Pontiac's magnum opus in Motor Trend leaves more questions

Motor Trend recently tested the soon-to-be orphaned Pontiac G8 GXP and left some questions unanswered. Orphaned because it was reported today, April 24th, 2009, that the Pontiac nameplate is being dropped. How unfortunate for another excellent domestic (though imported) car. The GXP is a fantastic bang-for-the-buck sedan but now there will be questions left unanswered. Unfortunately, it looks like we only get to enjoy it for one model year unless Chevrolet picks it up. And they absolutely should.

I must commend Motor Trend for instrument testing both the manual and automatic transmission versions. This is very rare in the automotive media arena. But it also dictates more extensive coverage. http://www.motortrend.com/roadtests/sedans/112_0902_2009_pontiac_g8_gxp_first_test/index.html

First, a clarification. the LS3 engine in the GXP is not the second most powerful version, it's actually the third and sixth in the LSX family. The C6 Corvette has two versions that are more powerful at 430hp and 436hp with the exhaust option. The LS7 in the Corvette Z-06, the LSA in the Cadillac CTS-V and the LS9 in the Corvette ZR1 are all much more powerful and top the list in the family.

Related to this, the octane requirement is reported to be "regular" or 87 octane, GM media online states it requires premium.

The rear diffuser was called "fake". How so? BMW made a less obvious yet purposeful change to the tail light surface on the 6-series for aerodynamic reasons, so how is the diffuser fake? Have you ever noticed the scallops on the bottom surface of mufflers? This is for aerodynamic reasons as well. Take a look at the diffuser on the 190mph+ Lamborghini Gallardo - it isn't very significant looking.

When a car is advertised as, "Simply the fastest, most powerful Pontiac ever" that pretty much obligates a top speed test, doesn't it? But it wasn't listed, why is that? Also, AutoWeek report the top speed was limited due to cooling reasons. What are the details regarding this lack of cooling?

Now that cars with six, seven or even eight speed automatics perform so closely to their manual transmission counterparts, the clear performance advantage of the manual has effectively been equalized. But once again, when testing them together, further analysis is mandated.

There are a few more questions regarding weight and braking. The weight differential between the two models is 74lbs or almost 2%. Yet the weight distribution is listed as being identical. How can this be? It doesn't have a rear transaxle. The 74lbs differential is definitely not over the center of the car. Finally the braking distance delta is 6ft. Is this accepted statistical variance or due to the weight differential? What is the typical variance found in braking tests?

So while this is Pontiac's best car ever, it is also quite low in domestic content. If similar to the G8 GT, it is roughly 8% if memory serves from a listing in AutoWeek a few months ago. Also, doesn't the previous generation CTS-V make the GXP somewhat redundant? Nicer interior, handles better, braking performance is probably better, it's lighter, essentially the same power, more aggressive gearing and it competes in the SCCA T2. The GXP could race in that class, but it is a bit heavy. The CTS-V may take the trophy again this year too, when big horsepower cars will give the Solstice GXP (another Pontiac) all it can handle at Road America, one of the fastest road circuits in the country.

This brings us to my final point. Motor Trend must stay relevant in this age of information by digging deeper, disclosing testing procedures, guidelines, atmospheric conditions and acceptable statistical variance.

We may never see a four-door car like this from GM again and I wonder, should they have just used the last generation CTS-V platform? Would it have mattered?