I had a jza80 twin turbo supra with the standard turbos running around 1 Bar (14.7 psi). This system worked well and you could tell when the larger turbo came on boost.This system is simple, but because I'm lazy I will let toyota say it in there own words.

 

Turbo System consists of 2 turbochargers. See Fig. 2. While No. 1 turbocharger provides boost pressure at low engine RPM and engine load

conditions, both turbochargers together provide boost pressure at high engine RPM and engine load conditions. System is equipped with a

Charge Air Cooler (CAC) to cool turbocharger intake air. Cooling of turbocharger intake air increases air density, resulting in increased

engine output. An intake air control valve is located on No. 2 turbocharger.

See Fig. 2. An exhaust by-pass valve and exhaust gas control valve are used in the turbocharger system. See Fig. 3.

During low engine RPM, intake air control valve, exhaust gas control valve and wastegate are closed and only No. 1 turbocharger

provides boost pressure. When boost pressure reaches a predetermined level, exhaust by-pass valve opens. When exhaust by-pass valve opens,

exhaust gas is delivered to No. 2 turbocharger and No. 2 turbocharger operates to provide additional boost pressure.

During high engine RPM, exhaust gas control valve and intake air control valve are opened. This allows No. 1 and 2 turbochargers to

provide boost pressure. At this time, even if exhaust by-pass valve operates, it cannot affect boost pressure, since it is downstream of

No. 2 turbocharger. During high engine RPM, the wastegate controls boost pressure of entire system.

The Engine Control Module (ECM) controls the wastegate, exhaust gas control valve and exhaust by-pass valve operation by using

a Vacuum Switching Valve (VSV) for each component. The ECM uses various input signals for determining VSV operation. The VSV controls

the pressure flow to an actuator for the wastegate, exhaust gas control valve and exhaust by-pass valve.

Courtesy of Toyota Motor Sales, U.S.A., Inc.

 

See like I said simple.

what about compound turbcharging? one turbo blows into another turbo. the first turbo is smaller to prevent lag 2nd one is larger and runs in the higher rpm

mercedes benz sprinters have this configuration but also have a boost flap inbetween the 1st 2nd turbo in the exhaust manifold.

interseting thing about turbo, is that the goal isnt to get maximum pressure, it's to get maximum volume of air flowing through engine.

 

These complicated multi turbo charger setups may hinder this when you start trying to move alot of air.....which maybe explains

why most twin turbo setups get thrown for a good single turbo setup when they upgrade etc.

 

but ive no real evidence to back this up....

Hi,

Now first of I'm no genius on car turbo setups BUT from my knowledge trying to run twin turbos and get flows matched is hard ie small and large turbos.

 

Problem that can happen with say a large turbo feeding a small turbo in the compressor side is HEAT. Discharge of a large turbo the air can be in the range of 200 degrees C now the small turbo at there max RPM that heat can affect the compressor wheel and they fail. Also causes huge surge problems and that.

 

ke70dave

"interesting thing about turbo, is that the goal isnt to get maximum pressure, it's to get maximum volume of air flowing through engine."

 

Just using what Dave here said that's correct Mass flow over pressure is what you need. Now turbos have flow maps and different islands of effect. You can have massive "boost" levels with little to know flow this would be crap. So you run a turbo where there most efficient finding a pair that can do this HARD to impossible. You would have to start looking at making your own compressor wheel and I only know of a few places that have the machining gear/casting gear to achieve this..LOL

 

Cheers

Cameron

I had a jza80 twin turbo supra with the standard turbos running around 1 Bar (14.7 psi). This system worked well and you could tell when the larger turbo came on boost.This system is simple, but because I'm lazy I will let toyota say it in there own words.

 

Turbo System consists of 2 turbochargers. See Fig. 2. While No. 1 turbocharger provides boost pressure at low engine RPM and engine load

conditions, both turbochargers together provide boost pressure at high engine RPM and engine load conditions. System is equipped with a

Charge Air Cooler (CAC) to cool turbocharger intake air. Cooling of turbocharger intake air increases air density, resulting in increased

engine output. An intake air control valve is located on No. 2 turbocharger.

