BIG turbo, BIG question !??

[turbo minivan]

ok, i have lots of turbos of difforent sizes laying around and a spare 2.5 laying around, so....you get the idea. my origional plan is to twin the 2.5 with 2 mitsus, but then i was thinking, "maybe i could use 2 twins to spool a MONSTER holset turbo". im, talking about a monster that came off a logging truck!! probly about 1.8 a/r ratio at least! im wondering, if i twin the engine, then instead of running the compressors into the intake, what if i ran the compressed air AND the exhaust out and into the down pipe where the holset could be? this would obviasly increase the volume and pressure of "exhaust" that COULD possably be enough to turn the holset. i know its deffinatley not the most efficient design and it wouldnt spool till about 4000 rpm but it would be freekin cool!! it probly wouldnt put out much more than 10 psi (if that) but the volume it put out would be out of this world! and think of seeing an omni with a turbo sticking out of the hood the size of a small child! what do you think? would exhaust pressure and 30 psi of boost turn a 1.8 a/r turbo?

[88jbody]

would be interesting to try for sure

[Koreth]

I'm trying to figure out how you would manage the exhuast routing to make that work. With what you describe, the mitsu turbines would be upstream of the holset turbine. Once and if you managed to spool the holset, how would you bypass the mitsus so you don't overspin the everliving crap out of them with the amount of exhuast that you would be making with the holset spooled? As I understand, anything over stock levels is already overspinning a mitsu.

[itoktoeatfish]

dont some big time pulling trucks use some sort of setup like this?

[frostburner]

yea its compound turbo charging, the only way i see this possible is major modificaiton of the engine bay to fit the setup in only thing is you have to set it up with the low pressure inducion going into the high pressure, turbovanman wants to do it the opposite way so i dont thin itll work quite as well or be very managable.. from what ive read of course on how big rigs do it.

[frostburner]

Quote:

Originally Posted by turbo minivan ok, i have lots of turbos of difforent sizes laying around and a spare 2.5 laying around, so....you get the idea. my origional plan is to twin the 2.5 with 2 mitsus, but then i was thinking, "maybe i could use 2 twins to spool a MONSTER holset turbo". im, talking about a monster that came off a logging truck!! probly about 1.8 a/r ratio at least! im wondering, if i twin the engine, then instead of running the compressors into the intake, what if i ran the compressed air AND the exhaust out and into the down pipe where the holset could be? this would obviasly increase the volume and pressure of "exhaust" that COULD possably be enough to turn the holset. i know its deffinatley not the most efficient design and it wouldnt spool till about 4000 rpm but it would be freekin cool!! it probly wouldnt put out much more than 10 psi (if that) but the volume it put out would be out of this world! and think of seeing an omni with a turbo sticking out of the hood the size of a small child! what do you think? would exhaust pressure and 30 psi of boost turn a 1.8 a/r turbo?

where are you going to get 30 psi from? u know with running twins the boost doesnt add up like that like. think volume not adding boost together liek that unless you are compounding the twins with eachother.. oh and i also think joining the compressed air with exhaust going into the holset is a bad idea because of pressure differences if im understanding what you wrote correctly. air or pressure will always take the least restrictive path and id ont tihnk the exhaust and compressed air will be equal to flow correctly. but.. try it and see what it does lol.. im just looking at it from a logical perspective

[turbo minivan]

the technical side of it all is a bit bunk for me, all im trying to accomplish is to hugely increase the amount of gasses going through the down pipe and into the holset. forget pressure difforences, im thinking volume. i guess i never thought of the mitsus being spun throught the hood once the holset starts to boost, guess ill have to consider that. and hey, if it dosent work, just take off the holset and pipe in the twins. its worth a try, shouldnt cost me any more than 30$ to do it all anyway. any more thoughts on how it might work?

[FTT843]

just rig up the one huge turbo, while ur at it snag a semi sized cooler to go with it

[xrattiracer]

find a proper sized single turbo for it. it will be easier, much cheaper, and it will actually work.

[greendog]

take the harder less traveled road...experementaion is always a good thing

[shadow9]

Not sure exactly what your trying to say here.... you cant run the mitsu turbos back into the exhaust. (I think thats what you were saying???) the easiest way to do it would be to route the mitsu turbos so that instead of having the charge pipe going into teh intake like it normally would, run the charge pipes from the mitsu's into the holset were the exhaust would normally go into itthat way the mitsus are spinning the holset and its intake pathe wont be restricted by the turbos on the intake side of them.... or maybe thats what you were trying to explain, sorry just trying to clarify, i dont see how your planning on plumbing them.
But definatly give it a shot and post lots of pics when your done

[daytonajesse]

Heres an idea.
run your exhaust through twin mitsu's and out the back, or probably even one will work. Run the air side of the mitsu(s) to the exhaust side of the holset by itself. Then have the air side of the holset go to your TB.
Less restrictions in your exhaust, and less headaches with exhaust noise, and potentially exhaust fire problems.

But I think I just said the same thing as ^^

[turbo minivan]

if you guys could see the size of this turbo youd understand why i want exhaust AND the compressed air from the mitsus to spool it. theres no way the compressors from the mitsus alone would spin this thing up, i have to use ALL the pressure and volume i can get. i also figutred a way to get it to spool like mad without spinning the mitsus through the hood... ill run a vac line from a nipple on the holset compressor, T it and run it to the waste gates of the mitsus, that way they will stay closed untill the holset start pumping, then the wastgates will act on the amount of charge air feeding the holset and slow it down or speed it up! just like having a real big and compicated wastegate.

[turbo minivan]

Quote:

Originally Posted by xrattiracer find a proper sized single turbo for it. it will be easier, much cheaper, and it will actually work.

i think your totaly missing the point!

[daytonajesse]

I think your forgetting how much air a turbo pumps, way way way more than exhaust from a motor. They could pressurize a room in seconds.
That being said you're right I really haven't a clue as to how big the turbo is.
My mouth is open should I insert my foot? :-)