What engines do you think work best with DCT and which with manual?

[pkimM3r]

Originally Posted by Billj747

The Mustang BOSS 302 has a 7,500rpm redline...

Now imagine how fast an F40 would be with a DCT!


DCT is heavier - not good for handling, braking, or accelerating (but the DCT does accelerate faster despite having to move more weight).

DCTs have more moving parts, run hotter, require more cooling = more weight.

DCT type transmissions are MUCH BETTER for turbocharged cars because the engine load is uninterrupted which keeps turbos spooled up. Lifting off the throttle during upshifts in manual transmissions requires the turbo to spool back up after the shift. Thus turbo cars (like the GTR or Porsche Turbo) benefit much moreso than naturally aspirated cars.

I'd love to see data of an E9X MT vs DCT overlay on a racetrack.

Manual transmissions are more 'pure', but DCTs are probably outright faster. Heck, most prototypes, top level GT cars, and F1 cars all use paddle shifters. Food for thought.

Evo tuners have had ecu controlled boost when shifting since 7 years ago. So it can be done in a DCT or an MT.

[cannga]

Originally Posted by Billj747

with "minor" :-) alteration by me
DCT type transmissions are MUCH **FASTER** (not necessarily "better") for turbocharged cars because the engine load is uninterrupted which keeps turbos spooled up. Lifting off the throttle during upshifts in manual transmissions requires the turbo to spool back up after the shift. Thus turbo cars (like the GTR or Porsche Turbo) benefit much moreso than naturally aspirated cars.

Billj, subtle and not often discussed, but very important point, and pardon my intrusive editing of your post :-). For anyone interested: In a turbo w/ manual transmission like my 997 Turbo, every time you let up on the gas during a shift, you lose boost and power; as opposed to the 997 Turbo DCT, where for the fastest start, you step on gas pedal, all the way to the floor, and don't let go during shifting, hence no loss of boost. The result is explosive and spectacular speed indeed. The only way to reduce boost loss during standing start for a manual turbo car is power-shifting (full-throttle shifting), but outside of professional racing circles, no private owner is going to do this to his baby.

Dual-clutch vs. manual is a case of personal preference, there is no right or wrong. For OP, it's not a matter of which engine, but:

1. Speed: DCT is faster, no matter which engine. It is *particularly* faster in a Turbo in standing-start, lower gears acceleration. Within DCT modes, FWIW Porsche's chief test driver, Walter Rohrl, has hinted he's no faster in manual mode vs. auto mode of the DCT/PDK Porsche Turbo. In other words, for amateurs, if being fast is the only concern, auto DCT is the mode.
2. Personal preference: Some like DCT, some like manual; it's a matter of personal preference, so no right or wrong, and, end of story. If you are a manual die-hard however, be VERY careful about switching; many who switch stay switched, but some do end up regretting the change. For the manual die-hards therefore, buying a DCT car without extensive testing could be a very costly mistake. For example, I have both types of transmission in my cars, love both but if I have to keep one car, it would be the one with the manual transmission; again, personal preference.

[nullrouted]

The best gearbox isn't MT or DCT -- It's really CVT

[Billj747]

Originally Posted by pkim1079

Evo tuners have had ecu controlled boost when shifting since 7 years ago. So it can be done in a DCT or an MT.

Unless you are referring to anti-lag (which has been around for decades and is not street able or realistic outside a racecar and is still probably not as good as uninterrupted boost in a Dct) anytime you let off the throttle and the bov releases pressure during even the fastest mt upshifts, you are at a significant loss to a turbo dct setup.

A GTR would be quite a bit slower with a MT.

[pkimM3r]

Originally Posted by Billj747

Unless you are referring to anti-lag (which has been around for decades and is not street able or realistic outside a racecar and is still probably not as good as uninterrupted boost in a Dct) anytime you let off the throttle and the bov releases pressure during even the fastest mt upshifts, you are at a significant loss to a turbo dct setup.

A GTR would be quite a bit slower with a MT.

i am not talking about anti-lag systems. In effect, its doing the same thing a DCT system is doing while shifting and is controlled by the ecu. I'll try to find the link but its a pretty old thread now.

