Compound Charging

[GP82]

Anyone got any experience or tried this, got me thinking after watching the Lancia Delta S2 vids (http://www.toyotagtturbo.com/forums/showthread.php?t=62673) which is supercharged and turbocharged. This is one turbocharger (small) feeding another (bigger). Would make for an awesome power delivery and a very broad powerband.

Looks easy enough to fabricate, i was thinking ct9 from 2500rpm, then like a td06 or summit comin' in 5500rpm obviously with a built motor revving up high or would a properly set up big single turbo be better with like nos or anti lag?

 

[The_Notorious_C_A_T]

I would have thought since hte ct9 is feeding the bigger one it would still be a bit restrictive?

 

[GP82]

The way i understand is for example when the ct9 is on boost from 2.5k to 5.5k, the waste gases going through will have spooled the bigger turbo and the energy going into the ct9 will get diverted out through a gate, therefore the ct9 stops doing it's job and the bigger turbo takes over.

I don't think the ct9's exhaust turbine will restrict for it to send the exhaust pulses onto the bigger turbo because the ct9 exhaust housing is way bigger compared to a primary runner on a turbo exhaust manifold.

 

[starlet666]

pretty sure the rear housings on the turbo's used for compounding are usually the same size.
just the front on one is a fair bit smaller... i usually only works on those big turbo's that have a few different size housings

 

[Starbus]

The setup's are right.

I've tried to explain how they work a few times with little sucess. But basically yes the big turbo blows into the little 1. The little isn't restrictive as the air is of a higher pressure and lower volume.

We are currently doing this setup on a starlet, wasn't planning to mention it till its finished, but seen as theres this thread.... Pictures will be on UKSC in a few weeks.

 

[GP82]

Awesome

Which turbo's will you be using for the setup?

Can you please post pictures here when you have completed it, would love to see how you have packaged the second turbo!

 

[Glanza D]

Awesome

Which turbo's will you be using for the setup?

Can you please post pictures here when you have completed it, would love to see how you have packaged the second turbo!

I know a little about this setup but its all in wraps untill its completed.

ill post picks if he doesnt as he's only a 5 min drive from me

 

[scot-ish]

dont the new bmw diesels use compound charging?

 

[Gord R]

Would be very interested in anybody being able to offer some advice on this, (pm if required , as Iv been researching quite heavily into this to try and find a more suitable hillclimb setup. All help would be much appreciated

 

[Starbus]

Awesome

Which turbo's will you be using for the setup?

Can you please post pictures here when you have completed it, would love to see how you have packaged the second turbo!

Turbo's will be ones that are commonly used in this scene, mainly so people have a better reference point.

dont the new bmw diesels use compound charging?

Not directly. Not a million miles off though.

Would be very interested in anybody being able to offer some advice on this, (pm if required , as Iv been researching quite heavily into this to try and find a more suitable hillclimb setup. All help would be much appreciated

PM me i'm sure we can help you out.

 

[GP82]

The little isn't restrictive as the air is of a higher pressure and lower volume.

The higher pressure lower volume will not increase thermal load on pistons like a big single turbo will. This means higher power is possible to achieve without major change in cylinder working conditions. There are lots of advantages to this setup like better efficiency because wheel speed’s are not as high to create compressed air to fill the required volume = increased ve inside cylinder. Better fuel efficiency can also be achieved without the risk of detonation or increased cylinder stress.

Think i’m gonna give it a go, need to find a good method to regulate boost, but first will have to prepare the engine for fuel delivery, compression ratio (into 7.0:1 maybe even lower) Select turbo chargers to be used. Trial fit and work a way to package it all in, don’t think this one will be stock rad friendly although we got it better/easier then most other car layouts!

 

[Starbus]

The higher pressure lower volume will not increase thermal load on pistons like a big single turbo will. This means higher power is possible to achieve without major change in cylinder working conditions. There are lots of advantages to this setup like better efficiency because wheel speed’s are not as high to create compressed air to fill the required volume = increased ve inside cylinder. Better fuel efficiency can also be achieved without the risk of detonation or increased cylinder stress.

Think i’m gonna give it a go, need to find a good method to regulate boost, but first will have to prepare the engine for fuel delivery, compression ratio (into 7.0:1 maybe even lower) Select turbo chargers to be used. Trial fit and work a way to package it all in, don’t think this one will be stock rad friendly although we got it better/easier then most other car layouts!

Have you copied that form another site or made it up? If you compress air it always gets hotter. (if you decompress it, it gets cooler also). Wheel speeds wouldn't change if you get the setup correct. Neither would the Ve of the engine. cylinder pressures are actually likely to increase. But this isn't directly related either IMO.

We've sorted the boost control, we are doing this on a stock engine. If you wrote the first bit, you'd know you wouldn't need a compression ratio of 7.0, that would defeat the object IMO, the only reason for compound charging in this instance is to have a wider powerband.

Ours won't fit with the stock rad. I doubt you could do it to fit with the stock rad to be honest. We will probably offer this as a kit in the near future.

 

[GP82]

Have you copied that form another site or made it up? If you compress air it always gets hotter. (if you decompress it, it gets cooler also). Wheel speeds wouldn't change if you get the setup correct. Neither would the Ve of the engine. cylinder pressures are actually likely to increase. But this isn't directly related either IMO.

We've sorted the boost control, we are doing this on a stock engine. If you wrote the first bit, you'd know you wouldn't need a compression ratio of 7.0, that would defeat the object IMO, the only reason for compound charging in this instance is to have a wider powerband.

Ours won't fit with the stock rad. I doubt you could do it to fit with the stock rad to be honest. We will probably offer this as a kit in the near future.

I have just been trying to research from the web, read a few pdf's. I had a read through this one;

http://www.enginehistory.org/Wright/TC Facts.pdf

Same priciple, different application, some good stuff in there from a primary source. I have just figured the wheel speed's would not change significantly. I had it in my head that the small turbo would not receive exhaust energy once the compound turbo is ready to give boost (spool up) hence the smaller turbo reaching high wheel speed's at high revs.

To be honest i did not have a clue of how this setup can work perfectly, but i understand it will be a high boost application with a compund turbo setup so my initial setup is going to be like a test and to try and make this experiment fail safe i had planned to drop the c/r of the engine right down Yes i am always thinking of ways to get a wider broad powerband and this is how i was attracted to the idea of compound charging. PM coming your way soon!!