I will get the oil temp data by taking the vdo oil temp sender (thermister) in the sump location and remove the thermister and modify it for a thermocouple (thermowell).

I can drive the oil temp gauge with a D/A converter as well as the CHT gauge by modifying my program to feed the signal from the highest cht of the 4 to the cht gauge so it will always read the highest temp from the 4 cht thermocouples.

I'm not worried at all about oil temp right now because my cooler/ducting system never goes over 200F while driving at extended rpms for a long amount of time.

Sandeep

I'm interested in datalogging too, so your experience is very helpful.

Why are you converting the thermistor to a thermocouple? Are you using thermocouples for ambient and fan inlet temps too? Why?

The auto max-reading gauge is very kuhl. Will you know what cylinder is being read while driving?

I'm converting to a thermocouple for oil temp because the IC's I use to read the TC's have an error of 0.5 F and their output is linear. No need to calculate or extrapolate the temp from graphs that are provided for a particular thermistor, whose output in not linear with temp.

For AAT and FIT, I'm also using IC's with a linear output but the IC tells the temp accurate to 0.5 F, no TC's here and the IC is the size of a pencil eraser ... very small. FIT and AAT won't get above 50 C and the IC's are very accurate in this range.

The auto-max gauge concept is for me to tell if the heads are too hot when I am racing ... I can always tell which cylinder was too hot when I look at the graphs after the run.

I could have used an LCD on the dash to give me the required information, but I like the look of the gauges ... and I don't want my dash to look high-tech ... I want it to look like VW could have built it in '74 :D

Sandeep

Sandeep,
Head temps are normally not a huge concern in road racing except on the straights.

In the infield you are working in the upper RPM and in a lower gear which removes load from the engine..

Your datalogger will show this very well..

Sandeep, are you sticking with a 1 Hz sample rate? How did you decide what was enough but not too much data?

Cool charts.. Whats the 'FIT' measurement?

Fan Inlet Temperature

While playing with this datalogger, I've got some cool graphs and I've got the RPM sensor working now. Just have the Rear Wheel Speed sensor to make up to have it fully operational.

I was taking 1 sample per second to see if the programming worked (it did) but have now changed the code to take 1000 samples of each channel per second, taking the average value to get an accurate value to store.

This is limited by the registors in the microcontroller as to how large a value I can get before I divide by 1000. I used 500F as the value to decide this ... hopefully the heads will never reach 500F :laugh:

Sandeep

Wow :eek: this a awesome thread. Since I'm going to use the FAT setup, already got my fan and ring back from the powdercoater (I told you Zen I'm going to bite off your old setup). All I need is the shroud. I also dig the techno stuff a lot too. The data logger you setup Sandeep sounds very cool. Are you going to write up a tech article on how to make your own?

Nick

Sorry, no tech article on this one ... too much time into developing this project .. I've actually put the knowledge I've gained at university to use :laugh:

Some interesting notes on run 2:

1. Highest average head temp on 1-2 is 316F
2. Highest average head temp on 3-4 is 324F
3. Greatest difference between average 1-2 and average 3-4 is average 3-4 runs 37.9F hotter than average 1-2 -> not sure how great of a difference this is ... is it acceptable ?, here is where internal vane design comes in.

1, 2, and 3 are at different times during the run.


4. Highest average head hemp 1-3 (front of engine) is 311F
5. Highest average head temp 2-4 (rear of engine) is 324F
6. Greatest difference between average 1-3 and average 2-4 is average 2-4 runs 13F hotter than average 1-3 -> does not seem to be an issue, is this difference acceptable ?

4, 5, and 6 are at different times during the run.

Keep in mind this is a pretty stock 2.0 GA T4, not a fire breathing 2316.

More data with RPM, RWS to come ! :eek:

Sandeep

Great to hear your progress and payback from school. It sounds like your data is worst-case differences over time. I think the instantaneous difference and rate of change is what would affect performance/longevity. Your data doesn't sound bad though. How hard and long were you on it for these runs?

