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    Re: 997 Turbo overbuust question

    Quote:
    Fanch said:
    The question is not if they could build a V8 rear engined sports car but why.


    Well I may not know much about the how, but I know a bit about the why. There are many drivers that prefer the high revving instantaneous linear power of naturally aspirated motors. The GT3 has pretty much topped out what can be done with current technology at around 400hp. Unless Porsche begins to significantly reduce weight (more than the 90 lbs that was achieved on the 997TT), then I think there is going to be a desire and expectation for a 500hp n/a motor. As the cylinder sizes are already quite large at 3.6L or 3.8L, there is not much more room to make the motors rev higher to make more specific output (hp/L). So, dispacement will need to be increased and that means either larger cylinders (already straining at the limit) or more cylinders...

    Re: 997 Turbo overbuust question

    Quote:
    Grant said:
    Quote:
    Fanch said:
    The question is not if they could build a V8 rear engined sports car but why.


    Well I may not know much about the how, but I know a bit about the why. There are many drivers that prefer the high revving instantaneous linear power of naturally aspirated motors. The GT3 has pretty much topped out what can be done with current technology at around 400hp. Unless Porsche begins to significantly reduce weight (more than the 90 lbs that was achieved on the 997TT), then I think there is going to be a desire and expectation for a 500hp n/a motor. As the cylinder sizes are already quite large at 3.6L or 3.8L, there is not much more room to make the motors rev higher to make more specific output (hp/L). So, dispacement will need to be increased and that means either larger cylinders (already straining at the limit) or more cylinders...



    What about increasing the stroke?

    Re: 997 Turbo overbuust question

    Quote:
    Crash said:
    Quote:
    Grant said:
    Quote:
    Fanch said:
    The question is not if they could build a V8 rear engined sports car but why.


    Well I may not know much about the how, but I know a bit about the why. There are many drivers that prefer the high revving instantaneous linear power of naturally aspirated motors. The GT3 has pretty much topped out what can be done with current technology at around 400hp. Unless Porsche begins to significantly reduce weight (more than the 90 lbs that was achieved on the 997TT), then I think there is going to be a desire and expectation for a 500hp n/a motor. As the cylinder sizes are already quite large at 3.6L or 3.8L, there is not much more room to make the motors rev higher to make more specific output (hp/L). So, dispacement will need to be increased and that means either larger cylinders (already straining at the limit) or more cylinders...



    What about increasing the stroke?


    Increasing the stroke means increasing the piston speed (has to travel farther in the same time - rpm). Increasing piston speed puts tremendous stress on all reciprocating parts (like conrods, crankshaft, bearings, pistons, etc.). So, long stroke is usually a way to make good torque at low rpm, but peak power suffers since it can't rev as high. That's why most high-power small displacement motors have large bore with small stroke and very high rpm...

    Re: 997 Turbo overbuust question

    Well, I suppose a 911 Turbo wouldn't be a 911 Turbo anymore without the turbos, right?
    And we should wait how good or bad the VTG technology works since nobody has experience with it yet.
    In my "fantasy", the VTG technology is actually perfect for sportscar since it should be possible to adjust precisely torque/power levels at certain rev figures. I don't know if this is true but theoretically, it should be possible. You hardly can do that with a normally aspirated engine without giving away torque/power at certain rev ranges.

    Re: 997 Turbo overbuust question

    I like the fact that they are improving the formula for turbo charging. They are always improving the dreaded turbo-lag whilst delivering linear torque. The only negative is that it may miss out on the "turbo rush" excitement of the older cars like the Porsche 959.
    Do you think the purpose of the new VTG technology was to make the car more driveable or to increase performance
    I look foreward to the review of the 997tt and how it compares to the 996tt without the VTG, not only the numbers for performance but more importantly how the engine delivers its power.

