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Re: booster function
overboost is available for both trannys.
it is available between 2000 and 5000 rpm and increases torque to 680 nm by raising turbo boost by 0.2 bar.
it also raises horsepower output in that given powerband in relation to no overboost cars.
it does not raise max horsepower, as this is reached at 6000 rpm where overboost is not available anymore.
the time limit of 10 secs. is basically theoretical as it is very unlikely, that you will floor it and spend more than ten seconds flooring it between 2000- 5000 rpm, so basically it is an always on feature.
personally speaking, they should have just raised the max. boost by those 0.2 bar throughout the whole rev range. this would probably resulted in the magic 500 hp figure and even more vicious acceleration.
then again, they want to sell us a turbo s in the future dont they...........
it is available between 2000 and 5000 rpm and increases torque to 680 nm by raising turbo boost by 0.2 bar.
it also raises horsepower output in that given powerband in relation to no overboost cars.
it does not raise max horsepower, as this is reached at 6000 rpm where overboost is not available anymore.
the time limit of 10 secs. is basically theoretical as it is very unlikely, that you will floor it and spend more than ten seconds flooring it between 2000- 5000 rpm, so basically it is an always on feature.
personally speaking, they should have just raised the max. boost by those 0.2 bar throughout the whole rev range. this would probably resulted in the magic 500 hp figure and even more vicious acceleration.
then again, they want to sell us a turbo s in the future dont they...........
Re: booster function
One very important thing: the overboost function is only available with the optional sports chrono turbo package. The overboost function is not a standard option of the 997 Turbo, no matter if the car has manual or automatic transmission.
We highly recommend to always order the sports chrono turbo package because it not only improves the driving experience, it will surely have an influence on resale value later on, even if you don't want to use it.
The sports chrono turbo package is definetely one of the must have options.
We highly recommend to always order the sports chrono turbo package because it not only improves the driving experience, it will surely have an influence on resale value later on, even if you don't want to use it.
The sports chrono turbo package is definetely one of the must have options.
Re: booster function
Quote:
BD 997 said:
PCCB too
Don't believe that PCCB is a must have option, nor that it will affect resale. I do not believe that if one were inclined to order PCCB that they would get much of a return on their money. That dosen't mean I don't think the option adds to the performance; just to pricey for mine.
Sport chrono plus IS a must have, however.
Re: booster function
Quote:
BD 997 said:
A car with PCCB will have a better resale I beleive.... IMO
That depends on what you define as better resale. A pccb equipped 997tt may make a quicker sale, however, you will lose the far side of 50 % of your cost to get the quicker sale. And, I don't think that a non-PCCB equipped 997tt will take much longer to sell. Therefore, what have you achieved as far as resale; a few days less on the market for a 40% return on your 10k; not for me. And that is the best scenario.
Re: booster function
Quote:
xandi911 said:
ok ok thanks for the help... so with the booster between 2000 , 5000 i will have more power in that revs?
if i put a 997tt racing a 997tt with the booster, the 997tt with the booster will beat the other without the booster??
It depends on the nature of the race-if the track is such that you will spend most of your time near or above 5,000rpm's, then the overboost benefit will be partailly neutralized, but at lower revs. (where the overboost is active), the difference will be greater. Also, I believe the Sports Chrono Turbo option is associated with sportier suspension settings, as well as increasing max. boost, also helping race performance
Re: booster function
Quote:
devo said:
Does h.p. rise accordingly during the overboosted rpm range? It would seem likely, right? I know Porsche does not advertise this; only addressing the torque curve.
I haven't yet seen the hp curves without and with overboost (OB), but I would imagine that, yes, what we'll see is the curve "flattening" with OB since one should see an incremental increase in hp between 2,000 and 5,000rpm's where OB is activated, but then trailing off between 5,000-6,000rpm as max. boost decreases back to baseline, so at 6,000rpm, where for this engine and programming, peak hp is advertised to hit (480PS), peak hp should be the same as boost pressure is back at baseline.
Moderator CF (or another internet-savvy rennteamer) might be able to drudge up a graph for us.
Re: booster function
Here you go.
Torque = HP x 7023,5 / rpm
HP = Nm x rpm / 7023,5
The higher boost pressure gives rise to a sudden substantial increase in the mechanical stress on the components and, above all, in heat-induced stress.
This results above all from the continually rising charge air and combustion chamber temperatures.
With regard to these processes and the maximum possible stress on the components, the Overboost function is limited to 10 seconds.
After this period, the original full-load pressure without Overboost is set.
As soon as the stress on the engine is relieved briefly as a result of closure of the throttle valve (e.g. after gear-shifting), the Overboost function can be activated again.
The Sport Chrono Turbo package is complemented by more agile all-wheel drive tuning and, in conjuction with optional Tiptronic S, by a modified starting programme.
