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

[Piwoslaw]

Any updates?

[jtbo]

Sorry for lack of updates, did not visited board during summer as there was much of anything happening in mpg front, summer is time when I don't drive as much because I'm on vacation so didn't need fill ups either.

I took aero mods off as winter is coming here, snow and aeromods is perhaps not good combination, car clearly rolls less and is bit more noisy now.

Well if we are accurate car did actually burst radiator yesterday and it is really not moving at all currently, I'm getting another car, but perhaps I fix ZX and sell it or keep, depending of how my future work lines up, but it is going to be now at least a month until ZX is moving again.

Replacement is going to be Volvo 340 1981 Variomatic, very thirsty, I know, but it is more like hobby car which I'm not going to drive much, it is just one for collection really.

I did took two fillups from my android device which I use to keep fuellog for my cars, I don't know about that price per unit if it does it right or maybe I have done it wrong, quite big difference in price per gallon.

With speeds I drive mods did work surprisingly well, I still left front air dam as it seemed to have greatest effect, so I let that be even during the winter too.

I did not manage to get as low as 3.6l/100km second time, must had wind from behind almost everytime I drove back then, car felt like going really well then and I should note that then I had front air dam so low that it scraped almost at every bump, had to take 50% off from it to stop it scraping constantly and everywhere. So I think that underside has some huge effect in this particular vehicle, close to one litre compared to unmodified.

So next week is going to be hypermiling at rental car, might be interesting

[Piwoslaw]

Originally Posted by jtbo

I took aero mods off as winter is coming here, snow and aeromods is perhaps not good combination, car clearly rolls less and is bit more noisy now.
[...]
With speeds I drive mods did work surprisingly well, I still left front air dam as it seemed to have greatest effect, so I let that be even during the winter too.

I'd say that the front air dam is the first thing that will cause trouble in the winter, especially in deep snow. Next would be wheel skirts, though I haven't had any problems with snow/ice/mud building up inside mine. The kammback causes no problems in the winter, in fact it keeps snow off the rear window.

[jtbo]

Originally Posted by Piwoslaw

I'd say that the front air dam is the first thing that will cause trouble in the winter, especially in deep snow. Next would be wheel skirts, though I haven't had any problems with snow/ice/mud building up inside mine. The kammback causes no problems in the winter, in fact it keeps snow off the rear window.

With amount of salt they use around here, there is not enough deep snow for front airdam to touch it, but as my kammback was made from thin wood it would not been able to whitstand the constant salt water bath, freezing water, and so on, also as design was not quite perfect it was not keeping rear window clean as well as it could been, so it is easier without mods however if mods would of been final and not prototype of course they would of been designed to whitstand the conditions.

Can't say that there would be huge difference, but certainly noticeable as I have now driven bit more.

Rental car hypermiling did not wen't so well, first rental car blew wheel bearing, second blew radiator, oh the irony, reason why I had to use rental car in first place was that my car's radiator had big leak.

Third one was better, did not fail but it was impossible to hypermile really, Yaris 1.4l D4D, accelerator had very short movement and engine management added more throttle without asking etc. Managed to do only 4.1l/100km with it.

My right hand is still bleeding a bit, radiator had rather sharp fins, so little space so managed to cut hand from thumb to elbow while trying to twist my arm, it looks bit like sliced or so, I always bleed while doing such things

[jtbo]

A-ha, finally did fill up the tank, not much driving during the winter, but what a horrible tank it was, barely better than 35MPG, usually conditions were such that car did not want to go, lot of snow on road, despite my best efforts I did not manage to meet even EPA/user's manual statement and I have been using all of hypermiling tricks, also have driven very slowly, I have had full grille block at front too for whole winter, but still no avail, probably would have been lot worse without all the tricks, but still what a poor tank it was.

2012-03-19
843 km 523.82 mi
6.58 L/100 km
35.73 mpg (US)

I have another car that I will use probably bit more for short trips, but maybe I try to beat my record and do some aeromods for this car too.

Only mod during winter was that front lip/dam, had no issues with that, but my bumper repair did not like when I used car as snow plow to open my driveway a bit, so I need to make new repairs for the bumper and I thought that I will make it so that there is fully new airdam that acts as bumper too, also planned a bit about new Kammback.

This time those will not be made from scrap parts, but from new sheetmetal to be more durable and with plenty of material, I should be able to make it bit better functioning too.

With help of mother nature, I have got some new shapes designed

[jtbo]

Lower grille block for summer time and stealth paint work



I might paint rest of it too, not quite sure of that yet. I try to achieve rat look.

Might call it eco-rat. At least it is super ugly

Lower grille block is actually made from clear plastic water jug, just cut, screwed in and painted, even I plan to make better parts for it for summer, I really like from salvage from garbage approach.

[jtbo]

I put my summer tire set to this horrible thing now, Continental Viking Contact 5 winter tires with really low rolling resistance.

Instantly it did roll better, but could of been better, of course it was wet weather, but also tire pressures were only 2.4bar, so need to add a bit of those.

One rear brake seemed to bind tiny bit, tire rolled only about a turn when I give it speed with hand, but wheel seemed not to heat up. I need to evaluate effects of that and when weather is better might open brakes, it is just one of the most annoying jobs that I know of. I hate those springs in drum brakes...

