Aftermarket Cadillac Modifications: Power

Once you purchase a pre-packaged sport tuned V-Series Cadillac, has the Factory pushed the vehicle as far as it can go, or is there some left on the table?  Is there anything else that could be done to these V-Series Cadillacs that would make them faster?

In a word, YES.  Like most tuning however, it is very good to start with a goal usage and power level in mind, and tune to those goals.  A classic hot-rodding question is: How much money do you have, and how fast do you want to go?

First of all, it depends on which V-Series Cadillac you focus on.  The STS-V and XLR-V have more in common with each other than the 2004-2007 CTS-V or the 2009+ CTS-V.

The STS-V and XLR-V are powered by the LC3 Supercharged 4.4L Northstar and make 440-469 hp stock depending on the model.

The 2004-2005 CTS-V was powered by the 5.7L V8 LS6 engine making 400 hp.

The 2006-2007 CTS-V was powered by the 6.0L V8 LS2 engine making 400 hp.

The newest V, the 2009+ CTS-V is powered by the Supercharged and Intercooled 6.2L V8 LSA engine making 556 hp.

LC3 4.4L Supercharged Northstar Tuning

For the STS-V and XLR-V the aftermarket offers re-tuning / re-calibration of the computer, cold air intakes, and performance exhausts.  Together these can net around 40 RWHP, or rear wheel horsepower.

LS6 or LS2 V8 Tuning (~400hp stock)

There is a rich suite of tuning options available for the LS6 or LS2, because they share a great deal of aftermarket development with ongoing LSx performance engine development.

Best bang for the buck items include:

  • Cam shaft — best done along with ported heads.  Cam/heads can add as much as 90 hp at the crankshaft for $2500 plus installation
  • Headers — long tube headers will cost around $1600 and add 20-30 RWHP
  • Supercharger — around 140 RWHP for US$6-7K
  • Dyno Tuning — results vary based on the other modifications on the vehicle, but give the best opportunity for gains from modifications.  Some level of custom tuning will be required with most changes.
  • LS7 Conversion — replace the LS2 or LS6 with a 505hp LS7
  • L92 heads / L76 Intake — To make the LS3 engine GM added the L92 heads to the LS2, so this is a known power combo. The 4.00-inch bore of the LS2 enables it to use LS1/LS6 heads, as well as L92-style heads (including LS3, LS9 and LSA engines).  The L76 intake allows the combo to fit under the hood.  For confusion, the L94 Engine in the current Escalade is an updated variant of the L92.

As an aside, not all adders are additive.  So while you might see 25 hp from adder A and 20 hp from Adder B on a stock setup, you might only reach +30hp from both together.

Second, to some extent a Supercharger works by “forcing” better breathing.  So if you plan to get a Supercharger, I would start with that.  If you want to stay all-motor, go with cam and heads and headers which all act to free up the engine’s breathing.

LSA Supercharged V8 Tuning (556 hp stock)

The LSA engine can be considered a Supercharged LS3 engine, with a steel crankshaft.  The LSA has rectangular port heads like the LS9 or L92 (Escalade engine) instead of Cathedral port heads like the LS2.  The rectangular port heads in the LSA flow a bit better than the cathedral port heads in the LS2.

Although the Supercharged LSA V8 is relatively new, the aftermarket offers include:

  • New supercharger snout to raise boost: with tuning around +74 hp for $2,500.
  • Dyno Tuning
  • Upgrade to the LS9’s Supercharger – Complete packages that include tuning, exhaust quote up to 700 hp, so +150 hp.
  • Upgrade the engine to the LS9:  The LS9 engine makes 638 hp stock.  LS9 Engine around $22K, so pricey
  • Headers with Tuning can produce around 50 RWHP for $2K
  • L92 Heads and Cam package – around 70 RWHP for $2,500 plus installation
  • Cold Air Induction kit

Cadillac Tuner pages:

Skidpad testing methodology

I am thinking something similar to the Pedder’s Suspension test of the G8 here:

wherein they show both lean angle of the vehicle while cornering and measure g-force attained on a constant radius skidpad. Those seem to be ideal ways to measure performance of the current suspension setup on the Cadillac CTS, then apply mods, and then retest to determine effect.

Also using a tire temperature gauge seems interesting, although only in test consistency.

Suspension thoughts

My 2005 CTS 3.6L has the base, or FE1 soft-ride suspension. Since I plan to drive it another year or two, I have decided to explore suspension options to add to the fun.

The factory suspensions are:
FE1 Softride
FE2 Luxury or non-height adjusting Sport
FE3 Sport
FE4 with FG2 CTS-V with ‘track’ shocks

Also available are Eibach and Hotchkis aftermarket sway bars and springs.

The CTS tends to measure 0.83g on a 200ft skidpad, and I am hoping to get to 0.87g instead.

A key part of this mod will be testing before and after each step mod to determine what effect.
So first I need to define a handy flat 200 ft diameter circular spot, then the method to be used to ensure consistent measurements.

I have my RaceTechnology AP-22 meter which measures Gs. I am studying the new meters and track data packs to see what will make the best test setup.