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    Re: 997 and sequential shifting

    Thanks Steve and Ferdie,

    but coming back to my original question, can this engine be pushed to 3.8? guess yes given Keith's comment on the 964. and does someone (ie RC !!) have some more info regarding the new gt3? It would make sense if that car would reach at least 400-410 hp if the new turbo starts at 480 or so and the S at 355. we shouldnt forget that the new entrylevel f430 starts at 490 hp. Porsche cant do much less with the heavy TT. what are your thoughts on this?

    turbolite

    Re: 997 and sequential shifting

    Trundle,

    can you give us some comments about the Sport-o-matic? Was before my time...
    Especially your personal opinion would be appreciated - since it didn't have to much success on the market!


    Turbolite,

    Koro (www.koro.de) for example increases the GT3 engine to as much as 4.8 litres but they use several patented items they have personally developed in the past. According to their own information they use patented crankshafts for example.
    Increasement in their 4litre engine is achieved by increasing bore alone - not too many information about their credibility. They seem to be very serious with their achievements though, done a lot of work for various car manufacturers and racing teams!

    Re: 997 and sequential shifting

    Quote:
    Ferdie said:
    Ahem, please name me a situation when you need to shift from 6th to 2nd gear...


    Actually, I just want to show you guys/gals the tech info. How about tracking long striaght into a hairpin corner!?

    Re: 997 and sequential shifting

    Thanks for the info - much appreciated!

    I'd say when you are going in 5th or 6th on the straight you will take way more time to decelerate than to downshift!
    Current sportscars have a deceleration of about 11 m/s2, which translates to about 2,5 seconds braking time from 200 to 100 kph!

    A faster downshift would definately be an advantage in everyday use but due to strain on drivetrain and lacking necessity in sporting situations I'd say it is rather negligble at its current stage of development.
    I just hope the boxes last 100k+ miles since the Euro-friendly TDIs in Golf, Touran and A3 can be equipped with this system by now!

    Re: 997 and sequential shifting

    Quote:
    Ferdie said:
    I'd say when you are going in 5th or 6th on the straight you will take way more time to decelerate than to downshift!


    Agree!

    Re: 997 and sequential shifting

    Sportomatic from 1968-79 produced approx 8500 units

    "An interesting addition for the 1968 model year was the semi-automatic Sportomatic transmission. Porsche felt that none of their customers would really want to give up complete control of their transmission so instead of a total automatic they combined a torque converter, an automatic clutch and a four speed transmission. They took their excellent four speed transmission and added a torque converter and a vacuum servo controlled clutch. The torque converter was what could be considered a "loose" one with a stall speed of 2600 rpm The clutch was disengaged by the vacuum servo when it received a signal from the micro switch on the shift linkage, so that when you grabbed the shift lever the clutch would release, you could shift and when you let go of the shift lever the clutch would engage again. With the high stall speed of the torque converter you could be a very lazy driver with one of these transmissions starting out in second gears and shifting directly to fourth when the car came up to speed. Or if you wanted, the car could be driven quite aggressively using all four gears and it would give very little away to the other 911s with their more conventional four or five speed manual transmissions.
    911s with these Sportomatic transmissions were a good solution for the people who still wanted a sporty Porsche, but spent quite a bit of their driving time stuck in commute traffic, because you could greatly reduce the amount of shifting necessary with this transmission. Unfortunately for the Porsche customers that liked their Porsche driving sans clutch this transmission was not an idea that really caught on in the U.S.A. and about ten years after its introduction Porsche ceased production of the Sportomatic .

    Re: 997 and sequential shifting

    Thanks a lot, Trundle!

    If I understand it right, the torque converter was rather soft and therefore a considerable amount of power should be lost in there, shouldn't it?

    The autom. clutch was set between torque conv. and gearbox? It didn't have a clutch pedal?

    How reliable was this system?

    Re: 997 and sequential shifting

    Quote:
    Steve in FL said:
    Quote:
    Ferdie said:
    what's the story about the 964 engine block? As far as I know the GT1-derived engine block, used in GT2/3 and TT, doesn't have any connection with previous models but was developed for racing purposes from scratch. Anybody can confirm this? Not sure on this one...


    The GT1 block was a water cooled derivative of the 964 block. Until Porsche switched to a re-designed block last year (changed to remove the last vestiges of support for the air cooled motors such as oil return tube holes) the 996 Turbo/GT2/GT3 blocks actually had a 964 part number.



    Keep in mind that the "old" Porsche 6-cylinder Boxer engines had separate crankcases and cylinder blocks. When the water-cooled cylinder block version of the engine was introduced, the old crankcase from the air-cooling days was still retained, so it was basically well over 20 years old!

    The change made last year (mentioned above) had more to do with replacing worn out old tooling than a redesign, but the opportunity would certainly have been used to update the design (such as eliminating any redundant oil return channels left over from the air-cooled days).

    The redesigned crank-case, cast in a different foundry by a different supplier, and probably in a different alloy, would automatically get a new up-dated part number. So I suspect that some of the stetements made above relating to the "block" should really have referred to the crank-case.

