Tag Archives: MPG

Cadillac Premium w/o Ethanol #motorama

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Most gas these days has 10% ethanol included. The ethanol mix works fine in modern cars, and that is 10% less gas to source.

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But will I instantly pull over in my Cadillac if a shop advertises ‘straight’, pure gas?

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Why yes, yes I will.

This station also charged a premium for the ethanol-free juice, but I considered it a pay to play treat.

Due to the high traffic and stops on our tour today no mpg comparison to report, but I like getting the pure stuff for a change –then back to the E10 the rest of the trip.

Would you pay extra for straight gas with no ethanol added if it were available locally?

Power versus MPG

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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?

Performance cost in MPG

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My current 2005 Cadillac CTS has a 3.6L V6 and is EPA rated for 16 city and 25 highway MPG using their current measure.  For argument sake this yields a mixed-driving target of 19 MPG.

I drive 15,000 miles a year, more or less.  So with my 2005 Cadillac CTS I might expect to need 15,000 miles / 19 MPG = 790 gallons of fuel in the next year.  The 3.6L CTS uses regular unleaded fuel, so let’s say $2.50 / gallon for a total of $2.50 x 790 gallons = $1,975 in fuel costs.

Here are the replacement performance V-Series cars I am considering:  the 469 hp 2008 Cadillac STS-V, or the 400 hp 2007 Cadillac CTS-V.

2008 Cadillac STS-V:  EPA rated 13 city 19 highway, 15 MPG combined.  With my expected annual mileage of 15,000 miles per year that would mean 15,000 miles / 15 MPG = 1,000 gallons of fuel.  Noting that the STS-V however requires premium fuel, which might cost $3.00 / gallon, that makes a total of 1,000 gallons x $3.00 / gallon = $3,000 in fuel costs.   So the Cadillac STS-V would cost an extra $1K/year, or $85/month in gas compared to my 2005 Cadillac CTS.

2007 Cadillac CTS-V: EPA rated 14 city 22 highway, 16 MPG combined. It also requires premium fuel.  15,000 miles x 16 MPG = 937 Gallons.  937 Gallons x $3.00/gallon = $2,811 in fuel costs.  So that CTS-V would cost an extra $836/year in fuel, or $70/month compared to my 2005 Cadillac CTS.

I plan to keep the next Cadillac for 5 years.  Comparing the new cars, STS-V will cost $200/year more than the CTS-V, or $1,000 over the 5 years.

On the other end of the spectrum, the current 2010 Cadillac CTS 3.6L DI V6 engine is rated at 18 city 27 highway for combined 21 mpg.  The current 2010 Cadillac CTS 3.0L DI V6 engine is rated at 18 city 28 highway for combined 22 mpg.  Either engine can use regular unleaded.  So replacing my CTS with the new 2010 Cadillac CTS 3.6L would yield a projected fuel cost of 15,000 miles / 21 MPG x $2.50/gallon = $1,785/year.  Although the new 3.6L has more power at 304 hp than the 2005 non-DI 3.6L at 255 hp in my car, the DI engine also gets better MPG, and is boosted by the 6-speed automatic vs 5-speed automatic.

Replacing my CTS with a 6-speed DI 3.6L instead of a 2007 CTS-V or 2008 STS-V model would save $1,026-$1,215/year.   However, the CTS DI 3.6L has respectable performance of 0-60 in 6.5 sec, while the 08 STS-V or 07 CTS-V will both accelerate 0-60 in under 5 seconds, out-brake, out-corner, generally out-perform the CTS 3.6L.  What cost performance?  Besides the initial price of entry, about $100/month in my case.  Is that worth the thrill of the added performance potential?  Would you pay another $1200 a year to drive a Super car versus a ‘normal’ sport sedan?