Some of you might remember i had a play with couple of wur-s on my 9a 16v and difference between two is about 10bhp and 15ft torque (run them on rollers at inters), my qstn is how dows it affect fueling? does increased preasure mean more fuel and power or other way round? By the way i took em apart as well and there is no hiden screw whatsoever to be found, the only way to alter things is by nocking the cilinder further in to compress the spring more against bi-metal strip wich will afect fuel flow. Any ideas?!
if it hasn't got an allen key adjustment behind the brass cap on the back then it must be an old fashioned wur of some kind (like they used on the porsche engines early '80s iirc). all the ones i've seen on valvers have had the allen key adjustment. piccy the wur adjusts 'control pressure' which basically allows the mixture to be adapeted wrt. temperature and load. have a look at this k-jet manual
Well feck me sideways! My rado must be the first 1 ever built cos got loads of different parts(older!), to other ones, and i also picked up couple of wur-s at inters and not 1 had adjustable allan key fingey! Cheers gti, just downloading the file u sent
My old stupid computer cant open yor file gti, any chance you can shed some light on wur, as i can adjust it by varying the preasure on the spring by moving the cilinder, just need to know whats better MORE or LESS preasure? fanku loads
Think of the wur as a valve.fuel passes thro it and back to meterhead.If the pressure is LOWERED(valve shut slightly)The flap in the meterhead will rise slightly higher than usual increasing fuelling.So when car is cold wur drops the pressure to increase fuelling and when warm raises pressure. The vacuum pipe on side of wur also makes wur drop the pressure to increase fuelling on accelaration. DONT GET THIS MUDDLED UP WITH SYSTEM PRESSURE. System pressure is controlled by the little valve in meterhead which you shim to increase pressure to about 5.4bar hope this helps
sambo, you probably need adobe acrobat reader. you can get it here: acrobat flusted's explanation is spot on. also, i've been told that the 'wur mod' sets the control pressure to be 48psi at idle when the engine is fully warmed up.
1. You control the engine by adjusting the amount of air entering, via the throttle. 2. the injection system measures the air quantity entering the engine and adds fuel acordingly, by increasing the fuel presure to the injectors. Air quantity is measured with an air flap, whose movement is opposed by the control presure. The air flap sits in a cone, whose profile adjusts fueling for different airflows, to try and suit the engines fueling requirements better than a purely linear fuel/air relationship. 3. The control pressure is a fraction of the system presure. The WUR controls the base control pressure, it automatically lowers from the base control pressure temporarily: when the engine is cold under increased load to richen the fuel/air mixture, by allowing the air flap to move more for any given airflow. You can adjust the base control presure permanently on the WUR, this will "shift/adjust", the whole charchteristic fueling curve set by the air flap and WUR, richer/poorer. Why does it work in this seemingly ar5e about face fashion? so that if the fuel system fails (blockage, etc)and the presure drops, the net effect will be a richer mixtue -> failsafe (fewer holes in pistons [:^(] ). summary: control presure v, mixture ^ if you've read the manual and the above sambo, and it's not clear, you can pm me. M. Edited by: mark25
that's not exactly true. the pressure to the injectors is constant and is set by the main pressure regulator in the meteting head (this can be raised with shims, as flusted points out). the amount of fuel delivered to the injectors is controlled using a plunger inside the metering head, which acts very much like a tap. when more fuel is needed the 'tap' is opened further by moving the plunger. the pressure stays the same.
To be as basic as possible the wur alters the pressure acting on the air flap, allowing it to move a greater distance for the same airflow when cold to richen the mixture. It puts (control) pressure on the fuel metering valve/piston in the metering had, the less pressure the greater the fuel delivery.
Thanks allot lads, great help! I'v just found out i'v been an idiot, my wur does have hiden screw at the back of it! The wur-s i bought must be 8valve, just had a play with 2 of them and they were much worse than my wur, i think i'l haftu make a trip to stealth and get vince to sort my car out. Anyway want be long till i get rid of crapflap and install my gsxr bodies!!! )
I highly recommend test flowing your injectors to insure even flow across all cylinders... The Lysholm Cabby is now flowing 350+ cc/min per injector these days...or approx 1.46 litres per minute... should hit 400cc/min/injector soon...and this is at stock 81 psi system pressure (this is with a Volvo 240 turbo CIS-Lambda (B21FT) fuel head)... EDIT: unless you have a boost sensitive WUR/altitude comp WURthe WUR only affects warm up running. It then settles at a specific control pressure. If the control pressure is for some reason lower things will be richer across the board up to the limit of the fuel plunger travel. I used VSAM to regulator control pressure for a while, I ended up taking it off the control pressure circuit and using it to control a lambda bypass so it allows me to control lower chamber pressure. Works real well for11 lbs of boost on my ABA/Eurospec 8v head setup...the wideband confirms good mixture as well... looks like there is enough fuel for 220whp at stock system pressure (81 psi)... Edited by: Peter Tong
what is the stock system pressure in K-Jetronic KR motor??? in 2L KR what system pressure should i use??? (what shim should i use??) and how much should i turn the idle mixture screw???
Stock system pressure 1.8 KR is around 5 bar / 5.5 maximum! The wur pressure should be 3.4 bar! no idea on the 2L, should imagine it's the same!! The idle screw? well you need an emissions gas anylyser to see what your mixture is to begin with, should be set to 2% - any local mot centre can do this for you!
sorry but i need some info... we have 1)WUR - base control presure 2)System Pressure - constant pressure to injectors 3)idle mixture screw - ??? ( i think that this alters the position of the plate and you can change how much the control plunger will open) what is the best way to richen my car??? and what of these are affecting the low - medium - high revs???
