Mizuno

Im currently getting an average of 16mpg on my c2 cab under 70% highway and 30% city driving. On the highway, I'm usually in the 3000-4000 Rpm range.

How do you drive on the highway to maximize your gas mileage? 6th gear even at speeds around 60mph? do you try to stay above 3000 Rpm to manage the engine?

Thx!

Neil Perry

Hi
Min revs without loading up the engine.

Thanks,

911ist

get a prius?

haygeebaby

Changing the stock ecu chip gave me better mileage.
Running minimum revs is hard to do. Hehehe - get a Prius !!!

Quadcammer

how fast are you driving?

3000 to 4000rpm? why?

Put the car in 6th gear, thats what its there for.

TravisB

Timely thread, my commute is going to be tripling in about a month (although mileage threads always conclude that there's no magic pill and it's up to the condition of the engine and the discipline of your right foot). I didn't buy the car for mileage but I'll be doing 50+ miles a day, 90% or so on the highway, so I'll be spending a lot of time in 6th in the mid-high 2000 RPM range.

Anyway, I've read a time or two around the interwebs that the engines don't "like" being under 3000 RPM, in the sense that it accelerates wear or is somehow bad for the engine but not really being specific. Is there actually any truth in that statement? I have a hard time believing it..might be a bit of a dog at lower RPM's but I don't see how 2500 vs. 3500 is going to make much of a difference.

trophy

16mpg, something is a miss here..... 6th gear is a very very tall gear for highway cruising.

A trip i did in Sept to Salt Lake City (1860 miles) I averaged 26+ MPG and that was at 85mph + all the way.

Even with ~560 track miles in between all of this @ 6.5mpg (she sucks the gas on the track) I averaged 15.5mpg.....

Quadcammer

Someone once said (can't remember who) that the timing chains bounced around a lot under 3000rpm, but 2500rpm is not anywhere near lugging a 3.6L 993 engine, so use 6th and enjoy it. As to the chains, I haven't seen any 993s with excessive chain or sprocket wear, or anything therewith associated, so I'd say you're fine.

ilko

How old are your O2 sensors? Replacing them with fresh ones will improve MPG even if you don't get an O2 related CEL. Whether the price of 4 new sensors (for MY96+ cars) is worth it is another story...

CorrdoBrit

Here's your answer
http://www.tornadoair.com/

kjr914

ilko,
I'm curious if you know why this is? Just optimized fuel/air mix? How much improvement did you see?

I'm seeing 16mpg around town/commute (~15miles) which isn't unexpected, but I don't ever get 26+ on long trips (perhaps still related to a heavy right foot under acceleration and I probably drive too fast as well...). I'd guess my fat *** (WB (minimal effect), C4S extra weight, plus DAS bar) cuts me down 1 mpg perhaps.

goofballdeluxe

Sorry, riding your car at, say, 60mph in 6th gear is going to do no harm to anything. The engine is fine under 3000 rpm at highway speed as well. In fact, Porsche designed the 6th gear specifically for highway cruising at around 60mph (and higher speeds) to maximize MPG.

The car will be fine doing 60mph in 6th all day long with no ill effect, even if the revs are well under 3000rpm.

ca993twin

Our engines work just fine at low RPMs as long as there is no load (not heading uphill, or using much of the throttle). When a "load" situation occurs, just downshift a gear or two. Even Rufus gets 22 MPG on the hiway. And turbos SUCK. With very low compression they are quite inefficient when not on the boost, and let me say they can really burn through the fuel when on the boost.

Quadcammer

really only need the fronts, rears are just catalyst monitors essentially.

quicker response from 02s=less wasted fuel.

keep in mind that winter blend fuels that are oxygenated will result in poorer fuel mileage and the cold weather results in worse gas mileage (longer warmup= longer time in open loop= fuel mileage not as good)

ilko

Despite the fact that the secondary O2 sensor only monitors the cat's efficiency, my experience with my Audi has been that both help. I installed a primary O2 sensor in that car last spring. Immediately noticed a +2MPG difference. Last week I replaced the secondary O2 sensor and got another +2MPG. That's based on what the trip computer in the cluster is telling me. YMMV.