Interesting finding - related to manual tranny only

[akak1997]

I Know that in cars with No traction control (Old ass VW) if you jerk when you shift gear, you suck at driving a stick. In that case, if your head jerk forward, that means your engine rev is slower than your tranny, so it basically brakes the car a bit and vice versa.
So, Just a thought, in the 135, with a JB3 and non run crap tires, with traction control on, you jerk from first to second the reason could be one or more of these:
1. the driver suck at driving a manual, I know I suck from time to time...
2. The computer cuts engine power since it sense that the engine going faster than the tires can keep up w/o spinning, so by the time your clutch fully engage, the engine is now SLOWER than the tranny. hence, head hits the windshield.
3. The computer jams on the rear brakes a bit coz it sense a slight wheel spin is gonna happen, hence, head hits the windshield.

Is that how traction control works?
comments?

Thanks

[jeremyc74]

Originally Posted by akak1997

I Know that in cars with No traction control (Old ass VW) if you jerk when you shift gear, you suck at driving a stick. In that case, if your head jerk forward, that means your engine rev is slower than your tranny, so it basically brakes the car a bit and vice versa.
So, Just a thought, in the 135, with a JB3 and non run crap tires, with traction control on, you jerk from first to second the reason could be one or more of these:
1. the driver suck at driving a manual, I know I suck from time to time...
2. The computer cuts engine power since it sense that the engine going faster than the tires can keep up w/o spinning, so by the time your clutch fully engage, the engine is now SLOWER than the tranny. hence, head hits the windshield.
3. The computer jams on the rear brakes a bit coz it sense a slight wheel spin is gonna happen, hence, head hits the windshield.

Is that how traction control works?
comments?

Thanks

The traction control works by sensing a difference in speed between the various tires. If the rear tires are spinning faster than the front, it kicks in to slow them down. That shouldn't be happening while you're driving around town.

The "jerk" everyone is talking about comes as you re-engauge the clutch after a gear shift. The CDV restricts how quickly the clutch can engauge, and the feel of the clutch pedel doesn't exactly match what's actually going on with the pressure plate. There's really no reason the traction control should be getting involved unless you're really shifting hard at high RPMs.

[pit1]

I haven't tried it yet, but I have my doubts. I'm with Moneterra, I think this is a user experience thing. (kinda like how our cars drive better when they're clean, right?) I'd be willing to bet those who believe there is a difference would stand correct ~50% of the time under a blind test, unknowing of current DSC system status.

Disable the system and the driver become more prudent, more careful and deliberate with their clutch engagement...accurately matching engine speed to trans speed then applying consistent deliberate throttle upon engagement. A agree this clutch (be it CDV or not) is inconsistent and fickle, but a deliberate, moderate, well time throttle input/clutch endagement makes or breaks your shifts in these cars. Same went for my E46, though my E30 was sublime.

[Evice]

Just Rev match it manually and you will be fine.. it is just bimmer engine is quick revving and unrevving. that's it. I have tried DSC DTC off today, and there was no difference, it is all about your control of throttle, CDV doesn't really matter in my opinion.

[Robert]

I tried it today and it makes no difference. The jerk is really caused by how abrupt you shift whether DSC is on or off. If you don't rev match on a downshift or release the clutch too soon or too late in a upshift you will experience the jerk. I have no problem under normal circumstance but when I want to go fast it becomes an issue.

[imported_mega]

I hate the cvd this is the only car where I have trouble shifting 1st to 2nd, and sometimes to 3rd, sometimes it does not want to release 1st gear if I try to shift too fast

[Caduceus]

Originally Posted by pit1

I haven't tried it yet, but I have my doubts. I'm with Moneterra, I think this is a user experience thing. (kinda like how our cars drive better when they're clean, right?) I'd be willing to bet those who believe there is a difference would stand correct ~50% of the time under a blind test, unknowing of current DSC system status.

Disable the system and the driver become more prudent, more careful and deliberate with their clutch engagement...accurately matching engine speed to trans speed then applying consistent deliberate throttle upon engagement. A agree this clutch (be it CDV or not) is inconsistent and fickle, but a deliberate, moderate, well time throttle input/clutch endagement makes or breaks your shifts in these cars. Same went for my E46, though my E30 was sublime.

You've pretty much described the PLACEBO effect. Many people think the placebo effect is imaginary. It's actually a real, demonstrable effect but it is caused by factors within the subject themselves, not the drug/equipment etc.

I suspect this is what the OP is experiencing.

I regularly drive my MT 135 in all three traction control modes and never notice a difference in the quality of the shift under normal driving conditions. Aggressive acceleration is a different story but that's a tyre/grip manifestation, nothing else.

[grish]

All right, you convinced me.... I am special

[penny]

Originally Posted by BlackjackMulligan

I notice a difference from when the climate control is on and when it's off with regard to jerkiness.......really.

Same here. It's kinda like having two extra people in the back seat. My shift points are much higher for a smoother ride.