Q. Everytime when the CVT indicator light is on, there will be fault code appear for service center to refer?
A. Offcoarse its stored in our computers memory. Keep in mind though that after 20 restarts of the engine without the fault code appearing it will be gone as it will be considered a one off, or solved problem.
Q. I notice that exora bold still roll back on even slight /gradual slope(not-too-steep slope). Normal auto gear vehicle only will roll back when the slope is too steep, if it is not steep enough, it's will lock at there. Is there anyway to make CVT lock it when reach slight/gradual slope? It is kinda dangerous esp for new driver.
A. You are correct. This is a know "issue", but is a design feature actually. Two things contribute to this:
First thing is what we call idle neutral, unlike all regular older AT's that have a constantly dragging torque converter or clutch, we open our clutch (a wet clutch, more pressure = more drag, even more pressure closes it) almost completely when you are pressing the brake and standing still. this way fuel is saved. If you release the brake a little time is needed to apply pressure to our clutch again. that is when you roll back a little, rollback only occurs on hills steeper than 10%.
secondly the engine cannot deliver a lot of power idling, when aircon is on, heavy car, on a hill, we can start closing the clutch in order not to roll back, but that will cause the engine to stall. When you apply trottle you will notice first the clutch opens a little bit so engine revs up, than we start closing the clutch, during revving up, you can encounter rollback.
What to do? use handbrake in stead of brake, this way we not shift to neutral (we only read regular brake signal not handbrake), use enough trottle, this way the engine produces engough power to close the clutch in one move.
Q. A lot bashes arguing CVT from proton will end up like honda city CVT, after few year, this cvt gb will fail and it's will cost a bomb for us to replace the CVT GB. Can you describe a bit on punch CVT and it's reliability issue?
A. We are looking into this, we do know income in malaysia is not like europe meaning people will choose repaired or reconditioned gearboxes above new ones. Possibility is that Punch will open a local brand to recondition gearboxes and sell at prices comparable to normal AT ones. As you know our gearboxes are tested till 250000km.
Q. A lot people(those basher) condemning on rubberband effect for proton CVT compare to those conti CVT(multitronic and etc). Rubberband effect quite obvious for punch CVT.
A. Rubberband effect is from CVT's that existed 30 years ago, we use a steel belt so not applicable.
Q. Overheat issue on CVT2. There is rumours saying that Saga FLX always break down due to CVT2 overheat. Is there any solution already?
A. We use a wet clutch, when you would move uphill at very low speeds it would slip almost constantly. We cool this clutch with CVT oil, this is pumped trough the clutch by our CVT pump, this pump is directly connected to the engine. So yes, when not driving as you should with a CVT (and you cannot know this as this is new) you can overheat it. Please compare to manual, if you would keep it on a hill only using the clutch you would burn it.
What to do? avoid long slipping clutches by applying enough throttle when moving uphill, the engine will produce enough power for us to close fast without long slipping period. Shift to N when you can, this will have a cooling effect on the CVT, if possible in N apply little throttle till lets say 1500rpm, this will rev up the pump and increase cooling.
these tips are only for extreme conditions! all other condition drive as you want!
Our CVT's are tested under extreme temperatures! Worst case scenario clutch will open, resulting in no drive as we measure temperature and in order not to break the CVT we will open clutch. You will have to wait a few moments, key on and off and there you go again, this is no breakdown!
Q. As you said "when you would move uphill at very low speeds it would slip almost constantly", how slow is the slow (car speed and engine rev)?
A. Speeds under 10km/h
Q. You have mentioned that the clutch is almost completely open while standing still with D engaged, is this the prime reason of slight lagging when slowly pressing the gas to move?
A. Yes, if you release the brake and immediately press the gas, this is the case. It is always better not to press the gas immediately unless you have to (uphill), you will notive less delay. That it isn't superagressive at launch (if you would mean this by lag) is calibration, it is to preserve both engine and CVT. it is called torque reduction, the engines power delivery is minimized, although full trottle.
Q. Could you give some advices/tips in using CVT when going uphill (e.g. Genting Highland)? Also does it have engine-breaking effect when coming down?
A. Yes it has an automatic engine braking, but only when trottle completly released. Even more engine braking can be applied by putting transmission in L mode. Also for uphill L mode comes in handy, lower ratio, more pulling power!
Q. Is there anyway to avoid CVT failure like honda city/jazz? Any special thing need to take care in order to longer the lifespan of punch CVT?
A. Nothing really special, just drive and enjoy. If would have to say one thing it is to let it build up it's clutch pressure after releasing brake or putting in D before going on throttle, that will be better for clutch.
