FX400 slippage?!

[patarch]

Hi guys,

So it's very very very cold here in Montreal, around -30c w/o wind chill factor.

I park my car indoors at night but it stays out for about 6 hours when i'm at work.

Leaving work today, i get on the highway, car is warmed up, I floor it in 4th gear to merge on and I experience very bad slippage from 4k to about 7k...

This stressed me out a bunch so I was nice to it the whole way home. Might of given it a bit a boost in 3rd with nothing abnormal happening.

This clutch has almost no miles on it and was broken in properly.

I doubt that my tires were spinning as the traction control didn't come on...

Could this be due to the extreme cold weather we are getting?!?

Should I run tests to see if I get slippage or should I be gentle to it until weather warms up a bit and then see?

What is my worst case scenario here? Am I looking at another clutch kit or I might be able to salvage parts?
Man I don't feel like throwing more money for clutch issues.

Thanks for any advice!

 

[mustache rash]

Was it a full kit with smf? That's crazy

 

[Gabriel1]

Sub'd

 

[patarch]

Yeah, full kit. I'm so pissed I can't even sleep.

 

[excelevant]

I have the full face, is your 6 puck ceramic?

 

[Baldeagle]

I have two thoughts. I’d think the extreme cold could be part of the issue. Just because the radiator fluid in your engine had time warm does not mean the flywheel or clutch plate had time to warm. It is possible the extreme cold reduced the friction coefficient between the clutch plate and flywheel.

But I think there may be a different cold temperature issue at hand here. Air at -30°C (-22°F) is about 27% more dense than air at 70°F. That means at -22°F your engine creates about 27% more power under full throttle than at 70°F. Because of the extreme cold, your Stage 2 engine may temporarily produce another 70 lbs.-ft. and over power your aftermarket clutch.

 

[Bender1]

I have two thoughts. I’d think the extreme cold could be part of the issue. Just because the radiator fluid in your engine had time warm does not mean the flywheel or clutch plate had time to warm. It is possible the extreme cold reduced the friction coefficient between the clutch plate and flywheel.

But I think there may be a different cold temperature issue at hand here. Air at -30°C (-22°F) is about 27% more dense than air at 70°F. That means at -22°F your engine creates about 27% more power under full throttle than at 70°F. If you are Stage 2, you’re probably always on the verge of over powering the clutch. Now temporarily add another 70 lbs.-ft. of torque due to the -22°F temperature and your stock clutch had no chance.

Source for this? This doesn't sound right at all.

OP - how many miles on your clutch?

Also - are you SURE it is slipping? I would guess it is temp related. You should be taking it easy in temps that cold anyway...

 

[Baldeagle]

Source for this? This doesn't sound right at all.

OP - how many miles on your clutch?

Also - are you SURE it is slipping? I would guess it is temp related. You should be taking it easy in temps that cold anyway...

http://www.denysschen.com/catalogue/density.aspx

According to this site, the air density at 70°F (50% humidity) is .0741 lbm/cubed foot. At -22°F (15% humidity) air density is .0901 lbm/ cubed foot. That is a 22% increase. (In my post, I quickly estimated 27%.) So 22% will still increase power by perhaps 60 lbs-ft of torque compared to 70°F. (Also, I edited my other post to reflect that Patarch has an aftermarket clutch.)

 

[Bender1]

No i get the density - but to assume that increases power by an equal amount is incorrect unless I am missing something huge.

 

[D Darko]

I can tell you my stock clutch slips way more when it's cold (>38 + or -) than when the temps are warm.

 

[Baldeagle]

Bender, I’ll research this, but I am pretty sure that power output is related to the amount of oxygen the engine has available to burn. (Provided the fuel balance remains correct.) I always thought there was a linear relationship. So as temp went down, air density went up, oxygen content increased equally as did power output. What do you know that is different?

 

[Bender1]

Bender, I’ll research this, but I am pretty sure that power output is related to the amount of oxygen the engine has available to burn. (Provided the fuel balance remains correct.) I always thought there was a linear relationship. So as temp went down, air density went up, oxygen content increased equally as did power output. What do you know that is different?

Power is definitely a factor of air density but you are limited by a few things:

1) Turbo won't compress past set pressure limits. Even if denser air is coming in, it still will only output at a set PSI
2) MAF would adjust AFR to keep in safe range.


You definitely get more power when it is cold out, but I don't think it is a direct correlation to air density.

 

[Blueteam]

I get

a stock 207 hp GTI at -30c vs 15c

288.15k/243k = 1.185 sqaure that and 1.088

So 207hp x 1.088 = 225.21 hp

Actually a pretty good gain.. also beyond numbers everything elese would work better like intercooler and junk..

2.5 golf for shits and giggles... 170hp x 1.088 = 184.96

So lets just drive 2.5's at -50 or so and we can be close to stock gtis at room temp..lol

 

[Baldeagle]

Power is definitely a factor of air density but you are limited by a few things:

1) Turbo won't compress past set pressure limits. Even if denser air is coming in, it still will only output at a set PSI
2) MAF would adjust AFR to keep in safe range.


You definitely get more power when it is cold out, but I don't think it is a direct correlation to air density.

I get your point. Even if there is a linear relationship between an increase in air density and an increase in HP, at some point a turbo charged engine would purposely cut back boost to protect itself. In effect, it may intentionally not take full advantage of the denser, oxygen rich air. That makes sense. Thanks. I guess the next question I have is how much more power would the engine produce in -22°F air before it protected itself? To some degree, it should still make more power at -22°F than at warmer temperatures. Whatever that temporary increase may be, is it enough to slip the clutch?

 

[Bender1]

I would think not. The clutch slip is coming because everything (including the friction material) is likely frozen solid. You should never run a car hard at temps like that. I start to ease off on mine in the low 20s (f).