Has anyone ever done this? I am imagining two different sized turbochargers plumbed to a plenum of exhaust from the manifold(s), and both feeding into the intake. I am unsure if the downstream air from one turbo will try and feed the downstream end of the other, but I imagine this has to happen a small amount with twin setups as well as nothing is every truly identical.
Vaguely sounds like the turbo setup on the 6.7 Powerstroke....
I think the Saab 9-5 with the 6 cylinder had an assymetric twin turbo system. these were used from 99-03.
cdowd wrote: I think the Saab 9-5 with the 6 cylinder had an assymetric twin turbo system. these were used from 99-03.
I believe those just had one turbo... driven off of one bank.
Put a check valve or some sort of pressure differential operated butterfly valve on the bigger one, problem solved.
Edit: Better idea, check valve on the inlets of both.
In reply to Swank Force One:
Yup, the dreaded 3.0t, which was definitely not the best engine effort to come out of GM/Saab.
Presumably the smaller one will spin up first and try to back-drive the larger one, then as the engine speeds up, the larger unit may try to back-drive the smaller. Seems like it won't work without some management.
Exhaust throttle might work, but hard to make work.....
kb58 wrote: Presumably the smaller one will spin up first and try to back-drive the larger one, then as the engine speeds up, the larger unit may try to back-drive the smaller. Seems like it won't work without some management.
I've seen experiments with valve to switch exhaust gas flow, but nothing was able to be reliable enough to come to market.
In reply to Fueled by Caffeine:
I think the primary concern is a boost leak out the intake of one turbo or the other.
Isn't this the same basic idea as "sequential" turbocharging, as used on the 2JZ-GTE in the Mk. IV Supra Turbo...Or am I misinterpreting your description?
Driven5 wrote: This is called "sequential" turbocharging, and is what was used on the 2JZ-GTE in the Mk. IV Supra Turbo.
I think the FD RX 7 was the same way.
Rusted_Busted_Spit wrote:Driven5 wrote: This is called "sequential" turbocharging, and is what was used on the 2JZ-GTE in the Mk. IV Supra Turbo.I think the FD RX 7 was the same way.
They had one turbo feeding another feeding the engine. I mean the engine feeding two turbos which feed the engine, but the two of them are not the same size.
Detroit Diesel does a somewhat similar trick with some diesel engines. First off, being 2-strokes they need a pressurized intake even at idle. So they supercharge the intake. Then they have a turbo which takes the intake fan up to a much higher rpm under load.
Vid starts with cylinder counts and then shows how turbocharging plays in:
http://www.youtube.com/watch?v=eusyBOvrqrc
Kenny_McCormic wrote: In reply to Fueled by Caffeine: I think the primary concern is a boost leak out the intake of one turbo or the other.
Naa.. Primary concern was a moving valve in the exhaust stream.
Dig around about this motor, that was but never was, and you can find pictures of the valve. http://www.allpar.com/news/index.php/2010/12/ram-1500-v8-diesel-2013-civilian-launch
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