Are you going to sell your system? There is a lot to be learned with real time data and having a cost effective solution would be great.

good info. question, since these are averages and you noted side-to-side and front-to-back, is #4 tweaking the averages at all? based on info that has been shared in the past, seems that is a hard one to cool since it sits almost under the fan. what was peak and average of #4 by itself?

also, how would you define the average load you were putting on the engine through the runs? traffic? hills? flat?

any idea how the age/miles on the engine factor into this?

what advance are you running? and what ignition?

These are instantaneous values taken per second ... but I agree that the rate of change is what affects performance/longevity. The average values are computed per second so at X seconds, the averages are Y.

The data is already captured to show this ... I will add another chart to show how the temps climb when I'm "ON" it ... would be cool to see how long it takes the cylinders/heads to cool from lets say 350F to 325F or to go from 300F to 350F while driving.

The runs I have posted, I accelerate with foot to the floor, through all gears until I hit 70 mph and then hold 70 till I have to slow for traffic. The RPM and RWS will clearly show this when I install them.

No plans to sell the system ... YET :D

Sandeep

play with this too. would have never thought this the case until i saw Jake doing it with my engine on the dyno. when the head's are hot, kill the load on the engine and do some repeated revving (~0-3k RPM) and watch the head temps drop.

Time (Sec) CHT #1 F CHT #2 F CHT #3 F CHT #4 F Oil Temp F AAT C FIT C Engine RPM Rear Wheel Speed (kph) Average Temp 1-2 (F) Average Temp 3-4 (F) 34 - 12 (F) Average Temp 1-3 (F) Average Temp 2-4 (F) 24 - 13 (F)

692 276.62 290.40 314.52 324.85 49.23 63.01 42.34 1.10 1.10 283.51 319.68 36.18 295.57 307.63 12.06
912 300.73 286.95 307.63 328.30 66.45 45.78 59.56 1.10 1.10 293.84 317.96 24.12 304.18 307.63 3.45
913 300.73 286.95 307.63 328.30 66.45 45.78 59.56 1.10 1.10 293.84 317.96 24.12 304.18 307.63 3.45
925 311.07 311.07 321.41 324.85 49.23 42.34 52.67 1.10 1.10 311.07 323.13 12.06 316.24 317.96 1.72
926 314.52 311.07 321.41 324.85 52.67 45.78 49.23 1.10 1.10 312.79 323.13 10.34 317.96 317.96 0.00
927 311.07 314.52 321.41 328.30 52.67 45.78 52.67 1.10 1.10 312.79 324.85 12.06 316.24 321.41 5.17
928 314.52 317.96 324.85 324.85 49.23 42.34 49.23 1.10 1.10 316.24 324.85 8.61 319.68 321.41 1.72
929 314.52 311.07 317.96 328.30 52.67 49.23 49.23 1.10 1.10 312.79 323.13 10.34 316.24 319.68 3.45
930 314.52 311.07 314.52 324.85 49.23 45.78 49.23 1.10 1.10 312.79 319.68 6.89 314.52 317.96 3.45
934 304.18 304.18 317.96 324.85 52.67 45.78 52.67 1.10 1.10 304.18 321.41 17.23 311.07 314.52 3.45
938 300.73 283.51 304.18 324.85 49.23 52.67 49.23 1.10 1.10 292.12 314.52 22.39 302.46 304.18 1.72
976 290.40 286.95 321.41 324.85 49.23 63.01 52.67 1.10 1.10 288.68 323.13 34.45 305.90 305.90 0.00
1045 297.29 297.29 324.85 324.85 49.23 83.68 59.56 1.10 1.10 297.29 324.85 27.56 311.07 311.07 0.00


Not sure how this will show up ...

Well that didn't work ...

Anyways, the greatest difference I get between #1 and #4 is 48F, and that is at T= 692s, 1 is 276F and 4 is 324F.

Sandeep