SiriMoto N1 Clutch Master Cylinder Review, With ACT HC10-HDSS Clutch

JT Si

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I'm starting this thread specifically to make available information about the SiriMoto N1 and ACT clutch kit, and my struggle with the combination.

I'm going to make this as simple as possible - As of this post, I would not recommend a SiriMoto N1 if you will use an ACT clutch kit. There is a high probability it will not work out of the box.

I have been in touch with ProCivic and it sounds like they are interested in updating the design of the N1 to accommodate the ACT clutch kit with its apparently unique adjustment requirements. I'll update this post as things change.


First, a story:

The design of the N1 pushrod is 8mm longer, and thus moves the clutch adjustment range from the OEM range out 8mm. This is important for the ACT clutch kit, and potentially Type R retrofit kits as well.

The taller diaphragm spring of the ACT clutch kit requires adjustment of the pedal to be much lower than OEM. This was easily possible with the OEM master cylinder, however the N1's longer pushrod meant I had adjusted the pedal all the way down until it butted up against the end of the pushrod and it still wasn't low enough.

At this position, the ACT clutch kit was still beginning to re-clamp the pressure plate via overextension. Not good.

After contacting ProCivic, I was suggested to install a bump stop on the floor to prevent the pedal from extending all the way. I refused to do this as the adjustment I still needed was in the range of 1/2-1" and a taller bump stop would have prevented the clutch position switch from allowing the car to start.

I swapped the OEM pushrod onto the N1, which did not fit very well. The ball end of the pushrod is a different depth and radius, and the OEM pushrod applies some tension onto the piston in the N1.

With this swap, I was able to adjust the pedal to the appropriate place only to find the pedal cannot lift high enough for the clutch stroke sensor to allow cruise control to activate (It thinks I'm riding the clutch). The unfortunate part is, I think the ball of the OEM pushrod tensioning the piston is probably why. If the pedal could come up literally 1-2mm, it would be enough to trigger the sensor.

At this point, I do not have a concrete course of action besides take a hacksaw to the N1 pushrod to shorten it or go buy a kzCMC from Eman, but those are sold out currently anyway.
I'll be working with ProCivic to get the N1 functioning correctly with my ACT clutch kit.


Second, observations about the N1:

Pros

1) The N1 has some quality hardware that comes with it, including a braided stainless steel line.
2) After disassembling the N1 to swap the pushrod, I have seen that specific parts are higher quality than OEM such as the piston and the pushrod
3) The N1 appears to have solved any gear lockout issues I had with the OEM master cylinder
4) The N1 is relatively inexpensive given it also comes with a new clutch line
5) The N1 is readily available

Cons
1) The deviation from the OEM adjustment range is disappointing and unwarranted. There is no reason to allow adjustment of the pedal to be higher than OEM, especially by 8mm! (This would translate to multiple inches at the foot pad of the pedal)
2) The internal spring is thinner and longer, which means the piston is fully retracted allowing for no free-play of the pushrod. This concerns me for the throwout bearing, and also I suspect is one reason for #3
3) The feel and feedback of the N1 is pretty much nonexistent. The pedal is less firm than OEM was, the engagement point doesn't provide much feedback through the pedal
4) The new clevis is shorter (maybe because they lengthened the rod?) and the new retaining clip isn't a safety clip like the OEM. I reused the OEM clevis and clip because it cannot come off by itself
5) The N1 uses a retaining wire clip instead of a snap ring like OEM, which made it a gigantic pain in the ass to swap the pushrods.
6) The N1 had no grease of any kind, anywhere. The OEM master cylinder had the ball end of the pushrod greased, which the N1 should have had at minimum.
7) Loss of cruise control sucks.

If the design of the N1's pushrod is modified to bring its length and adjustment range in line with OEM, I would have no problem recommending it despite its other shortcomings - It's inexpensive for what it is, and it still does appear to have fixed my gear lockout. I think a little more redesign of the N1 could make it excellent including a stiffer, shorter internal spring allowing for the OEM spec of free play, greasing the pushrod during assembly, and swapping that wire clip for a real snap ring.

