Compounds setups in general...

[1992gen1_fan]

Hello, Im slowly learning about compound turbo setups and how they work. I get the basic idea that the smaller high pressure turbo gives quick boost at lower rpm and helps the larger slow spooling one lite, providing more flow up into the higher rpm's.

This is the part I don't quite get. Matching turbo to turbo.
Seems like most use a hx35 and a bigger one. Would my vgt work with a hx55 or HT3B? It can spool very quick and exhaust restriction reduces as boost increases like a waste gate except the ex housing opens up to like 27cm instead.

My first question is, is there any other purpose for the small turbo other than quick spool? Can a fairly decent size (60/60) but quick spooling turbo work with slightly bigger (hx55 size<>) Why not?

[oldestof11]

It will work

[1992gen1_fan]

One problem I can think of is the weight of the VGT along with another turbo might be alot for the manifold. Maybe add a brace of some sort from the engine mount bracket up to the lower turbo somewhere..

One more question, in this setup the vgt would be the turbo attached to the manifold, correct? And the exhaust will go through the VGT into the bigger turbine, or is it the other way around?

Intake will come into the larger or the two and into the VGTs compressor and into the I/C, or the other way around again?

[4thesporty]

Most of your compatability questions are answered in this thread:

http://www.competitiondiesel.com/forums ... p?t=107957

For weight, you need to support the primary turbo with some sort of "hanger" down to the the block, otherwise your hot pipe will carry all the weight of the heavy primary turbo.

[Sutter1stgen]

I've found that a support bracket coming off of the manifold bolts is just as effective, yet easier to access and make.

[1992gen1_fan]

Thanks for the info

A while back I read something about someone running multiple he351ve's instead of a small turbo with a larger one. I can not find the thread anywhere, can't even remember if it was on this site

Whats your thoughts on 2 identical vgt's together for a set of small twins for towing ect?

[4thesporty]

your thinking off triples

[1992gen1_fan]

Ok yea I'v read about tripples some, using 3 medium size turbos. But would just 2 vgt's work?

[1992gen1_fan]

So, two VGT's together won't work?

[Sutter1stgen]

So, two VGT's together won't work?

Two vgts in a compound? Or in a triple setup? The triple setup I wouldn't know. But through research I read somewhere that a large and small vgt in a compound setup was hard to tune. I havent tried it so I don't know first hand. But then again how many peoe do you see running them compared to a conventional compound or triple setup?

[Mark Nixon]

So, two VGT's together won't work?

I would suppose that with enough fiddling and some dedication to the cause, you could make them work, but, boy would it be a PITA to synchronize the 2!

As far as the general lack of viable answers, I've found if it's not a mainstream "idea", you tend to get less enthusiastic responses.
It's hard for people to think outside the box, sometimes.

Mark.

[DodgeFreak]

would you gain enough with two identical vgts to even be worth it?? I think tripple vgts would be pretty cool but like posted before controlling them would be the hardest.

[oldestof11]

It will be a good setup for medium to high revving engines. Be surgy on the bottom end.

I planned out using 2 12v exhaust manifolds, cutting them down to split the exhaust into 2 sections. 1 turbo flange pointing down and 1 up. Run the exhaust outlets into the center and down/under the rear. Using a dual action air cylinder, I would use the boost from 1 turbo to close the others vanes. Then using the turbos own boost to close the vanes. This way if 1 turbo is boosting too much, the boost pressure will help open the others turbo.

[1992gen1_fan]

Sutter1stgen- Yea I was thinking run 2 he351ve's in compound.

Mark Nixon- Yea, I imagine it'd be a trick tuning the 2 vgt's in syncro. But If I knew the effort would be of any gain, I don't mind a bit of a challenge.

DodgeFreak- I was wondering what gain there would be in using 2 identical turbo's. If there would be a gain, thats what Im looking for. I plan to heep the fuel tuning on the fairly mild side to keep from getting too hot when towing. I have this single vgt fairly well tuned but I think it does lack. I was originally thinking about a compressor upgrade but...

oldestof11- I'll put that into consideration, getting my manifold setup that way might be a trick. I'd have to get someone else to weld it since I'v never welded cast iron. Sounds like a good idea to look into though.

[DodgeFreak]

It will be a good setup for medium to high revving engines. Be surgy on the bottom end.

I planned out using 2 12v exhaust manifolds, cutting them down to split the exhaust into 2 sections. 1 turbo flange pointing down and 1 up. Run the exhaust outlets into the center and down/under the rear. Using a dual action air cylinder, I would use the boost from 1 turbo to close the others vanes. Then using the turbos own boost to close the vanes. This way if 1 turbo is boosting too much, the boost pressure will help open the others turbo.

was you going to cap the ends of the manifolds or weld the two together?? it would be better if the turbos shared exhaust flow right?? We've (my cousin and I) have talked about doing it but with two stock hx35s....and even considered trying to compounds off both of those just for fun...It would be for fun and he has access to exhaust pipe cheap so it would be a cheap build if we would ever get time...lol.