Remapping the 14CUX for £100!
Discussion
Ive been messing around with the £100 Trigger wheels "UAFC" AFM piggy back unit to see what it can do. The idea is simple enough- it allows to to remap the AFM to change its output voltage, so the ECU will use a different load point in its pre-programmed fuel map, so you can easily fool the ECU in providing the amount of fuel you need at any given point. Ive played with this idea in the past using analogue techniques, but this is a whole new ball game, as it maps against both AFM voltage input and engine RPM. The big plus here is you can tweak the fuel at different engine load points, even if the AFM voltage is the same. ie, an engine doing say 2000 rpm with the throttle wide open may have the same airflow and an engine doing 4000 rpm under very light load, but the engines fueling requirements are different, so you need different mapping points.
Physically the unit is about the size of a packet of fags, and in a flimsy plastic case, so it needs to be mounted inside the car. It has 8 connections, basic supply, RPM, AFM in, AFM out, 2 pins for data logging, and one for a trigger signal to allow you to switch between one of the internal maps. The unit has 3 internal maps, select-able from a push button on the front.
I wired the unit into the AFM loom with 7 core trailer cable that makes a neat job. Once Id installed the required software and got it working, I could get a live readout of the AFM voltages and RPM, just like a fuel map display. Initially its was all a bit glitchy, as its prone to locking up with spikes from the ignition, but a set of resistive plugs, and a bit of extra filtering on the coil (RPM) input fairly much sorted it out. The USB cable supplied with it also has a lot of extra suppression built into it, so you need to use the correct one, not a stock PC one. The mapping tables are 16x16 RPM sites versus voltage sites,
So far I have managed to remap both the Bosch and Lucas AFM's to be voltage compatable with the 5AM (on the bench only). Here are plots for the 5AM vs the Bosch before and after mapping. The mapping example here so 0 RPM - 900 as its a bench test. The remaining RPM sites will need duplicating for on car use. The cell values of 100% mean no voltage change- less than 100 means a reduced voltage in percentage, or above 100% means more, up to a peak of 255- or 5 volts whatever is soonest.
This makes it simple to fit bigger AFMs without a rechip. If the injectors need upgrading, or fuel pressure increasing, the AFM output can be reduced to get the mapping back in line again.
Ive also recalibrated my own fuel map for a bit less fuel under light load, and a bit more for full load.
Im running a non cat map that means the ECU is not trying to correct any changes I make, but Ive found if you simply disconnect the Lambda probes and do an ECU reset, the ECU will run on the fuel maps basic values only, so you should be able to do the same tweaks with the AFM voltages, whilst monitoring the Exhaust or Lambda outputs to get the values correct (This requires a switch to remove the ECU input, but you still need the 12v supply and ground to get the lambda outputs to work.)
There is only so much I can do with road testing- I need to put the car on the rollers at some point (Probibly once Ive made the ignition mappable as well) , but basically dont bin the 14CUX just because it costs to much too remap, you just need £100 and a laptop!
Physically the unit is about the size of a packet of fags, and in a flimsy plastic case, so it needs to be mounted inside the car. It has 8 connections, basic supply, RPM, AFM in, AFM out, 2 pins for data logging, and one for a trigger signal to allow you to switch between one of the internal maps. The unit has 3 internal maps, select-able from a push button on the front.
I wired the unit into the AFM loom with 7 core trailer cable that makes a neat job. Once Id installed the required software and got it working, I could get a live readout of the AFM voltages and RPM, just like a fuel map display. Initially its was all a bit glitchy, as its prone to locking up with spikes from the ignition, but a set of resistive plugs, and a bit of extra filtering on the coil (RPM) input fairly much sorted it out. The USB cable supplied with it also has a lot of extra suppression built into it, so you need to use the correct one, not a stock PC one. The mapping tables are 16x16 RPM sites versus voltage sites,
So far I have managed to remap both the Bosch and Lucas AFM's to be voltage compatable with the 5AM (on the bench only). Here are plots for the 5AM vs the Bosch before and after mapping. The mapping example here so 0 RPM - 900 as its a bench test. The remaining RPM sites will need duplicating for on car use. The cell values of 100% mean no voltage change- less than 100 means a reduced voltage in percentage, or above 100% means more, up to a peak of 255- or 5 volts whatever is soonest.
