Allan Gibbs

I have the manual transmission and there's a little arrow right above the "mph" readout on the speedo that keeps telling me when I should upshift.

In the 1st, 2nd, and occasionally 3rd, it's usually around 3,000 rpm. Since, I'm in commute mode, I don't mind. But give and inch and the ECU takes a mile. It then starts telling me to upshift at 2,500 rpms for the 3rd and 4th at 1,800 rpms for 5th and 6th. I think my ECU really wants to be a PDK.

Anyone else follow the advice of your Boxster? I mean, I'm just human and can't make thousands of computations per second based on speed, incline, or engine conditions. So, whom an I to tell a computer it's wrong.

Macster

Automakers have found that upshift or real time fuel consumption indicators result in better gas mileage (or in the case of hybrids, longer battery life) and lower emissions.

For the Tip and now PDK the shift programs are tailored to deliver as good as possible results when the cars are tested for fuel consumption and CO2 emissions, especially the EU driving cycle.

For manual transmission cars though the shifting is up to the driver. But my info is that when manual equipped cars are tested the test driver is supposed to follow any car hints/directives regarding shift points so what you see is I believe the result of this.

Generally as long as the engine is warm you can follow the hints with no harm to the engine. Gas mileage will be quite good. The fuel consumption numbers on the window sticker were probably obtained by following the shift hints.

Or you can chose to ignore the hints too depending upon well whatever. There are times I seek to max. fuel economy and there are times when I make demands of the engine at the expense of fuel economy. IOWs, I'm in 'charge' and I'll drive the car as I see fit.

As an aside, both my '01 Camaro and my '06 GTO had that godawful skip shift BS feature that under certain conditions would have a solenoid redirect the shifter from 1st to 4th instead of allowing me to shift to 2nd or even 3rd from 1st.

The GTO also had an on-board computer which would display real time fuel consumption in MPG. I used this display often to help maximize the GTO's fuel consumption. That 400hp 6.0l V8 would really drink the gas if I didn't pay attention.

For the Camaro I just drove the car in such a fashion that the skip shift intervention was avoided. (Under certain torque demand conditions the skip shift was not active.) I only owned the car for around 4 months before I replaced it with the 02 Boxster. For the GTO I bought a Predator Obd tool that allowed me to modify the skip shift behavior. By 'modify' read disable. Then after a few years of GTO ownership I traded it in for a new (08) Cayman S.

Sincerely,

Macster.

renvagn

Macster could probably add to this, but I have heard that driving these engines harder than softer tends to keep the engine and IMS bearing happier. Lugging the engine down is never good, but said to cause reduced oil flow through the IMS. Porsche not providing consumer manuals and detailed information about current models is annoying for the enthusiast. With this being said, your car is a high performance sports car and not really made for 10 minute across town runs at 25 mph. Nothing gets warmed up and loosened up properly. I usually never let the revs drop below 2 grand and mpg is just fine.

Macster

This is to some extent modern mythology.

While it is true that these engines (no engine really) wants to be lugged around for various reasons, as long as one avoids lugging there's no real proof (or make that scientific proof that I know of) that says running the car harder is better than running it easier.

In fact, a case could be made that running the engine harder subjects the engine to more wear/tear from the added heat and increased mechanical forces from the higher operating speeds, higher loads.

If an engine fails prematurely from a failed IMS bearing or a failed rod bolt, who cares? The engine failed.

Besides, even if this were true, that the engine needs to be run harder to avoid premature engine failure, I think then Porsche would be at fault for not specifiying this type of usage (which for obvious reasons it would never do) or for building an engine that requires a style of driving that is quite foreign to what most owners of these cars can or will follow. We don't all live next door to an autobahn with derestricted speed limits. So Porsche if it builds engines that require this type of usage to remain healthy is not building engines for the market into which it is selling these cars.

My best advice to any owner of one of these cars is to drive the car and have a reasonable degree of mechanical sympathy/empathy for the engine (and in fact the entire car). These are not applicances, per se, but highly sophisticated complex assemblies and deserve a bit more consideration that one would give a toaster.

Some warm up before moving off from a cold start is better than none but there is no reason to overdo the warm up either.

Then reasonably gentle driving until the engine/drivetrain has come up to full operating temperature (which in some climates can take 10 or even more minutes of driving. One guideline I use is I assume (and I have checked the coolant temperature to confirm this) the engine/drivetrain is fully warmed up if the coolant gage needle has been at the 180 degree mark for several (5?) minutes. I do tend to err on the side of caution though and delay giving my cars the whip early in a drive, so almost invariably the needle as been at the 180 mark for longer than 5 minutes.

But once the engine/drivetrain is warmed up, then the entire engine's rpm range and hp/torque output is there for the using. And I use it, when it is safe to do so.

Obviously, though, if one keeps the tach needle pegged to just under redline the engine's life almost certainly will be shorter than it would be if operating at lower engine speeds.

Before shutting of the engine allow the engine some cool down time if it has just been run hard.

