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Anyone know why a lot of race cars use a SINGLE BIG turbo and generate big HP (often > 1200 HP) and all the viper tuners are going with TWIN turbos? Why not go with a single turbo?

If I remember right, the older Porsche turbos were single turbo applications too.
 

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The decision to go single vs. twin on the viper is dictated more by hardware than anything else. There really isn't an efficient and clean way to fabricate an exhaust manifold for the V10 to fit a single turbo. It's MUCH easier on V engines to fab a manifold that utilizes twins.
From a Supra perspective, I can tell you that twins don't give us an advantage over a single, primarily due to the fact that we have an inline 6 engine. Twins do nothing but give more lag and nominal power gains over a large single (remember, if you have twins on the I6 motor, you're using 1/2 the exhaust energy to spool each one, granted they are smaller than a single would be, but still not the most efficient design).
On the viper, you are using 5 cylinders to spool each turbo, but keep in mind that you have MAD cubes behind those cylinders to spool those turbos. Hope that answers your question.
Peter
 

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I think it would be possible to build a single turbo setup on a FULL race/drag viper. However there is more than enough room in the Viper to turn up the boost on the smaller turbos on the TT setups to hit that 1200rwhp number,...maybe not on gasoline.
 

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Go Fast, the properly sized single turbo with correctly sized compressor and turbine wheels will make more high end power than twins. Most likely, a single such as this would spool slightly slower than a pair of twins. Since nobody has done a single turbo or a pair of big twins yet, it is hard to say which one would make more power, spool more/less quickly/etc... I hear there are a few people designing a big single kit that should be out in the next 6 months. It should be interesting.

There should be plenty of displacement on the Viper motor to make turbo lag a nonissue for a medium sized/good power application with the single. It all comes down to the packaging. A single would be good to be done in a similar fashion as the supercharger kits: Same intercooler piping and air intake setup.
I think a big challenge for that type of application would be having so much longer of a path from the exhaust ports to the turbo. Remember, the further it has to go, the less heat energy there is available(as the exhaust travels away from the exhaust port, it cools) to spin the turbine side of the turbo. On a Supra, the inline 6 has a favorable(short) path to the turbo. Whether this can work on the Viper remains to be seen.
 

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A single turbo will always be more efficient than twins. It just isn't practical on an engine with exhaust manifolds on opposite sides. Ever seen a Subaru WRX turbo manifold? I think the only reason Supras and Rx7's did twin turbos is because 1: they could turn them on sequentially for low end power 2: marketing.
 

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Twins are used not only for convenience of plumbing on a V or horizontally opposed engine - they are used because being smaller - they spool sooner and therefore make for a better street engine - boosting low and mid-range better than a big single would that made the same top end power.

They smooth out the transition from normal off boost power to full boost power. A big single turbo is none to subtle....

In all out racing - a big single has an advantage as mentioned in that the engine only has to spool one not two... but when those giant race hair driers hit - they hit with all the grace of a sledgehamer thrown into a china shop!

In an all out assault Viper that would mean driving like a normal Viper (more or less depending on mods) until around 4000rpm, then there'd be this God almighty scream and a wack in the back like you just hit 1000hp of NOS! Without electronic controls to slow it down - only a Pro Mod car would handle it.

IN short - I wouldn't waste my time on a single Turbo Viper - but good luck to those who want to try something different.
 

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I have seen a single t80 on a C5 corvette. What a mess of plumbing. It was a race only car so they didn't care about cutting it up.
 
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