No lift shift ecu mod...granted its not as sophisticated as how the DCT doesn't cut boost, takes practice and is under WOT to redline but this is 6-7 years ago and I haven't followed, but maybe there has been advances in it.

[Billj747]

Originally Posted by pkim1079

i am not talking about anti-lag systems. In effect, its doing the same thing a DCT system is doing while shifting and is controlled by the ecu. I'll try to find the link but its a pretty old thread now.

No lift shift ecu mod...granted its not as sophisticated as how the DCT doesn't cut boost, takes practice and is under WOT to redline but this is 6-7 years ago and I haven't followed, but maybe there has been advances in it.

Ecu rev cut (for x amount of milliseconds) for wot shifts? Not sure how that'd work in a synchronized gearbox...

[HeartMD]

Originally Posted by Lute

LOL was that a GIF of walker texas ranger

[pkimM3r]

Originally Posted by Billj747

Ecu rev cut (for x amount of milliseconds) for wot shifts? Not sure how that'd work in a synchronized gearbox...

wouldn't be needed in DCT....works in MT - but it can be a bit more sophisticated.

[Billj747]

Originally Posted by pkim1079

wouldn't be needed in DCT....works in MT - but it can be a bit more sophisticated.

Im not clear I know what you're talking about. I was referring to a MT when I said synchronized gearbox (and not understanding how you would do no lift shifts with a MT)

[HeartMD]

Personally I love my MT but for a high powered engine Id definately go DCT.

[pkimM3r]

Originally Posted by Billj747

Im not clear I know what you're talking about. I was referring to a MT when I said synchronized gearbox (and not understanding how you would do no lift shifts with a MT)

Just watch a youtube video on it and watch the boost guage. You can actually do it without that sort of mod cant you?

[Billj747]

Originally Posted by pkim1079

Just watch a youtube video on it and watch the boost guage. You can actually do it without that sort of mod cant you?

Link?

[cannga]

Originally Posted by pkim1079

i am not talking about anti-lag systems. In effect, its doing the same thing a DCT system is doing while shifting and is controlled by the ecu. I'll try to find the link but its a pretty old thread now.

No lift shift ecu mod...granted its not as sophisticated as how the DCT doesn't cut boost, takes practice and is under WOT to redline but this is 6-7 years ago and I haven't followed, but maybe there has been advances in it.

Hi Pkim, I believe you are talking about 2 step rev limiter? None of us in the Porsche 997 Turbo forum has used it (for obvious reason - abusive to engine and clutch) but it has been discussed and yes, you are correct, I believe it could be done with ECU mod. See link below.

Billj, anti-lag? No thanks, not touching with a 10 foot pole!

>>>>>>>>>>>>>>
http://tunertools.com/articles/Launch-Control-101.asp
What is launch control, and how does it work?

Launch control (sometimes known as a stutterbox or 2 step rev limiter) are fairly simple, yet effective in ensuring consistent reliable launches at the track, strip or even on the street. The user defines a “launch rpm” that, when launch control is activated, the vehicle will maintain. This allows the user to hold the car at full throttle while still maintaining a suitable RPM for launch, based on vehicle capabilities, traction, wheel hop, etc. Turbocharged cars see an additional benefit in the ability to build boost before the vehicle leaves the line. These capabilities lead to smoother, consistent and reliable launches with maximum power from the moment you leave the line. This will help lower your 60ft times and/or help you be the first into the corner.

Note that launch control is not to be confused with Anti-lag, which is another method to aid in launch and off throttle boost. Anti-lag creates an explosion inside the turbo to maintain boost, even when the driver is off throttle or at a stop. Anti-lag is commonly used on rally cars and other turbo-charged race cars. It is VERY hard on the turbo and should not be run by anyone with a budget less than that of a race team as it will lead to premature failure of your turbocharger.

