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Crusin worlds most isolated city
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Discussion Starter · #1 ·
On just two occasions I have noticed that if I try to do a quick takeoff with low initial RPM of say no more than 1500, put the foot down a fair bit, the engine revs build up very slowly. Its not until about 4000RPM that it feels like its accelerating in the normal manner. Its like its in some sort of retarded mode! WTF??? Anybody notice this? Seems to do it only rarely. :confused:

Try it...
 

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Cayman Register Advocate
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On just two occasions I have noticed that if I try to do a quick takeoff with low initial RPM of say no more than 1500, put the foot down a fair bit, the engine revs build up very slowly. Its not until about 4000RPM that it feels like its accelerating in the normal manner. Its like its in some sort of retarded mode! WTF??? Anybody notice this? Seems to do it only rarely. :confused:

Try it...
Which transmission? With the Tipronic, If you take of easy it will start off in 2nd gear. This is not ideal for making use of the reduced low RPM torque.
 

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Crusin worlds most isolated city
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Discussion Starter · #3 ·
Its a 2010 Manual my friend.

Any 2010 owners with manual, please try this with sport mode on.
 

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OK, I'm going to make a guess. It sounds to me like you may be pushing the engine into a pre-ignition situation, which would be noticed by the DME and would result in the DME pulling the timing waaaaay back to compensate (retarding it). This would feel like a huge reduction in power.

I am going to bounce this off of the PCA Tech Chair for you, to see if he can shed some light.
 

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I can't guarantee the authenticity of this but here is what I was told, keeping in mind I have a '99 2.5L Tip Boxster. The computer that determines how the engine performs adjusts to your driving habits and can change by disconnecting the battery then reconnecting it, thereby resetting the computer. Once done if you drive the car at full throttle and red line it the computer will adjust to those driving conditions and perform accordingly. When I first got my Boxster it would shift itself (in D not M) around 2K rpm and get into 5th gear as quickly as possible. I did the battery disconnect and took the car out and drove it for a half day in the backroads so I could really make it perform. Now, even around town, the car will run up to almost 6K rpm before it shifts giving me more spirited performance. You'll have to research your vehicle to see if this pertains to your car. :cheers:
 

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Enjoying the drive.
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My only experience with something like this is in an S2000. If the engine isn't totally up to normal operating temperature, the engine does not use it's full range of RPM's and can act very sluggish. I am not sure if the Cayman engine has a protective fail safe like this, but it is a thought.
 

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On just two occasions I have noticed that if I try to do a quick takeoff with low initial RPM of say no more than 1500, put the foot down a fair bit, the engine revs build up very slowly. Its not until about 4000RPM that it feels like its accelerating in the normal manner. Its like its in some sort of retarded mode! WTF??? Anybody notice this? Seems to do it only rarely. :confused:

Try it...
1500 RPM is pretty low on the torque curve. There isn't much torque at 1500, and some (including me) would say 1500 RPM is lugging the engine. It partially depends on load. Some would say that cruising at 1500 is acceptable (I never do it), but full throttle at 1500 is definitely lugging.

Take a look at this torque curve. It's from a Gen 1 Cayman S. You don't have full torque until almost 4,500 RPM. Porsches have never been about drag racing. They are more about maintaining momentum on a curvy road or track. A fast time on a track will depend on your keeping the rev's up.

For more info, here are two threads where torque at low RPM's is discussed. I'm sure there are more if you care to search.

http://www.planet-9.com/cayman-boxster-chat/14276-cayman-s-torque-2nd-gear-low-rpm.html

http://www.planet-9.com/porsche-dyno-charts/27168-can-someone-explain-dyno-chart-owner-s-manual.html
 

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Crusin worlds most isolated city
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Discussion Starter · #8 ·
In this situation, Im just taking off from the lights in a spirited fashion. Not racing or anything remotely like that. Generally I might set the RPM between 1500 and 2000 just prior to engaging the clutch, but occasionally the initial revs may have been a bit lower than intended and when the go pedal was pressed the response was very lagged.

I going to try to reproduce this a bit more and then try it later with the Softronic flash (which is now ordered). My old flashed 06 car never did this and it response and driveability was far superior to that of stock 2010 :( .
Strange...

P.S. See the new torque curve for the DFI? Completely different.
 

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On Probation
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My only experience with something like this is in an S2000. If the engine isn't totally up to normal operating temperature, the engine does not use it's full range of RPM's and can act very sluggish. I am not sure if the Cayman engine has a protective fail safe like this, but it is a thought.
i agree.......is it at op. temp. when this happens ?
 

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On just two occasions I have noticed that if I try to do a quick takeoff with low initial RPM of say no more than 1500, put the foot down a fair bit, the engine revs build up very slowly. Its not until about 4000RPM that it feels like its accelerating in the normal manner. Its like its in some sort of retarded mode! WTF??? Anybody notice this? Seems to do it only rarely. :confused:

Try it...
E46 M3's were also famous for this exact thing with DSC not off. (possibly same as PSM not off)
If you had any, and I mean any, tire slip ie. paint stripe/crosswalk/dampness on the road,
the ECU would pull some combination of drive-by-wire throttle/timing and the car would bog badly.
On quick left turns at a light with oncoming traffic with the LSD it was really bad.
An opening would come up, you'd gas it, the inside wheel would lock and slip slightly,
the ECU would shut it down and there you were in the intersection with oncoming traffic and about 1/2 power....lol....not good.
Call Scott at Softronic and ask him about the ECU power reduction profile/inputs.....imho that's what's going on.
If a wheel speed sensor is loose/bad, could also cause all sorts of strange ECU issues related to this.
 

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Crusin worlds most isolated city
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Discussion Starter · #11 ·
Update:
Car now with some tuning, it does not do it anymore.
 

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Crusin worlds most isolated city
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Discussion Starter · #13 ·
Full exhaust, Plenum/TB, Filter.
 
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