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I was reading the post about the Saab that had a turbo on just one bank of the v6 and it got me to thinking about a dual turbo setup.
Imagine if you would a turbo on one bank of the Duratec that spools up up very quick, and another turbo on the other bank that spooled up later on in the RPM range but pushed a lot of air.
If you FI pros were to consider a setup like this, how would you go about it? Could the benefits of this setup work AND have an advantage over the current single-turbo systems we have? If yes, what type of turbos should be used?
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Sounds like a sequential turbo setup. i.e. been done on the Supra, except the supra is an inline six.
300zx, 3000GT VR-4,Audi S4/R4 are all examples of twin turbos.
I think you could do it but the small turbo would be a serious restriction once the big turbo kicked in, worse then just using one bank to drive one turbo.
Toyota used fancy plumbing to do it. The only way I could think of is to use a bypass type of valve like a wastegate that had two exhaust paths.
Hell, most people can't afford or even build a single turbo setup.
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"Absolut Rara."
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"Absolut Rara."
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not sequential, but sort of an intentionally mis-balanced setup. I suppose the best description would be "asymmetric".
It can certainly be done, but tuning it properly will be pretty difficult because the exhaust pressures would be significantly different; much like Saab's single bank turbo, only it would be even worse in a dynamic situation.
Like I said, it can be done, but the benefits of going through the extra effort aren't really there; but if someone decided they want to do it for real, I'd be more than happy to offer my engineering assistance.
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If both exhaust housings and turbine wheels were the same it wouldn't be as hard to do. But nonetheless, you still have the problem of space for such trickery in the Contour platform.
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"Absolut Rara."
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Originally posted by Stazi:
If both exhaust housings and turbine wheels were the same it wouldn't be as hard to do. But nonetheless, you still have the problem of space for such trickery in the Contour platform.
having the hot sides the same would sort of defeat the purpose I would think. At that point, wouldn't you simply size the compressor sides for a traditional twin setup?
One thing I don't get, is why don't more people size the turbine on the small side, and then go with a bigger, and more smoothly routed wastegate. Got the quick spool up, but have plenty of bypass space to prevent over speeding the turbo or presenting too much of a restriction to flow. Would make tons of sense when putting a big compressor on a small displacement engine
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Originally posted by Rara:
One thing I don't get, is why don't more people size the turbine on the small side, and then go with a bigger, and more smoothly routed wastegate. Got the quick spool up, but have plenty of bypass space to prevent over speeding the turbo or presenting too much of a restriction to flow. Would make tons of sense when putting a big compressor on a small displacement engine
What sizes are you talking about?
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Smaller turbine would improve spool up, but the downside is an increase pressure buildup in the maniflods and combustion chamber. This increases the cylinder temperature and also hurts cylinder filling as a consequence. But if you could sized it down a smidge the benefits would outweigh the adverse effects.
Realistically though, when you wants to add more boost, you want the transition from vacuum to boost to be gradual, in a FWD platform, to control wheel spin.
2000 SVT Turbo 295hp/269ftlb@12psi
#1 for Bendix Brakes Kits!
Knuckles rebuilt w/new bearings $55
AUSSIE ENDLINKS $70
Gutted pre-cats $80/set
A lack of planning on your part does not constitute an emergency on mine!
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