The idea behind the sequential turbo system is to eliminate as much lag as possible on the low rpms and still have punch at the big rpms. The sequential turbo setup is complicated and none of the aftermarket turbo upgrades are sequential. They are all parallel. If you don't like the feeling of sequential turbos the Supra can be converted to parallel twin mode (true twin) pretty easily. As far as twin or single turbo upgrades...in general, the single turbo spools faster simply because the exhaust gasses from all six cylinders are used to spool one turbo instead of two. If you can keep your rpms high (read: racing situation) then a huge turbo will offer the most power. But for street driving the amount of lag could make things pretty unpleasant. Although Clint says (don't get mad at me if I said this wrong please) "lag is highly overrated." He has a big twin turbo setup if I'm not mistaken. A big twin setup should theoretically be able to hit higher power numbers than a single because of the amount of air flow they can provide.
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By making this post I am not claiming to be an expert of any sort on the topic and should not be taken as such. It's just my opinion and worth what you paid for it.
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By making this post I am not claiming to be an expert of any sort on the topic and should not be taken as such. It's just my opinion and worth what you paid for it.