Just wondering if anyone knows how this works.

I've heard of clutchless transmissions where the tranny uses an electronic clutch to engage gears but I'm not familiar with this "no-lift" technology.

What does everyone think of this? Does this type of system require a beefier clutch? Will the clutch last longer in this type of system or will it burn up faster?

 

The only thing different is that you don't have to let off the gas while shifting hence "no lift". You still have to lift your foot off the clutch.

 

I understand that much, and the only other information I've seen is that there is some sort of algorithm involved in the shifting process.

I'm assuming that there is some sort of computer control that kicks in once the clutch is depressed but I'm interested in knowing how this type of system will affect the clutch and gears over the long haul.

Are there currently other applications that use this type of technology? Is Chevy somewhat pioneering this? Has it been done in the past and stopped?

 

My "bet" is that, rather than a "performance enhancement" feature, that this is more of a abuse prevention / warranty avoidance "feature".

The trans is likely the GM Europe F35/5, originally designed by Saab and used here on the Cobalt 2.0 LSJ SS/SC.

To prevent abusive power shifts, they probably programmed parameters that would back down throttle on the ETC and maybe timing. So, if you hold the pedal to the metal, the engine will still back off to reduce torque and driveline shock during shifts.

For example: On the 2.4 auto during a full power shift, the timing is retarded during the shift. While tweaking a friend's HHR, after some shift modifications, we got rid of the timing retard, but the ECM/TCM decided to reduce torque by cutting the throttle back to 40%. That was fixed!

 

A no lift shift is exaclty like CH said. You don't have to lift off the gas pedal. This allows the turbo to stay spooled and decreases the turbo lag. For those that aren't familiar...

Turbo lag is a term used to describe the time it takes for the turbo to spool to full boost during acceleration in between shifts. Since the turbo is run off of the exhaust gasses you have to get the exhaust flowing to "spool" the turbo. During a normal shift you release the gas and push on the clutch. This decellerates the engine and slows the turbo down. When you lift off the clutch and press on the gas into the next gear you now have to re-spool to turbo to get back up to the 14-20 psi. By keeping the gas pedal to the floor and not lifting you keep the exhaust gasses flowing and the turbo spooled much higher and therefore decreasing the time it takes to reach maximum spool. So with a Turbo engine PSI = Power... Having to rev an engine up and get up to 20psi then starting at 0 (which is what a NA motor is at during wide open throttle) and getting back up to 20psi can take a litte longer... however keeping the gas pressed can have you start over at 14psi and clib back to 20psi and will increase the overall 0-60 times and more importantly your 40-70mph which is your main passing speeds.

Hope this has someway helped... any clarification needed just ask!


EDIT::: we used this "no lift" style shifting on our Turbo Eclipse... building boost from 0-22 is a pain in the neck...

 

enOoNmAI, right on about the turbo lag theory, but remember, the current EcoTecs are a "fly by wire" throttle control.

You can keep your foot down, but I can guarantee you that the butterfly on the throttle body will drop down during the shift. For a talented driver, it should make little difference. For those of us who are less coordinated, it may even help!

GM may be hyping the SS for all it's worth right now, but when all the details come out, we'll find that they cut corners by not offering the F40/6 six speed manual and needed to limit speed shift abuse on the F35/5 trans, that the 4 wheel discs are right off the shelf from the Cobalt SS/SC & Ion RL, and that the lower (235 HP) auto version is because they found they needed to limit torque (lower boost) because of the limitations and longevity concerns in the 4T45E auto trans (same as current 2.2 and 2.4).

Still, overall, a nice package and I only wish they introduced it sooner!

 

I think Joe is likely on to something with his last post.

I would, personally, really like to see a 6 speed auto in a vehicle of this caliber along with a 6 speed stick. I've mentioned, many times, how I think this is becoming an industry standard and yet GM keeps tossing that old 4 speed into their vehicles.

 

With GM, it's all about the money, especially given their present financial woes. How much did they save by not having back lighting on the window switches?

Also, it seems for many years in the auto industry that their has been an ongoing battle for control at the top between the engineer types (read "car guys") and the financial types (read "clueless bean counters"). It alway seems that some of the best cars come about when the car guys have the upper hand and the most boring and short-changed cars when the bean counters have it.

 

Yup.. keep forgetting this DBW crap.. i miss the "good ol" days of throttle control and adjusting for the perfect 100% WOT position...

 

Now, if I can just get my dealer connections to take out their 1st SS and log it with HP Tuners.....

That would tell what's going on for sure!