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CORRUPT
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Hill start assist is a brake system thing which is totally unrelated to the clutch hydraulic system. Think about what's going on inside of the clutch system: the CMC is a piston inside of a cylinder that you use to push fluid through the clutch line to another piston inside of a cylinder. If everything inside of the system were totally solid then the amount of fluid displaced by the CMC would exactly equal the fluid entering the slave cylinder. When you have a damper in the system or soft lines, then some of the fluid displaced by CMC goes into expanding rubber lines or a metal diaphragm, as in the case of our stock CMC. Basically, it causes the slave cylinder to lag behind the master cylinder giving a less connected feel and more tendency to slip. The faster the CMC piston moves, the more pronounced this effect becomes. It's essentially smoothing things out for you by allowing more slip. If you see this as a benefit, then don't mess with it. If you want a more direct, connected feel to your clutch and have less tendency to slip, then deleting the diaphragm and upgrading the soft line to stainless would be the way to go.

Anyways, the clutch system is pretty independent of everything else and the vehicle eletronic system has no idea about what it's doing, other than through the clutch switches on the pedal. Those are external to the hydraulic system and will not be affected by any changes made to the hydraulic portion of the system.

Basically, no downsides other than making your crappy shifts more obvious...
 

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I think this is the reason I thought hill assist is related- idk about u guys but it took me some time to get used to it. Still tryna figure out how to get out of it quicker..feels like my car is stuck -not rolling back but not going up either, and dreading that sudden break in which the car will all of a sudden roll with the hill if ur not at the right engagement points of the clutch/throttle to get the car moving..ive gotten much better now but it was quite an adjustment from a non hill assisted car. Maybe someone can chime in on how to get out of the hill assist more quickly tho I know thats a bit off topic.

Nevertheless ive read elsewhere for further research on this topic (clutch delay valve) and decided I will try the cdv delete. So item 9..do u know if the parts are the same between years of our car? I know supposedly the clutch is supposed to be slightly stronger on the 13s (for the "added power" from the li-ion battery) but idk much about the rest of the system...

Anyways I trust my shifting enough not to destroy the drivetrain but I read the cdv leads to premature wear on the clutch? Fehh
 

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I finally got around to install one of Item9's clutch master cylinder with the delay valve removed in my 2009 Honda Fit Sport. Installation was straight forward plug and play with nothing to modify or hard line to bend. Bleeding the clutch line was easy from the slave cylinder with a pneumatic brake bleeder. Clutch pedal feel is so much better without the sponginess and more direct. You will feel a little bit of vibration from the clutch pedal without the clutch delay valve.

I just finished this last night and it should fix the issue. It basically bypasses the damping mechanism in the CMC. The two holes to the intermediate chamber are TIG welded shut and I drill out a bypass to the cylinder. I wanted to delete the "CDV" this way to keep the OEM hardlines, have stock pedal travel and have a nice OEM plug & play install. I also bead blasted it after I was done. I'll try to install tomorrow and see how much it improves my shifting.

I can do more of them...


Stock CMC with weld area sanded down.


Welded. Not bad for my first one.


Drilled through to the cylinder.


Bead blasted.


Closer up.


Partly assembled. The cover plate is also bead blasted.
 

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CORRUPT
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I suppose the "CDV" in the stock CMC was damping out vibrations propagating through the hydraulic lines... I have never noticed these vibrations in a deleted CMC though, because I don't rest my foot on the clutch pedal. If your foot is only on the pedal when you're shifting, then you'll probably never notice this.

Maybe the increased vibrations are a good thing, because they can remind you to keep your foot off the clutch pedal... You really shouldn't rest your foot on the clutch, because it will cause the throw out bearing to wear out prematurely and you have to drop the trans to replace it...
 

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I suppose the "CDV" in the stock CMC was damping out vibrations propagating through the hydraulic lines... I have never noticed these vibrations in a deleted CMC though, because I don't rest my foot on the clutch pedal. If your foot is only on the pedal when you're shifting, then you'll probably never notice this.

