moparguy

Another thread https://www.dieseltruckresource.com/...ad.php?t=37261, discusses using the subject turbos in a non-traditional setup for street/towing applications in the 400hp range.

I'm thinking use em in a traditional compounding setup. The goal being low cost, and super quick spool for lower hp trucks (400)while providing the air needed to cool when in working towing situations.

I like the idea of the little HY35 being the primary turbo with it's quick spool 9cm housing. This would really help when starting with a load on a hill, or on-ramp, that type thing.

I'm not the most knowledgeable person when it comes to turbos and twins, but would like to discuss this setup with those who are. I've got some fab skills and would not be afraid to tackle this package.

One concern would be barking. With my current setup, I've got to be very aware of rpm when towing at altitude. Gotta keep it above 2300 or so. Would a small twin setup be evenmore likely to need lots of rpm or less sensitive to barking?

Thanks, RR

Artsi_L

Small set would get on making boost real quick. Drawback is that it would choke before normal engine red line rpm.

I can do closer calculations if you decide on desired boost, and what primary you wanna run, maybe something crazy small as Holset HX40?
I've heard that some run HX50 as a primary in a tow setup.

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Calculations show that at 60psi boost a HX50 would run up to 2700rpm. (I don't know which trim compressor wheel compressor map I have, there are two wheel sizes I know of).
A HX40 as a primary would seem to choke at 1900rpm.

Forrest Nearing

WAY too small... do an HY on top and something bigger on bottom... HX55, HT3B-22, etc. it'll run worse than if you just had the HX35 on there if you compound the babies like that

bmoeller

Would definantly need an external wastegate on that. Drive pressure would be off the wall high.

BlueDually

the hy would be a real tight spooling secondary, A hy35 into a ht3b 22 would probably be great for towing, 450hp max.

moparguy

I was thinking hy into my current hx hybrid. My hx has a larger waste gate valve (1.25 with the opening opened to just over 1") with the divider drilled.

My prehaps flawed thinking is that the componding would allow boost to run in the high 40 or very low 50 range while keeping the turbos in there efficiency range. By not making hot air for the intercooler to work with I'd see a reasonable egt with no lag.

I'd like to move up to a set of 370 size injectors and be able to tow. No way I can do that as currently set up.

I know a larger single would work, but I already have a noticable lag at attlitude when pulling a loaded trailer. Hence the very small twins thinking.

RR

PourinDiesel

I say go for it.
Let us know how they turn out!

RonA

You will have better luck at lower fueling levels(400hp) with a 35/K31 setup versus a 3B. The K31 is more expensive but spools alot faster and has an external wastegate so you can keep the boost down for gasket preservation.