Mods for 90's Citroen Break (STW for folks in US))

[euromodder]

Originally Posted by jtbo

Yes, car is covered in clay, mud and who knows what, it is this time of year and these roads, no point washing car until about month or so.

If you don't clean it, the mods will be invisible in a few days

[jtbo]

Originally Posted by euromodder

If you don't clean it, the mods will be invisible in a few days

True, and also that will show where aero is lacking so it is easy to make improvements

This morning there was no wind as I drove small trip with car, I'm not sure if there really was much effect, but it felt that car did run target speed with less load than before, there was larger difference between uphill and level road, imo. Very subjective of course, so it is not so much of evidence from anything, somehow I just got feeling that at higher speed difference might be more notable, speed was decreasing rather slowly from downhill speeds, but I need to fill the tank and drive more, then refill again, to see difference, if there is such.

Already have heard comments like "who would do that to car" "poor car, it had done anything to deserve that", I guess not everyone can't be above average, that would put average just higher and such is not going to happen probably ever

It was -2C at the morning, more grille blocking would of been good.

[jtbo]

I made improvements to front airdam, first I made it too low, it scraped on everything, now I did cut it bit less low, but I still have to be bit careful about where I drive, even there is more than 2 inches of clearance under it.
It has now also side deflectors so that front tires are not seeing direct air stream.

Weather has been great, so can't tell how much effect airdam has had, however now I got some insane half tank, again filling slowly on same station up to filler neck.

67.16mpg, that is too low to be realistic (uhm, high in mpg that is), imo. However I drive again and fill again soon, then we know how it is, if I get unrealistically high reading (uhm, low mpg that is, thinking l/100km here again), then average of those must be closer to reality.

Also I found out that pressure in tyres had disappeared, so there was only around 32psi left, put again to 44psi, so now it coasts very very long time compared how car was when I started modding it, too bad there has not been time for really test these.

[Piwoslaw]

67mpg? That is insane!

Have you tried making the airdam lower only on the sides, in front of the tires? I believe this is the new trend in OEM airdams. The lack of the middle part reduces frontal area, but the extra air going under the car doesn't increase drag too much because of the smooth bellypan.

[jtbo]

Originally Posted by Piwoslaw

67mpg? That is insane!

Have you tried making the airdam lower only on the sides, in front of the tires? I believe this is the new trend in OEM airdams. The lack of the middle part reduces frontal area, but the extra air going under the car doesn't increase drag too much because of the smooth bellypan.

It is insane, that is why I can't believe that, not with just one tank.

That modern airdam is what I do if I can get smooth bellypan made and sideskirts added, but before that I think it is best to keep dirty air out from underside as much as possible.

I had lower airdam section at front of tires but there was less than inch of clearance and that was bit problematic with our rough roads, even this 2 inches (50mm) is scraping, but at least it is not scraping on road, just when going to parking places and at most extreme bumps on road, we have quite extreme, but I'm sure you know a lot from those as I remember your beautiful country had quite a few potholes years ago, maybe roads are improved by now?

I think that I'm coasting easily more than 30% of time, also I can pulse and glide in lot more now, so in my car, underside seem to have huge effect.

Must get a pic sometime, airdam still would need to be smoother and better angled, it is bit of variable angle still, but hoping to get it better soon.

I would like to install air guide on hood, to reduce wind noise, but front edge or near windshield, which is aerodynamically better?

[euromodder]

Originally Posted by jtbo

It is insane, that is why I can't believe that, not with just one tank.

Stll, it's what you recorded

I had lower airdam section at front of tires but there was less than inch of clearance and that was bit problematic with our rough roads, even this 2 inches (50mm) is scraping,

Don't make the air dam too low, it increases frontal area, and thus drag.
You could lose the aerodynamic improvement to the increased area.

As low as the lowest major car parts is OK.
Going deeper only adds extra area.

I would like to install air guide on hood, to reduce wind noise,

Are you sure it comes from the hood area ?
Wind noise is mainly due to A-pillar and mirrors, or wipers, if they are largely exposed.