Maybe the increased vibrations are a good thing, because they can remind you to keep your foot off the clutch pedal... You really shouldn't rest your foot on the clutch, because it will cause the throw out bearing to wear out prematurely and you have to drop the trans to replace it...
I don't leave my foot on the pedal, I notice the vibrations when the clutch pedal is on the way up off the floor :p

also I probably need to bleed the clutch or something because I drove to work this morning and the pedal was super mushy compared to last night :x
 

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Could this delay valve cause a lot premature wear on the clutch? I have heard of this but now facing a possible clutch replacement at only 66k I'm wondering if this had anything to do with it since I've never had to replace a clutch under 130k even beating the car daily... I will say even after over a year of driving this car I still do not like the way the clutch feels. A lot of times I delay in my starts because it feels like I do not have enough power at first causing a little more slippage that I would not ever normally have in any other car and I know this car has plenty of power... Although now I feel like it is too late with my clutch slipping in higher gears now at mid to low rpms. Also is it possible for this CDV to be damaged or not working properly causing the clutch to not fully be engaged all the time leading to a slipping problem? Maybe the internal parts to it are stuck causing very little presure to the clutch giving it the ability to slip easily under accel. in low to mid rpm range? I'm missing my mid 90's Honda more and more everyday...
 

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CORRUPT
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Are there any more of these valves for sale still? Hopefully i'm not the only one looking for one of these.
Yes, I'm still making these. PM is the best way to contact me about it. Sorry I missed your post earlier; I haven't been keeping an eye on this thread...

Could this delay valve cause a lot premature wear on the clutch? I have heard of this but now facing a possible clutch replacement at only 66k I'm wondering if this had anything to do with it since I've never had to replace a clutch under 130k even beating the car daily... I will say even after over a year of driving this car I still do not like the way the clutch feels. A lot of times I delay in my starts because it feels like I do not have enough power at first causing a little more slippage that I would not ever normally have in any other car and I know this car has plenty of power... Although now I feel like it is too late with my clutch slipping in higher gears now at mid to low rpms. Also is it possible for this CDV to be damaged or not working properly causing the clutch to not fully be engaged all the time leading to a slipping problem? Maybe the internal parts to it are stuck causing very little presure to the clutch giving it the ability to slip easily under accel. in low to mid rpm range? I'm missing my mid 90's Honda more and more everyday...
Like I said before, your clutch may not be worn down, but instead glazed over. Plenty of clutch material may still be there, but at the friction interface the material is ruined by being smooth and glassy. The CDV can contribute to this because it favors slipping to "protect" the drivetrain, but ultimately it is how the car is driven that determines whether this will occur or not. It can easily get ruined in one driving session, especially with an inexperienced driver... I let my brother drive my car one time and there were a few shifts where I was absolutely cringing. Sometimes, especially since I am supercharged, once the clutch has started to slip it would not grab until you almost completely backed out if the throttle. My brother kept his foot into it a few times... Never doing that again...

I will agree that the CR-Z clutch is barely adequate even for a stock car though. I know I won't be going back to a stock clutch ever...

So to answer your question, yes, the CDV does potentially contribute to more wear since it, by design, allows more slip to reduce shock to the drivetrain. However, the CDV is not a moving part that can get stuck; it is simply a metal diaphragm that flexes under pressure. It's pretty much impossible for it to fail, unless there was so much water in your hydraulic system it caused it to corrode away. You have bigger problems if that were the case...

Anyways, a CDV delete will help prevent some of the excessive slipping from occurring and give you more of that 90's Honda clutch feel. It's not capable of miracles though... You can still ruin your clutch if you tried hard enough...
 

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thanks can you tell I am desperate for an alternative to clutch replacement haha. So if the clutch is glazed over with plenty of material still left on it is it possible that driving it very easily and trying not to slip the clutch that eventually the glazed outside material would get worn off and leave me with a fresh clutch surface over time...? its been doing ok lately but I haven't gotten on it at all and have been very easy on it only driving less than 10 miles at a time. I have an hour and a half trip to make Saturday and I'm worried that after driving awhile and getting it hot it may start slipping again even on the highway.


Yes, I'm still making these. PM is the best way to contact me about it. Sorry I missed your post earlier; I haven't been keeping an eye on this thread...



Like I said before, your clutch may not be worn down, but instead glazed over. Plenty of clutch material may still be there, but at the friction interface the material is ruined by being smooth and glassy. The CDV can contribute to this because it favors slipping to "protect" the drivetrain, but ultimately it is how the car is driven that determines whether this will occur or not. It can easily get ruined in one driving session, especially with an inexperienced driver... I let my brother drive my car one time and there were a few shifts where I was absolutely cringing. Sometimes, especially since I am supercharged, once the clutch has started to slip it would not grab until you almost completely backed out if the throttle. My brother kept his foot into it a few times... Never doing that again...

I will agree that the CR-Z clutch is barely adequate even for a stock car though. I know I won't be going back to a stock clutch ever...

