Stupid question about turbo's

[marc_p]

Ok this might sound a bit stupid, but.........why can you get more power out of a single turbo setup than you can out of a twin turbo setup? Why not have 2 large turbos rather than one?

 

I know this might sound stupid, but I have been thinking about it for a while.

[Lbm]

Ok this might sound a bit stupid, but.........why can you get more power out of a single turbo setup than you can out of a twin turbo setup? Why not have 2 large turbos rather than one?

 

I know this might sound stupid, but I have been thinking about it for a while.

 

Or have 3 turbos?

[marc_p]

Or have 3 turbos?

 

Exactly, doesn't the veyron have 4?

[miko_supra]

You can get more power from to aftermarket turbos. They aren't preferred as it works out more expensive and are more laggy compared to a modern single set up from what ive heard

[miko_supra]

Exactly, doesn't the veyron have 4?

 

Yes but that's a w16 or whatever engine and not a straight 6:p

[Nic]

It's about the amount of air the turbo(s) can flow into the engine. A single turbo doesn't give more power than a pair of turbos flowing the same amount of air.

 

The small stock turbos can only flow so much air, the simplest and cheapest option to get more power is to fit a bigger single turbo that can flow more air.

 

You could fit a pair of bigger turbos that flow the same amount of air as the single turbo and achieve the same hp, but it would be more expensive and more complicated, as you'd need 2 turbos, 2 wastegates, a more complex exhaust manifold, you'd need to plumb them all together on the intake side and exhaust side and fit all this lot into a relatively small area in the engine bay.

 

The single turbo option is much simpler and cheaper in comparison, which is why it is the more popular option.

Edited October 9, 2008 by Nic (see edit history)

[marc_p]

It's about the amount of air the turbo(s) can flow into the engine. A single turbo doesn't give more power than a pair of turbos flowing the same amount of air.

 

The small stock turbos can only flow so much air, the simplest and cheapest option to get more power is to fit a bigger single turbo that can flow more air.

 

You could fit a pair of bigger turbos that flow the same amount of air as the single turbo and achieve the same hp, but it would be more expensive and more complicated, as you need 2 turbos, 2 wastegates, a more complex exhaust manifold, you need to fit them in a relatively small area in the engine bay and you need to plumb them all together on the intake side and exhaust side.

 

The single turbo option is much simpler and cheaper in comparison, which is why it is the more popular option.

 

Ahh, I get it now, but (and again excuse my ignorance) why not have a really big turbo and then a small turbo to reduce lag, basically like the standard setup but just bigger.

[Nic]

Ahh, I get it now, but (and again excuse my ignorance) why not have a really big turbo and then a small turbo to reduce lag, basically like the standard setup but just bigger.

 

The air from both turbos would have to flow together into the engine, the larger turbo would be flowing a lot more air into the intake than the smaller turbo, the pressure difference would cause the air to flow backward through into the smaller turbo causing it to stall.

Edited October 9, 2008 by Nic (see edit history)

[marc_p]

The air from both turbos would have to flow together into the engine, the larger turbo would be flowing a lot more air into the intake than the smaller turbo, the pressure difference would cause the air to flow backward through into the smaller turbo causing it to stall.

 

Ahh right, thanks Nic.

[Nic]

Have a read of these tech articles, they explain how the turbo system works.

 

http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

[Scott]

Ahh, I get it now, but (and again excuse my ignorance) why not have a really big turbo and then a small turbo to reduce lag, basically like the standard setup but just bigger.

 

The smaller the turbo the less exhaust gas needed to spin up the turbo. The soop flows enough exhaust gas at 2000rpm to spin up 1 of the stock turbos. At 4000rpm there is enough exhaust gas to spin up both of the turbo's so the sequential system lets this happen. If you were to change one of the turbo's to make it larger than the other, what Nic described would happen. If you make both of the turbo's larger it would take more rev's to spool up one and even more rev's to spool up 2 so the benefit would be lost as the first would be spooling between 3-4k and the 2nd would be spooling between 4-5k.

 

A lot of people think that the supra has a small turbo and a large turbo. This is not the case, they are both exactly the same. You could swop them over and it would work exactly as it does.

[charlton]

The soop flows enough exhaust gas at 2000rpm to spin up 1 of the stock turbos. At 4000rpm there is enough exhaust gas to spin up both of the turbo's so the sequential system lets this happen

 

Is this how a large twin setup works or would they both spool slowly at the same time?

Edited October 9, 2008 by charlton
Re-read a reply! (see edit history)

[Steviekid]

Is this how a large twin setup works or would they both spool slowly at the same time?

 

Almost all aftermarket twin's spool slowly at the same time, I think I've only seem one aftermarket sequential system.

[Scott]

Is this how a large twin setup works or would they both spool slowly at the same time?

 

As above, both spin up at the same time hence why they are so laggy. Would take a lot of work to get them working the way the sequential system works just now.

[tooquicktostop]

The big old singles are very laggy also, I had a T88 on my Skyline, this was a case of

 

nothing...nothing...spooling noise.....loud spooling noise........oh my good god.........then change gear