    Re: 997 Turbo overbuust question

    Quote:
    vinnie said:
    Do you think the purpose of the new VTG technology was to make the car more driveable or to increase performance




    To be honest, I think that Porsche introduced the VTG technology mostly because of environmental issues (future emissions laws, fuel consumption, etc.). And I wouldn't be surprised to see direct fuel injection on the next generation of the 911 Turbo. I doubt that the 997 Turbo S will have direct fuel injection like some early rumours indicated. First Porsche model to get direct fuel injection will be the Cayenne. After the Cayenne, the Panamera. And I suppose after the Panamera is introduced, it will be time for a new 911, the 998? Still some time to go...the Panamera is expected earliest in 2008/2009.

    Re: 997 Turbo overbuust question

    Quote:
    RC said:
    Quote:
    vinnie said:
    Do you think the purpose of the new VTG technology was to make the car more driveable or to increase performance




    To be honest, I think that Porsche introduced the VTG technology mostly because of environmental issues (future emissions laws, fuel consumption, etc.). And I wouldn't be surprised to see direct fuel injection on the next generation of the 911 Turbo. I doubt that the 997 Turbo S will have direct fuel injection like some early rumours indicated. First Porsche model to get direct fuel injection will be the Cayenne. After the Cayenne, the Panamera. And I suppose after the Panamera is introduced, it will be time for a new 911, the 998? Still some time to go...the Panamera is expected earliest in 2008/2009.



    As much as we all act so disappointed about DI, does it really matter all that much? How much difference would one notice compared to a normal engine anyway, besides the lower emissions and (theoretically) less consumption?
    Thing is, the 997 Turbo I see coming will be awesome, same with the Turbo S, with or without DI.
    Btw, RC, if the electronic AWD information is true, that would mean better straight-line performance, with all the torque being transmitted to only the rear two wheels, wouldn't it? Who needs DI with a car like that? Man, I can't wait until they release the X50

    Re: 997 Turbo overbuust question

    Quote:
    RC said:
    Well, I suppose a 911 Turbo wouldn't be a 911 Turbo anymore without the turbos, right?


    Of course, but I was looking into the future with the 911S and GT3 having a high-power n/a flat-8. Sure the TT and GT2 would still use a turbo version of the new 8 also...

    Re: 997 Turbo overbuust question

    On all the articles I've read recently on the 997TT the 0-62 times don't mention whether this is acheived using the overboost function.
    Now as this is an 'option' are these times without the overboost ? And therefore with the overboost will the 0-62 times improve ?

    Re: 997 Turbo overbuust question

    Quote:
    gbj said:
    On all the articles I've read recently on the 997TT the 0-62 times don't mention whether this is acheived using the overboost function.
    Now as this is an 'option' are these times without the overboost ? And therefore with the overboost will the 0-62 times improve ?



    You're making a very valid point, I was asking that myself.
    Personally, I think the performance times are achieved without overboost because the chrono sport package is optional and it wouldn't be honest to advertise performance figures with an optional feature. BUT: maybe Porsche will tell in the technical specs in a little footnote that "above performance numbers were achieved using the overboost function of the optional chrono sport turbo package...". We just have to wait and see. I still hope that the claimed performance figures are NOT achieved with the optional overboost function but on the other hand, Porsche marketing would be very dumb not to use the overboost values for a better looking performance chart.

    Re: 997 Turbo overbuust question

    Quote:
    Turbo Al said:

    BTW, I am betting the overboost feature (in the Sports Chrono Turbo package) will be automatically actuated in the Bosch-Motronic program-based on right foot-controlled throttle manipulation, rather than fired from a switch on the dash or steering wheel



    That is a very interesting point, the technology is there so that it can be actuated by the E-Gas system. I would prefer a combination system, where you could set it up to the way you would like it to be actuated, both by the E-Gas or a button and maybe even by the Sports Chrono when you pass a specific checkpoint on a circuit. It will be great if it could be fully integrated into the Sports Chrono package, the options are endless as to control and even lap time readouts on the overboost function.

    It will be a real bummer if overboost will only be available with sports chrono, as it basically comes down to that if you don't buy a electronic gadget that you may not actually like you will have to suffer with less power. I think all 9x7 must come standard at least with Sports Chrono not necessarily Sports Chrono Plus as its the coolest and most fun feature you can add to any sports car.