    Re: 997 and sequential shifting

    Fritz,

    do you know if there is any difference in the production process? What about your comment regarding different materials? Do you know anything in detail?

    Re: 997 and sequential shifting

    Quote:
    Ferdie said:
    The autom. clutch was set between torque conv. and gearbox? It didn't have a clutch pedal?




    The actuation of the mechanical plate-type clutch was prompted by a pressure-sensitive electrical switch in the shift knob, eliminating the need for a foot pedal.

    So it was not a good idea to absent-mindedly leave your hand on the shift knob in between gear changes, because it could cause the cluch to release unintentionally.

    Re: 997 and sequential shifting

    Quote:
    Ferdie said:
    Fritz,

    do you know if there is any difference in the production process? What about your comment regarding different materials? Do you know anything in detail?



    Ferdie,

    No, I do not.

    I would just automatically assume that the opportunity presented by making brand new casting moulds and a change of supplier would be used to profit from the advances in casting processes and metallurgy made over the quarter-of-a-century plus since tho original part was designed!

    Re: 997 and sequential shifting

    Quote:
    fritz said:
    ...So it was not a good idea to absent-mindedly leave your hand on the shift knob in between gear changes, because it could cause the cluch to release unintentionally.



    This switch wasn't activated by engine or suspension vibrations at all?

    I suppose you will fell and hear once the clutch disengages unintendedly...

    Share your opinon about the block's production process - I thought you might know some of the improvements there first hand... Thanks anyways!

    Re: 997 and sequential shifting

    well that was an excellent course on something i didnt knew too well...thanks all

    Re: 997 and sequential shifting

    Quote:
    Ferdie said:
    The 996 GT3 was actually heavier than the std. 996 due to a more complex suspension!




    The additional weight of the GT3 is in fact due to the "beefier" older-type engine and transmission, and not so much to the suspension.

    Re: 997 and sequential shifting

    Quote:
    fritz said:
    The additional weight of the GT3 is in fact due to the "beefier" older-type engine and transmission, and not so much to the suspension.



    What do you think about the "new" M97 engine, fritz? Do you think it could or would replace the "older-type" GT3/993 engine sooner or later? Take a guess.

    Re: 997 and sequential shifting

    Quote:
    RC said:
    Quote:
    fritz said:
    The additional weight of the GT3 is in fact due to the "beefier" older-type engine and transmission, and not so much to the suspension.



    What do you think about the "new" M97 engine, fritz? Do you think it could or would replace the "older-type" GT3/993 engine sooner or later? Take a guess.



    RC,

    I'll leave that kind of speculation to other people.

    Re: 997 and sequential shifting

    Pardon my ignorance, but is M97 the code for the 'new' 3.8 liter engine of the S ?

    turbolite

    Re: 997 and sequential shifting

    Quote:
    turbolite said:
    Pardon my ignorance, but is M97 the code for the 'new' 3.8 liter engine of the S ?



    Yes, its derived from the M96.03 of the 996 carrera, whilst the 996 GT3's uses the M96.79.

    Re: 997 and sequential shifting

    thanks Carlos!

    wasnt there a discussion focussing around the topic that the 996 carrera engine was to weak/didnt have appproriate oil cooling etc, so that it would not be able to work properly in a racetrack car like the gt3? (and therefore gt3 and the TT got the gt1 derivative). Does anyone now if the changes which have been made to the engine in the M97 version would be enough to allow it beeing used as basis for gt3 and tt? (guess that was RCs question as well!). I believe porsche would have some economic incentives as well to rationalize the different engine types they produce...

    turbolite

    Re: 997 and sequential shifting

    Quote:
    carlos fromspain said:
    ...Yes, its derived from the M96.03 of the 996 carrera, whilst the 996 GT3's uses the M96.79.



    Wait a minute, the GT3 engine shares the M96 engine code as well? This would clear up the rumours spread about 997 GT3s using the "M96" engine...

    Re: 997 and sequential shifting

    turbolite,

    Your welcome
    I think one of the main problems for the M96.03 carrera engine to be used for a GT3 and raced versions is that it doesn't have a dry sump like the M96.79 engine therefore with slicks it will suffer oil starvation. The carrera engine has what Porsche misleadingly calls an "integrated dry sump" which is a hybrid of them two you could say, but still no dry sump. Also the carrera engine is no good for the Turbo version because its not made to resist forced induction. So the Turbo also gets the GT1 derivative.



    Ferdie,

    As far as I know all 996's engine got the M96 code:
    - 996 Carrera 3.4l = M96.01
    - 996 Carrera 3.6l = M96.03
    - 996 TT / GT2 = M96.70
    - 996GT3 = M96.79

    So if the 997GT3 gets a M97 code it does not mean that its derived from the carrera engine, nor the Turbo versions. Now that you mentioned it, it could be a source of confusion of the 977GT3 getting the carrera engine rumors, I haven't though of that.

     
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