someone should try it

Charles · Jul 15, 2011

lubeowner said:
Would the bearings and the shaft in the little turbo be able to handle the stress of that high boost and for how long?

The second and third stages would be running at less than stock boost. Other than the increased exhaust temp they should outlast the chargers on a stock truck.

Don't the 6.4's make like 40lbs stock or something close? If the first stage made 25 and the stockers made 40 that would be over 132lbs of boost on the manifold, so obviously they would have to be backed down quite a bit in a triple turbo setup. Even if they only made 25lbs and the first stage made 25lbs that's still over 90lbs on the manifold.

I think they would just be loafing in a compound setup with a third charger.

cfdeng7 · Jul 15, 2011

Awsome I did understand it correctly. Great information here

powr2stroke · Jul 15, 2011

This is some good stuff right here

Dzchey21 · Jul 15, 2011

only concern would be 75 psi of boost, and 75 psi of back pressure on the stock small turbo shaft, thats working against eachother...

tripples would be cool, if it failed i could be the first to try... and fail at every combo possible LOL

lubeowner · Jul 15, 2011

What is the pressure drop across the little compressor in stock and this 70 psi setup?

Charles · Jul 15, 2011

Dzchey21 said:
only concern would be 75 psi of boost, and 75 psi of back pressure on the stock small turbo shaft, thats working against eachother...

tripples would be cool, if it failed i could be the first to try... and fail at every combo possible LOL

The force on the shaft is determined by the PR and the flow. Required power from the turbine needed to spin that compressor is flow times pressure + bearing drag. In the case of adding another compressor upstream the flow remains constant no matter what the pressure is ahead of the stock chargers, and the pressure actually comes down unless you want to blow the heads through the hood.

In other words, the force exerted on the shaft will be less than stock... if you run less than stock boost, which you invariably will.

Charles · Jul 15, 2011

lubeowner said:
What is the pressure drop across the little compressor in stock and this 70 psi setup?

Pressure drop? It's making pressure. If a stock truck made 30psi then that would be a combined pressure ratio of 3.04:1 across the wheels of the stock chargers.

If the same charger setup was only asked to make 20psi when paired with a third compressor upstream, then the combined pressure ratio across the stock wheels would only be 2.36:1.

If I took a stock truck and stuck it inside a room that I then pressurized to 25psig and then made a dyno pull that is in no way any different in terms of the turbocharging system than if I had a third compressor on the truck that was running 25lbs of boost with a 1:1 boost:drive ratio.

87jumpy · Jul 15, 2011

Suscribed... I want to see this work!

Charles · Jul 15, 2011

I think my last example should be stated again. What is being suggested here is exactly like taking a stock 6.4 superduty and sticking it inside a room and then cranking up the pressure inside that room to 20-25psig.

The turbochargers don't care. They're doing the same work, same shaft speeds, same shaft loads and all else. The CFM flow into the chargers is the same, the CFM flow through the engine is the same, engine VE is the same, blah, blah, blah.

The only thing that changes is the mass flow through the engine. A sh*t load more lbs/min are traveling through those chargers, but they don't give a damn because they're still running the same pressure ratios at the same volume flow. They don't care if the room is 0psi, 10psi or 10,000psi.

All the third compressor will do is artificially raise the atmospheric pressure from 14.7 to 30 or so.

Charles · Jul 15, 2011

The stock chargers wouldn't even be breaking a sweat at 100+lbs of boost with a third stage.

Seriously. With three stages the setup would be PERFECTLY happy in terms of shaft speeds and turbocharger stress at upward of 200lbs of boost. At 200lbs of boost each compressor would be required to make just over 21psi...

At 70psi the compressors in a 3 stage system are probably doing their best impression of a ceiling fan.

If you ran all three compressors at 30lbs of boost, which is very conservative for a modern centrifugal compressor, you would produce just shy of 400lbs of boost and each compressor would be perfectly happy doing it.

You would physically rupture the housings themselves before you ever hurt the bearings in a properly balanced 3 stage setup.

Dzchey21 · Jul 15, 2011

so your telling me to do it... LOL

Dzchey21 · Jul 15, 2011

some of the other notes, and possible benifits would be that you could probably tow anything you wanted, stock throttle response would remain, towing ect would be the same, only thing you would probably have to do is be sure to pull the fuel back for towing that way the boost isnt retarded high all the time. This would also allow for basically canned tuning, nothing custom required, lag in overdrive would not be there like single, and big twin set ups, which i have grown to hate over the last year and a half.

Damnit charles, tadd is going to hate me over this deal lol.

TyCorr · Jul 15, 2011

What would it take to hold a motor together running 400 lbs of boost?

How do 2,000hp pulling motors stay together running three chargers? Or is the duration of the cycle so short it doesnt matter?

You're a smart cookie Charles! Is this knowledge gained from experience or does it parallel your lifes work? Not trying to pry but I feel like Im sitting at a table discussing pump systems with engineers.

Dzchey21 · Jul 15, 2011

I also must note that my wife told me this set up must work, i dont get another shot LOL, she would probably like driving my truck again with stock turbos in the valley, and it would save me some coin, she might be more forgiving on later occurences if i save some money this time around.

White_monster · Jul 15, 2011

Haha. Wifes putting her foot down hey Dustin. Dustin do a proven setup if you don't get to retry it would be my way. This triple idea sounds possible thou.

Charles · Jul 15, 2011

TyCorr said:
What would it take to hold a motor together running 400 lbs of boost?

How do 2,000hp pulling motors stay together running three chargers? Or is the duration of the cycle so short it doesnt matter?

They usually gate them in the upper 100's to lower to mid 200's on boost depending on power if they're diesels.

The alcohol tractors running three aren't running 3 stages, just three chargers with 2 stages where the first stage is paralleled. They do this so that they can meet the flow demands of the first stage with a practically sized and priced charger that they can actually find, get parts for and service. They are usually in the sub 100psi range I believe.

You're a smart cookie Charles! Is this knowledge gained from experience or does it parallel your lifes work? Not trying to pry but I feel like Im sitting at a table discussing pump systems with engineers.

I don't know, lol. I've never worked in any field involving gas compressors and I've never experienced 400lbs of boost so it may all be bullsh*t...

Charles · Jul 15, 2011

Dzchey21 said:
so your telling me to do it... LOL

http://www.youtube.com/watch?v=KX5jNnDMfxA

Dzchey21 · Jul 15, 2011

Its funny you put that. I was gunna link that too but I'm on my phone

Charles · Jul 15, 2011

Dzchey21 said:
Its funny you put that. I was gunna link that too but I'm on my phone

And after you make a few dyno pulls with the stock chargers and a nice first stage after running for a year or so without issue.... you'll turn around to all of those who doubted the stock chargers ability to hang and respond....

http://www.youtube.com/watch?v=AsUW8JcnzZs