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Help me pick a clutch?
Hey Guys,
I need to replace my dying clutch; I've been researching and reading for a few days and here are my choices:
The car isn't a dedicated track car, but it's not my daily driver. I drive it to autox events and occasional weekend morning drives. Would love a friendlier clutch for crazy LA traffic (aka I'm a puss).
xoxo, -one lane |
FM1 is the only clutch you need to buy. They hold more power then the ACT, are cheaper, and have better pedal feel. I have not had a chance to try the new 949 clutches so I can't really comment on them, but knowing you are already close to their torque limit would scare me.
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Don't forget, the clutches are rated for torque at the crank, and you likely have listed the torqur at the wheels for your car.
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Originally Posted by shuiend
(Post 1380990)
FM1 is the only clutch you need to buy. They hold more power then the ACT, are cheaper, and have better pedal feel. I have not had a chance to try the new 949 clutches so I can't really comment on them, but knowing you are already close to their torque limit would scare me.
Originally Posted by x_25
(Post 1381006)
Don't forget, the clutches are rated for torque at the crank, and you likely have listed the torqur at the wheels for your car.
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My FM2 clutch with a 10.2lb flywheel isn't even too bad on the streets, comparatively. I'd definitely go with the FM1. 949 kit isn't enough.
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Originally Posted by .one lane
(Post 1381010)
I'm leaning towards the FM setup because I've never had a lightened flywheel before and the next step up in 949's 1.6 kits is sold out. Did you run the 10lb or 13lb flywheel with the FM1 kit?
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Originally Posted by shuiend
(Post 1381020)
I only buy the clutches and use the stock flywheel. I don't personally like lightweight flywheels.
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Originally Posted by shuiend
(Post 1381020)
I only buy the clutches and use the stock flywheel. I don't personally like lightweight flywheels.
Side note: I've read that the stock fw might be helpful when really pushing a bunch of power because of the higher inertia and less jolting transfer of momentum. |
I love light flywheels. 1.6l extreme with organic disk and a 7.8 lb 1.6l 949 or Fidanza flywheel feels like butter to me in a CSP car I'm building. also note the 1.6l clutch is a few pounds lighter and lower MOI than a 1.8l. it would not bother me at all on the street driven daily.
In my beast with over 300 ft-lbs Im running the same 1.6l XT with a 4 puck. It also has served me well and It is also not terrible to modulate. The clutch works fine but transmissions Hate that much torque though. |
Originally Posted by ridethecliche
(Post 1381034)
Why does fm recommend the lighter flywheel for turbos?
Originally Posted by ridethecliche
(Post 1381034)
Side note: I've read that the stock fw might be helpful when really pushing a bunch of power because of the higher inertia and less jolting transfer of momentum.
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One of the best mods to my Miata was removing half the weight from the flywheel. Track only, DD or whatever, lightweight FW is awesome. Stock FW lovers are pussies and should have their boost taken away..... fags
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Well that escalated quickly...
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Originally Posted by hi_im_sean
(Post 1381066)
One of the best mods to my Miata was removing half the weight from the flywheel. Track only, DD or whatever, lightweight FW is awesome. Stock FW lovers are pussies and should have their boost taken away..... fags
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Originally Posted by .one lane
(Post 1381010)
I'm leaning towards the FM setup because I've never had a lightened flywheel before and the next step up in 949's 1.6 kits is sold out. Did you run the 10lb or 13lb flywheel with the FM1 kit?
I didn't even consider that. That would put me around 250 tq at the crank (assuming 15% loss). Thanks for the heads up. |
FM2 with 10lb FM Flywheel, no ragrets.
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I've driven 949's original 1.6 organic and the new 1.6 hybrid. They're both extremely streetable, wouldn't hesitate to put either in a daily driver. That being said, I can't seem to find the hybrid version on 949's site anymore.
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Originally Posted by shuiend
(Post 1381194)
Real MEN only boost 1.8 cars. :vash2:
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Originally Posted by hi_im_sean
(Post 1381066)
fags
Originally Posted by shuiend
(Post 1381194)
Real MEN
Went with the FM1 w/ 10lb FW thanks, everyone! |
Originally Posted by bbundy
(Post 1381053)
I love light flywheels. 1.6l extreme with organic disk and a 7.8 lb 1.6l 949 or Fidanza flywheel feels like butter to me in a CSP car I'm building. also note the 1.6l clutch is a few pounds lighter and lower MOI than a 1.8l. it would not bother me at all on the street driven daily.