    Re: 997 Turbo overbuust question

    Quote:
    P O R S C H E770 said:
    Quote:
    Turbo Al said:

    BTW, I am betting the overboost feature (in the Sports Chrono Turbo package) will be automatically actuated in the Bosch-Motronic program-based on right foot-controlled throttle manipulation, rather than fired from a switch on the dash or steering wheel



    That is a very interesting point, the technology is there so that it can be actuated by the E-Gas system. I would prefer a combination system, where you could set it up to the way you would like it to be actuated, both by the E-Gas or a button and maybe even by the Sports Chrono when you pass a specific checkpoint on a circuit. It will be great if it could be fully integrated into the Sports Chrono package, the options are endless as to control and even lap time readouts on the overboost function.

    It will be a real bummer if overboost will only be available with sports chrono, as it basically comes down to that if you don't buy a electronic gadget that you may not actually like you will have to suffer with less power. I think all 9x7 must come standard at least with Sports Chrono not necessarily Sports Chrono Plus as its the coolest and most fun feature you can add to any sports car.



    Yes,

    What would be cool is a 6-speed manual tranny with a red button on the stick to fire the overboost-Bam! Whoosh! Sort of like NO or on a single jet aeroplane that relies on overboost on takeoff in case the jet misfires at a critical moment.

    Re: 997 Turbo overbuust question

    Quote:
    RC said:
    Quote:
    gbj said:
    On all the articles I've read recently on the 997TT the 0-62 times don't mention whether this is acheived using the overboost function.
    Now as this is an 'option' are these times without the overboost ? And therefore with the overboost will the 0-62 times improve ?



    You're making a very valid point, I was asking that myself.
    Personally, I think the performance times are achieved without overboost because the chrono sport package is optional and it wouldn't be honest to advertise performance figures with an optional feature. BUT: maybe Porsche will tell in the technical specs in a little footnote that "above performance numbers were achieved using the overboost function of the optional chrono sport turbo package...". We just have to wait and see. I still hope that the claimed performance figures are NOT achieved with the optional overboost function but on the other hand, Porsche marketing would be very dumb not to use the overboost values for a better looking performance chart.



    RC,

    That would be cool if those times were without overboost, since the numbers would then be even better with it!

    Re: 997 Turbo overbuust question

    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.

    Re: 997 Turbo overbuust question

    Quote:
    Paulo_Rangel_Melo said:
    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.


    No waiting - you can use it a million times (if you drive the car long enough). It is hardwired into the computer chip that controls the motor. You press the pedal and it goes - very simple. I suppose that the Sport Chrono will need to be turned on, but otherwise you just drive normally...

    Re: 997 Turbo overbuust question

    Quote:
    Grant said:
    Quote:
    Paulo_Rangel_Melo said:
    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.


    No waiting - you can use it a million times (if you drive the car long enough). It is hardwired into the computer chip that controls the motor. You press the pedal and it goes - very simple. I suppose that the Sport Chrono will need to be turned on, but otherwise you just drive normally...



    So if you're trying to do a 0-200 KM/H test (0-124 MPH), make sure you press the button twice. RC estimated that the 997TT will do it around 12 seconds.

    Re: 997 Turbo overbuust question

    Quote:
    Grant said:
    Quote:
    Paulo_Rangel_Melo said:
    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.


    No waiting - you can use it a million times (if you drive the car long enough). It is hardwired into the computer chip that controls the motor. You press the pedal and it goes - very simple. I suppose that the Sport Chrono will need to be turned on, but otherwise you just drive normally...



    Yep, this is how I foresee it. Two questions I have:
    1. Any thoughts on this 10-second limit? The more I think about this, the more I can't foresee overboost being activated continuously for that long anyhow, since one would normally rev the car higher than the top rpm of the overboost range-assuming he were driving the car properly.
    2. Any idea what else the Sports Chrono Turbo option (I would think a must-have given the overboost component) will contain based on the 997NA option, and would there be any other disadvantages to having the option on the 997TT just to get the overboost? Besides the annoying analog clock on top of the dash-Porsche should have integrated the clock digitally into the main console, IMO.

