Crown

Hello everybody I hope someone can clarify this for me

I have a GT2 and I have a Turbo S coming soon and I've been wondering about this for few weeks, I know the turbo S is all wheel drive which helps it reach to 100 from standstill faster than the GT2 but what about from 40km or 100km straight line to 200

the Turbo S is 3.3s from 0-100 and reaches 200km in 10.8s so the 100-200= 7.5s   (0-100) - (0-200) = (100-200) which is 3.3-10.8=7.5

and the GT2 is 3.7s from 0-100 and reaches 200km in 11.2s so 100-200=7.5s also (3.7-11.2=7.5)

GT2 wights 145kg less than the Turbo S and they both have 530 HP and the Power-to-weight ratio of the GT2 is 0.368 and the TurboS is 0.334 and that's not little imo

I don't think the PDK vs Manual will make up for that because I'm sure the GT2 figures was with the fastest and perfect shifts so whats the reason?

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

it's not as simple as a + and - calculation. a look at the powerband of both engines and gear ratios will provide a more accurate result.

i would assume that at higher speeds, the gt2 will be faster in in-gear times due to power to weight ratio. aerodynmics also play a vital role at these speeds. 

SciFrog:

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

so the PDK is 0.0s?

Turbocharger:

SciFrog:

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

so the PDK is 0.0s?

 

almost.....from what i recall driving the pdk turbo.

SciFrog:

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

With the same engine the Turbo would be faster above 200 km/h, due to the GT2's additional drag. That being said, we have no idea how good the new Turbo engine really is in delivering performance at its stated output.

intouch1:

Turbocharger:

SciFrog:

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

so the PDK is 0.0s?

 

 

almost.....from what i recall driving the pdk turbo.

Not only virtually zero shift times (0.003s per shift), plus no loss of boost during shifting...  Welcome to the 21st century...

SciFrog:

intouch1:

Turbocharger:

SciFrog:

How fast is a perfect shift? 0.2s? Times two, there's your 0.4s difference...

so the PDK is 0.0s?

almost.....from what i recall driving the pdk turbo.

Not only virtually zero shift times (0.003s per shift), plus no loss of boost during shifting...  Welcome to the 21st century...

Yup, that's the killer app for sure!

Slow In, Fast Out

bmw have that too. they keep the boost up but cut-off firing in the cylinder banks in order to allow for faster and smoother shifts.

the auto in the X6M is really magnificient and quick.

intouch1:

bmw have that too. they keep the boost up but cut-off firing in the cylinder banks in order to allow for faster and smoother shifts.

the auto in the X6M is really magnificient and quick.

 I am no longer sure whether loss of boost pressure is indeed a significant issue for manual gear-box cars. What I found out is that revs don't drop at all (at least based on the rev counter) during fast manual shifts. Thus, my logic is: if revs don't drop boost pressure should not drop either, right 

P.S.: I checked on this issue in order to find ways to mitigate the negative effects of manual shifts at higher speeds (>150kph) in comparison to Ferrari's F1 system in the Scuderia (you might recall the GPS chart I posted regarding the two car's relative performance on the Leipzig track). My conclusion to date is that the drop in speed results from the time required to shift gears (i.e. aerodynamics) but not from a loss of revs/boost pressure. This is bad news actually, as the time of my gear-shifts is probably very difficult to reduce further 

I was under the impression that when shifting the engine is not under load and therefore boost pressure drops off to some degree.

Sorry, might be a noob question, but if the revs don't drop... why do you shift at all?

MKSGR:

intouch1:

bmw have that too. they keep the boost up but cut-off firing in the cylinder banks in order to allow for faster and smoother shifts.

the auto in the X6M is really magnificient and quick.

