cd=0.325 to cd=0.31 in 3$ tape upper grill block

[ausias]

My car is a Seat Leon 1.9 tdi BXE 77kW (spanish VW Golf) you could see in the attached frontal view pictures the differences between a cd=0.325 gray 2006 version 5.2L/100km (EU averaged), and 0.30 2010 ecomotive (3.8L/100km).

My first tray has been blocking my upper front grill with tape because Seat uses a plastic one in a car with +37% mileage (-27% L/100km) than mine, and second because the Racing version of Seat Motorsport and other preparations use a different full blocked, partial blocked upper part of upper grill, full upper blocked but with a direct hole to airintake... all of them are PEtrol engines from 200 to 300 bhp, or diesel above 250 bhp. Mine with 105 bhp, maybe doesn't need higher air cooling on my radiator, front intercooler and A/C condenser than Racing Seat Leons producing 2 or 4 times the heat.

I will buy the upper grill made of plastic at Seat Dealer, but first I must to solve a little thermostat issue (that opens near 80ºC, and not 87ºC) that it seems very common on VAG engines. I discover it because of large data logging using OBDII port (with Vag-com 311.2, because is not needed CAN-BUS VCDS if you only want engine module be accessed).

I did some accurate runs at 18ºC and 23ºC (influence temp. difference below 1%), at 82-94-122 km/h, and because of overcooling my fuel consumption have a 4% increase (-3.9% MPG).

This first aerodynamic success of -5% drag has motivated me on going to 0.30 or even better. To improve my fuel consumption expected -5.2% on average. When my thermostat and aeromods will be adjusted i'm waiting for a -10% fuel consumption. From 6.7L/100km to 6.03L/100km, that is 35.1 to 39.0 us mpg.

If i did these mods with Seat original german design parts it will cost around 93€ (closed black grill+central spoiler+thermostat+G12 refrigerant). I will post my numbers then.

My actual numbers, open grill ->tape closed grill:
82 km/h: 4.36 -> 4.23 L/100km ; 53.9 -> 55.6 us mpg at 51 mph
94 km/h: 4.73 -> 4.57 L/100km ; 49.8 -> 51.5 us mpg at 58.4 mph
122 km/h: 6.67 -> 6.42 L/100km ; 35.3 -> 36.6 us mpg at 75.8 mph


Also I realized this morning that my TDI cam timing is -2.5 to -2.0, so my cam timing must be changed because is delayed. When the volkswagen plants makes the engine the cam timing is set now between -2.5 to 2.5 on PD engines (rotary iinjection pump range was -5 to 5) this margin is caused of visual accuracy on mounting. A perfect timing will need some trial and error occupying valuable minutes-man in the factory line. Better setting must be 0.0 to 1.0, but foud in several discussions in forums like Fred's TDI Page. TDIClub.com. VW TDI Enthusiast Community they say better cam timing is advanced one in the range 2.0 to 5.0. I have a 1.9 TDI 110 cv AHF with the timing at 5.0 set at the Dealer when changed the timing belt, and If i can i would swap this two engines altought mine has 58.000 mi, and the AHF engine 190.000mi. I'm going to set this and accurate measure the changes in fuel consumption.

I didn't expect my on road accurate measuring based on OBDII (wind and forecast also,...) will make me tuning the engine first,

[ausias]

I did some fine tuning in my camshaft timing and now I'm getting with the open grill this amazing figures L/100km@km/h:
3.90@82
4.23@94
5.75@122
when I try with closed grill I'm waiting for 3 to 4% additional reduction in fuel consumption.

[ausias]

I closed again my upper grill wich added to my actual fine tuning in the camshaft timing now I got this really amazing figures in L/100km@km/h:
3.80@82
4.02@94
5.50@122

Time to write a Success Story! +15 to +21 % us mpg, and -13 to -18% on fuel consumption in L/100km, Congratulations to me.
http://ecomodder.com/forum/showthrea...3-a-19233.html

[ecomodded]

I also plan on blocking my grill, I want to use a scrap bumper covers plastic, cutting it to fit one piece over the grill cutouts,a great thing about diesels is they run cool so grill blocking is less of an issue than with its gasoline counter part..
Great idea using vag com to find out your thermostats opening temperature, Do you know offhand if you can find the oil temp. and pressure in real time with the vag com free edition? if so then I may just mount a lcd screen instead of 3 or more gauges.

& Congratulation on your improved fuel mileage !

[Ladogaboy]

Nice numbers! This will probably one of the next budget ecomods that I do.

