Compound boost.

[cdrazic93]

Originally Posted by Jaden

And if you have half a brain, you'll actually learn some things too.

Im assuming thats sarcastic, since I doubt you want to start fights with everyone.

[Jaden]

Originally Posted by Spartarus

I suppose we will start at the beginning. Only basics at this point.

Increasing boost to make the engine move more air only works if you're not losing density as fast as you're adding pressure. That's part of the reason why non-intercooled turbo setups have a huge diminishing return in power as you raise boost.

Hence Mike's comment about cooling all of this boost.

If you can't maintain charge density, all you're doing is moving vertically on the compressor map, pumping the same mass of air at an ever-increasing pressure ratio, and ever diminishing efficiency, until you cross the surge line. You won't actually get any more air mass into the cylinder.

The rest of this chat is for another time and more beer.

EDIT: Oh, that whole statement was redundant. Mike already proved my point. Throw out your intercooler, get an interheater. Yay boost!

When it comes down to a choice between "many of those vastly experienced forced induction tuners must be full of shit" and "I may be misunderstanding things" What do you honestly think the right answer is?

you guys are now making a straw man argument that doesn't negate anything I've said.

that's why I brought up that in a compound boost setup so long as you have an intercooler in between the two fi systems you don't gain as much heat as you would charging it out of the efficiency range of a single system.

because you stay at the efficiency of each compressors efficiency at the boost they individually provide.

jaden

[CSG Mike]

Originally Posted by Jaden

you guys are now making a straw man argument that doesn't negate anything I've said.

that's why I brought up that in a compound boost setup so long as you have an intercooler in between the two fi systems you don't gain as much heat as you would charging it out of the efficiency range of a single system.

because you stay at the efficiency of each compressors efficiency at the boost they individually provide.

jaden

I've asked you over, and over, and over.

How do you propose you cool all this? It's easy if you just have an engine on a dyno with piping that can haphazardly placed. How do you propose packaging all this in the engine bay of a FRS/BRZ?

[scmil95eg]

Front mount air to air. Passenger seat water to air. Duh.

Isn't that how all daily drivers are set up?

[Jaden]

Originally Posted by CSG Mike

I've asked you over, and over, and over.

How do you propose you cool all this? It's easy if you just have an engine on a dyno with piping that can haphazardly placed. How do you propose packaging all this in the engine bay of a FRS/BRZ?

For the one I proposed, I would use a jrsc with the front mount intercooler and an upgraded S/C that is S trim, and then the air to water intercooler on the turbo from the works turbo. Like I said, it might be subject to heat soak since the interchanger for the water to air would have to be mounted behind the front mount air to air, but this isn't meant to be a track beast. It could also be possible to change the mounting brackets on the interchanger to mount it more to the side and use a taller, less wide air to air for the super charger which would allow them to be mounted side by side instead of in front of one another. It wouldn't be the cheapest thing to do, but what 600+hp 2 liter with carb stickers is??? And yes I know it wouldn't be carb legal...lol

The best thing for a track monster would be an LSX swap and an eforce. although that would likely require a hood modification to fit the eforce.

Jaden

[CSG Mike]

Originally Posted by Jaden

For the one I proposed, I would use a jrsc with the front mount intercooler and an upgraded S/C that is S trim, and then the air to water intercooler on the turbo from the works turbo. Like I said, it might be subject to heat soak since the interchanger for the water to air would have to be mounted behind the front mount air to air, but this isn't meant to be a track beast. It could also be possible to change the mounting brackets on the interchanger to mount it more to the side and use a taller, less wide air to air for the super charger which would allow them to be mounted side by side instead of in front of one another. It wouldn't be the cheapest thing to do, but what 600+hp 2 liter with carb stickers is??? And yes I know it wouldn't be carb legal...lol

The best thing for a track monster would be an LSX swap and an eforce. although that would likely require a hood modification to fit the eforce.

Jaden

Wut? Have you even researched the FI systems beyond a cursory glance?

How would you mount the JRSC FMIC with the WORKS heat exchanger; they want to occupy the same space.

Oh, and then there's the problem of a centrifugal SC with a turbo... that's a no-no.

[Jaden]

Originally Posted by CSG Mike

Wut? Have you even researched the FI systems beyond a cursory glance?

How would you mount the JRSC FMIC with the WORKS heat exchanger; they want to occupy the same space.

Oh, and then there's the problem of a centrifugal SC with a turbo... that's a no-no.

That's why I said one would have to be mounted in front of the other(the interchanger isn't very thick, the FMIC should fit in front of it with custom bracketry) and or the bracket on the interchanger would have to be moved and a taller, less wide air to air would be needed.

As far as the centrifugal S/C.. I'm starting to get the distinct impression you aren't even reading my posts. Talk shit about them yes, read them and try to comprehend them, not so much..