When the Sport button is pressed, drive-off is effected in 1st gear, instead of 2nd gear.
Torque = HP x 7023,5 / rpm
HP = Nm x rpm / 7023,5
The higher boost pressure gives rise to a sudden substantial increase in the mechanical stress on the components and, above all, in heat-induced stress.
This results above all from the continually rising charge air and combustion chamber temperatures.
With regard to these processes and the maximum possible stress on the components, the Overboost function is limited to 10 seconds.
After this period, the original full-load pressure without Overboost is set.
As soon as the stress on the engine is relieved briefly as a result of closure of the throttle valve (e.g. after gear-shifting), the Overboost function can be activated again.
The Sport Chrono Turbo package is complemented by more agile all-wheel drive tuning and, in conjuction with optional Tiptronic S, by a modified starting programme.
When the Sport button is pressed, drive-off is effected in 1st gear, instead of 2nd gear.
Re: booster function
Quote:
CF said:
Here you go.
Torque = HP x 7023,5 / rpm
HP = Nm x rpm / 7023,5
The higher boost pressure gives rise to a sudden substantial increase in the mechanical stress on the components and, above all, in heat-induced stress.
This results above all from the continually rising charge air and combustion chamber temperatures.
With regard to these processes and the maximum possible stress on the components, the Overboost function is limited to 10 seconds.
After this period, the original full-load pressure without Overboost is set.
As soon as the stress on the engine is relieved briefly as a result of closure of the throttle valve (e.g. after gear-shifting), the Overboost function can be activated again.
The Sport Chrono Turbo package is complemented by more agile all-wheel drive tuning and, in conjuction with optional Tiptronic S, by a modified starting programme.
When the Sport button is pressed, drive-off is effected in 1st gear, instead of 2nd gear.
Strong work, CF.
A picture is worth a thousand words.
Re: booster function
Quote:
xandi911 said:
ok ok thanks for the help... so with the booster between 2000 , 5000 i will have more power in that revs?
if i put a 997tt racing a 997tt with the booster, the 997tt with the booster will beat the other without the booster??
1. CF posted a pretty good descripton incl. a nice graph
2. yes, a car equipped with overboost would definetely outrun a non-overboost equipped car
3. do the math: if you have 0.2 bar more turbo boost, you also gain some horses, not only torque
Apr 6, 2006 1:31:39 PM
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Super Darius
- Rennteam Moderator
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- Loc: Italy-Como , Italy
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Reply to:
RC
Re: booster function
my dealer told me that the OB make the car take RPM faster,but no much Hp,in fact the graph posted from CF explain that the car have more power under OB effect,but not much than maximum power..
so..i think that a Sport Chrono Turbo 997 TT sure from 0-100Km/h and on all other performance time(0-400mt,o-200km/h,etc) will be faster than stock,but the car will not have much HP than stock..
so..i think that a Sport Chrono Turbo 997 TT sure from 0-100Km/h and on all other performance time(0-400mt,o-200km/h,etc) will be faster than stock,but the car will not have much HP than stock..
Apr 6, 2006 2:14:39 PM
- Alan(NJ)
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- Loc: Paramus NJ USA
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Reply to:
Super Darius
Re: booster function
"maximum possible stress on the components"
This might appear to be semantics, but I would substitute "allowable" for "possible". The 10 second overboost is probably a conservative factory decision aimed at ensuring that the car has a statistically acceptable warranty "model". This is along the lines of the break-in procedure in the U.S.is 2000 miles and is less than that in other markets.
I expect that in less than a year, someone on this board will be bragging how they and a tuner altered the software to allow longer OB. Before you ask - no it won't be me lol.
This might appear to be semantics, but I would substitute "allowable" for "possible". The 10 second overboost is probably a conservative factory decision aimed at ensuring that the car has a statistically acceptable warranty "model". This is along the lines of the break-in procedure in the U.S.is 2000 miles and is less than that in other markets.
I expect that in less than a year, someone on this board will be bragging how they and a tuner altered the software to allow longer OB. Before you ask - no it won't be me lol.
Apr 6, 2006 2:25:44 PM
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RC
- Rennteam Administrator
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- Loc: Rennteam HQ , Germany
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Reply to:
Super Darius
Re: booster function
Quote:
Super Darius said:
my dealer told me that the OB make the car take RPM faster,but no much Hp,in fact the graph posted from CF explain that the car have more power under OB effect,but not much than maximum power..
so..i think that a Sport Chrono Turbo 997 TT sure from 0-100Km/h and on all other performance time(0-400mt,o-200km/h,etc) will be faster than stock,but the car will not have much HP than stock..
Dario, I explained the HP/overboost relation in an older post a few months ago. You don't get OVER 480 HP but at certain rev figures (like the one in which the overboost is happening), you get more power.