In my beast with over 300 ft-lbs Im running the same 1.6l XT with a 4 puck. It also has served me well and It is also not terrible to modulate. The clutch works fine but transmissions Hate that much torque though. |
Since theses aren't turbine engines, it should be noted that the mass of flywheels are more important to transmission longevity as the engine output is increased.
http://www.epi-eng.com/images/Engine/ET-X-4%20Cyl.gif Lighter flywheels will be faster at the track up until the transmission reaches its limit. If we had stronger transmissions available we could go lighter on the flywheels with relative impunity. We need better transmission options. If your car makes a dyno measured 300wtq, that's the mean 0% on the chart. Your peak tq pulses are a wee bit higher. |
Originally Posted by ridethecliche
(Post 1381215)
What do you mean that transmissions hate that much torque? I thought six speeds were fine for 300?
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Originally Posted by bbundy
(Post 1381245)
you are joking right?
RTC, 300hp on the street is much different than 300hp on track. Think duty cycle. |
Originally Posted by sixshooter
(Post 1381221)
If we had stronger transmissions available we could go lighter on the flywheels with relative impunity. We need better transmission options..
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Originally Posted by hi_im_sean
(Post 1381246)
He's new and still reading and learning.
RTC, 300hp on the street is much different than 300hp on track. Think duty cycle. |
Originally Posted by bbundy
(Post 1381251)
There may be something too the heavier flywheel damping out the pulse peaks but I have broken enough transmissions to know it isn't close enough to make a big difference.....
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Oh right. Slicks change the equation entirely since they stress the trans far more.
I was just wondering if the lighter flywheel was part of the reason for greater transmission stress. Kinda like how the damper needs to get changed at higher power. I know these things aren't directly related, but mostly looking at things that need to be done as you push the power up! |
We call all seasons on high HP cars "transmission fuses" for a reason.
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How are you going to drive the car?
Take what you've learned about the flywheel and throw it in the trash. From what i've gathered, it's all about feel. I've chose to save cash. Soon as you start hammering gears and wheel hopping the game is over. The clutch and flywheel doesn't care, everything behind it does. |
Troof
9lb F1 ebay FW here. No ragrats. |
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Shots fired.
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https://cimg5.ibsrv.net/gimg/www.mia...5d58c1bd1a.png
The flywheel also performs another function as well, one of smoothing the engine's power pulses. As the engine turns, each cylinder goes through two distinct phases - the compression stroke and the power stroke. On the power stroke, the piston is driving the crankshaft. On the compression stroke, the crankshaft is driving the piston. Thus, for every other revolution, the crank alternates between "being twisted" and "twisting." The flywheel absorbs energy on the "being twisted" phase, and then returns the energy on the "twisting" phase, helping to smooth the engine pulsations. On a single cylinder engine, this pulse damping is of significance. On a one hundred cylinder engine, the pulses would be distributed so evenly that the flywheel damping would not be needed. For this reason, a heavy flywheel would be of less benefit to a V8 than it would be to a four cylinder engine. The damping effect of the flywheel is also assisted by the damping action of the harmonic balancer. In addition to the "flywheel" effect of the relatively heavy damper, the elastic material between the inner and outer portion of the harmonic balancer adds to the smoothing effect. This elastic material absorbs some of the "being twisted" forces, and gives back during the "twisting" phase. |
So increased chatter with lighter flywheels could also be due to this loss of dampening?
I wonder if folks have tested the clutch/flywheel combo with significant decel chatter and swapped out to the stock flywheel and found that the sound goes away. I know it's understood that it's a function of the lighter flywheel but increase in NVH means less damping, no? |
https://www.miataturbo.net/suspensio...h-83376/page2/
If you read the links I posted in there, you'll find that until you model the engine and trans, find their frequencies and determine the crossover points, any talk of damping beyond reasonable amounts (like having the harmonic there and any FW) is useless. In other words, 20 lbs of FW may be no more useful that 10lb on a given engine tranny combo, as 5 may be enough to damp any and all pulses to a satisfactory degree. Conversely, 20 could also have double the damping effect as 10 on a given combo, and that engine/trans may need 30lbs to be happy. https://www.miataturbo.net/suspensio...2/#post1213618 |
I like the FM level 2 clutch lots of torque capacity, good pedal feel, and smooth engagement. That said I did somehow manage to break the sprung hub on the clutch disk on a FM level 2 clutch kit. I don't think it had anything to do with quality of the parts but most likely my lack of mechanical empathy and a trip to deals gap.
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Originally Posted by Lee04vr
(Post 1387170)
I like the FM level 2 clutch lots of torque capacity, good pedal feel, and smooth engagement. That said I did somehow manage to break the sprung hub on the clutch disk on a FM level 2 clutch kit. I don't think it had anything to do with quality of the parts but most likely my lack of mechanical empathy and a trip to deals gap.
