I looked at some more performance differences between the Austro and Conti 155 HP equipped DA42’s.
Speeds are KIAS. All at MTOM (useful load comparable), ISA conditions.
So the heavier Austro-DA42 (plus 115 kg) with its less favorable CoG distribution (forward) has noticeable less favorable performance in most areas.
Exactly what I predicted 5 years ago 
Very interesting are the huge differences in slow speed handling, due to mass and more importantly drag. The Thielert is a very audacious optimization of the Mercedes engine with all the expected difficulties that killed the company and took years to get right but that is normal because why does Mercedes have to invest €1.5b to develop an engine when Mr Thielert can make significant changes to it for just a few millions? The Austro on the other hand is a very quick adaptation of the Mercedes engine with no real optimizations in weight and size. A much more conversative project with lower investments and as expected less initial trouble. As it stands today, I would say that the CD155 is by far the better engine compared to the Austro. If Conti actually get an improved TBR, it will be even more so.
I personally would definitely favor a CD155 DA42 over an Austro edition.
Achimha.
Your views on the Thielert engine situation are interesting, the financial downfall of Thielert was largely due to the corrosion issues that the engine had in the cylinder head, this corrosion was due to an electrolytic action between the cylinder head and the diamond heat exchangers with the cooling fluid being the electrolyte. It should be noted that these problems did not happen with the Thielert retrofit engines that used Thielert supplied heat exchangers.
The Austro engine is a more conservative design using the cast iron crankcase ( hence the extra weight ) but it should be remembered that the most Austro design team had previously worked on the Thielert engine and bringing this knowlage to the party gave Austro the knowlage of what did not work well so it is not surprising that they had a product that worked well from day one !
Yes, you confirm my point. Thielert innovated (lighter crankcase) and then as with every modification in engineering, the problems showed up later. The Thielert investors lost everything, the early customers got a lot of hassle but in the end a good engine came out of it (sponsored by the original investors) that Continental was able to pick up for peanuts and now they have a good engine that cost very little to develop and can go from there.
I very much sympathize with the electrolytic cooling problem because I was chasing a very similar issue on a common rail boat engine for years which was eating through oil coolers like there’s no tomorrow (one in 3 weeks!). Only after sitting with the engineer that originally developed the cooler (which by huge coincidence turned out to be pilot friend with whom I had toured Poland!) we were able to figure out what happened. The clever manufacturer (Volvo Penta) thought they could take a modern car engine which has a cheap aluminimum oil cooler and attach a classic marine style copper seawater cooler. Seawater + copper + coolant + aluminium was an interesting combination, clearly beyond the intellectual capacity of Penta and eventually only the very latest BASF Glysantin G48 showed to work. I’m sure it’s still eating aluminium but the pace is slow and my shelves are still stocked with replacement coolers 
Developing an engine is incredibly difficult and tedious. My engine developer friends at Merc tell me that despite all the greatest talent and computers, it’s still mostly black magic and done via trial and error.
I just received an e-mail from ATA in Southern France informing me that upgrading a DA42 with CD-155 engines will cost 165 k€ + VAT if done by the Diamond factory at LOAN, or 140 k€ if done by Crosby Aviation on Jersey.
Furthermore Diamond have so far converted one airplane – the one used for the STC approval, and Crosby have upgraded 2 aircraft, including their demo aircraft.
No wonder given the prices.
@Emir or @aart, do you have any different input wrt this upgrade?
I had the same information from my service center (in Merville)
That upgrade can’t be done by a regular service center.
They don’t just change the engine but also all the cooling system.
Rather that the 2.0s I will go for the Austro engine DA42-VI.
I flew one (converted from 1.7L) and it’s really nice. Much power nice climb rate almost no vibration anymore…
Don’t forget that the 2.0S is 1200 hours TBO instead of 1500 for the 2.0 and 1800 for the AustroEngine…
On the operating cost, it’s quite big…
Romain
Did the early DA42s vibrate??
It’s not really a vibration
I can’t explain it right in English.
The AustroEngine is smoother
boscomantico wrote:
Did the early DA42s vibrate??
Like Romain’s last post I would not say the Thielerts vibrate, but you definitely feel the difference between the CD-135 and the AE300. I did my MEP training on a CD-135 equipped DA42 and went on to fly with the AE300. I have not flown with the Thielert 1,7 l
The AE300
Romain wrote:
Rather that the 2.0s I will go for the Austro engine DA42-VI.
So would I if I had a rich uncle (or even the DA62). Given the prices I do not think a 2.0s conversion makes sense, expecially because you would in most cases also need to upgrade the GPS to WAAS.
Romain wrote:
Don’t forget that the 2.0S is 1200 hours TBO instead of 1500 for the 2.0 and 1800 for the AustroEngine…
On the operating cost, it’s quite big…
What is the overhaul/replacement cost for a 2.0S? Approximately.
