Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review

BobbyA

Senior Member
First Name
Bobby
Joined
Nov 19, 2018
Threads
14
Messages
77
Reaction score
59
Location
Fredericksburg, VA
Vehicle(s)
2018 Civic Si Coupe (PRL Stage 1, Hondata FlashPro, PRL Flex Fuel e85, HardRace Rear Mount, Megan Racing Strut Bar) Wish List: PRL Catted Downpipe, Eibach Pro Springs Kit, Seibon Carbon Fiber Hood & Trunk.
Country flag
This is very informative, thank you for sharing & the pics. To confirm, you were able to do all the work through the top of the engine bay, hood open. You did not need to remove the bonnet and crawl up under?

Also, do you by chance have a Part Number for the Slave Cylinder?
Sponsored

 

tehSteve

GrayBeard McGootch
Joined
Sep 3, 2017
Threads
43
Messages
587
Reaction score
375
Location
NJ
Vehicle(s)
Si
Country flag
This is very informative, thank you for sharing & the pics. To confirm, you were able to do all the work through the top of the engine bay, hood open. You did not need to remove the bonnet and crawl up under?

Also, do you by chance have a Part Number for the Slave Cylinder?
It's faster and more convenient to do it under the car. For the removal, installation, and bleeding parts.
Do yourself a favor and also install the PRL SS line at the same time.
 

blinkz0rz

Senior Member
First Name
Jrod
Joined
Sep 18, 2018
Threads
4
Messages
164
Reaction score
105
Location
Chicagoland
Vehicle(s)
2018 FC1 Civic Si, 1997 Dodge Dakota, 1972 Plymouth Roadrunner 440, 2010 JKU Jeep Wrangler
Vehicle Showcase
2
Country flag
Well I took a slightly different route to remove the c-clip holding the cap down. As you can see I put a cut in the side so I could get a better angle to lift the clip up, but still kept the crevice intact. Removal took about 5mins total to pry the clip out and pull the cap off.

I talked to the mechanical engineer at work about the slave and his idea was to cut it. We agreed that the cut should not inflict any additional movement so the clip could pop out. (If it does, oh well, I bought this as second slave so I could do the delete anyways.)

View attachment 127147

Honda Civic 10th gen Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review 20181211_103715


Honda Civic 10th gen Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review 20181211_103741


Honda Civic 10th gen Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review 20181211_103702


Honda Civic 10th gen Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review 20181211_104212
 

Attachments

  • 0 bytes Views: 0

blinkz0rz

Senior Member
First Name
Jrod
Joined
Sep 18, 2018
Threads
4
Messages
164
Reaction score
105
Location
Chicagoland
Vehicle(s)
2018 FC1 Civic Si, 1997 Dodge Dakota, 1972 Plymouth Roadrunner 440, 2010 JKU Jeep Wrangler
Vehicle Showcase
2
Country flag
I finally got around to installing the PRL Cobra, SS line, and CDV delete.

First impression is amazing, this (in my opinion) is how a clutch should feel. My car is factory stock with no Ktuner, just the CAI and clutch slave improvement.
 

absolude

Senior Member
Joined
Dec 18, 2017
Threads
9
Messages
368
Reaction score
96
Location
GTA
Vehicle(s)
KW SC 2007 CSX Type S, 2023 PWP Si
Country flag
Thanks for replying.

Did it anyways. Probably in a week I'll think differently but for now I'm not liking it.

It's nice when starting in first and in relaxed driving when short shifting.
In spirited driving now the clutch responds quickly now but the 1.000lb. flywheel takes its time and now is my responsibility to wait and time the clutch release. With the valve in place the clutch release was better suited to the flywheel, I feel. Now I'm waiting for revs to go down and it seems like an eternity, especially compared with my other car where they drop in less than an instant.

The way I see it now this mod is better done at the same time when replacing the flywheel for a lighter one. This car badly needs a light flywheel.

Things may be different for the Si, not sure if we share the flywheel.

Thinking to order a new or buy a slightly used one that wasn't modified yet and keep mine for later.
Have the KTuner.
Checked the Rev hang delete(hope that's how it works) and the revs don't seem to hang anymore but they just drop painfully slow.
OK, quoting my own post here.

I have to go back to what I said.
It is NOT true the revs are going down slowly. Because I'm aware of the increased drivetrain shock caused by this deletion, I was trying to be too precise with my shifts.
I was looking at the needle and tried using that for rev matching. Only when I couldn't do it, I realized the needle is far from accurate and in reality the revs drop very fast. They are "right there" for spirited driving, though.

