Hi Is there any benefit of me getting some G60 clocks for this , and not use my 16v clocks Just wondering if i can still keep the MFA working , i can get the rev counter working off the management i am using , so was wondering about the boost and its effect on the MFA ? Cheers
Ok cool , will hunt some down , i guess i could keep the speedo from my valver clocks in a G60 Base unit
I use MK2 clocks on many a turbo conversion. No issues with the clocks not being "boost aware". In fact on a recent study of MPGs I found the reading for the average MPG to be 5% greater than the actual used fuel. No need to get G60 clocks.
Cool , good times !! do i need to use any one way valves or anything, wondering where to take a vacum feed
Will I have not. On my own car at one time I have run up to 22psi during calibration and testing. Clocks still fine to date at 12 psi "low boost". When I was in that stage of development my fuel economy was in the teens and I made regular trips to the pumps
so the average mpg is 5% out, which is probably due to the clocks not understanding boost if you want the MPG to be accurate you need the correct clocks. but really, i doubt even with G60 clocks its going to be right as I guess the calculations will be based on the G60 engine, with a turbo and modified 16v lump I doubt it will be correct. Not that you can trust the mpg display even with the engine totally matched to the clocks, my 8v clocks always told me I was getting around 35mpg with the std 1.8 lump, which was definitly not the case. Then when I put the 16v engine in it started to read low 20s (same clocks), which was more like it! edit: plus G60 clocks will have the redline in the wrong spot for a 16v. Thinking on it I'd just leave the clocks be and do proper calculations to see how far out the mpg figures are. I suppose to be 100% 'correct' you would want Golf limited clocks, but good luck with that one
Right I appriciate that you are using common sense to answer the question here. But you also should appciatate that I own and calibrate more than 15 MK1-3 boosted vehicles some which have original N/A clocks. These vehicles can be compared with other N/A vehicles MK1 -3 that also have the original clocks. Questions like these get asked during builds and I am more than willing to answer using a more practical approach, in addtion to common sense. I do not think the engine type has anything to do with the average mpg MFA readings. Looks to me it would be calculation that would be a function of manifold pressure, distance and engine speed, integrated over MFA sample time and stored in two memery regions of the cluster. If you are calculating 35mpgs by zeroing clocks and filling with X litres looking at the fuel gauge position and after a certain mileage your MFA shows 37mpgs for the same drive cycle on a turbocharged vehicle that is running less vaccum than stock, you really think the MFA is telling porkys because the engine is boosted? If anything it will read worse ( underestimate) as you are likely to be at atmos pressure sooner. Now my specific vehicle was calibrated to achieve 33mpgs as a personal target, but delivers up to 35mpgs (calculated). The MFA reported 36mpgs. On another outing driving a bit in the sprit (hard!!) it returned 27mpgs and the MFA reported 25mpgs. Given that I may make a misjudgement of much fuel (based on gauge position) was in the tank before filling, the MFA to me reads pretty well on this boosted application. I have done similar with other Mk1 to Mk3 vehicles fitted with 20vTs or VR6Ts and seen the same trend There are times when the gauge would read slighty under what is thought to be the actually fuel economy. I have seen this happen on N/A vehicles too. There are many other reasons that dertermine the final reported MFA figures, But I have done this experiment on more than one occasion, for various travelled mileages and found that the MFA in VDO or Motometer clocks is no less accurate with the vehicle as N/A or boosted. So based on what was said above, my experience it is not worth it to find G60/Rallye clocks for use on a boosted mk1 or 2 if you are concerned with average FE readings.
That's all fair enough, but the fact remains VW use a different clock PCB/mfa computer for the G60 km clocks than what is fitted in the Digifant GTI km clocks. I can't think of any other good reason this would be required except for the fact it needs to understand boost? Could be something else I haven't thought of This also goes for the digifiz dash, there are no clocks listed for the G60 engine code at all, just 8v and 16v GTI. At the end of the day even if it was miles out I think its more important to have the correct rev counter rather than the mpg display being exactly right, so leave the std clocks in. I forgot in my 1st post that the rev counter would be incorrect for a 16v application otherwise I wouldn't have mentioned it! Its also interesting to note the vacuum sender itself is also different, 1 bar for the n/a engines, and 2bar for the G60 engines. (this part isn't included with the clock pcb part numbers, so this isnt the reason for the different clocks)
Apart from continental differences with litres/100km and vehicle speed in kph, the G60 digi 1 ECU sends a low amplified engine speed signal to the rev counter. This is different to digifant and K jet vehicles for Golf Mk2. Similar in Corrado/Passat 31. Hence the change in cluster PCB. As said the mpg readings not that off out on the 1 bar sender, already proved that with the tests done on various vehicles with N/A clusters and boosted motors. Plus who no one drives at 100% WOT on boost all the time, in that case the N/A sender will just clip and report poor FE anyway. On the filp side if you drive hard all the time who cares about mpgs! This is correct 1 bar (+15%) for MK1/2 units and 1.2bar (or 3psi gauge) for Corrado/Passat clusters in N/A guise. 2bar for boosted varients (14.5 psig). Ulitmately, for small delta in mpg reading inaccuracy you will get for driving in boost during a transient condition it is not worth it to replace the cluster. This holds is true for 20vT converted vehicles.