[jtbo]

Originally Posted by euromodder

Stll, it's what you recorded


Don't make the air dam too low, it increases frontal area, and thus drag.
You could lose the aerodynamic improvement to the increased area.

As low as the lowest major car parts is OK.
Going deeper only adds extra area.


Are you sure it comes from the hood area ?
Wind noise is mainly due to A-pillar and mirrors, or wipers, if they are largely exposed.

I had no evidence from anything else, so until I find some error, I must trust that be correct.

Drove bit more, now 1150km and still 1/4 tank left, if last 1/4 tank in gauge is same as in reality, then it would be again about same kind of FE, but I'm not 100% sure that it is, surely it is very close as I have usually seen 500km at half tank, and each quarter has been pretty much of 250km, that has made 5.5 to 5.8l/100km, but now with my current tank I'm again travelling some insane distances compared to time before mods and hypermiling, just drove slowly.

Frontal area increase is bit of issue of course, but there are parts that are quite low, like spare wheel and rear bumper is like parachute, so I put it quite low and then I hope to add sideskirts to control air entering underside a bit more.

Car's front bumper is not very high to begin with, but I did put it some 7,5cm lower with airdam, it seem to have quite large effect to fuel consumption, but I must gather more data to be able to say anything for sure, it might be that weather has been much nicer than before.

Better Kammback might help more, my current is rather crude with lot of sharp edges.

Wind noise comes from wiper and a-pillars + top of windshield. with air guide that would push air bit upwards, I might be able to reduce wind flow around wiper and also maybe would be possible to make air to hit windshield on bit better angle, at front of hood it did look better in flow illustrator, but that is not much of tool for the job, imo. There might be however point as air directed up would take time to come back down, if it comes down, other way would be to install it right at front of windshield, making cover for wiper blade (I have only one of them).

As I painted wheel skirts there was perhaps bit less rubbernecks, but people still stop and stare when I'm on traffic lights, maybe I should put some text to sides, like "lesser minds can't comprehend." or something as subtle and friendly. Most seem to think that someone would actually do such things for car because of looks, my mind is not enough to understand why anyone would do that, so I did order few stickers that remind with warning that has some strong wording how reading a tuning magazine will turn person to idiot, I think those will fit in very nicely.

[jtbo]

This is bit crazy week, I have to do quite few miles on road. Now most recent tank was bit less than previous one, might be because of my right foot too, but still over 64mpg, that is quite good for such car as ZX, front airdam is doing miraclous things it seems, it can't be that there would be error in two fillups and as I managed to get a lot further than before airdam with a tank, I can only point airdam being one responsible from better FE.

That is almost 10mpg change that has happened after I did install airdam, it is quite a lot, imo. might be that it is partly because maybe I have just adjusted to mods, like wheel skirts and kamm + now airdam.

Will see more results by end of a week.

[euromodder]

Originally Posted by jtbo

I had no evidence from anything else, so until I find some error, I must trust that be correct.

With tanks of 67 and 64 mpg, I'd say that's confirmed

Car's front bumper is not very high to begin with, but I did put it some 7,5cm lower with airdam, it seem to have quite large effect to fuel consumption

That's a big improvement - I really need to start modding my car

other way would be to install it right at front of windshield, making cover for wiper blade

I'd go that way.
The ZX's hood already has a nice upward slope to it, and the angle with the windshield is not excessive either.

maybe I should put some text to sides, like "lesser minds can't comprehend." or something as subtle and friendly.

Groar puts his fuel mileage on the window.
Something like "3,5 L/100km, et vous ?" might get their attention !

reading a tuning magazine will turn person to idiot

[jtbo]

My next tank will be disastrous, it is garden work time and it means I need to haul some supplies, our hills are rather steep here and I need 3rd gear to get up without flooring the car, when I have trailer full of stuff.

Empty trailer is like if I would have handbrake on all the time, full trailer is so heavy that car is really struggling with it, 60kph is ok, but trying to do 80kph is almost impossible at uphills.

Naturally I did put tire pressures to 44psi on trailer too.