Which Idle Valve?

[madspikes 41 1 Cars]

I'm guessing anything 'modern' will use flyby-wire throttle, so dont require an idle valve! So a nice helpful person suggested I do this, you know who you are! A home made flyby-wire throttle scares the living-day-lights out of me!

 

The VW G40 and G60s use a bosch 4-wire valve which looks very much like the 2 wire, but is a stepper motor controlled item. I even linked to a picture of one earlier in the thread.

Edited November 22, 2009 by madspikes

[petert 549]

It's taken a lot longer than I thought, and thanks to my son, here are some settings that worked for me. I'll probably tweak it a bit more once the engine is run in. Can't risk glazing up the bores.

[madspikes 41 1 Cars]

This is the temp measure I have come up with to deal with the idle valve problem!!!

 

 

Now let me explain...

 

Yes, I looks a mess, but its a development system. Once I know the size of the 'throttle', generated by the isolation valve I can made the system proper, and make some proper pipes and things up.

 

I have used a two wire bosch valve which I have tweaked so that when no voltage is applied, the valve is closed. The valve is currently connect to a switch, so its just fully open or closed. The valve outlet is connected to the inlet manifold via a standard plumbing type isolation valve. Using the isolation valve is the cleaver bit.... I can use this valve to adjust the maximum amount of air required to get the cold idle correct, or if the idea fails I can just close the valve, isolating the system. If I get time, and this works, I will try and get the system working in PWM mode to try and get a auto adjusting idle! The other option is if it works is to use the MS to do the switching, on and off.

 

Currently the flick of the switch adds 400rpm on warm idle, but there is plenty scope of adjustment either way!

 

 

Yes, I know the idle valve is the wrong way around, but works fine for what I want to do, all previous attempts at using this valve were with it the other way around.

 

 

Mad.

Edited November 23, 2009 by madspikes

[Tom Fenton 1,524]

Do you have to wear a cowboy hat and shout YEE HAR! when adjusting this?! LOL. Only joking, I know what an arse that valve is. I've had another idea which I'll reveal when I've tried it!

[madspikes 41 1 Cars]

Why would I wear a coyboy hat when plumbing.... However I do pull my trousers half way down over my arse... I and charge myself £80 just to look at it, the plumbing not my arse!

 

No offence to any plumbers out there....

 

Yes its a bodge and not up to Mr Fentons engineering standards, and to behonest not up to mine....but it sort of works. Time and money dont allow for a better test setup. Already from this I know that a 8mm diameter 'throttle' is too big! This setup give me seperate adjustable 'warm' and 'cold' idle, which for the moment will do.

 

After a proper run this morning.... turning the valve on gives a warm idle of 1800rpm and turning it off gives 1400rpm. Pre this valve warm idle was 1100rpm.... I even screwed the idle screw in more when I put this valve setup on! With the valve on, cold idle is spot on for a few minutes!

 

My response.... This idle valve is pants, bring on the stepper motor!

 

 

I've had another idea which I'll reveal when I've tried it!

- A hand opreated cable that attaches to the throttle to open it a little on cold mornings... Thats my other idea!!! Not really. Tom i'm really intrested in your new idea.

 

 

 

Mad.

Edited November 24, 2009 by madspikes

[cyman 1 1 Cars]

This is what i'm using with my s/c.

[madspikes 41 1 Cars]

Looks interesting, whats that from?

 

I've acquired a stepper motor valve thing from a 106 / 306 just need to build a housing and control circuit! Should be done by July!

 

 

Mad.