Possible Psychosomatic Observation/Question...

"JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t" (jawzx2) 01/22/2015 at 16:34 • Filed to: None

0

21

Ok, So now I'm on my second winter with the 2014 FieSTa, and the real cold weather has been with us for a couple months and I have noticed something, something that I noticed with my previous 2011 Hyundai Elantra Touring, something that I initially chalked up to psychosomatic new-car-owner-semi-insanity as until I experienced it in the Hyundai I had never noticed it on any manual transmission car I had owned prior to the Hyundai... But I'm absolutely sure the FieSTa is doing it too (unless I'm insane)... here's a list of cars with manual transmissions that I have driven in VERY cold winters before and never noticed this:

1982 Volvo 242 (racing clutch, so that almost doesn't count)

1989 Audi 100 Quattro

1989 Mazda Protege LX

1986 Mazda B2200 4x2 pickup

1994 Mazda B2600 4x2 pickup

1992 Alfa Romeo 164-S

1995 VW Pasat VR6

1998 Audi S4

2000 Toyota Corolla CE

2004 Hyundai Elantra Sedan

1978 Volvo 240 wagon

1989 Volvo 240 wagon

1995 Volvo 850 wagon

1999 Ford Escort Wagon

1985 Ford Escort

1976 (Mercury) Capri II

1992 Toyota Tercel sedan

1992 Dodge Dakota 4x4

2000 Toyota Rav4 (2wd)

1996 BMW F650 motorcycle (yes, I have ridden this in the winter extensively)

this is by far not a complete list of manual trans vehicles I've driven in cold weather in my life, but only the ones that I had also driven in warmer weather often enough to feel fairly certain that I would have noticed The Thing (I own(ed) the '82 242, Alfa, Corolla, Elantra sedan, Protege, B2600, and BMW each for at least two winters so I consider myself expert on those...)

so... the thing:

When it's really cold (below freezing) the clutch engagement point is noticeably higher. It seems that this DOES change with driving, but I have to go far enough to completely warm up the driveline and under-hood area. Warmer ambient temperatures return the clutch engagement point to it's normally expected location

Anyone else notice this? Am I insane? If this is a Real Thing, how come I only noticed it these two most recent cars? I can think of nothing that makes the 2011 Elantra Touring and the FieSTa special/different vs. other things I've driven aside from being from newer production years... differing (newer) clutch friction material or hydraulic fluids? New alloys in the pressure spring?

Am I getting senile at age 36?

Brian Silvestro > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:38

0

Well since the idle is so high when I first start up the car, I literally just pull away without ever having to touch the gas.

I'm sure that doesn't help at all, and has very little to do with your situation.

But I felt obligated to comment because we have the same car.

crowmolly > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:40

1

Not insane. Could be the clutch fluid heating or a difference in clutch friction material as you stated. My vote is fluid.

Axial > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:41

0

Density of the clutch fluid changes with temperature. That's the most likely cause of altering catch points.

pitstop_pitowski > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:47

1

I am soooo glad that you pointed this out. I have a 2014 FoST and it does the exact same thing you mentioned. This was my first manual since 2004 and I also never remember this happening to my prior 3 manual transmission cars pre-2004.

jariten1781 > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:48

0

I haven't noticed a change to the engagement point, but I've certainly experienced the transmission fluid getting much thicker. It actually feels way better...on mine when it's warm everything chunks...feels like it's lubed with water. Will be switching to something thicker come Spring.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > crowmolly 01/22/2015 at 16:48

0

My initial thought was fluid too... both the ET and the FieSTa use brake fluid for the clutch hydraulic fluid, (but so did a number of the other cars listed)... one thing both the ET and the FieSTa have that the other cars on this list didn't have is EBD (Electronic brake-force distribution)... I wonder if that could have something to do with it too? Both vehicles feed fluid to the clutch master cylinder from a tap on the brake master cylinder rather than just having an open, shared reservoir like many older cars with hydraulic clutch/brake shared fluid...

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > Axial 01/22/2015 at 16:51

0

I think you're right, it has to be about density change of the fluid with temperature...

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > pitstop_pitowski 01/22/2015 at 16:54

0

Nice to know I'm not alone in experiencing this *AND* it being a new experience!

crowmolly > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:55

0

It may also be the design of the hydraulic system itself. Lines, orifices, and so on. Or T/O bearing design.

I know LS1 six speed F-bodies had issues with fluid return and dead pedals (look up "drill mod") when you powershift the hell out of the car.

OPPOsaurus WRX > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 16:57

1

I've noticed it to with the WRX

Axial > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 17:00

1

I should think that it would make the catch point lower to the floor, though. Cold should result in higher density which, in practical terms, means the volume decreased. Less fluid should require you to apply more pressure to get it to move the mechanism the same distance. I know that, for my clutch, if there is less fluid, I have to press the pedal further in.

Maybe it's a pull-type vs. push-type clutch kind of thing?

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > Axial 01/22/2015 at 17:19

0

See, that's What I would have thought too... @crowmolly above, had a suggestion that it might have to do with the design of the hydraulic system, perhaps in combination with the density change of the fluid... it still seems like it's opposite the expected behaviour though...

Denver Is Stuck In The 90s > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 17:24

0

My truck does it. It drives me nuts when going into first at a stop light

Spoon II > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 17:42

0

I'm voting fluid too, although I've never noticed it myself, my list of driven cars isn't quite so extensive! Also, kudos to you for the winter motorcycling as well!

Textured Soy Protein > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 17:43

0

In my old Mazdaspeed 6, it wasn't so much that the engagement point changed, but the clutch pedal would get sticky when it was super cold out. Instead of springing back up like usual it'd kinda take its time returning after I pressed down on it. I'm assuming because it was a hydraulic clutch and the hydraulics got all gloopy when the temp approached zero.

Axial > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 17:50

1

Well, most modern (read: '80s and onward) hydraulic clutch systems are self-adjusting. It is plausible that it might be over-correcting with the weird viscosity changes.

Axial > jariten1781 01/22/2015 at 17:55

0

Funny you mention that. I have two Corvettes with the same ZF6-speed transmission in both, though the newer one has different cut gears to reduce noise. The older one shifts great in the warm and even better in the cold. The newer one gets a bit chunky in the cold but is a doll when warm.

petebmwm > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/22/2015 at 21:48

1

does it have a clutch delay valve? Coupled with fluid temp, this could be it.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > petebmwm 01/23/2015 at 07:38

0

further research yields this info: FoSTs, WRXs and post-2006 Hyundais all Definitely DO have clutch delay valves. No information I can find on the FieSTa seems to be definitive either way, but the suspicion, based on this and some other noted behavior is that it at the very least has a restrictive hydraulic line, and probably does have a clutch delay valve. This may indeed be the reason. I had never heard of this device until you mentioned it.

petebmwm > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 01/23/2015 at 08:29

0

bmw's have had it for years and it makes the clutch feel like shit, we manual tans bmw owners take it off and it away.

NoahthePorscheGuy > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 02/04/2015 at 21:54

0

FiST tranny definitely acts differently in cold temperatures.