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Old 05-22-2014, 02:47 PM   #1
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Default thrust bearings and aftermarket clutches

I want to know if anyone here as had significant thrust wear when using an aftermarket clutch that that has a higher thrust load than stock. I know its common to bypass the clutch switch to reduce wear

Im torn between the Fm1 and the new 949 supermiata clutches

And yes ive searched on this topic already
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Old 05-22-2014, 04:54 PM   #2
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I haven't heard of any failures directly attributed.
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Old 05-22-2014, 05:52 PM   #3
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You know my fm2 came with an over-ride clip but I never installed it. I really don't know how much it's going to help considering it saves you from depressing the pedal once a drive cycle vs the other hundred times you actually use the clutch pedal on an average drive.

I've been trying out something else on start-up since the clutch has been installed. I turn the ignition to run/start first then slowly depress the clutch pedal until the car cranks. That way you don't need to fully depress the pedal and put unneeded pressure on the crank when in reality, the clutch over-ride switch activates in less than half the pedal travel. (at least on my car)

I don't know if it does anything, but it makes me feel all warm and fuzzy inside.
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Old 05-22-2014, 05:57 PM   #4
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Quote:
Originally Posted by flounder View Post
You know my fm2 came with an over-ride clip but I never installed it. I really don't know how much it's going to help considering it saves you from depressing the pedal once a drive cycle vs the other hundred times you actually use the clutch pedal on an average drive.

I've been trying out something else on start-up since the clutch has been installed. I turn the ignition to run/start first then slowly depress the clutch pedal until the car cranks. That way you don't need to fully depress the pedal and put unneeded pressure on the crank when in reality, the clutch over-ride switch activates in less than half the pedal travel. (at least on my car)

I don't know if it does anything, but it makes me feel all warm and fuzzy inside.
until one day the switch activates before clutch is disengaged and you drive through a wall.

that'll definitely feel warm and fuzzy
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Old 05-22-2014, 06:07 PM   #5
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I never start my car in gear, I can see why that could be problematic though.
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Old 05-22-2014, 06:09 PM   #6
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in that case you should just use the clutch switch override that FM provided cause it actually will reduce wear on your shaft

pun might be intended
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Old 05-22-2014, 06:52 PM   #7
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The clutch interlock override is so that you're not shoving the crank into the thrust bearing with your foot *while there's no oil pressure*. That's very different from shifting at a traffic light.

As for driving through a wall -- I've done it once or twice, the car jumps forward an inch or two (you did park with the parking brake on, right?) and then immediately stops when you go "oh ****" and let go of the key. It's not a big deal unless you like to park with zero clearance.

--Ian
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Old 05-22-2014, 06:53 PM   #8
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Quote:
Originally Posted by flounder View Post
You know my fm2 came with an over-ride clip but I never installed it. I really don't know how much it's going to help considering it saves you from depressing the pedal once a drive cycle vs the other hundred times you actually use the clutch pedal on an average drive.

I've been trying out something else on start-up since the clutch has been installed. I turn the ignition to run/start first then slowly depress the clutch pedal until the car cranks. That way you don't need to fully depress the pedal and put unneeded pressure on the crank when in reality, the clutch over-ride switch activates in less than half the pedal travel. (at least on my car)

I don't know if it does anything, but it makes me feel all warm and fuzzy inside.
I don't have sources available off hand (bitog comes to mind, but I didn't save the links), but most engine wear happens during start-up and for a short period right after. With that thinking, putting large amounts of force (by pressing in your clutch) on the crankshaft (and your thrust bearings in that case) is probably a sure-fire way to make it worse. That is the norm though and the wear seems small enough for the life of the average car... then again, the average car in America is no longer manual...


Clutch wise, I highly suggest a 1.6L size clutch that fits the power you plan to make. that would err on the 949 side from your two choices. I do have an FM clutch and have no complaints though, its very easy to modulate. I hardly noticed a difference between stock. That's definitely a +1 for streetability. I don't have any experience with the 949 clutches.
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Old 05-23-2014, 03:03 PM   #9
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My 95 starts without clutch in, some prev owner did it and I love it. Its the only mod on the entire car that I am aware of besides mis-matched seats and a cat off a 944 for some ungodly reason.

It actually does make a lot of sense to avoid full load on the thrust bearing on startup/0 pressure. IIRC many cars in European markets don't require clutch in to start. Just us North Americans who put a few hundred Audi 5000s through garage walls back in the day.

I also leave it in neutral at stop lights rather than just hold the clutch in. Will continue to do that until I use a real sender for my oil pressure and get an actual idea of what its like at idle.
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Old 05-23-2014, 03:28 PM   #10
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Quote:
Originally Posted by Sparetire View Post
My 95 starts without clutch in, some prev owner did it and I love it. Its the only mod on the entire car that I am aware of besides mis-matched seats and a cat off a 944 for some ungodly reason.

It actually does make a lot of sense to avoid full load on the thrust bearing on startup/0 pressure. IIRC many cars in European markets don't require clutch in to start. Just us North Americans who put a few hundred Audi 5000s through garage walls back in the day.

I also leave it in neutral at stop lights rather than just hold the clutch in. Will continue to do that until I use a real sender for my oil pressure and get an actual idea of what its like at idle.
hehehe, Europeans probably tend not to have as many garages as Americans.
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Old 05-23-2014, 06:54 PM   #11
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Quote:
Originally Posted by Sparetire View Post
My 95 starts without clutch in, some prev owner did it and I love it. Its the only mod on the entire car that I am aware of besides mis-matched seats and a cat off a 944 for some ungodly reason.

It actually does make a lot of sense to avoid full load on the thrust bearing on startup/0 pressure. IIRC many cars in European markets don't require clutch in to start. Just us North Americans who put a few hundred Audi 5000s through garage walls back in the day.

I also leave it in neutral at stop lights rather than just hold the clutch in. Will continue to do that until I use a real sender for my oil pressure and get an actual idea of what its like at idle.
Even once you have a real sender you should do it to save the clutch hydros.
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