there is paper versions sold to this model too, but XUD9TE should have that foam filter, it is bit noisy for my liking, but there is less restriction and that might do something to economy, not quite sure about it.

[Hauki]

Ok I was doing research today, and it is definitly not OBDII, even the early HDi's were not OBDII and only about 2003 I think they became that format. So I will have to measure fuel consumption the old fashnioned way.

Here is something useful for Scudo/Expert/Jumpy/Dispatch owners. There is no official fuel figures anywhere for them as they are a van but I got the official figures from Fiat;



So Scudo 1.9 TD @ 90 kmh;

6.1 l/100
46 MPG IMP
38.5 MPG US

So I am quite happy with that, it makes my goal of 5 l/100 (56MPG UK - 47MPG US) achievable. Maybe even a little further.

So far I have increased tyre pressure to 3 bar and that has already helped coasts alot. Next will be airdam, I was running some tests in flow illustrator and it wasn't pretty;

Unmodified:


With dam and skirts;


I know the drag being caused from the air traveeling underneath the van is messy because I wash the van, drive 5 minutes down my dirt road and the back doors are thick in dirt ;(.

As for winter, it has not affected me too much but that has been in Volvo S40 and 240 petrol, I can grille block the front entirely and using the block heater really helped save fuel. But this is the first diesel I have had so I don't know how Finnish winters affect diesels.. although I am so south I am practically in the Baltic sea so it does not get so bad here as the mainland. As soon as I can afford it I will be getting a set of lowering springs I have seen for £150 which lowers front 40mm and rear 30mm. I will never have more than 300kg (max payload is 750kg) in the van so I think this is safe to do.

So mine is running slightly cooler which means the thermostat needs replacing, but I quite like that fact, it means I can grille block a bit more. So I will leave the thermostat as it is for now. Besides those Motonet thermostats in my experience only last 2 weeks anyway so I would need one from the stealers aswell.

[jtbo]

I think that even you would have higher temperature in engine set by thermostat, it would not require any more cooling as amount of heat produced would still be the same, thermostat would just direct that heat to radiator bit later.

I just learned from another thread that with wagon shape (which yours is also I think) diffuser at 0 degrees would be best, so when you make bellypan make sure that rearward section is level with ground and not at angle of rear bumper.

My winter consumption increase comes from fact that I mostly used car when there was lot of snow on road, couple of times there was so much that car did not want to go faster than 50-60kph, also I had winter tires with studs that are with bit larger diameter and that made rpm to go below 1800 which is where engine is not making power to climb all these central Finland hills.

I have been thinking that as diesel has always open intake and only amount of fuel injected is adjusted, then it acts lot like lean mixture gasoline engine, that should make it better with bit higher rpm and low load, but with turbo we are punished by higher rpm as turbo starts to build up boost and that increases amount of fuel injected.

That has lead me to thinking that maybe it would be possible to improve fuel economy by limiting boost to 0.2 bar or bit less, it would of course be very bad for performance, but it would allow one to use bit higher rpm than 2200, so that usable range would be bit more than 1800-2200. However it is still something I need to think more, but just a thought.

[Sven7]

Originally Posted by Hauki

With dam and skirts;
Attachment 10588
.

First I'd like to make clear that Flow Illustrator is a toy and not really fit for serious testing. Otherwise it has been posted that the optimal ground clearance is about 5" (12cm) so making a NASCAR style air dam will not be ideal. Just make the dam low enough to "cover" any suspension or chassis components that stick down and combine that with a full belly pan. Is the Scudo front or rear wheel drive? Especially if it's RWD you could see up to 15% aerodynamic improvement with a well-made belly pan, which will translate into about a 7% fuel economy boost.

Also here is the image jtbo was referring to.

Good luck!

[ecofreak]

Put in a smooth underpan. It will fare better than just an air dam.

[Hauki]

Woohoo just done a 250km trip and fuel usage was 5.2 l/100 km!

I kept it at 95 kmh the whole way and it was an incredibly flat road

The van was totally empty, i wonder what difference it will make with a few hundred kilos load, I will find this out next week.

[euromodder]

Originally Posted by Hauki

Woohoo just done a 250km trip and fuel usage was 5.2 l/100 km!

Nice one !
Especially as it isn't a passenger car

I kept it at 95 kmh the whole way and it was an incredibly flat road

Try 85 kph if you're not pressed - though it may be less economical due to the time spent driving.

The van was totally empty, i wonder what difference it will make with a few hundred kilos load, I will find this out next week.

Nothing much on a nearly flat motorway.

Your rolling resistance will be a bit higher, and it'll take more fuel to get it up to speed - but if you do enough distance at a constant speed, the overall effect will be small.