To make you understand: let's say that the engine outputs 400 HP at 4000 rpm. With the overboost, you have 440 HP instead of 400 HP. Again, this is just a hypothetical example, not an accurate one. Check CF's graph and you'll see the HP increase while the overboost is active.
So although you don't get more MAXIMUM power, you get more power in the lower/mid rev range where the overboost is active. And of course this means that performance is improved.
Also don't forget that the overboost isn't a one-time thing or something which needs to pause a few minutes until it can be activated again. The overboost is always there for 10 seconds, no matter how often it is activated.
Now try to do the math: if you get several overboost activations during a 0-200 kph (125 mph) acceleration run, don't you think performance is improved?
I heard that a 997 Turbo WITH overboost active runs from 0-200 kph (125 mph) in 11.8 seconds instead of the factory claimed 12.2 seconds (Tiptronic). I know that 0.4 seconds don't sound much but sub-12 seconds is impressive.
Apr 6, 2006 2:40:29 PM
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Super Darius
- Rennteam Moderator
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- Loc: Italy-Como , Italy
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Reply to:
RC
Re: booster function
Quote:
RC said:Quote:
Super Darius said:
my dealer told me that the OB make the car take RPM faster,but no much Hp,in fact the graph posted from CF explain that the car have more power under OB effect,but not much than maximum power..
so..i think that a Sport Chrono Turbo 997 TT sure from 0-100Km/h and on all other performance time(0-400mt,o-200km/h,etc) will be faster than stock,but the car will not have much HP than stock..
Dario, I explained the HP/overboost relation in an older post a few months ago. You don't get OVER 480 HP but at certain rev figures (like the one in which the overboost is happening), you get more power.
To make you understand: let's say that the engine outputs 400 HP at 4000 rpm. With the overboost, you have 440 HP instead of 400 HP. Again, this is just a hypothetical example, not an accurate one. Check CF's graph and you'll see the HP increase while the overboost is active.
So although you don't get more MAXIMUM power, you get more power in the lower/mid rev range where the overboost is active. And of course this means that performance is improved.
Also don't forget that the overboost isn't a one-time thing or something which needs to pause a few minutes until it can be activated again. The overboost is always there for 10 seconds, no matter how often it is activated.
Now try to do the math: if you get several overboost activations during a 0-200 kph (125 mph) acceleration run, don't you think performance is improved?
Yes Christian..
you tell what i whant to tell....but you explain it better
in fact i whant to tell that under OB effect the car have more power,but not more maximum power.. and the 4000 RPM/400HP example you made,is really clear!
can't wait to see first test and first review
Apr 6, 2006 2:58:44 PM
- Dock (Atlanta)
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Reply to:
CF
Re: booster function
I overlaid the 997 Turbo's power curves (with OB) on the 996 Turbo with GIAC Stage 2 power curves. As expected, the VTG turbos provide better area under the curves up to about 3500 rpm. Between 3500-4000 rpm the Stage 2 and the 997 Turbo are essentially the same, and above 4000 rpm the stage 2 has more power.
Apr 6, 2006 5:35:02 PM
- xandi911
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Re: booster function
Quote:
xandi911 said:
hmm thanks for the help.. so with the booster , the power will be near of the 480 hp more time... the booster increase something like 30 hp in the curve between 2000 to 5000.. the booster can be activated in any gear?
Any gear?! Is that a trick question... you mean is it also activated in reverse?
Re: booster function
Quote:
bluelines said:Quote:
xandi911 said:
hmm thanks for the help.. so with the booster , the power will be near of the 480 hp more time... the booster increase something like 30 hp in the curve between 2000 to 5000.. the booster can be activated in any gear?
Any gear?! Is that a trick question... you mean is it also activated in reverse?
semantics semantics semantics
Re: booster function
take any turbocharged car ,increase the boost by 0.2bars ,you will gain hp. what christian said is right .in the old days when i increased the boost of my lancia integrale ,i gained 30hp,and it felt much faster. IMHO the fact that porsche is not claiming any hp change is due to the fact that you only get those 0.2 bars for ten seconds max.....
Re: booster function
it can't be so difficult guys....
they claim torque increase, as maximum torque is raised from 620 to 680 NM.
they do not claim hp increase as there is no hp increase. maximum hp remains 480 hp at 6000 rpm.
between 2.500 and 5.500 the overboost car develops more hp than the non-ob car, but both deliver 480 hp max.
10 seconds or whatever, when overboost is on the engine develops more horsepower.
really surprised that something so straight forward can cause so much confusion
they claim torque increase, as maximum torque is raised from 620 to 680 NM.
they do not claim hp increase as there is no hp increase. maximum hp remains 480 hp at 6000 rpm.
between 2.500 and 5.500 the overboost car develops more hp than the non-ob car, but both deliver 480 hp max.
10 seconds or whatever, when overboost is on the engine develops more horsepower.
really surprised that something so straight forward can cause so much confusion
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