This makes it simple to fit bigger AFMs without a rechip. If the injectors need upgrading, or fuel pressure increasing, the AFM output can be reduced to get the mapping back in line again.
Ive also recalibrated my own fuel map for a bit less fuel under light load, and a bit more for full load.
Im running a non cat map that means the ECU is not trying to correct any changes I make, but Ive found if you simply disconnect the Lambda probes and do an ECU reset, the ECU will run on the fuel maps basic values only, so you should be able to do the same tweaks with the AFM voltages, whilst monitoring the Exhaust or Lambda outputs to get the values correct (This requires a switch to remove the ECU input, but you still need the 12v supply and ground to get the lambda outputs to work.)
There is only so much I can do with road testing- I need to put the car on the rollers at some point (Probibly once Ive made the ignition mappable as well) , but basically dont bin the 14CUX just because it costs to much too remap, you just need £100 and a laptop!
Edited by blitzracing on Sunday 2nd June 19:15
Edited by blitzracing on Sunday 2nd June 19:25
Based on the email exchanges mark and I have had I'm going to be buying one of these to try it out .. could really do with a large engine car eg 5 litre or at least a high power 4.5 to push the AFM output and see what it all means in the real world. If anyone is interested in losing their car for a week sometime soon for a labour-free install and mapping session that would be cool. pm me if interested, cheers.
GasMunkey said:
I had a on board wideband gauge when I ran the. 14cux and found the fueling to be fairy good(best chip for me was the 4.3) IMO but with the size of the cam I had cold starting was nightmare, could this be dialed out?
Would a mega jolt compliment this system well?
You would be better off messing about the the engine temp sensor for cold start issues- not the AFM.Would a mega jolt compliment this system well?
As for ignition- Its a matter of cost- a megajolt is basically a megasquirt but without the fueling, and takes quite a lot of installing with all the coil packs and wiring. Once you have gone this far then the whole MS package would seem to be a good idea. Also friend of mine installed the Megajolt, and had some rather odd idle problems (erratic high and lumpy idle) having fitted it with the 14CUX that was not easy to sort, (The 14CUX needed reprogramming for some reason) and he did not see an MPG or BHP improvement over the dizzy. Id personaaly add the Aldon Amethist at £200 for mappable ignition, and leave the rest of the HT as is- well thats my plan anyway. As long as your dizzy is not too worn, I doubt the timing error difference between a trigger wheel or the distributor trigger will make much difference.
Very interesting thread, mapping is the next thing on my 'to do' list 
spitfire4v8 said:
Based on the email exchanges mark and I have had I'm going to be buying one of these to try it out .. could really do with a large engine car eg 5 litre or at least a high power 4.5 to push the AFM output and see what it all means in the real world. If anyone is interested in losing their car for a week sometime soon for a labour-free install and mapping session that would be cool. pm me if interested, cheers.
YHMspitfire4v8 said:
Based on the email exchanges mark and I have had I'm going to be buying one of these to try it out .. could really do with a large engine car eg 5 litre or at least a high power 4.5 to push the AFM output and see what it all means in the real world. If anyone is interested in losing their car for a week sometime soon for a labour-free install and mapping session that would be cool. pm me if interested, cheers.
Always welcome to borrow the Griff. The biggest issue with this you have still have the basic fuel map in place- so this will control the maximum injector time avalable, which probibly wont be long enough for a boosted application if your are looking at 300 bhp plus. If you look at the 5ltr fuel map, there are a lot of hex FF's in there which I assume means you have already hit the top of the available injector time (Im not sure on this as I dont fully understand the map layout). This means you will need bigger injectors and then recalibrate the whole AFM range down to suit the new injectors. You also want to avoid using the Lucas 5AM as its voltage output saturates around 270 BHP, which means any meaningful voltage range for higher power outputs is lost, and UAFC recalibration wont fix this. Im sure however its do-able, as the turbo system that Torqueflow have designed works on the same principle, and the Torqueflow AFM is recalibrated with variable resistors plus the stock map. A 16 x 16 digital map in the UAFC going to be much more accurate and controlable however with a bigger AFM like the Bosch or 20AM. Technically I dont see an issue, but it may not be plain sailing, as the calibration a low airflows needs to be spot on as the voltage changes for small airflow changes are quite large, so I can see it being pretty time consuming.
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