Age vs Condition and fueleconomy.gov

[CANCarbGuy]

Hey guys and girls, long time visitor to the site, first time posting. Not long ago I was in a situation that raised some questions that I'd like some opinions on.

Recently, I helped my cousin buy her first vehicle due to her heading off for university. Due to a low budget, we only had 2 options. The first was her friend's 2001 Honda Integra sedan (1.8 I4, 4 speed auto transmission). He let us borrow it for a few days and I expected it to do well, but MPG came back at a disappointing 19.5/ 28 (hand calculated). I thought for sure we'd at least break into the 30's. The other option was her next door neighbour's 1989 Buick Electra Park Avenue (3.8 V6, 4 speed auto transmission) that the family was selling (the owner had been moved into an old folks home). We convinced them to let us borrow it for a weekend to test it out, and we got a solid 19/ 29 mpg. Between the two, the big difference between them was the condition. The Integra, maintenance wise, looked to been beaten and neglected as far as I could tell. it sounded fine, but the oil, spark plugs, air filter, all were old and black with use. One of the spark plug wires had electrical tape wrapped around it in one area, and I didn't even want to think about things such as alignment, tire pressure, fuel filters, etc. The Buick on the other hand, was in mint condition. Everything from rubber suspension parts to the air cleaner looked new. As far as I could tell, everything was %100 up to date maintenance-wise.
Also, the Integra had roughly 201,000 KM's, the Buick had 186,000.

Now here's the weird part: After my cousin bought the Buick, I checked fueleconomy.gov to see if what we got MPG-wise, was normal. For the new ratings, the Integra is rated at 20/28, so we actually got pretty close. The old ratings rate it at 24/30. The new ratings for the Buick is 17/26, but the old ratings are 19/28, which again, we almost hit spot on.

So, to close, my questions are: How much does long term maintenance really effect fuel economy? And, how the heck did fueleconomy.gov reach their conclusions about what MPG ratings older vehicles should get? To be honest, I'm still a little skeptical that a 27 year old, V6 powered Buick was able to meet/ exceed it's original ratings while the lighter, 15 year old I4 Honda wasn't even capable of meeting its new ratings. Don't get me wrong, I know that a full, in-depth tuneup would do it wonders, but would it be enough that it gains back the 4.5 city and 2 highway MPG's that it would need to reach it's original rating as well? All thoughts, options, and general speculation welcome.

[niky]

They obviously didn't retest all those old cars to the newer standard, so the adjustments are likely purely math.

[redneck]

The other option was her next door neighbour's 1989 Buick Electra Park Avenue (3.8 V6, 4 speed auto transmission). My cousin bought the Buick and we got a solid 19/ 29 mpg.

I had one and without a doubt, it was one of the nicest cars that I have ever owned. (comfort, ride, styling and engineering)

I was getting around 20/30 mpg so your 19/29 mpg is spot on.

That particular 3.8 in my opinion, is/was the best engine GM has ever produced.

When I sold it, it had around 240,000 miles on it and still ran like a champ with zero mechanical issues.

Knowing what I know now, I would get a MPGuino and wire it in.

I'm sure there's untapped potential there.



>

[Ecky]

The gearing in the Integra is likely what kills the economy.

[ChopStix]

Originally Posted by redneck

I had one and without a doubt, it was one of the nicest cars that I have ever owned. (comfort, ride, styling and engineering)
I was getting around 20/30 mpg so your 19/29 mpg is spot on.
That particular 3.8 in my opinion, is/was the best engine GM has ever produced.
When I sold it, it had around 240,000 miles on it and still ran like a champ with zero mechanical issues.....
>

x2
Those cars and that engine are great, had one, drove the hell out of it seemingly forever! We put around 250k miles on it then ironically the engine blew up in a fast food drive through sitting there idling. Complete WTF moment. But loved the car otherwise.

[California98Civic]

You are not going to get a whole lot more out of that Integra. The auto trans is a major reason (as is its gearing, as Ecky already stated). Maybe you'll be able to put some distance between it and the Buick in terms of FE once the neglected work on the Integra gets done. Further improvements would be possible in the Integra because you can use its OBD2 port for a ScanGauge or UltraGauge to monitor your driving with greater precision than I think an MPGuino can offer.

But none of that matters if the Integra has been so neglected that it costs you real money in repairs in a short while. Given what you describe in oil, spark plugs, and cables, I would wonder if the AT fluid has ever been changed.

And that Park Avenue is so 80s!



Go with the Buick.

[niky]

Originally Posted by Ecky

The gearing in the Integra is likely what kills the economy.

Come to think of it, differences in gearing could explain why the Buick does better. The Integra's final drive is pretty short, and changes in the highway speed on the EPA tests could affect it more than the Buick. The sliding scale EPA adjustments don't seem to take that into account.

[93tracerwagon]

Most cars were much lighter in the early 90's than they are now. The Mid-size buicks, Ford Tauruses, etc all got into the 30's during this period. Gearing is probably a big cause. I believe the GM's run about 1500 rpm at highway speeds. I drove with a relative in a 92 auto Taurus and I in an 88 Escort manual tranny and he got the same or better mileage on our trip.

Just take a look at some of the weight gains by cars in the mid 90's... it's shocking.....The Crown Vic went from less than 3,000 lbs to about 3500, the Escort added about 10% or more. The Honda Civic was about 2000 and now is between 2700 and 3000. VW Rabbit from the 80's about 2,000 , The Golf about 2900.

Older models will tend to get better city mileage if properly tuned and better highway if aero improved.

I'm hitting well into the 40's highway and approaching 30 with mixed city driving ( about 50% of the time on city highway and 50% crawling in Chicago rush hour traffic or locals) in a lowly, but lightweight 93 TRacer/ Escort wagon with auto.

[hayden55]

The old sport oriented B-series and K-series Honda motors just get terrible gas mileage in general. The Acura TSX with the K-series 2.0 barely got 29mpg as well. Honda sold a v6 accord beside it and it was rated for the same or more mpg... (I could get 29 in a tsx and 31 in a v6 accord)
I'd probably attribute it to horrible gearing and the volumetric efficiency below v-tec is more than likely terrible as well.
Fun cars though if you aren't in it for mpg's. But we aren't so... haha

[CANCarbGuy]

Thanks a lot for the responses guys and girls, I really appreciate it. Come to think of it, the Integra's rev's were a little high on highway. I'm more of an old school carburetor guy when it comes to tuning and eeking out MPG's, and wasn't quite as familiar with what computer controlled, fuel injected engines should be getting. Mind you, I am kinda happy my cousin bought the Buick. WWWAAAYYYY more comfortable to drive.