Compounding vs Twin

[justinray]

I've looked a lot into the turbo availability and options for us, including retrofitting PSD turbos, Cummins turbos, etc.. And wanted to know what y'all thought about a couple of different ideas..

1. A Banks Sidewinder running from each bank, into a custom intake manifold or hat. I think this would actually be cleaner than the banks already on my truck, because there would be no Firewall issue, only fender well and steering clearance issues. I also think this idea warrants the lack of an intercooler since I could keep both turbo's in their maps. I know it wouldn't push any more boost than I already have, but it would supply more CFM.

2. A Hypermax Pulse system fed by a Banks Sidewinder fed normally. This would be a rough, long setup due to the turbo's needing to be 'on top' of eachother and the firewall clearance issues. It would definitely need an intercooler because running this setup I would likely run out of the maps of both turbo's, but this would net more boost and hopefully comparable cfm's to the twin setup as described above.

Since I got my journeyman card at work, I can use the apprenticeship shop for anything I need and could easily fab up-pipes and downpipes, mounts and whatever else, the oil line's wouldn't be much of a task with tubing bender/cutter and some fittings, and I'm slowly emptying my engine bay out to make more room (batteries going in the toolbox soon, radiator overflow going in a cylindrical container soon, attached to the radiator, hydroboost brake booster, electric vaccuum pump, and thinking about removing the entire a/c system since it hasn't worked since I bought the truck).

 

[88beast]

a typical turbo wont work very well on a diesel for a compound setup but if you size the first turbo right you will see lots of boost. you want one bigger than the engine and one smaller ideally. this will allow the small turbo to spool in low rmp and very fast while the large turbo will spool high rpm and will make the big boost.
a compound setup can run some really high boost, this becomes issue two. 60 psi is out of range with studs still iirc. you will want studs and some beastly headgaskets or even fire rings to keep everything together. ive looked into this and for an old idi it is not worth putting all your money into the r n d for it.

now for the twin setup this is more doable. you want to size a turbo to work for half the engine 222 cu in. this will allow one turbo per bank with superior performance. run a banks dmax style intake they flow some really good numbers and will help a ton. now the next issue would be oil drain. you will need to drain to a point lower than the turbo and ideally sitting the turbo in front of the vc and then using an ic for each side that is mounted in the hood would make a good option. this will give short routing, good air to cool the engine bay, and with a well designed intake that uses the cowl or under the bumper you will have a bullit proof setup

ive rethought my turbo setup again and have came up with a new plan. i am going to mount the turbo on top of the motor like stock. use a 3 inch dp as a uppipe and a custom dp will go on the pass side of the motor under the truck. this will open up more space and along with redesigned valve covers and a custom turbo mount i will be able to easily work on the turbo and will have access to the objects around it. the wiring i am curently doing is related to the placement of this turbo. also oil drain will go into the valvecover and not the valley pan. this is due to a custom pedistal and ease of maintence.

 

[Black dawg]

The way that I have understood sizing turbos for a compound set up is, First turbo is sized to the requirements of the NA engine. Turbo #2 is sized according to the airflow requirement of the engine with the first turbo.

So, just as an example, to make 10psi on engine that pulls in 400cfm you need a xx turbo.
Now that engine with the turbo moves 600cfm, and you would size the second turbo to add the desired amount of boost + cfm increase on top of that 600 cfm.

I have no actual experience with this, and what I know I read, so someone with actual experience would probably be better informed.

 

[88 Ford]

I've looked a lot into the turbo availability and options for us, including retrofitting PSD turbos, Cummins turbos, etc.. And wanted to know what y'all thought about a couple of different ideas..

1. A Banks Sidewinder running from each bank, into a custom intake manifold or hat. I think this would actually be cleaner than the banks already on my truck, because there would be no Firewall issue, only fender well and steering clearance issues. I also think this idea warrants the lack of an intercooler since I could keep both turbo's in their maps. I know it wouldn't push any more boost than I already have, but it would supply more CFM.

2. A Hypermax Pulse system fed by a Banks Sidewinder fed normally. This would be a rough, long setup due to the turbo's needing to be 'on top' of eachother and the firewall clearance issues. It would definitely need an intercooler because running this setup I would likely run out of the maps of both turbo's, but this would net more boost and hopefully comparable cfm's to the twin setup as described above.