If I aim to 3.5l/100km, that should not be too much to achieve, I believe.

edit:
I have been trough fuel logs and done bit of thinking, also put more tire pressure but that seemed not to make too much of effect.

For some reason weather affects a lot to my fuel consumption, wind and if it is wet, snow seem to kill fuel economy completely.

Also car seem not to slow down incredible fast, but it does not gain speed on downhill as well as before either, mostly what is different is one tire being normal summer tire and front lip is not on as well as spare wheel under the car is missing as it is that 4th wheel.

When driving on level ground car does go rather lightly, but it seem to need adding of throttle to smallest hills or it will stop middle of hill. However it seem to go as far with as little of speed decreasing when I coast down.

When I hit damp section on road it is like pushing brake slightly, car slows down clearly, but there still is no change in boost gauge, it reads more or less 0 on normal driving on level road.

So, maybe tires are causing lot higher amount of rolling resistance on wet road, I have read that around 15% is effect of wet road. Also I think that air going under the car is causing now a lot more drag and front lip had helped previously with that, also spare tire location might act as a parachute now, so it would need covering up.

Need to get car to MOT station and when that is done, I will need to start putting something together for aeromods department. Even mods don't seem to make much of difference when you put them on, taking them off is making car feeling like it would have handbrake on.

That front lip seem to have rather large effect at least, steep long hill where I now (with only lower grille block) get speed increase from 40kph to 80kph was with front lip 90-95kph and with mini kamm, wheel well covers, grille blocks and really low front lip 105-110kph, I guess it is around that much that mods can help.

I did try to do some coast down testing of cd and rolling resistance calculations, but it is really difficult to find level smooth road in here, almost every second on video there is loud BANG as there are rails across the road, also car is jumping up and down constantly and there is always downhill or uphill, oh and corners, 200m of straight is quite typical between corners, need to travel quite a bit to find some road that would be suitable for proper testing.
From numbers I managed to record I got CD of 0.247837426 and CRR of 0.018858425
Now I don't believe even a second that CD could be that, .35 I might believe is good salesman would say that, but .25 level is impossible. Sure car has aerial deletion and roof rack deletion, but it is station wagon.

[jtbo]

I did do more coast down testing as now roads are frozen/dried out.

Cd = 0,362654627
CRR = 0,013188244

There are bit room for error as road had uphill at both ends, rather slight and also tiny turn too, several cracks on road and generally very bumpy road surface.

I did only three drive back and forth as it was already past midnight, but there was no single other car out there.

Results might be better if I would do two series of six test so that car would warm up, it was below zero so it takes bit of time to car to warm up and start moving properly.

Anyway I found out that it does coast a lot better than what it did at daytime, certainly wet road surface causes a lot of rolling resistance with my tires.

Now I have at least base where to compare when installing mods.

I hope to make mods so that they would be easy to take off and put back for testing, but how to attach them to achieve that, is still bit of mystery to me. Maybe I just drill holes and put those bolts where other end is smooth and round, I can put wing nut to other side or nylock nut. It might be just tad difficult to drill completely trough the trunk door, it has so small frame around window and as it is some form of plastic/composite it might not be strong enough for that.
Hood is no issue (wiper cowl) same for front bumper.

Rear seats I take off soon, had bit of accident and managed to have coolant canister leaking to seat for few days, so I think seats are useless now, at least I can now change car taxation class for cheaper.

Intercooler air pickup is from upper two grille holes, I can perhaps block partly/fully two lower grille holes from upper grille, but for better effect, maybe I should try and move intercooler air pickup to lower grille where are those two places not blocked up yet?

Intercooler is at top of the engine and cooling effect is by ram air kind, faster one drives, more air goes trough intercooler. I wonder what location might provide least restriction while maintaining airflow?

Sadly intercooler is made so that it is part of intake manifold, so I can't relocate it, it would be easier to manage airflow to it if it would be at front.

[Piwoslaw]

Originally Posted by jtbo

I did do more coast down testing as now roads are frozen/dried out.

Cd = 0,362654627
CRR = 0,013188244

Those numbers look much better. When I was doing my coastdowns a while back I noticed that passing cars had the greatest effect on the results - one truck going the opposite direction could nullify the whole test run

[jtbo]

Originally Posted by Piwoslaw

Those numbers look much better. When I was doing my coastdowns a while back I noticed that passing cars had the greatest effect on the results - one truck going the opposite direction could nullify the whole test run

There is really big margin of error however, with only three runs I get lot of variation with even 1kph difference, I need to do more tests and use GPS, speedometer is not enough accurate and as error in speedometer is not same all the time it can throw results off by good amount.

Also need to find more level road.

I did test and watched videos again, inputted data again and now I got cd 0.24 when using speedometer numbers, did same yet another time but used corrected values, not sure if corrected values were right and got cd 0.56.

So even smallest error can cause huge effect and one needs to really make that at least 6 runs and with gps it would be lot easier to get correct speed, update rate of 1 second in gps should be enough for testing too, so perhaps next evening I can do bit better, also wind should be more calm then, it was not big but certainly enough to affect last time.

One way to improve accuracy would be to do 12 runs and just average two same way runs to table so one would get double accuracy, well at least in my mind.

Either way, all measured cost downs are good when comparing to runs done with mods, just that mods still need to be made and installed, but soon :P