So, I was wrong, the revs are not going down slowly. In fact they seem to drop a bit faster comparing to my 8th.gen Si, that also has the delete done.
On that car I can actually smooth it out a little but on the 10th.gen the engagement is quite brutal. One has to get it right.
Now I understand why my tuner is pretty firm against this mod.
 


BoostedDreams

Senior Member
First Name
Heisenburg
Joined
Apr 15, 2018
Threads
95
Messages
1,990
Reaction score
1,216
Location
South East Florida
Vehicle(s)
2019 Type R, 2006 Mazda 6
Country flag
Good afternoon CivicX. Decided to do another write up on my latest modifications I thought I should share incase you haven't came across this very neat mod... I've done some research in the past and came up an article regarding the clutch delay valve (CDV) inside the slave cylinder and the positive outcome and results from deleting the valve. I've stumbled across several articles regarding the CDV delete anywhere from Bimmers to Honda's. Interestingly enough, I noticed @PRL Motorsports created a write up and did the CDV delete to their 10th gen Si as well... Now I personally haven't had any issues regarding clutch slippage during normal operation but when I'm WOT and shift in the upper RPM's its very noticeable the clutch slips briefly as I'm switching gears and causes a delay when shifting. I thought it was because of Rev Hang mixed with a weak OEM clutch (Although I still find the OEM Clutch to still be on the weaker end) and I just left it at that. I eventually found out the reason to the brief slippage is because there is a valve inside the slave cylinder the slows down the flow of the clutch fluid, therefore causing the clutch to slow down during engagement after shifting gears. Removing the valve allows the fluid to flow quicker, allowing the clutch to engage at a higher pressure. In other words, the clutch has a stronger bite and RPMs drop immediately when shifting gears like how a transmission is supposed to. Pretty much the point of having the CDV is for novice drivers who don't have experience driving manual gearboxes and really dumbs down the operation of the transmission.

To quote PRL:

"What does removing the CDV do? The engineers at Honda has been putting a CDV system on many of the recent platforms to reduce drivetrain shock. The CDV allows the clutch system to simulate "slip" in an attempt to save the transmission/drivetrain. However, for racers and enthusiasts looking for more of a raw driving experience in his or her car this can be annoying. Removing the CDV greatly improves clutch engagement which in turn improves 60fts and shift times. The other cool thing is this mod costs $0 aside from a new bottle of clutch fluid needed to bleed the clutch system. :thumbsup:"

"The CDV is located in the slave cylinder which is attached on the front of the transmission. The slave sylinder can be removed by taking out the two 12mm bolts holding it on. Next you will need a 14mm and 10mm wrench to remove the clutch line from the slave cylinder. Now the slave cylinder assembly should be able to be completely removed."

---------------------------------

After deleting the CDV, it made a world of a difference! It honestly feels like I have a whole new clutch inside the car, almost making it feel like I have a Stage 1 clutch...That noticeable of a difference. :yes: The Clutch bites instantly with no slips during normal driving and aggressive high RPM operation MUCH better and RPM's drop between gears and shifting motion became much more fluid and natural. Best part is, it cost me $0. Only thing I bought was a bottle of brake fluid to top of the reservoir during the clutch bleeding process.

I figured it only made sense that since I was taking apart the slave cylinder and having to bleed the clutch afterwards, I should buy PRL's Stainless Steel Braided Clutch line in the process and kill 2 birds with 1 stone. ;) With the combination of the CDV Delete and the PRL SS line I have nothing but good to say about this mod. You can tell the difference even with the foot. The clutch feels more stronger and firm when pressing & depressing the pedal, how it should have felt out of the factory. :doh:

Here is the link to PRL's thread for more information: https://www.civicx.com/threads/10th-gen-civic-1-5t-clutch-delay-valve-removal.13105/

Link to PRL's Stainless Steel Clutch line, only cost about $42 after shipping. : http://prlmotorsports.com/2016civic15tstainlesssteelbraidedclutchline.aspx#.WpdJT-jwaUk

Here are some pictures with captions for reference purposes, enjoy!