 I am no longer sure whether loss of boost pressure is indeed a significant issue for manual gear-box cars. What I found out is that revs don't drop at all (at least based on the rev counter) during fast manual shifts. Thus, my logic is: if revs don't drop boost pressure should not drop either, right 

P.S.: I checked on this issue in order to find ways to mitigate the negative effects of manual shifts at higher speeds (>150kph) in comparison to Ferrari's F1 system in the Scuderia (you might recall the GPS chart I posted regarding the two car's relative performance on the Leipzig track). My conclusion to date is that the drop in speed results from the time required to shift gears (i.e. aerodynamics) but not from a loss of revs/boost pressure. This is bad news actually, as the time of my gear-shifts is probably very difficult to reduce further 

you do loose boost when shifting in the manual car. that's the reason why the 997.1 turbo auto is faster than the manual. the ecu in the auto is programmed to maintain boost levels.

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

Joost:

Sorry, might be a noob question, but if the revs don't drop... why do you shift at all?

I should have explained it better... What I meant is: the revs drop only after you release the clutch again. I.e. the time delay between declutching, changing gear and releasing the clutch again is so short that revs don't drop in the meantime.

Ferdie:

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

 To test this I already plan to do my GPS measured upshifts with the throttle continuously pressed down (should not do any harm as the max revs are electronically controlled anyhow... Hopefully :-)).

Ferdie:

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

Bingo

At constant speed thus RPM on the highway, boost pressure drops.

Boost pressure is linked to engine load am I wrong?

trip:

Boost pressure is linked to engine load am I wrong?

yes, but it's electronically governed using rather compicated alogarithms taking lots of feedback into account. therefore it works better in the automated package than with 'human' input i.e. shifting.

Turbocharger:

Hello everybody I hope someone can clarify this for me

I have a GT2 and I have a Turbo S coming soon and I've been wondering about this for few weeks, I know the turbo S is all wheel drive which helps it reach to 100 from standstill faster than the GT2 but what about from 40km or 100km straight line to 200

the Turbo S is 3.3s from 0-100 and reaches 200km in 10.8s so the 100-200= 7.5s   (0-100) - (0-200) = (100-200) which is 3.3-10.8=7.5

and the GT2 is 3.7s from 0-100 and reaches 200km in 11.2s so 100-200=7.5s also (3.7-11.2=7.5)

GT2 wights 145kg less than the Turbo S and they both have 530 HP and the Power-to-weight ratio of the GT2 is 0.368 and the TurboS is 0.334 and that's not little imo

I don't think the PDK vs Manual will make up for that because I'm sure the GT2 figures was with the fastest and perfect shifts so whats the reason?

here we go...
 

the way you are thinking is not wrong  both  will do 7,5 from 100 to 200 OK

the thing is..

FIRST :the GT2 will reach this thing with at least a  good driver, the pdk with my granma DRIVING.

2nd:  theoretically the GT2 has slower SHIFTS. so  this means that always the GT2 is accelerating faster than the PDK, To conpensate the shift time and reaching the same SPEED at the same time. 

While the GT2 is shifting, the PDK is still accelerating and putting some distance in the GT2. 

3rd: comparing  cars to reach same speed vs time, doesnt mean the car faster for a small difference, will be WINNING or in FRONT or AHEAD the other...  IF the comparo is  DISTANCE vs time  yes the car with small time will BE ALWAYS IN FRONT.

4th: YES if both cars PDK and GT2 reaches exaclty 100-200 in same time, i bet a million dollar, PDK will had put 1-2 car lenght in the GT2. THIS ITEM IS CONFIRMED by   FIRST, 2nd and 3rd STEP.

its a phisical Thing.

xandi911:

here we go...
 

the way you are thinking is not wrong  both  will do 7,5 from 100 to 200 OK

the thing is..

FIRST :the GT2 will reach this thing with at least a  good driver, the pdk with my granma DRIVING.

2nd:  theoretically the GT2 has slower SHIFTS. so  this means that always the GT2 is accelerating faster than the PDK, To conpensate the shift time and reaching the same SPEED at the same time. 

While the GT2 is shifting, the PDK is still accelerating and putting some distance in the GT2. 

3rd: comparing  cars to reach same speed vs time, doesnt mean the car faster for a small difference, will be WINNING or in FRONT or AHEAD the other...  IF the comparo is  DISTANCE vs time  yes the car with small time will BE ALWAYS IN FRONT.