Since I got my journeyman card at work, I can use the apprenticeship shop for anything I need and could easily fab up-pipes and downpipes, mounts and whatever else, the oil line's wouldn't be much of a task with tubing bender/cutter and some fittings, and I'm slowly emptying my engine bay out to make more room (batteries going in the toolbox soon, radiator overflow going in a cylindrical container soon, attached to the radiator, hydroboost brake booster, electric vaccuum pump, and thinking about removing the entire a/c system since it hasn't worked since I bought the truck).

The Sidewinders compressors would work decently depending how much boost you wanted but IMO the turbine housings would be on the big side and would cause slow spoolup. Also you can still intercool a twin setup but it would be slightly more piping...

As for using the Hypermax and Sidewinder together, their compressor size is to similar. Like was said before, you want one big and one small turbo. Also as far as fitment goes, you could leave the Sidewinder in the stock location and you could move the passenger side battery and put the big turbo up there. That's what a lot of companies do on the PSD and Duramax.

 

[88 Ford]

Oh and another thing with the twin Sidewinders, there are turbos out there that are a lot cheaper and would work better as well. An Hx35 with a 12cm housing comes to mind...

 

[FordGuy100]

There is also the setups that use the "atmosphere" and "pressure" turbo's (sequential I believe). If the name suggests it, one is for pushing high volumes of air, while the other is good at actually providing pressure.

It also gets confusing because it seems like most interchange all those terms as well.

 

[88 Ford]

From the research I have done on this topic, sequential turbos use a small turbo to spool on the low end and after the big one spools the small one is actually bypassed, usually bypassing the turbine side. Toyota Supras have that kind of setup. The are even some newer BMW diesels running really cool advanced setups like this as well.

 

[tanman_2006]

Holset turbos spool quickly and easily. Dual 12 cm or one of the newer model hybrid 9cm turbos (flow better than you would think) would work decently in twin or as the small turbo in a compound set up.

 

[FordGuy100]

HY35's have the 9cm housings and flow more cfms than the HX35's (HY35's are found on automatic 24 valve VP cummins).

 

[justinray]

Oh and another thing with the twin Sidewinders, there are turbos out there that are a lot cheaper and would work better as well. An Hx35 with a 12cm housing comes to mind...

Since I already have one sidewinder, I think it would be cheaper to buy another, and I believe they are better fitted for half the engine than the entire thing, the turbo seems too small by itself, it spools out too early.

 

[redneckaggie]

from what i have understood the sidewinder spools fairly late on these trucks which suggests an inefficient turbine housing with all 445 ci feeding it, I can imagine that only having 222.5 feeding it would have to make things plenty worse. I forsee you redlining the engine to get them to boost.

 

[justinray]

from what i have understood the sidewinder spools fairly late on these trucks which suggests an inefficient turbine housing with all 445 ci feeding it, I can imagine that only having 222.5 feeding it would have to make things plenty worse. I forsee you redlining the engine to get them to boost.

My sidewinder maxes boost with no load in every gear with slightly less than 3/4 throttle. I would rather see high CFM and low boost than High boost and low cfm, I DON't really need boost out of the gate, I like to see a lag and a spool, not an idle and a spool with a lot of over the top throttle that gets wasted due to lack of CFM to compensate the fuel.

 

[jaluhn83]

Ive done some thinking on the twin setup, just cause seems like it'd make a much cleaner install then running all that piping around. However, I came to the conclusion that there's a lot of clearance issues to be solved, primarily the steering column, AC box and shock mount towers. Plus all the accessories and mount brackets.

You'd also want to make sure both turbos were identical in configuration and probably age / wear, since imbalances will result in imbalance in cylinder loading, back pressure, etc.

For the amount of effort you'd be much better off doing all the design work to find a properly sized set of turbos and work from that. I'd bet also that you could find a T3 or similar that would fit your needs and be much more available than the sidewinder. Plus being better matched.

Might also be worth looking into a variable vane turbo (late model PSD / Cummins) and fitting that and some sort of a custom control system. I'd bet you could get similar results and much more flexibility, just have to do some research.

 

[88 Ford]

HY35's have the 9cm housings and flow more cfms than the HX35's (HY35's are found on automatic 24 valve VP cummins).

Doesn't it depend on which one? I thought they were also on the 4bt? I might be wrong though...

 

[tanman_2006]

Us gm guys use an A Team Turbo (name of the turbo) and it is found in 2 non gated sizes. Very good quality and has seen a lot of abuse (yrs and miles) on 6.5s. I have a non gated Ford banks turbo and they do not compare, makes the banks look like a pos.