So to answer your question, yes, the CDV does potentially contribute to more wear since it, by design, allows more slip to reduce shock to the drivetrain. However, the CDV is not a moving part that can get stuck; it is simply a metal diaphragm that flexes under pressure. It's pretty much impossible for it to fail, unless there was so much water in your hydraulic system it caused it to corrode away. You have bigger problems if that were the case...

Anyways, a CDV delete will help prevent some of the excessive slipping from occurring and give you more of that 90's Honda clutch feel. It's not capable of miracles though... You can still ruin your clutch if you tried hard enough...
 

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CORRUPT
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So if the clutch is glazed over with plenty of material still left on it is it possible that driving it very easily and trying not to slip the clutch that eventually the glazed outside material would get worn off and leave me with a fresh clutch surface over time...? its been doing ok lately but I haven't gotten on it at all and have been very easy on it only driving less than 10 miles at a time. I have an hour and a half trip to make Saturday and I'm worried that after driving awhile and getting it hot it may start slipping again even on the highway.
Yes, I've heard of people claiming this is possible, but most of the time I think it just gets worse. The more surface area that is glazed, the harder it is to get rid of. Once it gets past a certain point, there will be no going back. The areas that are not glazed are doing more work and are more likely to become glazed themselves. Also, since you now have smooth surfaces sliding past each other, there isn't really anything other than clutch dust to wear away at it. Maybe if you had a "slotted" surface like some performance brake rotors have, you could wear past the glazed material, but then your clutch wouldn't last long anyways because the slots are always doing that, glazed or not. No one wants to drop the transmission any sooner than they have to, so that's why we don't see slots on clutches.

It doesn't sound like yours is too bad, so you could try to get by for a little while longer, but you should still start thinking about getting it done soon. I would try to avoid putting back in an OEM clutch if you are going to go through the effort of replacing it. Supposedly the 2013+ CR-Z clutches are a little better, so that may be an option, but an aftermarket clutch is going to bring your shifting experience to another level... However, this may also require Flashpro to deal with the CKP sensor false misfire issue...

HPD clutch from a Honda dealer might be an option too if you don't want to get a Flashpro. It's on them to fix it if that misfire issue comes up... It's not available yet so we'll see how that all shakes out...
 

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ya I have come to turns that sooner or later it will happen and I did start looking at clutches and I don't have any plans on going back to factory. I've seen a few online they seem to all be around $500 or at least the ones I was looking at. Its not a race car and in the past I've always just went with a small upgrade to stage 1. This CKP sensor you talk about is that the crankshaft position sensor your talking about? If not I have no idea what it is or how it effects the car but I'm already mad if your telling me an aftermarket clutch is not plug and play like most cars...
 

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Yes, the CKP is the crankshaft position sensor. Through the sensor, the ECU can determine if there is a misfire occurring. Sometimes the reduced mass of an aftermarket flywheel will create enough difference in the harmonics of the crankshaft, that it will cause the ECU to think a misfire has occured, even though one hasn't. There is a CKP relearn procedure, but I've had no luck with that. Hondata has a solution for this with the Flashpro, but Honda, now that they are offering upgraded clutch, might also have to deal with this issue with a factory ECU reflash. I suspect this very issue may have been what caused the delay in the HPD supercharger kit...
 

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CORRUPT
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The flywheel is part of the clutch. If you switch to any other clutch, you will get a flywheel with it. It doesn't matter what part the change in mass is in, if it isn't the same as stock it may cause an issue. It's not just about clutches; lighter weight pulley, lighter crankshaft, heavier rods/pistons and even a supercharger can all affect the signal that is output by the CKP sensor. It was very intermittent for me, so there may be no problem at all for some others. Mine only showed up when running the car hard for some time. I think there are some other CR-Zs with clutches done, but as far as I know, I'm the only one with this issue. I have lots of mods though... Being supercharged and having a clutch that's 4 lbs lighter, probably came together to just push me over the edge into mysterious CKP false misfire hell...

Anyways, this discussion is getting a bit off topic for this thread about CDV deletes, so it will have to be continued in a thread more specific to aftermarket clutches. NOT in my build thread either...
 

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I understand the flywheel is part of the clutch assembly however I find no reason to replace a perfectly good fly wheel when it can just be cheaply resurfaced and when I'm not looking to go that far into upgrades. most clutch kits normally just come with your clutch pressure plate throw out bearing and alignment tool. I've only replaced one of the flywheels in the 4 cars I upgraded with a new clutch kit and that was just because I wanted to go with a much lighter flywheel although even then I didn't seen a huge difference going from my stock 26lbs flywheel to an 8.5lbs flywheel probly just me tho. thanks for the info
 
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