4th: YES if both cars PDK and GT2 reaches exaclty 100-200 in same time, i bet a million dollar, PDK will had put 1-2 car lenght in the GT2. THIS ITEM IS CONFIRMED by   FIRST, 2nd and 3rd STEP.

 

its a phisical Thing.

I got what you mean and I knew the facts where right about the Turbo S and the GT2 being equally the same in speed vs time from 100-200 and you have an interesting point about distance vs time and I agree with you on that

but what I was confused about is how a car that has a big advantage in power to weight be equal from roll to 200 with the heavier car, I guess its about the PDK vs Manual after all

yup. technological advantage.

Ferdie:

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

Just checked it: if you keep the throttle fully pressed on up-shifts boost pressure still goes down a bit - but significantly less than if you release the throttle while changing gears.

Can anybody with a more in-depth knowledge tell whether keeping the throttle pressed on upshifts might do any harm to the engine? My assumption is that the rev limiter prevents any damage (if not it would not work properly as its function is to immediately cut-off gas supply if the rev limit is exceeded) 

MKSGR:

Ferdie:

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

 

Just checked it: if you keep the throttle fully pressed on up-shifts boost pressure still goes down a bit - but significantly less than if you release the throttle while changing gears.

Can anybody with a more in-depth knowledge tell whether keeping the throttle pressed on upshifts might do any harm to the engine? My assumption is that the rev limiter prevents any damage (if not it would not work properly as its function is to immediately cut-off gas supply if the rev limit is exceeded) 

The rev limiter protects the engine, but you are still putting higher loads on the gearbox's synchronizers and on the clutch than would otherwise be the case.

fritz

fritz:

MKSGR:

Ferdie:

MKSGR:

 Thus, my logic is: if revs don't drop boost pressure should not drop either, right?

Boost pressure is rather linked to throttle input than RPM.

 

Just checked it: if you keep the throttle fully pressed on up-shifts boost pressure still goes down a bit - but significantly less than if you release the throttle while changing gears.

Can anybody with a more in-depth knowledge tell whether keeping the throttle pressed on upshifts might do any harm to the engine? My assumption is that the rev limiter prevents any damage (if not it would not work properly as its function is to immediately cut-off gas supply if the rev limit is exceeded) 

The rev limiter protects the engine, but you are still putting higher loads on the gearbox's synchronizers and on the clutch than would otherwise be the case.

 Many thanks for the answer  Would you expect a significantly smoother (i.e. more linear) acceleration using the "do not release throttle" technique or would you rather expect similar acceleration performance as in the "release throttle" scenario  I.e. is the method suitable to improve lap times (at the cost of higher clutch and synchronizer wear)?

Turbocharger:

xandi911:

here we go...
 

the way you are thinking is not wrong  both  will do 7,5 from 100 to 200 OK

the thing is..

FIRST :the GT2 will reach this thing with at least a  good driver, the pdk with my granma DRIVING.

2nd:  theoretically the GT2 has slower SHIFTS. so  this means that always the GT2 is accelerating faster than the PDK, To conpensate the shift time and reaching the same SPEED at the same time. 

While the GT2 is shifting, the PDK is still accelerating and putting some distance in the GT2. 

3rd: comparing  cars to reach same speed vs time, doesnt mean the car faster for a small difference, will be WINNING or in FRONT or AHEAD the other...  IF the comparo is  DISTANCE vs time  yes the car with small time will BE ALWAYS IN FRONT.

4th: YES if both cars PDK and GT2 reaches exaclty 100-200 in same time, i bet a million dollar, PDK will had put 1-2 car lenght in the GT2. THIS ITEM IS CONFIRMED by   FIRST, 2nd and 3rd STEP.

 

its a phisical Thing.

I got what you mean and I knew the facts where right about the Turbo S and the GT2 being equally the same in speed vs time from 100-200 and you have an interesting point about distance vs time and I agree with you on that

but what I was confused about is how a car that has a big advantage in power to weight be equal from roll to 200 with the heavier car, I guess its about the PDK vs Manual after all

no matter what tecnique you use in the gt2 to SHIFT, it will never represent the pdk..
 

the thing is not only because the manual lost boost in every change, the pdk shifts the next gear in a such smooth and perfect way that always puts the car in front of any gear shift any pilot with a manual one

TECNOLOGICAL ADVANTAGE.

xandi911:

Turbocharger:

xandi911:

here we go...
 

the way you are thinking is not wrong  both  will do 7,5 from 100 to 200 OK

the thing is..

