Clutch delay valve?

[NJ Drive]

Just wondering if there is one on the Yaris.

[CTScott]

No. The Yaris has a very basic clutch master cylinder. On the Toyota models that do have it, it is called the Clutch Orifice Valve, and it is mounted to the firewall.

[NJ Drive]

Thanks Scott. Most of the CDVs that I am used to are in the slave cylinder FWIW.

[bronsin]

Never heard of a CDV. What is it?

[ilikerice]

If you have to ask, you will never know

[tooter]

Originally Posted by bronsin

Never heard of a CDV. What is it?

Hey bronsin,

I didn't know either and found this on Wikipedia.

"A clutch delay valve is an automotive component added to the clutch system of an automobile to standardize clutch engagement speed. Its purpose is to engage the drive train of an automobile without introducing shock to the drive train components by engaging too quickly. By preventing drive train shock, CDVs also prevent an automobile's balance from being upset, which aids in handling characteristics.

Clutch delay valves operate on the principle that engagement only needs to occur at a certain rate to be efficient and that engaging at a quicker rate can damage the drive train components of an automobile. Engaging the drive train to the engine too quickly can damage drive train parts, including the transmission, differential half shafts, axles, and CV joints.

Engaging the drive train too slowly can damage the clutch friction disc and cause clutch slippage.

Clutch delay valves operate as one-way restrictor valves that limit the volume of fluid that can move through the lines in a given time. This ensures a steady quick and firm engagement without being too fast for the drive train to handle since clutches can quickly disengage but re-engagement is damped. The clutch delay valve slows clutch engagement and was intended to reduce drivetrain shock in the event that an inexperienced driver quickly engaged the clutch at higher revs."

Greg

[Absolutely Red 12]

Originally Posted by ilikerice

If you have to ask, you will never know

Im guessing you didnt know either!!

[bronsin]

Hmm nothing I need on my car. Sounds like its meant to help those who go through clutches way too fast?

Another thing to go wrong and cause trouble.

For me.

[NJ Drive]

The reason I brought this up is because clutch engagement on my car varies, a lot. Sometimes it is a quick grab and go, other times it feels like there is at least twice the pedal travel until there is a clampload. I can almost swear something is altering the travel. This is occurring during brisk takeoffs, not drag racing. I will attempt a bleed to see if that helps at all.

[ilikerice]

Originally Posted by Absolutely Red 12

Im guessing you didnt know either!!

True

[bronsin]

Originally Posted by NJ Drive

The reason I brought this up is because clutch engagement on my car varies, a lot. Sometimes it is a quick grab and go, other times it feels like there is at least twice the pedal travel until there is a clampload. I can almost swear something is altering the travel. This is occurring during brisk takeoffs, not drag racing. I will attempt a bleed to see if that helps at all.

If it helps with the problem please post it here so others with the same problem can get the benefit.

When I had a clutch car I bled the clutch slave once a year to prevent this sort of thing also to get fresh fluid near the seals to keep them from leaking. If the slave leaks you arent driving the car...

[bronsin]

It may also be the poor transition from idle to low speed these drive by wire cars have. My ECHO with cable actuated throttle had much better drivability.

[scioncrew]

Tilton makes a flow control valve but its not cheep. Jegs has it for $160.00. here is the link for tilton
http://www.tiltonracing.com/sites/de...l%20Valves.pdf

here is the valve on Jegs web site
http://www.jegs.com/webapp/wcs/store...+control+valve

in my opinion i don't think this is a good idea on a street car. but i could be wronger.

[tooter]

Originally Posted by bronsin

It may also be the poor transition from idle to low speed these drive by wire cars have. My ECHO with cable actuated throttle had much better drivability.

Running a 1ZZ throttle body totally eliminated that issue.

Because the butterfly is 9mm larger in diameter, it creates the effect of opening faster with the same amount of drive by wire gas pedal input. Feels just like a cable throttle.

[bronsin]

Do you have a link to an install proceedure?

Its not an issue for me because I have an automatic and have adpated to it. But others with manuals may want to try it.

[yaris2010RS]

Originally Posted by tooter

Running a 1ZZ throttle body totally eliminated that issue.

Because the butterfly is 9mm larger in diameter, it creates the effect of opening faster with the same amount of drive by wire gas pedal input. Feels just like a cable throttle.

^ Y HAS NO ONE ELSE EVER SAID THIS?

Does anyone else have an input on this? So all i have to do is switch to the 1ZZ TB and my gas lag feels to be gone? is it a Plug and play or dies the TB require modification?

[WeeYari]

Originally Posted by yaris2010RS

So all i have to do is switch to the 1ZZ TB and my gas lag feels to be gone? is it a Plug and play or dies the TB require modification?

Refer to tooter's Manifold Adventure thread. The last entries deal with his trials and tribulations regarding the 1ZZ TB.