Greetings!
I'm currently dropping an 1987 2.5 turbo in my 1990 300D 2.5 and noticed a difference in turbo compressor wheels. The 90 has 10 blades and the 87 has 12? Does anyone know if there is a compression ratio difference? I also submitted an inquiry to D&W diesel.

It's the same turbo. Count them again, I'd bet you missed a pair.

Just Kidding!

Check out the following link...

http://hartford.craigslist.org/pts/365060428.html

This is the only way I can post pictures, sorry.

Looks like the 87 uses a TB2510 while the 90 has a TB2535. In other words slightly different Garrett T25's (Vs the 300's T3).

I'd just use the one in the best condition.

I agree with ForcedInduction here and recommend you use the one thats in the best condition. If they are both in great condition I would say use the newer model, it might be slightly more efficient.

__________________
green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

Well there is no shaft play in either turbo. The 1990 turbo has almost 300K miles on it and the 1987 has 90K. The 1987 turbo has a little more resistance than the 1990, similar in comparison to a new and used wheel bearing. Both spin freely, but the 1987 has a slight resistance which could be due to lack of use.

What I've discovered so far as differences on these engines.

I've noticed on this engine swap that the heater core lines are different, turbos, egr, turbo outlet section piece, and injector pump. I'm sure there is more as I start the assy.

Check the craigslist link above for updated pics.