    Re: 997 Turbo overbuust question

    Quote:
    SoCal Alan said:
    Quote:
    Grant said:
    Quote:
    Paulo_Rangel_Melo said:
    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.


    No waiting - you can use it a million times (if you drive the car long enough). It is hardwired into the computer chip that controls the motor. You press the pedal and it goes - very simple. I suppose that the Sport Chrono will need to be turned on, but otherwise you just drive normally...



    So if you're trying to do a 0-200 KM/H test (0-124 MPH), make sure you press the button twice. RC estimated that the 997TT will do it around 12 seconds.



    If you are trying for a 0-200kph time, then you will rev the car well beyond the 4,500rpm overboost limit-likely to near redline, then change gears-the 997TT most likely will require ?3rd or 4th gear on the manual to get to 200kph, so the overboost will go on and off at least three times on its own as you rev in a given gear over 4,500rpm-to get you to your target speed.

    Re: 997 Turbo overbuust question

    Quote:
    Paulo_Rangel_Melo said:
    Hey RC.

    Sorry for my ignorance.

    But how many times can you use the overboost function?You use it and then you have to wait some time to cool it off or this "gismo" work diferent.

    Thanks.



    Well, actually it works 10 seconds at FULL throttle and as soon as you release the throttle and you're using FULL throttle again, the overboost jumps in again for another 10 seconds. This is not the same thing like BMW uses on the M5 (launch control), you don't need to let it "cool off" or anything similar. I can imagine that Porsche built in some sort of "overheating" protection, meaning that if you're activating overboost too many times one after each other and the oil/water/turbo charger temp is getting a little bit too high, it may be automatically shut off by the motronic.

    And yes, when you take the foot off the full throttle lets say after 5 seconds because you have to upshift and you fully press the throttle again, the overboost jumps in again for another 10 seconds (or less).
    It is simple: FULL throttle = 10 seconds overboost.
    I can also imagine that in the 6th gear for example, the overboost function will not work at all or just at certain speeds to prevent the car to get too fast (someone could release the full throttle at top speed, apply it fully again after a second, release, apply, release, apply and so on to try to increase top speed with more boost. But I'm sure that Porsche has taken care of, maybe in designing the gear ratio in a way that the 6th gear provides top speed shortly before the rev limiter jumps in.

    There is a lot of speculation right now about the overboost function but one thing is for sure: it will dramatically improve acceleration times and slowlier than 8 seconds from 0-100 mph and 12 seconds from 0-125 mph would be a huge disappointment for me.

    Re: 997 Turbo overbuust question

    Quote:
    RC said:
    There is a lot of speculation right now about the overboost function but one thing is for sure: it will dramatically improve acceleration times and slowlier than 8 seconds from 0-100 mph and 12 seconds from 0-125 mph would be a huge disappointment for me.



    RC,

    I suspect you will NOT be disappointed.

    Re: 997 Turbo overbuust question

    so does the overboost work better on a 6speed or Auto???

    Re: 997 Turbo overbuust question

    10 seconds will get us to more than 100mph already....wow

    Re: 997 Turbo overbuust question

    FWIW an aluminum small block chevy V8 racing engine weighs about 50# less than a m96 motor and could be made to fit similar confines. So, I don't think it's impossible to put a V8 or flat 8 in a rear engined 911 configuration. Where there's a will there's a way!

    Re: 997 Turbo overbuust question

    Quote:
    C4S Surgeon said:
    FWIW an aluminum small block chevy V8 racing engine weighs about 50# less than a m96 motor and could be made to fit similar confines. So, I don't think it's impossible to put a V8 or flat 8 in a rear engined 911 configuration. Where there's a will there's a way!



    it wont happen for the same reason that the cayman isn't faster than the 911. The 911 is an icon. it has a certain persona that porsche wouldn't dream of tarnishing. The flat 6 is part of that persona

     
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