First and Foremost, I highly recommend a set of scribe/picking tools like this one. There is a "C" locking ring that locks a metal cap that is a bitch and a half to take off. Luckily for me, it only took about 10-15 minutes to wiggle it out. Once you take it off, you can use a set of needle nose pliers preferably with grip teeth and pull off the metal cap. Once you take it off you will see the white CDV valve in the inside (See pics below). You can use the same tools you used to take off the "C" locking ring to take off the valve and then throw the valve away!

20180228_181609.jpg

Here is where the Slave Cylinder is. Its attached in front of the transmission. All it takes is a 12mm socket with a ratchet to remove the slave cylinder off the tranny and a 10mm wrench to remove the clutch line off the slave cylinder.
20180228_181726.jpg

How it looks after removal of the SC. I put a ziploc bag so it can catch the clutch fluid coming off the line.
20180225_100434.jpg

Picture of the Slave Cylinder out of the Vehicle. On the left side of the SC is where the metal cap and locking ring is located. I completly forgot to take a picture of how it looks but its self explanatory once you take off the SC and see it for yourself! This is also when you use the picking tools and pick out the locking ring.
20180225_100501.jpg


20180225_100543.jpg

This is how it looks once you take off the C locking ring and the metal cap on the other end of the slave cylinder. This is the Clutch Delay Valve inside the SC
20180225_100518.jpg

This is the C locking ring and the Metal cap that needs to be removed. This is to be installed back exactly how it was, once you remove the clutch delay valve inside.
20180225_100536.jpg

This is the Clutch Delay Valve the needs to be removed and thrown away.
20180225_100704.jpg

This is how the inside of the SC looks once you take off the Clutch Delay Valve
20180225_100725.jpg

PRL Stainless Steel Clutch line Installed
20180228_164705.jpg

Zoomed in shot of the Clutch Line
20180228_164717.jpg
Props to you for doing this. After reading your thread I decided to tackle this, even ordering the same tools you have.
Well, I managed to remove the Slave Cylinder, but literally spent a good hour trying to get that "c ring" out and couldn't. Ended up stabbing myself a few times too. I was only able to manage pushing it in a circle. Frustrated as hell, I gave up, and installed everything back. I doubt I'll be trying this again. Would love to know what your technique in getting it out was.
I will probably just pay someone to do it. I also had a bitch of a time getting the 12mm bolts back in. I could get 1 in, but it was so hard to align the second one, with the hard line and clutch push rod attached.
On a side note, you do need a 15 or 16mm open end wrench to hold in place the nut in order to remove the 10mm clutch line. It took me a few minutes to realize this.
But yeah, I wasted 3 hours, Im exhausted, and all scratched to hell for nothing.
 

THATSi

Senior Member
First Name
Nick
Joined
Jul 22, 2018
Threads
8
Messages
173
Reaction score
60
Location
Orlando FL
Vehicle(s)
17 Civic Si
Country flag
This is gonna sound dumb but as no one has ever seemed to cover this part talking about all this but I got a ?. When I had my clutch done and the line and did the CDV delete I bought a 2nd slave and had shop delete the CDV in it and install it. Well now that bitch is leaking some 20k miles later. So I'm sitting here and I'm looking at putting the old slave back on and I see the BMC, am I to assume the CMC and reservoir to bleed it is under the battery?
 

THATSi

Senior Member
First Name
Nick
Joined
Jul 22, 2018
Threads
8
Messages
173
Reaction score
60
Location
Orlando FL
Vehicle(s)
17 Civic Si
Country flag
This is gonna sound dumb but as no one has ever seemed to cover this part talking about all this but I got a ?. When I had my clutch done and the line and did the CDV delete I bought a 2nd slave and had shop delete the CDV in it and install it. Well now that bitch is leaking some 20k miles later. So I'm sitting here and I'm looking at putting the old slave back on and I see the BMC, am I to assume the CMC and reservoir to bleed it is under the battery?
To answer my own question it's fed off the brake MC, which is about to stupid for reasons I won't get into, no need to remove the battery looking for it like I did
 

blinkz0rz

Senior Member
First Name
Jrod
Joined
Sep 18, 2018
Threads
4
Messages
164
Reaction score
105
Location
Chicagoland
Vehicle(s)
2018 FC1 Civic Si, 1997 Dodge Dakota, 1972 Plymouth Roadrunner 440, 2010 JKU Jeep Wrangler
Vehicle Showcase
2
Country flag
To answer my own question it's fed off the brake MC, which is about to stupid for reasons I won't get into, no need to remove the battery looking for it like I did
So exactly where is it leaking, the Slave side or a line coming from the MC?
 