[California98Civic]

This is interesting. Nice results. But I'm not totally clear how the test was constructed. For example, how did you control throttle? Cruise control? Use a gauge of some sort to monitor it? And I'm intrigued by the CD calculatinos but I can't see how you reached these CD values from your MPG numbers.
Thanks,
james

[ausias]

Originally Posted by ecomodded

I also plan on blocking my grill, I want to use a scrap bumper covers plastic, cutting it to fit one piece over the grill cutouts,a great thing about diesels is they run cool so grill blocking is less of an issue than with its gasoline counter part..
Great idea using vag com to find out your thermostats opening temperature, Do you know offhand if you can find the oil temp. and pressure in real time with the vag com free edition? if so then I may just mount a lcd screen instead of 3 or more gauges.

& Congratulation on your improved fuel mileage !

Blocking the upper grill of a Beetle? ahahah
I tested a Skoda Octavia 1.9 Tdi 110cv AHF wih upper grill block because it uses the same vag platform of New Beettle and I also get -4% fuel consumption or 1/0.96 more mpg , so -5% in cd.
I decided covering my upper grill on Seat Leon II because 2011 New Beetle uses the same vag platform of Golf V/VI, Jetta, Octavia, A3, ...

knowing coefficent of rolling resistance, cd and engine power in liters per hour needed to maintain each rpm you could predict fuel consumptiom. I also used power torque and BSFC map (eficiency map).

Fuel consumption in L/100km has units of force if we transform liters in energy being divided by distance. With gear ratios, diferential ratio and wheel radius we can also predict torque wathever we want (if eficiency map is known).
Fuel consumption in L/h measured from ECU give power because L iters mean energy with some conversion factors (if eficiency map, BSFC, is known or well aproximated very low uncertainity results are easy to obtain).

Nevertheless, I'm wondering if cam timing is affecting OBDII ECU fuel consumption, torque values because my las average full tank diesel filling get me 6.6L/100 km on average, although my data logging on higway driving with on large 220 km travels of 5.4 L/100km or city insane and inefficient driving of 6.26L/100km.

Furthermore I'm wondering if real fuel saving is produced when Torsion or Camsahft Timing is set advanced (maximum i could get is +2.9) when my Engine Channel 15 says fuel consumption of:
4.3 at 82 kmh
5.2 at 94
7 L/100km at 122 kmh

All this values are result of averages of N between 600 to 1000 counts, measured at night on the same higway closed loop with no climbing or downhill, no wind, etc.

I did some prePhD investigation and works on data logging onboard Railway, Tramway,Car,Speedboat,Crane, drivers eye movement,... on doing risk assesments, road safety, modelizing physics for virtual simulators, etc.

I have my own fuel consumption model emphirical-theroteical that I used to predict fuel consumption on driving similutarors, or electric trains, petrol engines, diesel engines, turbo, variaible geometry turbos, etc. I'm using Matlab, etc.

Cd calculation is from fuel consption changes derived, my direct measures on aeromods are Top Speed improvements (using power torque, power to wheel, calculations, drag forces, engine drags, etc.) and relative fuel savings (-4% L/100km means in my car, with my tires, gears, engine eficiency very aproximated map, etc. a cd reduction of -5%, -8% air drag coeficients means a theoretical -6% fuel consumption but not in all rpm beacuse of nonlinear eficiency, tire rolling resistance weight, etc.).

If my fuel consumption model (empirical tested on diesel or electric train, some diesel cars, some petrol SUV, diesel large VANS and some Sport cars my prediction's uncertainity used to be +-0.1L/100km or less) predicts -4% reduction if only changing cd (make says my car has 0.33 or 0.325) from 0.325 to 0.31 and I measured -4% "real" OBDII fuel consumption only aero changes made, I think iterations of changing cd parameter get me 0.31 value as best fitting, I'm agree with that value being the new one.
I mounted grill block and spoilers from 2010 Seat leon Ecomotive (make says cd=0.3) I realized realtive improvement being correlated to predictions if cd used in my calculations is down to 0.3.

Recently I upgraded my full grill block with a rear grill 90% polycarbonate block, sso I reduced Intake temperatures and results are near 0.3 maybe 0.305, but I'm sure far enough from original cd to measure precise changes.

I'm sorry about so long explanation, maybe hard to understand.

[aerohead]

In past years the Society of Automotive Engineers SAE published reports on road-testing protocols.
There recommendations were to do a preliminary warm-up cycle of at least 35-kilometers at a continuous 80 km/h in order to stabilize the tires and all lubricants at an equilibrium temperature,and in so doing,stabilize the powertrain losses.
Without the warming cycle,mpg numbers were penalized until the vehicle reached 'equilibrium.'
I wasn't sure that you might be doing this during tests.Just wanted to mention it.

[ausias]

Originally Posted by ausias

I closed again my upper grill wich added to my actual fine tuning in the camshaft timing now I got this really amazing figures in L/100km@km/h:
3.80@82
4.02@94
5.50@122

Time to write a Success Story! +15 to +21 % us mpg, and -13 to -18% on fuel consumption in L/100km, Congratulations to me.
http://ecomodder.com/forum/showthrea...3-a-19233.html

Maybe It's time to Myth Busted Camshaf timing feuel saving.

