Temperature difference before and after turbo

Hi Alfred

I believe that would depend on your intercooler size and location.  The installation manual calls out flow rate needed but I do not see a specific temperature delta.  

Cheers

I calculated temperature-delta due to compression only (before intercooler) and result is +9,5 Celsius degrees (delta-MAP is 3.6 inches). This means that in case of OAT 30 C degrees, before intercooler air should be at 40 C degrees and, after intercooler radiator, something less.

Unfortunately my Manifold Temperature shows 58 C degrees!

I understand that in the engine cowling temperature is high and this increase to rise the temperature in all air line. I understand that the turbo element (turbine+compressor) are hot due to EGT, but the idea that air is entering with +28 C degrees respect OAT in my cylinders, seems to me very anomalous... What do you think about?

I’ve not seen these numbers published by Rotax but I know that in the automotive world a turbocharged and intercooled engine will see intake manifold temps at a rise of 10 C to 30 C depending on airflow over the intercooler and demand on the compressor.  

Edge Performance has a video on YouTube showing a dyno test of a stock 915.  I clipped a photo (attached) showing the ambient air temp of 55C and intake manifold temp of 68C. So the net rise in temperature is 10C less than yours, but I would think they are testing in optimum conditions with fan driven airflow over the intercooler.  

I’m sure this is varies for different types of aircraft depending on airflow. You could start a new post asking other 915 owners the simple question: what is your typical intake manifold temperature?

Here is the video, about 2/3 way through they pan to the right hand screen where this information is displayed.  
https://www.youtube.com/watch?v=WOfqdxyj8NE

Thank you Jeff! Interesting video e information. But in the test ambient temperature seems to be 5.5 Celsius degrees!

You are right. Surely intercooler airflow is an important variable.

I started another post as suggested ;-)

Yes the first time I looked at it I thought the ambient temp was 55, and I thought that was suspect of being in error.  Now that I see it is 5.5 that seems suspect also. You would think the dyno chamber would be close to normal room temp.