THATSi

Senior Member
First Name
Nick
Joined
Jul 22, 2018
Threads
8
Messages
173
Reaction score
60
Location
Orlando FL
Vehicle(s)
17 Civic Si
Country flag
So exactly where is it leaking, the Slave side or a line coming from the MC?
It leaked at the slave, oddly enough from the rod end, not the end where the cap and o-ring were removed to delete the cdv, maybe just got a defective one from Honda, either way problem solved and I didn't bother to remove the cdv from my original slave I put back on and for daily driving I like it better with the cdv there in the ss clutch line. I'm 36 and learned to drive on a stick, it's firm and smooth but forgiving. If all I ever did was track the car I would want it gone. Worth having a back up with cdv delete to pop on when you do goto the track, they're fairly inexpensive
 


BogdanM

Senior Member
First Name
Bogdan
Joined
May 28, 2018
Threads
0
Messages
196
Reaction score
107
Location
Romania
Vehicle(s)
2018 Civic Sport Plus 1.5 MT
Vehicle Showcase
1
Country flag
Just a thought regarding the shocks that will end up into the drivetrain after this mod: the first one affected will not be the transmission but the dual mass flywheel. At first the flywheel will dampen all the shocks and as it does this it wear itself out quicker than in stock form. I don't know the price of a dual mass flywheel in US but in EU they are quite expensive.
 

LilToTo17

Senior Member
First Name
Kevin
Joined
Jul 14, 2017
Threads
71
Messages
3,162
Reaction score
1,441
Location
Santa Rosa, CA
Website
wheelwell.com
Vehicle(s)
98 Civic EX with SI Conversion-Sold, 2017 Civic Si Sedan
Vehicle Showcase
1
Country flag
Just a thought regarding the shocks that will end up into the drivetrain after this mod: the first one affected will not be the transmission but the dual mass flywheel. At first the flywheel will dampen all the shocks and as it does this it wear itself out quicker than in stock form. I don't know the price of a dual mass flywheel in US but in EU they are quite expensive.
Should opt to get Emans or @k20z3allmotor custom CMC (Clutch Master Cylinder) where the cdv is still intact and you don't have to worry about extra stress on the drivetrain. Fixes gear lockout issues and can shift as intended to quickly. Therefore you don't mess with the slave and all is good.
 

absolude

Senior Member
Joined
Dec 18, 2017
Threads
9
Messages
368
Reaction score
96
Location
GTA
Vehicle(s)
KW SC 2007 CSX Type S, 2023 PWP Si
Country flag
I was going to reverse this mod and go back to a new, unmodified SMC and then I had this thought. Please correct me if I'm wrong.
I was thinking, since the car comes stock with rev hang, the delay valve will slow down the clutch engagement, giving time for the revs to drop.
On a tuned car, with no rev hang I'm afraid the delay will make impossible for a smooth engagement because the revs will always have the time to drop too much.
Is this a possible scenario for a tuned car with no rev hang?
 

BoostedDreams

Senior Member
First Name
Heisenburg
Joined
Apr 15, 2018
Threads
95
Messages
1,990
Reaction score
1,216
Location
South East Florida
Vehicle(s)
2019 Type R, 2006 Mazda 6
Country flag
I was going to reverse this mod and go back to a new, unmodified SMC and then I had this thought. Please correct me if I'm wrong.
I was thinking, since the car comes stock with rev hang, the delay valve will slow down the clutch engagement, giving time for the revs to drop.
On a tuned car, with no rev hang I'm afraid the delay will make impossible for a smooth engagement because the revs will always have the time to drop too much.
Is this a possible scenario for a tuned car with no rev hang?
The drop isn’t THAT drastic so you’ll still benefit. I have a stock SMC for sale if you want to give it a shot and remove the delay valve. $60 shipped
Ps you could always turn cruise on and it enables rev hang again (if you have ktuner)
 
Last edited:

whiteSIR

Member
First Name
John
Joined
Jul 5, 2019
Threads
3
Messages
25
Reaction score
8
Location
Vancouver
Vehicle(s)
2019 Civic Si Sedan
Country flag
Did the mod today but I realized I put the nut on backwards on the slave master (the nut you remove after the C ring with nose pliers). You guys think there is going to be an issue with this if I leave as is?
Sponsored

 


 


Top