http://forums.vwvortex.com/zerothread?id=1112547 anyone read this.............anyone tried it?? whats your thoughts?? Edited by: Trev16v
Interesting. I'm reading that Charles O. Probst book he mentions myself at the moment, which can be bought from Amazon.co.uk.
Interesting idea. I am also interested in what I heard to be a good mod for 8v's. Taking an Audi 5cyl or Gti 16v WUR and replacing the 8v model. I heard this is good for better fuel flow. I am also interested in what Vince does at Stealth with his WUR mod on 16v's
Didn't read it all, but the idea seems to be an alternative workaround for the fact that the 8v WUR is crap when the engine is under load. By the sounds of it, he's trading off engine temperature variability sensing for better supply under load. A decent idea, but nowhere near as satisfactory as the solution that VW came up with when they built the 16v engine. i.e. to have a vacuum feed on the WUR to increase fuel supply under very high load. Personally (although I've not had the experience) I would choose the now pretty standard 16v WUR replacement instead, as you don't forfit the temperature variability change. Comments? p.s. AFAIK at steath they drill through the tamper proof casing on the back of the 16v wur to turn the pressure up (down?) a bit to further increase fuel supply under load.
Sounds like a bit of a bodge to me. Keeping the WUR cold is like running with the choke on all the time, he was prolly running too lean before, but moving the WUR would then richen out the mixture to compensate, prolly hasn't fixed the initial problem. Prolly also worth bearing in mind that US spec CIS systems have lambda feedback that (assuming it's working in this case) would keep the mixture at 14:1 under most condtions anyway (except WOT). I like the idea of having th WUR and hence the control presure manually ajustable, more things to tweak I suppose, but it might help me fix my WUR problems.
Lambda controled K Jet (KE) does not have a WUR as cold running enrichment is adjusted using the same control pressure actuator (sometimes called differential pressure valve) as is used to control air/fuel ratio when warm. GTi is right that by "fooling" the WUR, either by cutting the heater feed, moving it or adjusting the lower spring stop (which I believe is what Stealth do) you are trading off increased fuel flow for the loss of cold running quality.
Lambda controlled K-Jet is just that, K-Jet w/Lambda, not KE-Jet. K-Jet w/Lambda uses a so called Frequency valve that sits on the side of the fuel distributor. The WUR is used on this setup as well. KE-Jet uses, as you correctly states, the Differential Pressure Regulator, and no WUR.
Golden, my car has had the Stealth WUR mod since last July - It starts and idles on the button hot and cold, no 'over rich' hunting what so ever
What p1sses me off is when someone corrects you for no other reason than to try and score points. K Lambda was never available in this country; my point was that any lambda controlled car in THIS COUNTRY would not have a WUR. Why dont you try and be helpful instead of going on some ego trip? I often simplify what I write on this website so that less qualified people can understand it. I try to be helpful and wouldnt be able to if I had to write down everything I post to be technically 100% accurate, I know what K lambda is, what KE is, what KE Motronic and what KE3 is. If you want to get really anal mentioning K Lambda with its influence on cold start is rubbish as closed loop doesnt work until normal operating temperature. Gary, I wouldnt expect a car thats had the WUR mod to overfuel as what has effectively happened is the change in mixture ratio between cold and hot has been reduced, if anything it would be slightly weaker when cold than before.
Are you saying that the tamper proof adjustment only affects the way the WUR acts due to temperature? My previous belief (completely uneducated!) was that it would affect the way it acts due to vacuum[/I}, therefore making it possible that the WUR mod's effect will be regardless of temperature. ????
Agreed,most/all? closed loop systems works the same way You're more than likely right G - I was only pointing out that the car doesn't behave any differently to how it did before Edited by: G_V_K
No you understood correctly. The way it works is to lower the control line pressure allowing the airflow sensor plate to move higher for a given load increasing the fueling. This is what it does when cold to give you a richer cold mixture. What I'm saying is that by making the WUR adjustment the difference bewteen cold and hot control pressure is reduced, so once the mixture is set up correctly for hot running, the mixture may no longer be rich enough when cold.
of course! the adjustment is the base line, so the level of effect caused by either vacuum or temperature will stay the same; causing the behavoir you describe.
so........................ive got a audi5cyl. WUR on my 2l mk1.......with vacuum pipe et al. its not worth putting it in a cold place then??
Hope you don't mind me butting in but...i have K-star on my Mk1 and I believe this works in a very different way to K-jet. Does this mean that the 16v WUR mod would be a waste of time?
You Brits might not know this yet, but the world isn't Anglo-centric anymore, so what you post on an international site like this or the Vortex gots to be correct, unless you want to confuse a lot of people not living on a small island in the Atlantic. BTW, I assume you folks never got the Golf/Jetta Syncro with the GX engine ? This is not correct. True enough, closed loop doesn't apply for the first few minutes (especially with a non heated OXS), but the warm up mode of a K-Jet Lambda system still differs from that of a basic K-Jet: During startup and initial warmup, the Lambda Control box gets a signal from the thermo switch on the underside of the water flange on the front of the head. As long as this switch is closed, the control box makes the Frequence Valve operate with a duty cycle of 80%, creating a rich mixture. When the switch opens, the duty cycle drops to a steady 50%. Then, after a few minutes, when the OXS has reached operating temp and the system is in closed loop, it will fluctuate around 50% to keep the mixture at lambda. Edited by: espen w
Yep, we sue did get both Golf and Jetta Syncros, not sure on the GX engine bit as don't know my codes, but if that translates as 1.8 Carb then thats the one we got in both body shells.
I am not prepared to get drawn into a protracted argument with you over this. Although Im sure the guys who run this website would be the first to tell you, everyone is welcome on this site, but it is primarily for Club GTI members as its funded by their subscriptions and run by hard working club members. So youll forgive me if my loyalties lie with fellow UK members and not the rest of the world. Secondly you have yet again just been picky rather than taking a genuine interest in the thread subject matter. We are discussing the potential effects of WUR modification on cold start and cold running. I could spend hours on this site correcting people but I dont see the point unless its a matter of safety or wildly inaccurate. Maybe you could try and post positive suggestions and information rather than getting into a p1ssing contest with me, which you will loose, if only for the fact that whether you like it or not this is a UK site. Youve already proved your ignorance, as we did get the GX engine here without Lambda control.
