Unimogadventures - Our build and travel thread

[Iain_U1250]

I got myself and anemometer, just a cheap one off Amazon to do a few tests on airflow through the radiator.

I've got a 16" Bosch fan I had spare off an Audi S4, and it works quite well.




I did a few tests yesterday, and some more scientific ones this morning.






I copied a similar method as another Unimog owner did on a stock mechanical fan and bare radiator.



The results are similar to what I got, and I have an a/c condenser and another fan in front of the radiator.

The airflow varies quite a bit across the radiator as you can see in the results.


I did the all the test with the bonnet up.



I'll figure out the way to fix the anemometer to the radiator and connect it to my laptop, and go for a drive and see how much airflow comes through when I am driving. I might have to resort to using cable ties and strapping it to the grill.

 

[Iain_U1250]

Another project done, I've fitted a new bigger water - air intercooler and heat exchanger, with a bigger fan as well. I found the old one was leaking after 70,000km /9 years, so decided it was worth fitting something a bit bigger, The old one developed a leak, and whilst the engine was running, the boosted air from the turbo would blow water out the system, but parked up, the water would leak out, but since the intercooler is lower than the intake, it ran back down into the turbo, not the engine.


This is the new setup








The new heat exchanger, with a 11" SPAL




This is the new intercooler - it is twice the size of the old one.

It seems like I have some thing quite similar in size to the S600 / S65 OEM heat exchangers so on mine, with about one third of the power, so maybe it is a bit of overkill.

Intercooler size. The new one has 297 cu inch / 4866cc
Heat exchanger size - 12"x12"x2" / 305x305x50mm = 4651cc

Mercedes S600 Heat Exchanger 02-05 (536-hp, 5.5-liter twin-turbo V12 )
580x 265 = 1537 cm2 x 21mm = 3228 cc


Mercedes S65 Heat Exchanger 04-05 *630hp, 6.0-liter twin-turbo V12 )
580x 465 = 2697 cm2 x 21mm = 5664 cc





The intercooler is not vertical, but tilted to that there is more space under the intercooler for the air coming through the radiator to escape out the bottom of the engine bay.



I've made sure there is enough flex between the intercooler and the engine, with a double hump hose from the turbo to the intercooler, and a 3.25" to 3" 45 deg silicone elbow from inlet to the crossover pipe, then a 3" 90 degree elbow to the intercooler.

Initial test drives have shown it is has dropped the intake air temp from around 70-75C, to around 63-70C, with out running the electric fan. I'll set that to come on with the intake temp gets over 50C, and off again when it is 45C, and see if that makes a difference.

It has all taken a bit longer, I I bought a new toy to play with - our new beach van.

I started life as an airport taxi shuttle,



but is a bit different now.