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if you increase boost, eg 1 bar boost spring then more fuel is needed I assume this is where the WUR comes into play and why an adjustable warm up regulator would be ideal.
Until I get the afr gauge in I cant confirm anything, but the warm control pressures must provide the correct fueling on cruise and boost, as the car boosts the fuel drops approx 1.3 bar from the max warm control pressure, if the warm control pressure is initially incorrect ie to hi the car will run lean when boost kicks in and melt pistons, warm control pressure to low and the car runs to rich on boost.
I have made the WUR adjustable so can adjust cold pressures externally with out opening the WUR
Warm control pressure you cannot make adjustable on our 964 turbos as you would have to drill a hole at the bottom, this would mean you then lose the altitude fuel setting function.
Our cars are not efi so adjusting the boost manually surely means there is no adjustment in fuelling as the fuelling is controlled by the WUR, so in theory turning down the boost means fuelling would still be at it setting of a 1 bar boost spring, so running rich, as their has not been any adjustment in fuelling ,well this is what I think, I could be wrong.
O.K. i see The k-jetronc is only suitable to a very limited extent for adapting performance increases, it does not offer the possibilities of an EFI.
I usually drive with 0.9 - 1.0 bar boost pressure, i.e. with the factory setting or slightly above. The engine has so far tolerated this well because of the full load enrichment.
The adaptation of the WUR to more power is limited and laborious. I'm not 100% sure, but as far as I can remember the full load enrichment can be adjusted with an adjustment screw in the lower membrane. The screw can be reached by removing the round sheet metal cover at the bottom of the housing.
if you remove that whole sheet then you lose the ability of the altitude fuel enrichment.
Fritz do you run a AFR gauge,
It is my understanding that adjustment of this screw will alter WCP, which Im not sure until I test on an AFR gauge, in turn affects the boost enrichment
At the moment my AFR monitor installed in another car, but I will reconnect it soon.
Yes, I remembered that incorrectly, the tin cover only allows access to the height pressure can only. The adjusting screw is in the membrane above and it influences the position of the pressure piston on the membrane. When the membrane is pushed down against the spring by boost pressure, the WCP drops and the mixture is enriched.
So there are to different influences on the WCP and i guess if you try to adjust they will influence each other.
from what i found, the mityvac will always drop the fuel pressure by 1.3 bar +/- 0.2bar, if the diaphragm is working correctly in the WUR, so you could in theory set the warm pressure and then see a drop of 1.3 bar on boost, how rich depends on where you set the warm control pressure is initially set.
the cold control pressure can then be set afterwards as I believe adjusting this does not affect the WCP.
I have now managed to build the WUR, final pressures are all well within spec
1.Cold control pressure at 17.5c 41psi, factory spec allows a range of 37psi to 43psi
2.Warm control pressure after 10mins of WUR heater activation, 62psi, factory spec is between 68 and 62psi, I set it lower so I have a slightly rich AFR on boost
3.Boost enrichment at 0.5 bar boost pressure, fuel pressure dropped 19psi, factory spec is 19psi
4.Drop in pressure after 10mins of switching off pump, 28psi, factory spec allows a pressure drop of up to 23psi
5.Drop in pressure after 20mins of switching off the pump was 26psi, factory spec allows a pressure drop of up to 20psi
05-14-2023, 06:30 PM
