Setup for compound turbos
 

Im trying to figure out how the turbos should be setup and if im right with my thinking. Should ty be setup like this: engine to the bigger turbo then feeding to the smaller turbo with a wastegate in between the two. Im not sure if that's correct or if there's a better setup.

PM RAWilliams he just fabricated his own compound set up and has a thread in the Dodge Tech Section of the forum.

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Its for a 98.5-02 but he can tell you the basics.
https://www.dieselbombers.com/5-9l-2...urbos-2-a.html

Small turbo is on the exhaust manifold, larger primary turbo is on a bracket bolted to the engine.

Filter goes on the compressor inducer(cold) side of the primary turbo. The outlet(exducer) side of the compressor housing is plumbed into the inducer of the secondary(small) turbo. Then from there the air is fed into the intercooler. On the Exhaust(hot) side the manifold feeds the secondary turbo, then the secondary turbo feeds the primary turbo through a hot pipe and finally the exhaust gas is expelled through the primary turbo and down the down pipe.

Thanks! Should I have a wastegate or not?

YES. External gate screw internals gates. They are extremely ineffitiant and allow more boostto be built than you want.

Thanks for the help!

Definitely wastegate! A buddy of mine is running the same set up I am, and plugged his WG. BLEW UP his top turbo from over speeding. PDR claims that a HX35/S400 set up can make 600HP as long as the HX is gated at 12 PSI. I am working on getting mine HX35 WG to open at a reduced psi. Spools up retarded fast with it set at 46 PSI though. Even though it is set at 46PSI, I can easily exceed 54PSI.

Sweet...im going to put it all together then run some tests and mess around with everything til I figure out exactly how I want it.

That's the way to do it! Adjust it to your likings.:tu:

Remember the small turbo is the "heater turbo" in effect it is the one to raise egt's the most as it is the most restrictive. WG it to reduce the flow thru it and bypass to the big one and let it The big one handle the majority of flow and your egt's will be manageable. Remember FLOW is more important than boost. Boost is heating the air. FLOW makes the power. For the same flow the smaller turbo will boost (RESTRICT) it more. So use the little guy to get it lit and let the big man do the man's job.

RAW, its true a HX35 over any 74/75/76mm primary can make over 600HP. We had a 12V that had that setup and with a blown HG and only making 40PSI on the Dyno laid down 578HP.

That's impressive...ill work on it so I will have the correct flow so I have manageable egts

Good to know. Do you know what the 35 was gated at? I', thinking about a 14cm gated housing, and doing a HX35/40 hybrid. I already have the HX40 for the parts.

To keep the egt's down the built in wastegate is not big enough on the small turbo. Put a bypass wastegate before the small turbo and then redirect the gasses back to the big turbo and you will have very manageable egt's. And it will make maore power. One gent did not wastegate before the small and had egt troubles and then did as I said and his total boost was the same, but egt's reduced and the horsepower was 100 higher at the same boost levels.

So where can one find one of these External Wastegates to work with a HX35 compound system? I found these guys, but there web site is very limited,
ENGINEERED DIESEL - WASTEGATE SYSTEMS

If you fabbed your own kit- you can easily make a "bypass" wastegate before the hx35. The mods like hx40 compressor etc to the hx35 are not worth it. Save the money for the skyrocketting diesel prices!!!! And engineered diesel is good - real good - but I am not sure of the price. If you get a 40-60 mm wastegate and use 2 1/4 bypass pipe- wow! And you can get the pre-bent pipes - you cut them and weld - on ebay.