[cannga]

Originally Posted by Billj747

Unless you are referring to anti-lag (which has been around for decades and is not street able or realistic outside a racecar and is still probably not as good as uninterrupted boost in a Dct) anytime you let off the throttle and the bov releases pressure during even the fastest mt upshifts, you are at a significant loss to a turbo dct setup.

A GTR would be quite a bit slower with a MT.

Very good point. I was talking to a 911/993 Turbo owner a while ago and vaguely recall he mentioned that the very early Porsche 993 Turbo's did not have blow-off valve and as a result, when driver for example approaches corner and lifts throttle to slow down, the car/engine would continue to maintain speed for a split millisecond (!) because of boost remaining not being blown off. Does that sound plausible?

BTW, am I talking to *the* Billy Johnson, or a member of the team?

[pkimM3r]

Originally Posted by cannga

Hi Pkim, I believe you are talking about 2 step rev limiter? None of us in the Porsche 997 Turbo forum has used it (for obvious reason - abusive to engine and clutch) but it has been discussed and yes, you are correct, I believe it could be done with ECU mod. See link below.

Billj, anti-lag? No thanks, not touching with a 10 foot pole!

>>>>>>>>>>>>>>
http://tunertools.com/articles/Launch-Control-101.asp
What is launch control, and how does it work?

Launch control (sometimes known as a stutterbox or 2 step rev limiter) are fairly simple, yet effective in ensuring consistent reliable launches at the track, strip or even on the street. The user defines a “launch rpm” that, when launch control is activated, the vehicle will maintain. This allows the user to hold the car at full throttle while still maintaining a suitable RPM for launch, based on vehicle capabilities, traction, wheel hop, etc. Turbocharged cars see an additional benefit in the ability to build boost before the vehicle leaves the line. These capabilities lead to smoother, consistent and reliable launches with maximum power from the moment you leave the line. This will help lower your 60ft times and/or help you be the first into the corner.

Note that launch control is not to be confused with Anti-lag, which is another method to aid in launch and off throttle boost. Anti-lag creates an explosion inside the turbo to maintain boost, even when the driver is off throttle or at a stop. Anti-lag is commonly used on rally cars and other turbo-charged race cars. It is VERY hard on the turbo and should not be run by anyone with a budget less than that of a race team as it will lead to premature failure of your turbocharger.

Very informative but not talking about the 2 step which bounces the revs at x rpm to allow for maximum launch. No lift shift is while the car is in motion.

[pkimM3r]

Originally Posted by cannga

Very good point. I was talking to a 911/993 Turbo owner a while ago and vaguely recall he mentioned that the very early Porsche 993 Turbo's did not have blow-off valve and as a result, when driver for example approaches corner and lifts throttle to slow down, the car/engine would continue to maintain speed for a split millisecond (!) because of boost remaining not being blown off. Does that sound plausible?

BTW, am I talking to *the* Billy Johnson, or a member of the team?

I wonder if he meant that it was not a vent to atmosphere blow off valve but one that recirculates the air. The evo ix and x were like this.

[Billj747]

Originally Posted by cannga

Very good point. I was talking to a 911/993 Turbo owner a while ago and vaguely recall he mentioned that the very early Porsche 993 Turbo's did not have blow-off valve and as a result, when driver for example approaches corner and lifts throttle to slow down, the car/engine would continue to maintain speed for a split millisecond (!) because of boost remaining not being blown off. Does that sound plausible?

BTW, am I talking to *the* Billy Johnson, or a member of the team?

I think all 993s had diverter (ricirculating BOVs) valves as well as 930s.

There are turbo'd cars that don't have a diverter or BOV, but the back pressure on the turbo once the throttle body is closed shocks the turbo, killing spool and is really hard on the turbo. I'm not sure about the car still accelerating because once you close the throttle plate, it starves the engine/creates vacuum. But if we are talking milliseconds then yes there probably would still be a rush of boost during the milliseconds the throttle was being closed compared to an na car...?

I'm just the guy in my profile.

Originally Posted by pkim1079

Very informative but not talking about the 2 step which bounces the revs at x rpm to allow for maximum launch. No lift shift is while the car is in motion.

I'm still interested in details.