Compound boost.

[EAGLE5]

Don't knock the Lincoln Logs, yo!

[Jaden]

Originally Posted by CSG Mike

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...

When I say small, I mean smaller, not necessarily small. The idea is to use a smaller faster spooling compressor to further compress the charge.

You seem to think that since you're flowing 50 lbs a minute through a compressor that is designed to flow 30 lbs a minute that you're going to be outside of the efficiency range of the turbo.

That''s not quite what happens though. There is a slight increase in temp for a couple of reasons. The primary being that you've already compressed the air that's coming in to the secondary. A good IC will fix most of that though.

The second reason is that the charge is denser so the compressor map for the secondary isn't as exactly compatible for this application.

That's why I included the math for compensating for it in one of my posts.

The secondary believes the air it's getting is a just a dense atmopshere. It doesn't know it's been compressed. It may be a little hotter than atmopshere, so a slightly hot, dense atmosphere.

So the pressure ratio is the most important thing to look at for the secondary.

Think of it as though you would need to divide the airflow by the p/r of the primary charging source to determine what the secondary airflow would need to be, but that's not entirely accurate. That's why there has to be some slight compensation for determining the secondary's airflow requirements.

You seem to think that if the primary is pumping out 50lbs/min, the secondary needs to be able to flow that much too. It doesn't, it doesn't have to flow any where near that. It would need to be able to efficiently flow closer to 28 lbs a minute depending on what your primary's p/r is and that's because it's compressor map wasn't done based on an atmospheric of 25 or 30psi, it was done based on an atmopheric of closer to 14.5 or 14.7. The reality is that the secondary is just like using a single turbo that is compressing an atmospheric that is at 25 or 30 psi.

Jaden

[Jaden]

Here's an excerpt from a muscle mustangs and fast fords article...

Future-Fast Charge Cooler Upgrade
In addition to the budget boost, the Vortech supercharger kit also offered something we refer to as future-fast. Future-fast is the ability to upgrade the system in the future as finances allow. Since the power output of the supercharged motor is a function of the normally aspirated power output multiplied by the boost pressure, we can further increase the power output of the combination by either upgrading the motor or increasing the boost.

Yeah I guess these guys are full of shit too....Again all you guys can do is character assassination attempts and bullshit quips. As I've already stated, it's not quite as simple as the above but it's a damn good starting point and is almost meted out to the TEE in REAL LIFE...

When you guys learn what shit is and how it functions get back to me.

Jaden

p.s. how many compound boost setups have you done. I've done THREE... I've also done a supercharged mustang and a twin turbo f body.

[Tcoat]

Originally Posted by Jaden

p.s. how many compound boost setups have you done. I've done THREE... I've also done a supercharged mustang and a twin turbo f body.

Pics?

[CSG Mike]

Originally Posted by Jaden

p.s. how many compound boost setups have you done. I've done THREE... I've also done a supercharged mustang and a twin turbo f body.

I don't. I prefer cost effective, functional setups.

What's the end hp/liter of those 3 compound boost setups? Have they actually been driven hard? Not "I beat on it on the dyno", but a "can @CSG Mike overheat the car without abusing it" hard.

[CSG Mike]

Originally Posted by Jaden

When I say small, I mean smaller, not necessarily small. The idea is to use a smaller faster spooling compressor to further compress the charge.

You seem to think that since you're flowing 50 lbs a minute through a compressor that is designed to flow 30 lbs a minute that you're going to be outside of the efficiency range of the turbo.

That''s not quite what happens though. There is a slight increase in temp for a couple of reasons. The primary being that you've already compressed the air that's coming in to the secondary. A good IC will fix most of that though.

The second reason is that the charge is denser so the compressor map for the secondary isn't as exactly compatible for this application.

That's why I included the math for compensating for it in one of my posts.

The secondary believes the air it's getting is a just a dense atmopshere. It doesn't know it's been compressed. It may be a little hotter than atmopshere, so a slightly hot, dense atmosphere.

So the pressure ratio is the most important thing to look at for the secondary.

Think of it as though you would need to divide the airflow by the p/r of the primary charging source to determine what the secondary airflow would need to be, but that's not entirely accurate. That's why there has to be some slight compensation for determining the secondary's airflow requirements.

You seem to think that if the primary is pumping out 50lbs/min, the secondary needs to be able to flow that much too. It doesn't, it doesn't have to flow any where near that. It would need to be able to efficiently flow closer to 28 lbs a minute depending on what your primary's p/r is and that's because it's compressor map wasn't done based on an atmospheric of 25 or 30psi, it was done based on an atmopheric of closer to 14.5 or 14.7. The reality is that the secondary is just like using a single turbo that is compressing an atmospheric that is at 25 or 30 psi.

Jaden

I'm going to introduce you to the concept of a restrictor...

[Jaden]

Originally Posted by Tcoat

Pics?

They were between 20-30 years ago. We weren't so much about posting it on a non existant internet then.

The f body was an 84 trans am, the supercharger was a 5.0 95 mustang and the compound boosts, were three 6.2 liter diesels, an 84 3/4 ton gmc 4x4 an 86 GMC dually and a 92 GMC jimmy.

All were compensated for mechanically so the ECU manipulation is new to me. The transam was a boxed carb, the mustang used a mechanical FMU, etc...

Jaden

[Jaden]

Originally Posted by CSG Mike

I don't. I prefer cost effective, functional setups.

What's the end hp/liter of those 3 compound boost setups? Have they actually been driven hard? Not "I beat on it on the dyno", but a "can @CSG Mike overheat the car without abusing it" hard.