The real thing is throttle response changed a lot if cam timing is advanced retarded or out of range but in a starting engine region (go out of range and soon car will not start and will get cold start problems). Top Speed changes are very noticiable between -5% to +3% from my standar timing. The best result of +3% was obtained when my Torsion or CAm Timing is set to 0.0 and my aero addons included low spoiler, fixed wheel spoilers (I had broke right one) and 90% upper grill block with cold air intake and top of radiators(a/c condenser, intercooler and coolant radiator) wind exposed. REaltive measured fuel consumption is about -6%, if efficiency supposed constant drag Force will be -6% and -8% drag coefficient could be responsible of that change (drag is a parabollic function of speed, at large speed and with rolling ressitance negligible aproximations could be done: 2 times the speed need 4 times de force needed, or 103% speed means 106.09% force, or 96% force means sqrt(1/0.96)=102% speed). Because at Top Speed I measured -4% L/100km but max power torque curve being limited by ECU it seems and less throtle means less Load and lower efficiency (in a non linear maner Brake Specific Fuel Consumption (BSFC) Maps - EcoModder) like my cd go down again and is near 0.3. If my own car height, width, 3d fronal shape is equal to Seat Leon Ecomotive (almost equal front original grill not fitting in 2005-2008 versions, and only in restilyng) if I add central lower spoiler and did my own block grill, I think my expected cd of what VW says is coherent result of my numerical model curve-fitting.

I lost in my own explanation I think I overanswered your questions.
I'm sure my aerodynamical improvements are working, but I suspect BOSCH EDC16 ECU is missing some high precision sensors. Maybe when ECU says 7.0 L/100km at 122 (+2.9 cam) it's not 107% fuel consumption but 93%. I will test with full tanks or large trips of hundred of kms.

I think 10% improvement in specific fuel consumption its the limit, becuase better of 190g/Kwh BSFC I think is difficult of an engine expected to do 200 or 210 g/KWh as best.
I know the same engine with ECU maps could range from 190 to 260 g/Kwh, 166 bhp to 230 bhp versions, best of 200 but 250/260 at full power 4000rpm etc. I'm motivated to learn how to obtain DIY ECU optimization on fuel economy if I can without spending a lot of money (300 to 400€) on a chiptunner. I would need first doing a backup of my ECU, after chip tuning other backup and comparing two binaries (Is there any software to do this? ). These firsts attempts challenged me.

It will be helpful if any of you could do the same tunning of the camshaft and test on full tank average L/100km or mpg mileages, and share our data. Or if you try some data logging OBDII.

[ausias]

Originally Posted by aerohead

In past years the Society of Automotive Engineers SAE published reports on road-testing protocols.
There recommendations were to do a preliminary warm-up cycle of at least 35-kilometers at a continuous 80 km/h in order to stabilize the tires and all lubricants at an equilibrium temperature,and in so doing,stabilize the powertrain losses.
Without the warming cycle,mpg numbers were penalized until the vehicle reached 'equilibrium.'
I wasn't sure that you might be doing this during tests.Just wanted to mention it.

I did with stabilizaed fue and coolant temperatures, I'm limited of 3 channels recording with vag-com (1 channel 4.5 Hz, 3 channel 1.5 Hz), I could measure intake temps also (all the test ambient temperature ranged from 18 to 21ºC, 291 to 294K ik think it's the same), I run 2 km of city, 22 km at 122 kmh, 22 km at 94, 22 km at 80, and sometimes some power torque curves or more speed.

TEmperatures oscillations were low, and I seen at 122 and with grill blocked stabilizez temps in first km and minutes. I did test in the same conditions I could. I plot the data in Excel and did averages and std. desv. and all of them are compatible. Maybe 122 runs were affected a lot and better fuel consumption could be measured.

I've seen oil temp in previous Tdi I get on MFA and vag-com, but I need to find if exists on my engine i what channel (I don't have label file of exact block names for my BXE engine).

I used to pre-warm the engine before Vehicle Technical Inspection (ITV in spain) with A/C at maximum and without turning off the engine when in line, because here opacity and emissions are measured (I clean EGR and Intake if needed as periodical maintenance). I'm scientist but in my University we don't have acces to SAE, because almost of the engeeners are in the Polytechnic University of Valencia.

A sample of what I get with logging includes:
,Group A:,'006,,,,Group B:,'007,,,,Group C:,'015
,,Speed,Bin. Bits,Load,Bin. Bits,,Temperature, ,Temperature,Temperature,,RPM,Torque,Fuel Consump.,Torque

I attached some plots of my fuel consumption model, data logged using vag-com, and a table of averages values and standard devisation.

Added answers and fuel "improvements" using a 90% upper block made from polycarbonate. And different values measured from different cam timing with this new aerodynamic setup. In this thread: http://ecomodder.com/forum/showthrea...3-a-19233.html