FIRST :the GT2 will reach this thing with at least a  good driver, the pdk with my granma DRIVING.

2nd:  theoretically the GT2 has slower SHIFTS. so  this means that always the GT2 is accelerating faster than the PDK, To conpensate the shift time and reaching the same SPEED at the same time. 

While the GT2 is shifting, the PDK is still accelerating and putting some distance in the GT2. 

3rd: comparing  cars to reach same speed vs time, doesnt mean the car faster for a small difference, will be WINNING or in FRONT or AHEAD the other...  IF the comparo is  DISTANCE vs time  yes the car with small time will BE ALWAYS IN FRONT.

4th: YES if both cars PDK and GT2 reaches exaclty 100-200 in same time, i bet a million dollar, PDK will had put 1-2 car lenght in the GT2. THIS ITEM IS CONFIRMED by   FIRST, 2nd and 3rd STEP.

 

its a phisical Thing.

I got what you mean and I knew the facts where right about the Turbo S and the GT2 being equally the same in speed vs time from 100-200 and you have an interesting point about distance vs time and I agree with you on that

but what I was confused about is how a car that has a big advantage in power to weight be equal from roll to 200 with the heavier car, I guess its about the PDK vs Manual after all

no matter what tecnique you use in the gt2 to SHIFT, it will never represent the pdk..
 

the thing is not only because the manual lost boost in every change, the pdk shifts the next gear in a such smooth and perfect way that always puts the car in front of any gear shift any pilot with a manual one

 

TECNOLOGICAL ADVANTAGE.

 You are extremely smart 

Honestly, I do know the difference between the different gear box technologies. I have extensive driving experience with each of them, of course. The question I address above is: how can the disadvantage of manual gear boxes be mitigated in track driving situations. In Leipzig, for example, the Scuderia seems to benefit primarily (if not exclusively) from its advanatages on fast up-shifts (at around 175kph in the GT2, see blue line in chart below). The disadvantage the GT2 has in these situations seems to add up to nearly a second (!) per lap. Just as a result of four such up-shifts at higher speeds per lap. Thus, I am trying to find a technique to reduce the time lost on shifts. This and some proper tires (Michelin Cup instead of the wet performance oriented regular Corsas) should give the GT2 enough to kill little Scuderia's cruising around in Leipzig 

MKSGR:

Would you expect a significantly smoother (i.e. more linear) acceleration using the "do not release throttle" technique or would you rather expect similar acceleration performance as in the "release throttle" scenario  I.e. is the method suitable to improve lap times (at the cost of higher clutch and synchronizer wear)?

Not sure if the additional wear stands in sensible relation to the benefit. If you do not release the throttle during shifts, the engine might run into the limiter without engaged transmission and could be recorded in the ECU, if I am not mistaken. If you do release the throttle, the boost pressure will drop inevitably.

If I am not mistaken, there are devices available [to amateurs] to read out and record the boost pressure under these circumstances. On a gasoline car, the incoming air is controlled by the throttle body, unlike on a diesel-engined car airflow through the engine is correlating with RPM.

Apart from the boost pressure, your above mentioned short-shifting technique will provide additional momentum from the engine as applied RPM numbers are slightly higher than necessary, a concept that BMW is using on the 7-speed DCT [M3] at highest shifting speed.

does anybody knows  if the pdk is the best DCT  in the market???

my sources tells me that pdk is created by pórsche and a company...

and the others factorys like ferrari bmw etc... USES the GETRAG  isnt it??

until i know pdk must be the faster with 0,040 sec time of shift...

GETRAG = 0,060 sec???

Porsche PDK = ZF

Ferrari DCT, BMW M DKG and DKG, Mercedes SLS AMG DCT = Getrag

Audi S Tronic, VW DSG = Borg Warner

McLaren MP4-12C DCT = Graziano