Power versus MPG

In selecting my next Cadillac, I am drawn the to highest performance models available within my budget.  More is always better right?

My model for the ‘right’ 0-60 time for a sport sedan is 5.5 to 6  seconds this year.   Performance of cars as a whole changes over time, as automobile performance improves.

The current CTS DI 3.6L will do 0-60 mph in 6.3-6.5 sec.  The CTS should be below 6 seconds with 304 hp, but it also gained a bit of weight with added features, and has fuel economy minded gearing.  Yes I recognize that is kind of in the same range, but let’s assume for this discussion that quicker is important.  So the CTS 3.6L is just on the upper edge of my desired performance envelope, and is right in the right zone for MPG.

Now, the 2006-2009 STS-V with 469 hp will go 0-60 in around 5 sec, or as Cadillac measured in under 5 seconds.  However, this model gets 19 mpg highway compared to the CTS DI 3.6L V6 MPG of 28 MPG highway.

One compromise candidate is the 2005-2009 STS 4.6L V8, with the 320 hp VVT Northstar.  This sedan gets very close to 0-60 mph in 6 sec in most tests, and has fair fuel economy at 24 mpg highway.

The new Gen2 CTS-V with 556 hp supercharged 6.2L V8 will do 0-60 mph in under 4 seconds with a Cadillac test driver, or just over 4 seconds with a magazine writer driving.  The new CTS-V is still outside of my budget however, and also gets 19 mpg highway.

The 2006-2007 Cadillac CTS-V with 6L LS2 V8 engines would do 0-60 in under 5 seconds, and are rated at 24 mpg highway.  So these are interesting, but they will soon be out of warranty.  I like to keep my daily driver under warranty, so if there is an issue I can simply drop it off for service, pick up a loaner car, and be on my way.  These are also only available in manual transmissions.  A manual is okay for me, but is challenging for other members of my household.

So this thought process leaves me wondering if I should change my target from “as quick as possible” to “as quick as possible and still get more than 24 mpg highway”, or similar.

In this range that 5 mpg costs around $1000 per year given my mileage per year and average gas prices.  So would you pay $1000 per year for another 150 hp, or 47% more power?  I suppose over the 5 years I plan to drive the car that is less than the cost of a Supercharger or similar power adder.

How many MPG is more power worth to you?

2 thoughts on “Power versus MPG

  1. that question is ever more pertinent these days with the constant rising gas prices. along with the return of the enthusiast car. with technology these days there should be no reason we can’t have our cake and eat it to. 300hp 30mpg for the entry level v6 is a good target. gm is right there with the camaro and for has the mustang. caddy is really close with the 28 mpg cts v6.

    here’s the burnout radio formula for eating that cake.

    high output di v6 with variable timing, or a large bore turbo di 4cyl al la the buick regal. a 6 speed close ration gear box with a tall and i do mean TALL 6th gear. come to think of it 5th gear should be fairly tall as well. why? well this is where you get those vaunted mpg’s.

    here’s how it works. you floor it, light the tires up in a cloud of smoke, nail the shift to second, snap in to third up the on ramp, by then you should be nearing highway speeds so you ease it in to cruising gear, and run along a 70+ mph while your engine sips that glorious nectar we call gasoline at 30+ mpg.

  2. Yes, but if you want the Supercharged 6.2L V8 that can spin the tires going in to third gear and that means 20 mpg and not 30 mpg, therein lies the problem. At least I did have the CTS-V spin the tires coming out of a corner at 60 mph, so close enough.
    There actually is some support for the best fuel economy is to get to speed quickly and so gain the benefit of cruise MPG, but the argument is for accelerating at the peak torque and not to redline.

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