![\"\"](\"http:\/\/caddyinfo.com\/wordpress\/wp-content\/uploads\/2011\/05\/2009_44L_LC3_STSV.jpg\" "\\"2009_44L_LC3_STSV\\"")
<\/a><\/p>\nAn engine dyno as in the graph above measures horepower at the crank (hp).\u00a0 A chassis dyno measures horsepower at the wheels (whp).\u00a0 Horsepower at the wheels includes inefficiencies of the powertrain.<\/p>\n
For an automatic RWD automobile, powertrain inefficiencies often run 20% of the power.\u00a0 So for a 469 hp STS-V, one might expect to measure 469 x 0.8 = 375 hp at the wheels.\u00a0 From my research, most STS-Vs measure 360-370 hp at the wheels, so perhaps a bit more than 20% loss at 22-24% due to luxury isolation in the powertrain. One outlier pulled 379-387 whp however.<\/p>\n
HP is often used to indicate hp at the crank, and whp, or wheel horsepower, is used to indicate horsepower at the wheels.<\/p>\n
To go from chassis dyno wheel hp to hp at the crank, divide by 1-inefficiency.\u00a0 So if inefficiency = 20%, WHP\/(1-20%) = WHP\/80% = crank hp.<\/p>\n
The classic hot rodding questions are,<\/p>\n
- \n
- How much money do you have?\u00a0 and<\/li>\n
- How fast do you want to go?<\/li>\n<\/ul>\n
The hidden gem in this discussion is, before you sink a ton of money into your car, you should have a plan.\u00a0 If you want to achieve a specific goal, then you might start with a different car, for an extreme example.<\/p>\n
![\"\"](\"http:\/\/caddyinfo.com\/wordpress\/wp-content\/uploads\/2009\/12\/09-4.4L-V8-LC3-STS-V-LoR_n.jpg\" "\\"09")
<\/a>Supercharged Northstar<\/p><\/div>\n
My goals for developing my STS-V:<\/p>\n
- \n
- It is a Cadillac: maintain luxury features,\u00a0 & avoid “noise for noise sake”<\/li>\n
- Test and Tune:\u00a0 only add \/ change items which prove to add performance<\/li>\n
- Phase 1:\u00a0 500 hp, so 400 whp<\/li>\n
- Phase 2: 550 hp, so 440 whp<\/li>\n<\/ul>\n
What will that let me do?<\/p>\n
- \n
- Be happy that the Cadillac STS-V is tuned to optimum performance<\/li>\n
- Enjoy the journey of researching, selecting, testing, and writing about the Cadillac Project<\/li>\n<\/ul>\n
My first Project looks set to be a Spectre intake from Jaime at StreetSideAuto<\/a>.\u00a0 In Spectre’s tests the intake added 40+ whp.\u00a0 True Street Motorsports<\/a> has agreed to help with testing the new intake once it arrives using their Dynojet dyno.\u00a0 First we’ll establish a baseline for the STS-V stock.\u00a0 Then hopefully we can get clear before\/after apples to apples tests with and without each modification.<\/p>\n
In my True Streets Motorsports correspondence they refer to the test as “Project Cadillac”, hence today’s title.<\/p>\n
Other project ideas in sight:<\/p>\n
- \n
- Custom Tuning<\/li>\n
- Intercooler pump, reservoir or heat exchanger mods<\/li>\n<\/ul>\n
More to come as things change, arrive, and evolve.<\/p>\n
What would you like to see tested on a Cadillac STS-V?\u00a0 If you have a performance product you would like to have independently tested on a Cadillac STS-V, please let me know.<\/p>\n","protected":false},"excerpt":{"rendered":"
I am enjoying my 2008 Cadillac STS-V; it is a terrific design right out of the box.\u00a0\u00a0 Cadillac pulled out some stops in developing this unique 4.4L Supercharged Northstar variant.\u00a0 For example, the exhaust manifold was extrude honed to optimize … Continue reading