See Fig. 2. An exhaust by-pass valve and exhaust gas control valve are used in the turbocharger system. See Fig. 3.

During low engine RPM, intake air control valve, exhaust gas control valve and wastegate are closed and only No. 1 turbocharger

provides boost pressure. When boost pressure reaches a predetermined level, exhaust by-pass valve opens. When exhaust by-pass valve opens,

exhaust gas is delivered to No. 2 turbocharger and No. 2 turbocharger operates to provide additional boost pressure.

During high engine RPM, exhaust gas control valve and intake air control valve are opened. This allows No. 1 and 2 turbochargers to

provide boost pressure. At this time, even if exhaust by-pass valve operates, it cannot affect boost pressure, since it is downstream of

No. 2 turbocharger. During high engine RPM, the wastegate controls boost pressure of entire system.

The Engine Control Module (ECM) controls the wastegate, exhaust gas control valve and exhaust by-pass valve operation by using

a Vacuum Switching Valve (VSV) for each component. The ECM uses various input signals for determining VSV operation. The VSV controls

the pressure flow to an actuator for the wastegate, exhaust gas control valve and exhaust by-pass valve.

Courtesy of Toyota Motor Sales, U.S.A., Inc.

 

See like I said simple.

 

 

there is no smaller/larger turbo in any toyota twin turbo set up, both turbos are the same size.

In the system you are talking about, the bypass valves stop the exhaust gas going through the front turbo, a small passage allows the gas in the 123 exhaust manifold to enter the 456 manifold and spool the back turbo quicker, when the back turbo makes a certain pressure, the front bypass valves are opened and the front turbo spool instantly due to the extra exhaust gas.

 

Edit: I need to L2read hey.

Edited January 23, 201115 yr by Benno

2. The 1jz-gte in the jza81 doesn't run this system. It's just a plain old parallel twin turbo set-up. Only the 2jz-gte runs the above set-up.

 

There's no such thing as a JZA81 with a 1JZ - all JZA80/81s were 2JZ, either NA or twin-sequential-turbo.

There's no such thing as a JZA81 with a 1JZ - all JZA80/81s were 2JZ, either NA or twin-sequential-turbo.

woops, meant jzx81, I had chaser in my head for some reason, There is no such thing as a JZA81 anyway....... ignore my last comment.

apologies to go baby go

Edited January 23, 201115 yr by Benno

thing is with having one small and one big turbo wouldnt the small turbo spin to fast and be out of the limits of its capability? or because its the first turbo or they arnt blowing though each other it doesnt spin to fast?

 

I'm quite interested in variable pitch turbos, they seem like a great idea being able to offer the same pressure at all RPM correct me if I'm wrong

thing is with having one small and one big turbo wouldnt the small turbo spin to fast and be out of the limits of its capability? or because its the first turbo or they arnt blowing though each other it doesnt spin to fast?

 

With non-identical sequential setups, the first turbo is usually bypassed when the second one comes on song (there is a changeover period where both are running to allow the secondary turbo to spool up fully) like the supercharger in a twincharger system.

Edited January 27, 201115 yr by Hiro Protagonist

so with that does the small turbo get powered by all the cylinders, then feed the larger turbo? or does the small on get powered by two cylinders, larger turbo powered by two? so I'm just confused in how they are set up :hmm:

so with that does the small turbo get powered by all the cylinders, then feed the larger turbo? or does the small on get powered by two cylinders, larger turbo powered by two? so I'm just confused in how they are set up :hmm:

It works off an exhaust valve, or butterfly valve in the exhaust before reaching either of the turbo's. Watch the vid, it explains it well. Once the smaller turbocharger is close to its limit or a pre determined boost setting, the valve will flow all exhaust gasses to the larger of the turbo's. Once the boost pressure drops from the larger turbo the valve starts to open and flow through the smaller turbo. I prolly didnt explain it very well lol. Anyway, back on topic, itd be cool to see a twin turbo 4age, twins or compound, either!! I think some setups just have the wastegate fully open on the smaller turbo once the larger comes on boost. I'm still researching a little.

Edited January 29, 201115 yr by ae824ate

it would just be some thing different and unique. i would like to see some one work with a veritable pitch turbo to.