Q. When u said the CVT is tested under extreme temperature, how extreme is it?
A. We do summer and wintertests, wintertests go up to -40degree, summer tests are extreme high temps and mountains.
Q. If the car is in extreme condition, i believe the CVT oil might be degraded earlier than expected. Is there a way for us to check if the CVT oil is still at its functional condition to lub and cool the CVT?
A. You cannot check but there is no need to. 60000km is fine as in service manual. (or 2 years)
Q. The CVT overheat issue, if i understand correctly from your replies, mainly touching on the cluth. In worst case, the cluth will open to avoid further damage. So, the CVT(belt, "gear") remains safe. Is that right?
A. Temperature build up in clutch is the problem, that is why it opens. Gears, belt, are not sensitive to these temperatures.
Q. So, the cluth is a wear and tear stuff then? how frequent it needs to be replaced?
A. It is designed to equal normal lifetime of a car.
Q. Can you give an insight as to how the VT3 has been improved over the VT1F?
A. VT3 is based on VT1 allthougth the whole control stategy and hydraulic system changed. This makes it easier and safer controllable. For example the strategy to apply the clutch is constant learning program that remaps every time you shift to D so that clutch wear over time will be compensated. Also the gearbox has a lot more safety in a way that importtant components will be protected if something would go wrong. Offcoarse every failure is investigated on VT1 and prevented in VT2.
Q. Is the Exora the first car to be fitted with the VT3?
A. Yes it is, but the VT3 is very similar to VT2 that we are supplying for multiple years. Some mechanical components are changed to withstand higher torque (eg Gears) and the final gear ratio is different. All service parts for VT3 are same as VT2.
A. CVT's with wet clutches (ours) are much more efficient than the ones with torque converter. With the converter you have an indirect connection between engine and transmission. With clutches it is direct. CVT driving needs some getting used to, but once you understand it a bit better you will enjoy it much more than a regular AT. You can make smooth driving by closing the clutch veeery slow, but if the driver applies a lot of trottle it means he wants to move... and fast! so we close the clutch fast, as it should. I think overall the exora with CVT is smooth and as i drive (sometimes very fast) i don't experience this jerk, just "feel" the car and things will be OK!
Q. When the car comes to a stop (during the slow down/deceleration), i can hear a very obvious humming sound. If i switch to neutral, this noise will go away instantly. The noise is also obvious when the car is downhill with engine braking.
A. The low speed noise when descelerating is CVT related however, as your SA told you also engine makes similar noise. If you drive very slowly, little throttle you have this whoewhoeeee noise, this is the Airco compressor. You can see if you switch of aircon during the noise. Those two are very similar. But as you say, it's not that bad, all gears make noise, some just isolate it better than other. For me it's not bothering. We take in into consideration however and it is one of the action point to further improve on this matter.
Q. Regarding - Chiptuning and AT gearboxes:
A. First of all it's never good to chiptune engines that use a AT gearbox, second of all I don't recomment to chiptune this CFE engine in particular! We have run quite some test, and soms tests with blow off valves not working causing overpressure from the turbo (that is what they will do) with disastereous consequences! This engine is still highly based on a non turbo engine, therefore components are allready on their limit.
As for the CVT 220Nm is indeed a maximum when it goes for mass production. same as a VW golf GTI is max 220hp for production, this does not mean you don't have any reserves but from that point you will shorten the lifetime. Why is this so critical for CVT? A CVT uses a steel belt pressed in between two pulleys, by varying clamping on the second and first pulley you shift. When you are not shifting you still need clamping force to push the belt so it wouldn't slip. This pressure is based on the torque the CVT needs to handle -> high torque? high clamping force! this torque is told to our control unit from the engine ECU. When you chip your car however the ECU will tell us the stock 205Nm and not the real 235Nm resulting in possible damage. Even though we do have some safety build in, i highly discourage chipping the ECU.
Keep in mind that proton will retract warranty in these matters!
Q. Regarding - CVT overheating?
A. Our CVT will never overheat doing high speed due to the oil cooler installed. Flow through is cooler is very high at high speeds (both oil and wind going trough).
Q. When in a traffic jam (even on a level road), should we shift to N at every available opportunity? Or does frequent shifting back and forth from D to N and back affect the lifespan of the CVT gearbox?
A. On normal roads or traffic jams the CVT and clutch will never overheat. We have a system that asks the engine to lift up idle speed and turn on the fan in order to get more oil trough our CVT and clutch.
No need to shift to N for normal traffic or jams. Only when uphill driving longer period in a jam, I suggest to put in N if possible. We will not simply open the clutch when it overheats but we will gradually limit engine torque as temperature rises. No issues like this have been reported however, so don't worry too much
Source: Questions and answers on CVT Saga, Exora, P3 - Autoworld Forum
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