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Twin Turbos.....

632 Views 14 Replies 9 Participants Last post by  HIBBoyScott
When you look at cars like the 3000GT VR-4, 300ZX turbo, Mazda RX7 turbo, and Toyota Supra turbo (all since extinct by the way) they all have dual turbos. In the 3000GT and 300ZX you get the boost of both turbos at the same time. However, the RX7 and Supra have a sequential turbo system in which you get the first turbo intially and the second one further up the RPM range.... Which is better...?? I have driven the Toyota Supra turbo and have noticed that second surge around 4000 RPM's or so. I'm not sure about the S4, but when my friend drives his I don't notice that the individual turbos are activated sequentially (due to the linear power deliver...... Just a thought for you guys to ponder. Personally I liked the turbo system of the 300ZX more than I did the Supra (with the boom.. BOOM)..
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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 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.

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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Originally posted by EricK:
Thanks for that description Scott...

No prob, just make sure to take note of my sig.

Person A:"Are you an auto expert?"
Me:"No, but I did stay at a Holiday Inn Hotel last night."
Like anyone is gonna get what the hell I'm talking about right there...oh wells.

[This message has been edited by HIBBoyScott (edited November 14, 2000).]
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Originally posted by IS300GTE:

you are right about the supra being converted easier. it has also been proven that the supra stock turbos, will make more hp on the dyno in parallel mode, but most people don't like it and convert back, because of the extra lag time.

as far as singles spooling faster, it depends on the amount of rotating weight and a host of other things, to determine whether a big single will spool faster than 2 smallers, being a given that they are rated for flowing the same amount of cfm's.
I was talking about big twins, not small. The key phrase being "in general."
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