@LilToTo17 feel free to leave as many I-told-you-so's as you see fit.

Edit: Upon further inspection of my OEM master cylinder, the lack of free play is due to the collar on the pushrod not holding the piston spaced away from the pushrod when the clutch is fully engaged and the pedal is up. a curious design choice but probably not the problem I thought it was. This does affect how adjusting the clutch pedal would be done, changing from the service manual procedure which expected the OEM spec of free play. At this point I'm not sure a spring change would improve anything.



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Veradian

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When I installed this CMC, I had a similar issue with the cruise control, fortunately it went away after a few days and cruise control is working as intended again. Hopefully the same will happen in your case?
 
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JT Si

JT Si

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When I installed this CMC, I had a similar issue with the cruise control, fortunately it went away after a few days and cruise control is working as intended again. Hopefully the same will happen in your case?
What clutch are you using it with?
 

Veradian

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What clutch are you using it with?
I'm using the FX350 w/ SMF

I'm sure it has something to do with our differing experiences, but I'm having a totally different experience than you...
 
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JT Si

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I'm using the FX350 w/ SMF

I'm sure it has something to do with our differing experiences, but I'm having a totally different experience than you...
It's probably the massive diaphragm spring on the ACT pressure plate.
 

Veradian

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Any more updates? What did you and ProCivic wind up doing?
 
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JT Si

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Any more updates? What did you and ProCivic wind up doing?
I'm running the N1 with the pushrod swap from the OEM master cylinder while they re-design the N1. They are keeping me updated so once they have a new version I can try it and make sure it works with my ACT clutch.

It's been working alright, some weird vibrations under specific scenarios but that might just be my bad routing of the new clutch line causing it to shift and pick up vibrations. I won't have much else to report until I get a new version and am able to install it.

In the meantime, I am still seeing soft lockouts occasionally but it's rarely when I'm hard on it WOT. Something about moderate throttle running up to a moderate RPM (50-60% throttle running up to something like 4500) seems to trigger it still.
 
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LilToTo17

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I'm running the N1 with the pushrod swap from the OEM master cylinder while they re-design the N1. They are keeping me updated so once they have a new version I can try it and make sure it works with my ACT clutch.

It's been working alright, some weird vibrations under specific scenarios but that might just be my bad routing of the new clutch line causing it to shift and pick up vibrations. I won't have much else to report until I get a new version and am able to install it.

In the meantime, I am still seeing soft lockouts occasionally but it's rarely when I'm hard on it WOT. Something about moderate throttle running up to a moderate RPM (50-60% throttle running up to something like 4500) seems to trigger it still.
Or just get Eman CMC and have 0 issues
 
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JT Si

JT Si

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Why did you upgrade from the oem cmc?
https://www.civicx.com/threads/some...clutch-help-me-hypothesize.46497/#post-764969

Something went wrong with the OEM clutch hydraulic system. I assumed it was the master cylinder. I had bought the N1 to swap it in eventually so I took this occurrence as a reason to do the swap.

Or just get Eman CMC and have 0 issues
If it comes to that, it comes to that. They are making an effort to update the N1 to work with the ACT clutch. In the meantime even with its handicaps the N1 is functioning better than the OEM master cylinder was. Why should I hurry to spend $260 on the kzCMC if I don't need to?
 

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https://www.civicx.com/threads/some...clutch-help-me-hypothesize.46497/#post-764969

Something went wrong with the OEM clutch hydraulic system. I assumed it was the master cylinder. I had bought the N1 to swap it in eventually so I took this occurrence as a reason to do the swap.



If it comes to that, it comes to that. They are making an effort to update the N1 to work with the ACT clutch. In the meantime even with its handicaps the N1 is functioning better than the OEM master cylinder was. Why should I hurry to spend $260 on the kzCMC if I don't need to?
I mean spend the $$$ and have 0 issues or need to have it upgraded again lol. I mean the fact that it wasn't good enough the first time should tell you something.
 

                           

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