Boost Options

[rammertide07]

Searched another way and found some stuff. I like the way one guy explained it:

"Basically, the objective of Turbochargers and Superchargers are the same: To force a larger amount of air into the combustion chamber, adding oxygen to the combustion process, increasing the force of the explosion, resulting in a stronger power output.

The basic difference is the way they are themselves driven, more than what they actually do to the engine.

Basic difference: Supers are driven by the engine power - Turbos are driven by the exhaust pressure, but in general, the idea is exactly the same.

Superchargers (blowers) are mechanical, and use a belt from the crankshaft to the blower axle to spin up and compress the air through the intake. A deficit of this way of doing things is that the force it takes to drive the supercharge is taken from the engine, reducing power output slightly compared to a turbo at the same pressure rate. A benefit however, is that the supercharger adds power in a very linear way. The more revs on the engine, the more revs on the blower, hence more power increase. This makes the power very smooth and easy to control.

Turbochargers use the pressure of the exhaust gasses to spin up a turbine. The benefit of this is that you have no mechanical strain on the engine, and get full effect from the added pressure all the way to the driveshaft. Deficit is that it relies on the pressure of the exhaust gasses to build, causing what is know as "turbo-lag", where almost no increase is found at low revs, but once the pressure is built up, the power increase is very sudden and can be hard to control. Another benefit is that the pressure can be a whole lot higher from a turbo than from a supercharger, easily higher than what the engine can handle, which is why turbo systems often include a valve - or "wastegate" - to allow excess pressure to bypass the turbo. This valve is the cause of the little whistling sound that turbos make when taken to the limits. Turbos are also known to "tick" after the engine has been shut off. This is the turbine spinning down.

Want power? Go turbo! Wan't torque and controllability? Go supercharger! Want quick and cheap fun? F*ck air - go nitrous!"

So guess thats why the duramax had the supercharger feeding the turbos. Instant pressure on the "exhaust side" of the turbo to spin them up faster and the turbos are capable of producing more boost...and the supercharger can keep them spun up even after engine rpms drop. Except I dont think boat engine rpms drop. I would see it as a benneficial set-up in something with a transmission though.

[rammertide07]

But there's always the option of getting the GTP38R to get that out-of-the-hole repsonse I'd be looking for. I wish the diesel sales site had a payment plan for some of the stuff. I actually talked to xtremediesel.com and they said they could set up something like that.

[907DAVE]

That's what credit cards are for....as long as you don't mind paying a little interest on your borrowed money.

[TwinTurbo]

Originally Posted by rammertide07

So guess thats why the duramax had the supercharger feeding the turbos. Instant pressure on the "exhaust side" of the turbo to spin them up faster and the turbos are capable of producing more boost...and the supercharger can keep them spun up even after engine rpms drop. Except I dont think boat engine rpms drop. I would see it as a benneficial set-up in something with a transmission though.

Just want to clear up this statement a bit - first I'm not sure what setup you were looking at but I don't think you could set them up this way, the setups I've seen the turbos feed the supercharger - so at low boost from the turbos the supercharger is creating a vacuum on the compressor wheels and basically making them freewheel. As heat and RPM build the exhaust begins to spin the freewheeling turbos faster and provide more air than the supercharger requires so there is pressure now between the turbos and the supercharger which enables the supercharger to compress it even further than just by itself - very similar to a compound turbo effect at peak power. Hope that makes sense - feel free to correct if I'm wrong.

[907DAVE]

They can be set up either way.

Empire Diesel has turned out a few rigs that have a ProCharger feeding a turbo.

I post more on this later.

[rammertide07]

I tried looking for the particular set-up/application I saw. But you can google "supercharger feeding two turbos" and it will pull up some stuff.

[TwinTurbo]

Originally Posted by 907DAVE

They can be set up either way.

Empire Diesel has turned out a few rigs that have a ProCharger feeding a turbo.

I post more on this later.

Thanks Dave always nice to learn something new, I guess its all in how you size them huh?

[rammertide07]

Originally Posted by TwinTurbo

Just want to clear up this statement a bit - first I'm not sure what setup you were looking at but I don't think you could set them up this way, the setups I've seen the turbos feed the supercharger - so at low boost from the turbos the supercharger is creating a vacuum on the compressor wheels and basically making them freewheel. As heat and RPM build the exhaust begins to spin the freewheeling turbos faster and provide more air than the supercharger requires so there is pressure now between the turbos and the supercharger which enables the supercharger to compress it even further than just by itself - very similar to a compound turbo effect at peak power. Hope that makes sense - feel free to correct if I'm wrong.

It's giving me a headache trying to draw that out in my brain Only way I can imagine it, seems like the turbo would work against the supercharger.... But I did a quick search on it and it does seem to work. I would like to see that system drawn out. Would that set-up be more benneficial than supercharger feeding the turbos?

Right now I'm looking at buying a big truck turbo....for future use

[roary]

Just curious, but what are you planning on putting the "big truck turbo" on? And are you meaning a Semi truck turbo?

[rammertide07]

Originally Posted by roary

Just curious, but what are you planning on putting the "big truck turbo" on? And are you meaning a Semi truck turbo?

My truck.... and yes, it came off a semi or a heavy equipment diesel. I seen someone that took one off a cummins semi and fabricated the setup. They moved the passenger side battery tray (relocated the battery) and set-up the turbo there. Not sure how they plumbed it, but it worked with the stock/aftermarket turbo that was already on it.