I've never done the increase efficiency in a small displacement engine with compound boost before, I've done need more boost because the engine can take it. So I'll admit that there may be some stuff that I'm missing, but the concepts I'm NOT wrong about. I've also NEVER claimed that I could build a compound boost setup that's suitable for you to take to the track. Your last name isn't Iler is it?

Jaden

[CSG Mike]

Twincharging a Diesel is a *COMPLETELY* different ballgame from twincharging a gasoline engine...

Twincharging a Diesel for huge output is fairly common. Twincharging a gasoline engine for big output will never be more efficient than using a single stage system. The space requirements are completely different, as is the inherent strength of the engine itself, built or not.

Now I understand why you have your stance. A lot of it would be accurate in the diesel world.

[johl]

wow this thread really did turn out like I predicted.

you can own all the patents you want, but with no real world evidence your calculations and theories will always remain just that.

you claim to want to start a discussion on compound boost however you refuse to listen to anyone at all. based on the history of other users such as CSG Mike I would listen to what they have to say. you don't have to agree with it but you shouldn't flat out deny everything he says as though he is trying to deny your choice in religion with science.

you come across as an elitist, arrogant A hole. you post long winded replies using rather loose calculations. you seem to do this to make yourself appear more intelligent than the average person.

once again, I may be entirely wrong about you and your ideas on compound boosting and I encourage you to prove me wrong

[Jaden]

Originally Posted by johl

wow this thread really did turn out like I predicted.

you can own all the patents you want, but with no real world evidence your calculations and theories will always remain just that.

you claim to want to start a discussion on compound boost however you refuse to listen to anyone at all. based on the history of other users such as CSG Mike I would listen to what they have to say. you don't have to agree with it but you shouldn't flat out deny everything he says as though he is trying to deny your choice in religion with science.

you come across as an elitist, arrogant A hole. you post long winded replies using rather loose calculations. you seem to do this to make yourself appear more intelligent than the average person.

once again, I may be entirely wrong about you and your ideas on compound boosting and I encourage you to prove me wrong

You probably aren't wrong about me. I am an arrogant asshole in some respects and I'm far more intelligent than the average person... As far as being wrong about compound boost, I've already provided links of people who have shown in the REAL WORLD that what's being said is wrong and what I'm claiming is right. You have to remember, I'M NOT the one who claimed I can show theoretical mumbo jumbo, I'M the one who has shown real world examples. IT was THEM who claimed they can show a theoretical 2liter that makes 200hp N/A making 500hp at 7psi, NOT ME...

When someone is saying something that is fundamentally wrong, that aspect is NOT up for discussion.

The thread was meant to discuss the benefits and pitfalls of compound boost.

Not to try to hash out that you need to consider boost AND FI system airflow.

THAT is a given...

If that fundamental understanding of what boost is and does isn't accepted, no discussion can take place.

Beyond that, What I've said about compound boost has been meted out in real world examples EVERY DAY. If compound charging was as difficult to cool as Mike tried to make out after failing at trying to prove that airflow(FI system, not engine) is all that matters then the tens of thousands of compound boosted diesels that are out there wouldn't go anywhere.

The reason that there aren't more examples of low displacement compound boost is mostly to do with cost, complexity and lack of understanding of the benefits, not because they don't work right. Everyone is about peak power and get confused when they have a 850hp turbo that they can only get 500hp out of.

They don't seem to understand that that 850hp turbo is only capable of providing 85lbs a min of air when it is running at a P/R of 3.5 or 4, not less than 2 like it does in a compound boost system.

As I've already stated, I have projects in the works. The first one should come off in the next couple of months and you guys will see it soon enough. In the mean time, I'm building up my other block for a compound boost setup, so I guess you guys will just have to wait and unlike my current project, I will be posting update photos as I go on the compound boost project. I have pictures of my current project but i'm not showing them yet. I'm trying to do something special with it that prevents me from posting updates.

Jaden

[weederr33]

-________-

[Toyarzee]

Originally Posted by Jaden

I'M the one who has shown real world examples.

No you haven't...

Originally Posted by Jaden

and I'm far more intelligent than the average person...

Let me be an asshole too and assure you that you aren't.

See, my responses don't require 10,000 word essays but accomplish just as much lol. Enjoy keyboard warrior

[Jaden]

Originally Posted by CSG Mike

Twincharging a Diesel is a *COMPLETELY* different ballgame from twincharging a gasoline engine...

Twincharging a Diesel for huge output is fairly common. Twincharging a gasoline engine for big output will never be more efficient than using a single stage system. The space requirements are completely different, as is the inherent strength of the engine itself, built or not.

Now I understand why you have your stance. A lot of it would be accurate in the diesel world.

The point is that it won't be less efficient in the end when done right and it gives you a better torque curve and more earlier in the RPM band.

Absolutely diesel engines are built much stronger, having 100+PSI is not uncommon.

As I've said, It becomes different in the way it has to be planned out and finding FI systems that are efficient at the P/Rs you need them to run at is more difficult. That's what having this discussion was meant to be about.

You can run Turbos in Diesels at their maximum most efficient airflow levels because the purpose is different.

You're trying to get more boost than a single turbo is efficiently capable of providing.

The difference here is that you are trying to get more boost earlier on and at higher flow rates than a single turbo is efficiently capable of providing.

The trick is finding that right combination of high flow at low boost (efficiently) primary FI system and the right quick spooling or quick to get boost rather in the case of pos. disp. s/c, secondary to get the boost levels you need at the rpms you want with the flow the engine can take efficiently.


This was just meant to be a discussion about this and to try to find that right combo. But if people aren't understanding the underlying principles which are the same in both applications, the discussion goes like this one has.

Jaden