After months of researching and searching, I finally got my hands on what I believe are the best available intake and exhaust manifolds for the OM617A.
The most power MB got out of the OM617 was in the experimental C111 concept cars built in the late 60s/early 70s. The motor broke 9 different diesel & gas world records.
That OM617 produced 228HP, and was capable of 200+ MPH. (So this is my Ultra4 motor now

). The
C111s are interesting to read about, they got their extra power from upgraded manifolds, an intercooler, bigger turbo and a modified cam (which I’d love to find the specs on).
That intake manifold is the same as what’s on some
1975-76 W115 cars. I was pretty excited to find one and get my hands on it. Unfortunately, it didn’t play well with the 404’s engine bay. It could have worked, but I’d have to move the firewall near the passengers feet and would need a ton of work to get an intercooler in there. So I kept looking for this other exhaust manifold I only read about….
In the 90s MB came out with
a light cab over van and AMG designed an OM617 for it. It had a very similar intake to the one above but it didn’t swing out from the block as much so it was taller and the intake was at the front vs the side. Two big bonuses for fitting in a Unimog's engine bay. The one I scored off Germany’s eBay a month ago showed up today and you can really tell the difference.
While I can’t find many specs, I’m counting on the fact that these were designed by AMG 30yrs after the ones in the C111 vehicles that they will have equal or better performance. 🤞🏼
The exhaust manifold pictured are found in some 79 300SD models cars. Also hard to come by because they have the largest primaries of any OM617 exhaust manifold and no egr components to disrupt flow.
aaaaand my stainless pie shapes showed up from Summit today so I can finally start finalizing the downpipe size/shape. If things line up the way I hope, I could actually have a straight straight-pipe exhaust.
