Dear 001,

Reports are coming in from all over the net that the CTS-V is falling shy of it's advertised 400hp. Is this the begining of a class action lawsuit similar to what happened to Ford over the 1999 Mustang Cobra?

Click here to view the report.

FWIW this low HP rating has been observed all year, and it seams to be the norm rather than the exception...ugh! There is an interesting thread developing on this over at the Caddy Forums here.

Here is one of the stand-out posts:

"...(1) I believe I am comparing apples with apples...
as I am trying to compare *averages*...
For the Z06 numbers, there are 123 dyno runs in the
350-359 range, and 162 runs in the 350-364 range.
That's a lot of data. While a 1000 data points would be better... that's not possible. It's a classic bell curve graph centered ~356rwhp. That should account for dyno variances, temps, <1K miles, etc.

Here is the whole thread:

The author is very specific about posting *stock* numbers and no cheating.

I concede that more CTS-V data is needed... but the trend is looking bad... the average of the dyno's is:

(2) Cal, imho, using your data would be comparing apples to oranges... i cant use your numbers, as you are the highest pull - and only one data point.
Averages: 321 vs. 356 => 35hp are missing!

(3) crank hp vs. wheel hp: I have read that 12-15% is a good number for newer (manual) cars... the 20-25% numbers are old. The logic is that in an effort to increase fuel efficiency, car mfg's are minimizing tranny losses, drivetrain losses, friction losses, etc. This raises the crank to wheel hp ratio. Dont know if that's true, but both Z06 and V have IRS, similar tranny, same engine...(Adam Note below)*..
drivetrain losses cannot account for the missing hp.
Some data: The Z06 is at 12-13% (405hp / 355whp), Dinan uses 12% - the Dinan M5-S2 is rated at 470hp and dyno's at ~415hp, Vipers have 10-11% loss (See Viper forum), the Ford Lightning auto tranny (4R100) loses 11.2%! (see Lightning forum).

Dont know what's going on.... maybe GM had to detune the engine to reduce wheel hop and/or prevent broken rear ends.

I appended this post with what I felt was a more technically acurte comparison (Adam Note)* "..A more apt comparison is the GTO to CTS-V. The CTS-V is the next Gen (sigma platform) version of the platform (omega) that underpins the GTO. They have pretty much identicle drivlelines with the exception of the motor. (LS1 to LS6).

Now looking at LS1 Corvettes to Z06 Corvettes, off the top of my head I recall they tend to range from 300-310 Rwhp for the LS1 and 356-ish for the Z06 LS6.
On the exact same car exact same platform.

So why do we not see that same spread (45-55 RWHP) between the GTO(ls1) and CTS-V(ls6)?..."

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