The whole point was with a hugely broad airflow as indicated in the compressor map, using a centrifugal s/c as the primary could be hugely beneficial by providing high airflow at even low boost levels and then using higher boost on the secondary turbo at lower rpms would allow you to use the airflow from the large S/C earlier in the rpm band by increasing overall boost earlier on than the large S/C is capable of on its own.

The point of using a pos. disp. as a secondary is that it provides max boost fairly early on and continuously through the rpm band giving benefit on a large turbo as the primary because the secondary boost is fixed, much less complicated than a turbo compounded into another turbo where you have to control both waste gates.

What I'm suggesting is that a smaller quick spooling secondary turbo could be beneficial in the same way by providing the extra boost early on for a broad flowing centrifugal s/c so that the engine will have the boost necessary to ingest that much air earlier in the rpm band.

The best compound boost setup has meted out to be large turbo into smaller quicker spooling turbo, but they are more difficult to control and for these purposes, it's difficult to find a good combination of them that stay within decent efficiencies. That's one reason I'm suggesting a larger centrifugal S/C as the primary because it has a much broader efficiency range compared to most large turbos.

Jaden

[weederr33]

This thread is useless now. It's just arguing. I'll just pioneer a twin-charge set up myself sheesh!

[Tcoat]

Originally Posted by Jaden

This thread is to discuss the potential of, the pitfalls associated with and the benefits of compound boost.

.

Apparently not.


It appears to me to be one guy that will not listen to what others have said if they in any way differ from what he has in his head.

[Jaden]

Originally Posted by Tcoat

Apparently not.


It appears to me to be one guy that will not listen to what others have said if they in any way differ from what he has in his head.

I have no problem discussing them. If the suggested ones are legitimate and not issued in a derogatory fashion.

cooling the air for two separate FI systems is a legitmate one, but not in the way initially indicated.

A carte blanche, how are you going to cool this? is not a legitimate pitfall. Not when the intimation was that it is inherently more difficult to cool compound boost charges over single system charges. It only is more difficult to cool in regards to positioning of multiple cooling systems.

We had to get past the whole not understanding that boost and turbo airflow are both relevant so that engine airflow in a low displacement engine is increased before we could discuss cooling the charges.

Jaden

p.s. Someone claiming that boost has no relation whatsoever in a boosted application and only Turbo airflow does, is not just "in any way different", it is completley wrong and discussion can't continue without understanding how and in what way boost AND turbo airflow play a roll in a FI application and how they affect ENGINE airflow(which is the only thing that affects power generation).

[CSG Mike]

Originally Posted by Jaden

That's why I said one would have to be mounted in front of the other(the interchanger isn't very thick, the FMIC should fit in front of it with custom bracketry) and or the bracket on the interchanger would have to be moved and a taller, less wide air to air would be needed.

As far as the centrifugal S/C.. I'm starting to get the distinct impression you aren't even reading my posts. Talk shit about them yes, read them and try to comprehend them, not so much..

The whole point was with a hugely broad airflow as indicated in the compressor map, using a centrifugal s/c as the primary could be hugely beneficial by providing high airflow at even low boost levels and then using higher boost on the secondary turbo at lower rpms would allow you to use the airflow from the large S/C earlier in the rpm band by increasing overall boost earlier on than the large S/C is capable of on its own.

The point of using a pos. disp. as a secondary is that it provides max boost fairly early on and continuously through the rpm band giving benefit on a large turbo as the primary because the secondary boost is fixed, much less complicated than a turbo compounded into another turbo where you have to control both waste gates.

What I'm suggesting is that a smaller quick spooling secondary turbo could be beneficial in the same way by providing the extra boost early on for a broad flowing centrifugal s/c so that the engine will have the boost necessary to ingest that much air earlier in the rpm band.

The best compound boost setup has meted out to be large turbo into smaller quicker spooling turbo, but they are more difficult to control and for these purposes, it's difficult to find a good combination of them that stay within decent efficiencies. That's one reason I'm suggesting a larger centrifugal S/C as the primary because it has a much broader efficiency range compared to most large turbos.

Jaden

So you want to choke the big supercharger compressor with a small turbocharger compressor, and heat the charge up unnecessarily?

Each exchange of heat results in a loss of efficiency. Energy exchange is not free.

So a compound sequential twin? There's a reason sequential turbos are no longer in production for cars...

[CSG Mike]

@Jaden, please answer this question.

Have you ever boosted a car before?

[Tcoat]

Originally Posted by CSG Mike

@Jaden, please answer this question.

Have you ever boosted a car before?

Go take a look at his history of creating threads and other posts. I think you will quickly see that the answer is a resounding no (even if he claims otherwise).

[KR-S]

@Jaden, what exactly is your background in engineering?