fpena944

Yeah but on roads you don't know you might get hit with the "fun tax" that pulls up behind you and shines these bright lights in your rear view mirror!

I think when I went on my DE I was in the single digits for fuel economy. What a fun use of hydrocarbons!!!

Gaspasser19

Mine is quite clearly at 3200

sbpsu354

I have the same slight surge at 3100 to 3200 rpm

ttreat

Yes, I really want to avoid the "fun tax".

I feel much better now that many of you have posted your opinions that cruising in 6th gear shouldn't be a concern. I thought it would seem rather sensless to have to cruise down the highway with the engine roaring just to keep the car from lugging. Otherwise, we might as well put Honda 4 cyl engines in our cars.

yasuro

when i first brought my 996 home i did manage 11 MPG the first 2 days. basically i used ~13 gallons of gas and traveled 140 miles (my tank is a bit smaller because i drive a C4).

i still spend most of my local/city driving in 3rd gear. i cruise around town @45 MPH in 3rd at around 3000 RPM. i definitely avoid lugging the engine :P

ivangene

LOL -
I didnt know why I put a 5 or 6th gear in for the first year !! 120 is plenty fast!!
(actual speeds may be exaturated)
hehehehe

Macster

Is it a "surge"? A transient increase in Rpms or acceleration? Or is just more like a bit there's a bit extra peppiness that continues?

These engines have a resonance valve in the intake manifold that is manipulated around the 3K rpm point to take advantage of the way the air moves through the intake system.

When this valve is opened, not only does this perk up the engine -- provide a bit of a boost in HP/torque -- the intake sound changes as well.

This is normal.

If you are experiencing a transient increase in rpms or acceleration, that is you are holding the throttle steady or steadily applying more pressure to the throttle and experience a momentary increase in acceleration that is not normal and that is not due to the resonance valve in the intake manifold opening or due to the VarioCam system being activated (at least assuming these are not malfuctioning and changing their state due to some mechanical or electrical malfunction).

Both the VarioCam and intake resonance flap are controlled by the engine controller.

Each has a specific rpm level at which a state is selected. (Other inputs also can affect if a state is selected, for instance coolant or oil temperature.)

Each has a specific rpm level at which the current state is deselected. The separation in rpms is several hundred rpms so unless you are accelerating the car up to and over 3K rpms then releasing the throttle and allowing the car to slow until rpms drop several hundred rpms below the activation rpm level there is something else going on. Probably something not normal, to state the obvious.

Under normal driving conditions, that is if you can manage to hold rpms constant within 200 rpms (or so) a state once entered will not be left again. The rpms must decrease or increase by around 200 rpms in order for a state change to occur.

Sincerely,

Mactser.

Jim Griffin

On long drives, I vary my RPMs by going into 4th and 5th periodically on my Tiptronic. I usually like to keep my RPMs about 3000-3500 all the time around town, using the manual mode, IF I kept my car in 5th on a long trip with 24-2800 RPMs, I would wory about lugging the engine. I know when my wife drives the car only in auto mode, afterwards, when I drive it it seems sluggish and takes a few minutes at higher RPMs to clear out the slugglishness. After a business trip, I can always tell when my car has been drivem in auto mode because it doen't have that spark it usually has when I drive it regularily in the manual mode at least 3000RPM or higher.

Pac996

I hope you have heard of how you can advance (+) and retard (-) the ignition timing so that this explanation might register. The cams spins in relation to the crank spinning with the pistons on it. The difference of cam spin to crank is expressed in degrees ie + or -. If you go negative with the cam degree then it places more power in the higher rpms. + degreeing puts the power band lower in rpms. "Vario-cam" meaning variable cam where it will change the degree of the cam depending on your rpms. So it's a game of always having the best power the engine can throw out. Take for granted the vario cam is changing the cams degree to negative numbers when at higher rpms.

Now hehehe the advancing and retarding the ignition is the opposite concerning where it puts the power. Advancing ignition sparks early so that by time a faster spinning engine fully ignites the fuel the piston is near top dead center and not sparking late in the combustion cycle. Just remember they are opposite in power dabbling.

My personal opinion? rpms are related to cops saying stop doing that or pointing laser guns on the hwy. Other than that just cruise it and stay away from doctors or they'll have you gulping meds the salesmen recently offered them kickbacks for selling.

sheatley

He has a 2001. Did the 2001 have a variocam?

Macster

IIRC all M96 water cooled engines came with VarioCam, which is variable intake valve timing.

VarioCam Plus came in circa 2004 (?). (My 03 Turbo has it and it appeared on other engines afterwards not before, so I'm guessing the 2004 number.)

VarioCam Plus is intake valve timing with intake valve variable lift control as well.

I have an intake lifter from a VarioCam Plus engine on my office desk. Very cool device.

Sincerely,

Macster.

Macster

The sluggishness is just the Ecu having adapted to your wife's style of driving. I'd be worried if when you got in car after wife and engine not sluggish but just the opposite. Would mean she's been out doing a bit of street racing or cayon carving, the bad girl!

2400 or so rpms not lugging engine unless you're climbing a steep grade. Even then as long as you don't give engine full throttle but ease it on a bit until rpms climb that is not lugging engine.

Porsche knows as well as anyone can how these cars are driven and has designed the engine and transmission to deliver good torque at lower rpms, though of course then engines do pull well to redline and deliver the goods when asked.

Sincerely,

Macster.

Pac996

My advise is just drive it. If it has been sitting take it easy on it till the rubber and plastics have sealed back up. Rubber and plastic do a little shrink or expand game at times when lacking normal usage. Just drive it and don't feel bad if you....well.....sort of open it up The cars a killer so don't expect it to fall apart from easy cruising. BUT if you give us time to set up the youtube video cameras we will advise you to stay in top gear using 5-7000rpms. Just give us the route and I'd be glad to hang back behind you videoing

rudy1024

Or worse... your wife is letting someone else drive the car... (Did I say that outloud??? j/k...)

Enjoy the car - if the IMS worries you that much, you should have bought a different car...

Rudy

htny

for US, 2002+ for variocam plus on NA cars, 2001 for turbo

basically all the 3.6s

per Porsche "VarioCam Plus combines intake-side camshaft control (VarioCam) and intake- side valve lift switchover (Plus). The valve lift control system consists of switchable flat-base tappets on the intake side actuated by an electro hydraulic 3/2-way directional control valve. The intake camshaft provides two different cam profiles with corresponding valve lift curves to act as required by selectively switching the relevant cams. The flat-base tappets have two nested lifters which can be locked together with a pin. The inner lifter is in contact with the small cam and the outer lifter with the large cam. A hydraulic compensation element takes care of any dynamic valve clearance adjustments."