Compound turbo question

[Tymatthew]

Would my super b special and a hx40w be a good set up for a compound system?

 

[AH64ID]

BD sells a set of towing twins with the Super B Special as the primary turbo, but the secondary turbo is smaller than a HX 40 for quicker response. 

 

What are you goals and uses? 

[Mopar1973Man]

Better consider ARP head studs too. Being most will end up beyond what stock head bolts will hold comfortably.

[Tymatthew]

It’s already got the head studs....so I should go with something smaller than the 40...don’t really have any goals, just want a truck that can pull 8k up the mountains at good speed and still be fun to drive around....I have an extra turbo and was just thinking about doing it...

 

[Mopar1973Man]

So what do you have done to your truck? You might fill out your signature and/or your garage so we all know what you've done modification wise. 

 

I currently tow an 8k RV trailer with no issues on a single HX35/40 hybrid and 150 HP injectors.

 

https://mopar1973man.com/garage/vehicle/103-2000-jayco-eagle-296-fbs/

 

https://mopar1973man.com/garage/vehicle/101-2002-dodge-ram-2500/?show=mods

[Tymatthew]

I will update all that....not sure on what’s been done to it, I bought it wrecked from a shop that bought it from the original owner....the only thing I know for sure is that it has 175 over injectors...head studs...quadzilla....did have compound turbos but one was ruined in the wreck...a new intercooler....3 piece manifold with studs....I rebuilt the tranny with a suncoast kit to Handle 500hp and rebuilt the front end...I’m a 12 valve guy...never owned a 24 and I haven’t really messed with my 6.7 so the electronics are kinda new to me....

 

[Mopar1973Man]

Yeah, I would suggest the twins. I'm borderline with my setup but 175 HP injectors I would suggest the twins. 

[Tymatthew]

What about the hx40?....i definitely wanna keep the super b as my big one couse I love it but I’m thinking that 40 might be too big for the small one...is there any info out there on how to set up the wastegates on compounds?

[Mopar1973Man]

HX40 from what I understand has a weaker shaft that why most don't use the HX40 outright. This why the HX35/40 Hybrid came to be. The compressor is the HX40 but the turbine is the HX35 shaft which is stronger. Just takes a few turbo barks and the Hx40 shaft will break.

 

[AH64ID]

A stock turbo would work really well with a Super B Special for towing twins. 

 

You'd probably have to do some wastegate porting as well, but it would be fun in town and great with a trailer. 

[Mopar1973Man]

I've heard that too. But I'm going to admit that I'm not schooled enough to talk in the twin world. 

 

Being I don't quite have all the info. I've got to ask @AH64ID how can it work well as a smaller turbo? Wouldn't the back pressure be a problem for the stock turbo in the twin setup? Being that it can only do about 30 to 35 PSI and the turbine side is getting overwhelmed. Being the exhaust would go to the HX35 then to the Super B right?

[AH64ID]

Yes the exhaust would go to the HX (or HY) and then to the Super B Special. 

 

Using the stock turbo in twins usually has the WG open around stock levels, or lower, so that the exhaust pressure stays decent. It does often take WG porting, to increase flow around the turbine. 

 

The benefit to using the Super B Special as the primary is you get to use a smaller secondary, so you have stock (or faster) response and you get the upper end performance of the Super B Special without the lag they are known for. It makes for great towing and mild street power, but the turbos are too small for racing or bigger hp applications. These turbos would really shine towing at higher elevations. 

 

[Tymatthew]

Noice couse I’m at higher elevations.....I can get a hx35 cheap from a buddy..

 

[Mopar1973Man]

25 minutes ago, AH64ID said:

but the turbos are too small for racing or bigger hp applications.

 

Totally agree. 

 

The HX35/40 Hybrid I'm running is an OK turbo for sprinting down the highway but beyond that, it does get hot EGT wise. I would have to back down to +75HP injector to actually gain control of EGT on a WOT stand. It can smack out a good 40 to 45 PSI boost run but the exhaust housing is too small. 

 

I might gain a bit if I ported the wastegate out and took some of the divider out. 

 

Being it normal to set the cruise and forget it. Then passing other vehicles typically not a big deal. Also, I'm not in it for racing but normal daily driver. 

 

Thanks. @AH64ID

[Dieselfuture]

20 hours ago, Mopar1973Man said:

The HX35/40 Hybrid I'm running is an OK turbo for sprinting down the highway but beyond that, it does get hot EGT wise. I would have to back down to +75HP injector to actually gain control of EGT on a WOT stand. It can smack out a good 40 to 45 PSI boost run but the exhaust housing is too small

That's why I'm staying at level 3 on the quad. Whither my turbo and 7x10 I can get to where I need and stay just below going in danger zone. If i use wiretap, it will be more powerful but will get in high egts and boost. I'm happy with maxing out canbus and staying safe. 

[dieselautopower]

A hx35/ super B special (64/71/14 .80 gated) is a little small for a primary, but you can make it work.  Peak HP would be lowered to about 450-500HP, but spool up would be very fast.

 

The BD towing kit is  57/65/14 over a 66/74 with a larger turbine housing like  1.10AR and rated for for about 550HP max.

 

Ironically the superB special is rated at about 600HP max as a single  turbo, but is not very happy towing at high elevations.

 

 

[Tymatthew]

Good to know......thanks