Gen1 CTS-V: Supercharger?

In my previous article about performance mods for Cadillacs I mentioned the great gains possible in the LS2 with a Cam/head package, and I argued that if you intended to add a Supercharger you might do that up front instead of doing a cam/head modification.  One advantage of a supercharger add is that it leaves no question as to the drive-ability of the car, and maintains a smooth idle.

Let’s look at the current situation for supercharger modification options.  The Cadillac solution of course, as used on the 2009+ CTS-V with LSA supercharged V8 is a TVS1900 supercharger.

The Corvette LS9 engine uses the larger 6th generation TVS2300 supercharger, and some CTS-V owners have found that if they upgrade from the TVS1900 to the TVS2300 they gain significant horsepower.  Based on my reading, it appears that the TVS1900 is good on a 6.2L engine up to around 800 crank horsepower; you would want the TVS2300 if you are targeting above this number.

For the 6L LS2 engine in the 2006/2007 for most applications the TVS 1900 Seems a better fit than the TVS 2300.

The previous Magnuson supercharger kit for the 2004-2007 CTS-V used the 5th generation MP112 1.84L unit.  That setup for LS6 engines made 6 psi of boost, and added on average 130 whp according to Magnuson.

Interestingly, the STS-V and XLR-V 4.4L engines used a modified version of the MP122 unit.  It adds 10 cubic inches to the M112, so rounds up to a full 2L of displaced air.

The size indicates the amount of air displaced with each revolution of the blower.  So at the same RPM and gearing the MP112 will pump 1.84L of air, the TVS 1900 will pump 1.9L of air, and the TVS 2300 will pump 2.3L of air.  The new TVS units are also more efficient, will make more power at the same boost due to lower heat added to the air charge, and are quieter.  The simple amount of air pumped per revolution does not tell the whole story.

TVS means Twin Vortices Series.  The new TVS series superchargers are 4-lobe Eaton units with 160 degrees of twist along the rotor.  This simulates twin vortices of air rushing into the intake system.  The 5th generation units like the M112 or M122 used 3 lobes with 60 degrees of twist along each rotor.  All TVS superchargers have a 2.4 pressure ratio capability and a thermal efficiency that exceeds 70 percent, which enables more compact packaging and greater output.  The M112 1.84L unit was replaced effectively by the TVS1320 (1.3L) unit due to the greater efficiency of the new series.

The LSA engine in the 2009+ Cadillac CTS-V is basically a supercharged LS3.  So it differs from the LS2 engine in the 2006/2007 CTS-V not only by the fact that it is supercharged but also because it has different heads, among other differences.

So how would a TVS2300 do when added to a ‘stock’ LS2 engine?  Try 130+ RWHP added, which seems oddly similar to the Magnuson number for the MP112 on a CTS-V.  My impression is that the TVS models have more head-room and can provide more air at lower temperature, and be spun faster with less loss of efficiency.  It is not clear to me from the raw numbers in kit claims that one system has more output in a near-stock setup than the other.

A supercharged 2007 CTS-V that pulled 350whp (wheel hp) stock, with a supercharger it might then make 480 whp.  Not surprisingly approximately what you might expect of a 2009+ CTS-V at the wheels.

Superchargers costs start around $7,500 plus installation, but reach beyond $10K depending on the kit and options.

With a Supercharger, premium fuel will be required.

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