Semi-automatic transmission question

lexus

#1

I was just wondering how the different kinds of “semi-automatic” transmissions differ and how they work. Do semi-automatic transmissions uses clutches or torque converters? I looked on Wikipedia under the semi-automatic transmission article and it says that they use electronic equipment that actuate clutch changes while at the same time offering manual gear changes through paddle shifting. My confusion comes from the current models Lexus IS and the Toyota Camry. I own a Lexus IS and I have a V6 with paddle shifters. According to the wikipedia definition of a “semi-automatic transmission” my car should have a electronically actuated clutch. However, I am pretty sure that my car has a torque converter and not a clutch. PLease correct me if I am wrong. On the Lexus website it says that my car has “Six-speed paddle-shift sequential automatic Electronically Controlled Transmission with intelligence

(ECT-i)”. On the other hand, my friend has a current model Toyota Camry which also has the option of being “manual”. However, instead of having paddle shifters, the Camry’s “manual mode” is located at the shift knob of the gear box. On their website, Toyota calls this tranny “6-speed Electronically Controlled automatic overdrive Transmission (ECT-i) with intelligence and sequential shift”. How is the transmission in my Lexus different than the tranny in the Camry? Do they use torque converters or clutches? How are each of them classified? Are they classified as semi-automatic transmissions according to the Wikipedia article? Sorry for the long message, this topic just really really confused me. Thanks!!


#2

There are two general types – shiftable automatics with torque converters and automated manuals with one or more clutches. The first are more advanced automatics and can be manually shifted up or down. Most will kick down a gear or two if you floor the accelerator and will not let you hit the rev limiter without up shifting.

Dual clutch F1 style transmissions (Audi, BMW, Ferrari, Maserati, Lamborghini, etc.) are computerized manual transmissions. They have one or more clutch plates in place of a torque converter. They function like a manual transmission, but with computer control. More fun to drive in sports cars, but too expensive for basic transportation.

A Toyota Camry has a shiftable automatic, an Audi S4 has a dual clutch DSG.

Twotone


#3

How about the Lexus IS? Does it have the dual clutch F1 style transmission or does it have the shiftable automatic like in the Camry? Because it does have paddle shifters and according to the wikipedia definition of an automated manual, the Lexus IS would be the kind with the dual clutch F1, right? Or wrong? In other words, the Lexus IS is an automated manual (the more expensive kind). Right or wrong? Also do you know what the type of transmission found in the Camry is called? I looked up shiftable automatic in wikipedia and I couldn’t find it.


#4

The 6 speed in the IS is just a tradtional automatic with paddles. Even the IS-F has a normal automatic torque converter and all, even though it’s an 8 speed.

The only Lexus with dual clutch automated manual is the upcoming Lexus LFA , it can be yours for the low low price of $375,000


#5

Paddles are just switches, and can be used on either type of transmission.


#6

Yes, but with a dual clutch setup the shifting is much faster than it is with regular old slushbox.