And lastly, I dare say the oil change interval given by the owners manual is at least double what is best for the engine.

Use a good (Porsche approved) oil, of the proper type and viscosity grade for your area, and change the oil/filter more often. An argument could be made that someone who drives his car infrequently, uses it for short trips, really should have his engine's oil/filter changed more often, but this is contrary to what most people believe. They like to believe little use means extended oil/filter services are ok.

Sincerely,

Macster.

Cpa4S

so by following the computer you save $1,000 per year in gas if you are lucky - probably more like $500 or less.


not lugging it is the best fun you can have in these cars. the pull and sound in the low gears when driven between 4k rpm and 6k rpm -

i say it is the deal of the century!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

racer

My 1987 944 has the same "shift light" to preserve fuel economy. Often times I feel like adding a bit of black tape over that part of the guage so it stops annoying me, so I know how you feel.

Macster

It depends upon how closely one follows the computer's recomendations regarding shift points and how far one deviates from these.

With my 06 GTO if I drove the car agressively, the instant fuel mileage would drop to single digits. Under hard acceleration in the lower gears fuel consumption would drop to 5mpg. I do not remember being able to drive the car safely and look at the instant mpg reading at higher speeds. The thing would reach hyper legal speeds in nearly no time and I avoided these.

If gas consumption alone was not enough to cause me to temper my driving towards the more economy friendly style, the very likely possibly I'd lose my driver's license was the added incentive.

With the Boxster if I drive it a bit more agressively the fuel consumption declines maybe 10%. Again though I can't or won't drive it agressively all the time. The area in which I live, the traffic and other stuff I have to deal, with just doesn't enable me to be that agressive with the car, and remain a safe and law-abiding driver.

With Turbo, it is much the same as with the GTO. While the Turbo does not have a real time instant mpg readout it does have an average mpg readout and I can watch this reading drop from a bit over 20mpg to the mid-teens in no time if I am agressive with Turbo. One hard throttle acceleration from near zero mph to the speed limit when pulling out onto the freeway is enough.

Depending upon how many miles one chose to drive agressively vs. not to much, the fuel savings could be considerable. Even if I were in the Boxster at its approx. 26.6K miles per year average distance if the mpg dropped from say 25mpg to 22.5mpg that's the difference between using 1064 gallons vs. 1182 gallons. I filled up last night and paid $3.939 for over 10 gallons of Shell V-Power 91 octane. Thus at today's gas prices I would save around $465 by remaining a conservitive driver vs. being the more agressive driver, even in the the Boxster, provided I didn't lose my license (or worse) first.

Sincerely,

Macster.

Allan Gibbs

I'm learning to ignore the shift up light again (after all, I ignored it for almost 400 miles). I'm just glad that, per the ECU, that I haven't been lugging the engine. In commute mode, some of my upshifts put me to around 2,000 - 2,200 when I get to the next gear. I was starting to worry that was a little to low but at that point, the upshift light is suggesting one more gear. I'm not convinced being under 2,000 is a good thing.

On a side note, I had a 1996 Trans Am and remember skipshift. I hated it. On another side note, my first automatic and my last car was a 2008 Audi TT. I'm not sure the ECU had the transmission's best interest at heart. At times, it would upshift while I was going up a hill and the engine would sometimes give a little rattle.

Carcam

Hit the sport button and the shift triangle goes away- another reason to like the sport setting.

renvagn

Sounds familar. You have probably found that it also shifts smoother at close to 4 grand and above. Problem is you carry so much speed at that point it's a ticket waiting to happen on the street.

Cpa4S

1st, 2nd and 3rd can be taken close to redline in the appropriate spot and there is no issue of speeding tickets.

4th and 5th are where you rpm it down and OD it a bit.

Macster

I don't know what the speed limits are where you live/drive but my 02 Boxster 2.7l 5-speed in 3rd gear can break every speed limit here in the good old US of A and still have over 1K rpms to go before the engine hits redline.

Sincerely,

Macster.

Byprodriver

CAFE (corporate average fleet economy) is a big issue for Porsche another reason the baby Box will probably get built.

Allan Gibbs

Hmm. Good point and tje CAFE tax may make a plausible argument that the the shift up light may not be as good for engine longevity.

Macster

Yes. And emissions (CO2) in EU.

There was a time when Porsche thought its CAFE numbers could derive some benefit from its ownership of VW (back when Porsche was trying to take over VW), piggyback on VW's cars and its CAFE/EU numbers. Then when the roles reversed there was still some thinking that Porsche could piggyback on VW's cars and not have to worry as much about this.

But other EU countries with their own auto industry (France and Italy to name two) complained/protested and it was decided that the dividing line between an automaker that could be exempt or not held to as restrictive rules/regulations was lower than Porsche (I think it was based on annual sales).

So then Porsche had to come up small(er) cars that would help its situation and larger cars/vehicles (hybrids) that it could also use their better fuel economy and lower emissions to improve its situation here in the USA regarding CAFE and in the EU for whatever EU has for CAFE over there.

Sincerely,

Macster.