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Originally Posted by curly
(Post 1387232)
I've seen that failure a couple of times, seems pretty easy with aggressive driving or tracking.
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Originally Posted by curly
(Post 1387232)
I've seen that failure a couple of times, seems pretty easy with aggressive driving or tracking.
The ACT HD street clutches we've been getting people with their K swap kits have done very well and are rated at 245 tq with the organic disc. |
I'm displeased with my FM1 clutch; I was extra vigilant not to go into boost when driving. I followed FM recommendation to ensure proper break in, and the clutch slipped when I tried to hit WOT in 4th gear. The clutch had over 500 miles on it.
I wonder if FM can do anything about it? On a happier note, the 10lb flywheel is awesome. |
Not trying to hijack this thread but..... My car makes 215 wheel torque. Bought car recently and believe it has FM Stage 1. Throw out bearing squeals a lot but clutch doesn't slip. About to replace whole assembly with either FM Stage 1 or 949 racing clutch kit. Afraid the 949 might be too weak for my power.
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Originally Posted by 01Romanss
(Post 1389396)
Not trying to hijack this thread but..... My car makes 215 wheel torque. Bought car recently and believe it has FM Stage 1. Throw out bearing squeals a lot but clutch doesn't slip. About to replace whole assembly with either FM Stage 1 or 949 racing clutch kit. Afraid the 949 might be too weak for my power.
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Originally Posted by Chiburbian
(Post 1389405)
You sure it's the throwout bearing? The shift fork tends to squeak against the clutch master cylinder rod. A dollop of thick grease is said to fix it. I have verified that the squeaking I hear is that and NOT the throwout bearing in my car.
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Thanks for the input. I'll check it out. It would be great if that is the problem. However, the sound I hear is the high frequency whirring and squeaking sound as I rest my foot on the pedal and just begin to push the pedal in. It sounds and feels like the throw out bearing making contact with metal. The previous owner tracked the car and I believe the bearing had a lot of work to do.
Thanks, Dan |
Originally Posted by sixshooter
(Post 1381336)
https://cimg5.ibsrv.net/gimg/www.mia...5d58c1bd1a.png
Just throwing it out there that the mean torque of a 300wtq engine is a long way from the momentary torque of the same engine. It appears to easily be twice as much. A larger flywheel lowers the peak and raises the valley, evening the energy out. A flywheel is an energy capturing and releasing device, an energy storage device. Would you want over 600ft lbs of force on a couple of gears in the transmission at one instantaneous moment if you were trying to protect it, or perhaps instead smoothing it a bit? It depends on how much you enjoy the lightweight flywheel's responsiveness versus exchanging transmissions, I guess. Literally just washed the grease off my hands from installing a FM clutch/flywheel on my son's car..... The stock engine rotating mass plus the clutch/flywheel is what...nearing 80ish pounds? So you are saying the by installing the 8.7 pound lighter flywheel I have increases peak torque (spike) to the transmission by 50 foot pounds on a 300hp engine? Feeling like a dumbass after reading this.... |
I'm not saying anything much, just posting data and info found on the interwebbez.
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Great read, and very timely for me.
Though sadly it seems there's no good ( oem feel / streetable & available for current purchase ) clutch option to run a moderately boosted 1.8 with a 1.6 clutch setup. |
Originally Posted by phocup
(Post 1390310)
Great read, and very timely for me.
Though sadly it seems there's no good ( oem feel / streetable & available for current purchase ) clutch option to run a moderately boosted 1.8 with a 1.6 clutch setup. To me it feels better than stock with a firm pedal and a shorter, faster, engagement. It rev matches 10X better, and upshifts are much faster and are way less effort for the syncros. Took me about 5 minues to get used to. Zero chatter. Not bad for a clutch that can and does live behind a 450hp car! They also make a level one clutch that is fine for most sub 325-350hp goals. I am sure that clutch would make anybody happy. |
That's a 1.8 clutch. I'm hoping to keep the smaller 1.6 size because (a) I just got a shiny new Fidanza in not more than 100 miles ago and (b) lower MOI for autox.
949 just got back to me actually. They have a new shipment of clutches coming .. no idea when though. LOL. |
If you get the clutch and flywheel you can use whatever you want...if you want the flywheel that is
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Anybody got an opinion on FX Racing clutches from Apex Clutch? Their prices seem too cheap.
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Originally Posted by djcarr
(Post 1407987)
Anybody got an opinion on FX Racing clutches from Apex Clutch? Their prices seem too cheap.
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^ He's posted it before, and it still remains good, solid advice. You ignore it at your own peril.
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