Shopping for a Cadillac STS-V

Cadillac created the V-Series Concept in 2004, with the release of the 2004 Cadillac CTS-V.  V stands for Velocity.  V-Series Cadillacs are luxury vehicles, as are all Cadillacs.  But they are also Gentleman Racers.  The V-Series features more than adequate  power plants, high performance track-tuned suspensions, high performance braking systems, additional engine and transmission cooling, and generally heavy-duty, series gear for enthusiasts who want to have serious fun with their Cadillac.

The Cadillac STS-V was produced from 2006 through 2009.  It featured the Sigma platform, Sachs tuned suspension, 4-piston Brembo Brakes front and rear, a 469 hp Supercharged (MP122) 4.4L DOHC VVT V8, and all the luxury features and accommodations available on the Cadillac STS.

Performance: the performance of the STS-V should be similar across the various production years, because the weight and power did not vary.  0-60 mph time was measured in around 4.8-5.1 sec depending on the magazine and the day.  Quartermile time is 13.1-13.3 sec at around 106 mph.   Skidpad performance was measured as high as 0.90g and as low as 0.83g.  Knowing the hardware I feel that 0.87g – 0.90g is probably representative.  Top speed is electronically limited to 155 mph.

The STS-V uses a Magnusson MP122 supercharger, putting out 12 psi.   So for argument sake, knowing that atmospheric pressure at sea level is 14.7 psi, and knowing that a supercharger adds approximately 4% power per psi, we can calculate that the supercharger adds 48% power.  Max efficiency is 7%/psi, but 4%/psi with real-world efficiencies and pumping losses. So the base 4.4L DOHC VVT V8 unblown might make 316 hp.  And we can recognize that the tuning that this hand-built gem of an engine received at the Tech Center allows the lower-displacement 4.4L Northstar without the supercharger would make similar power to the normally aspirated 4.6L DOHC VVT Northstar, which makes 320 hp.

One example of the detail work on the STS-V is that the exhaust ports and head of the engine are extrude honed.  This is a process that forces an abrasive material through the heads.  Typically used in racing applications, this increases horsepower by increasing the airflow through the engine.

The STS-V’s 469 horses arrive at 6400 rpm, but at least 395 of the 439 peak pound-feet of torque are available between 2200 and 6000 rpm.  The idle quality of the STS-V is even more stable than the already exemplary STS, due to the increased rolling inertia of the Supercharger.

All Superchargers generate heat; it is a by-product of compression.  The STS-V uses an air to liquid intercooler to help reduce the heat of the incoming air charge, with a separate cooling system for the intercooler.

Pricing: is a great resource for used vehicle pricing.  Currently they suggest the following STS-V pricing for a used example with 30K miles:

2006: $24-26K Private Sale; $29K Retail

2007: $28k-30K Private Sale; $33K Retail

2008: $30-32K Private Sale; $36k Retail

2009: $43-46K Private Sale; $50k Retail

Newer models will continue to be under Warranty.  Also, in 2008 the STS-V gained a Heads-Up-Display (HUD), which is a desirable feature.  I hope to continue to monitor STS-V pricing, and pick up a 2008 Model once they are available around $25K for a very good example with under 30K miles.

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.

New Cadillac CTS-V Detail Photos

Cadillac has new CTS-V photography up.



Standard CTS interior appearance; only notable is no wood trim — looks like the V series is sticking with the high tech look.  When the STS-V came along, the wood trim steering wheel was skipped because it is a bit slick for use on the track.  I’m guessing that the same rule was used here.

CTS-V Front Brake Calipers

CTS-V Front Brake Calipers

The 2009 Cadillac CTS-V employs Brembo’s dual- Cast 14.5-in (370mm) rotor for the first time in North America, with six-piston monoblock front calipers. Unlike traditional cast iron discs, dual-cast discs are made of two materials – cast iron and aluminium – and offer many advantages, including a 15-20 per cent reduction in weight, greater driving comfort, less corrosion, wear and resistance to fade, and better braking performance.

Brembo discs

Brembo discs

Mesh Grill

Mesh Grill

Standard mesh grill is a brand feature of the Cadillac V-Series performance vehicles.

Supercharger Beauty Cover

Supercharger Beauty Cover

Beauty shot of the CTS-V’s LSA engine.  This engine is unique to the Cadillac CTS-V.  It is basically a Supercharged and Intercooled LS3 OHV V8, making 556 hp.  The engine in the new ZR1 Corvette is also a Supercharged 6.2L V8, but the LS9 engine is hand built and uses a larger, 2.3L supercharger where the CTS-V uses a 1.9L Supercharger.