Hey guys,

I have spare stock turbo laying around, complete with pedestal. Are there any threads about adding a second turbo? I know I'd have to replace head bolts with stronger studs, find a good oil source, adapt the exhaust, etc. Anyone tried it already?

Thanks.

 

What do you call twins ?
One one each side? Or running them inline with each other ?

 

Twin "parallel" stock turbos has been done before. IIRC they were kind of laggy. Plus, I haven't seen any parallel setups really make too much lower on fuel only on a diesel.

IMO, not worth the trouble. Especially with what can be done with a decent single turbo.

 

I was thinking about a parallel setup. I forgot about the lag issue. Probably when it comes down to it, it'd lose boost because both turbos wouldn't spool up to full revs. Ok, forget I asked. :-)

 

Its an interesting thought though!

 

But two free turbos beat an expensive big boy...it just needs fuel...LOTS of fuel!!

 

Not always. I'd be cutting the exhaust feed to the turbos in half, so they'll take longer to spool up and they'll probably never get to full boost. Now if I have two turbos with a smaller A/R, that would work.

 

Its one thing to talk about this in theory, but the actually application would be a night mare.

 

Even with a smaller A/R you still need more fuel.

 

The physical logistics would be the hard part. The turbo for the left bank would have to be a mirror image of the existing one. You'd need separate custom up-pipes for each exhaust manifold to separately feed each turbo, and a separate downpipe to run down the left side, if there's even room. The other advantage, of course, would be true dual exhaust, with no two consecutively firing cylinders blowing exhaust into the same exhaust stream (which is the real objective of dual exhaust).

Since the OBS cab/frame was not initially designed for a turbocharged diesel engine, the stock setup is already a tight fit, with the well-known compromise of a god-awful stock downpipe. Fitting such a thing into an OBS truck would be just short of a nightmare, alleviated somewhat by a body lift. An SD truck would be a more welcome host for such a setup, since it was designed AFTER the PSD engine, and therefore designed to accomodate it.

 

I don't have any real experience in the matter but I have been doing some reading on turbos lately. When it comes to dual turbos, it seems that a sequential setup is the more popular choice of late. I believe it is usually done with a quick-spool, small turbo first, feeding into a larger, comparably laggy one. Apparently this gives the best boost vs rpm performance with a good compounding effect at high rpms. I don't remember which way the exhaust usually goes - parallel or counter flow through the 2 turbos. Of course there's LOTS of engineering that goes into these setups, and even if you could trial-and-error a decent setup on our trucks, fitting it all under the hood (as has been said above) will not be fun/possible. That said, I bet someone has done it already in a pulling rig or something :-) If anyone knows of such a setup, please post links - I'd love to read about it!

 

There are some parallel setups out there running, even one in an OBS truck. That OBS has a build thread on PSN somewhere. That was a nicely done parallel setup

There are also several compound setups out there in OBS trucks. The most popular would have had to been the WOP 4x4 race truck.

There are also triple turbos in two stages that have been done in OBSs. The WOP Lightning had triples when it was still a PSD and a sled puller up in NY by the name of Jacob Partridge had triples as well. I now have the BTS trans that was in Jacob's truck. Lol

Twin compounds are plumbed like this, basically..

exhaust exits the engine into a smallish turbo that will spool fairly quickly. Exhaust exits small turbo into a large turbo. Exhaust exits larger turbo and out the exhaust system.

Intake side works like this. Air comes in via the air filter into the large "atmosphere" turbo, boost exits the large turbo compressor housing and enters the inlet side of the smaller turbo, air exits the smaller turbo and goes into the engine. There may or may not be an intercooler after both stages.

There is a lot that goes into compound setups and tuning them would be a real pain if you don't understand pressure ratios.. lol

 

in the black truck with log built manifolds? thats the one i was reading about a while ago.

wonder if a quick spool housing would help anywhere enough to make a positive difference.

 

There was a guy in the North West that seemed to have his parallel set-up dialed in he was sled pulling with.

So, there are like thousands of compound turbo set-ups in the truck pulling, tractor pulling, and drag racing world, and 1 with parallels.
Should tell you something right there......

If you are stubborn and really want twin turbos of either variety, plan on 2 to 3 years before they even come close to running well. And that's with thousands and thousands of dollars in custom made turbos, and thousands more in custom tuning, not to mention all the custom made parts and other expensive go-fast supporting mods, and $$$$ engine build to hold the power.

I've run 3 different homemade versions of compounds so I speak from experience, just stick with a good 'ole single charger!!

 

I totally forgot you had twins and triples back in the day. Lol.