Howdy folks, I just bought a 1991 Dodge D350 based Swab Ambulance, with the 5.9 12v engine in it.

It's currently got a pair of really rather cheesy exhaust stacks on it, which led me to look at the exhaust setup as a whole, and start doing research. Which led me to a page here, https://www.dieselbombers.com/5-9l-r...bo-5-rest.html talking about downpipe upgrades and so forth.

One of the issues mentioned was the amount of bend in the stock downpipe. And, indeed, looking under the hood I can see that the first elbow out of the turbo is bent pretty sharply.

Another thing I wanted to deal with was the air intake path, and making that as cool as possible.

Combining these ideas led me to this one: What if I rotated the turbo on the exhaust manifold flange, somewhere between 5 and 15 degrees (I haven't taken any even preliminary measurements yet) so that the exhaust output was pointing down already, and the air intake was pointing up? At that point, I could (basically) just cut a hole in the hood and make an airbox that fit up through said hole, thereby drawing in cold air from outside the vehicle.

Now, clearly this is a fabrication intensive project, either requiring some sort of machined adapter to let the turbo be moved or a completely new fabrication exhaust header with the flange rotated, as well as rerouting / fabricating the oil feed and return lines, and the airbox, downpipe, and hood work. That part of it I can handle.

What I don't know is whether altering the position of the turbo like that will cause problems, especially if I end up driving up a steep hill, further tilting the turbo off its normal orientation. I'm specifically wondering about oil flow / sealing / leakage issues, making sure the oil drain line is still pointed down enough, and so forth. This is the first turbocharged vehicle I've ever owned that I have contemplated modifying (my wife's turbodiesel Jettas are definitely not on the cutting block, ever... ) so I have basically zero experience with turbochargers. I found a couple articles saying "never more than 15 degrees", but I don't know if that's "You can do it if you have to, but it's a stupid idea" or "It's actually ok to do this".

Thoughts? Kudos? Ridicule?

 

Can it be done? Yes. Should it be done? Not really.

An adapter to "clock" the turbo in the direction you want will cause more problems then it will cure. Assuming it is a standard D350 pickup cab (more or less) there are now 4" downpipes for the 1st Gen trucks that make the hard bend and come in either H1C/HX35 or HX40 style flanges, so no real need to clock the turbo for the exhaust's sake. If things are REALLY tight, there are the "cobra head" options too. Most everything I've read or heard claims 5" to be way overkill for a single turbo, aftermarket or stock, unless you're running something massive as a single charger. A few aftermarket exhaust companies even tried to claim that the turbo likes a little bit of constriction closest to the turbine to keep exit speeds up...but I haven't seen data on that and I'd probably say it too in order to sell my not-overly-massive exhaust systems.

As for the intake, why can't you do what you are suggesting with it as is? Run an elbow off the intake side over to the fender, build a well insulated and sealed-to-the-hood box for the air filter, then add on a scoop, either through the hood like a Shaker or under the fender like some "ground snorkles" available, and ride on with cooler intake temps and lower EGT's!

Search "cold air intakes" and "BHAF Big Honkin Air filter" for some buildups on intake systems.

 

Notice the bolts? Loosen all six on the housing, rotate housing to desired position, tighten bolts. Both housings have bolts that you can loosen to clock it. All the while, leaving the center cartridge alone. No need to worry about oil feed and drain.

 

Clock it ya squib