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...I am assuming that when the injector size is changed within the ST software there is no alteration to the fuel map values. So the map is injecting the same values for any injector size. That means a 30lb injector is injecting a hell of a lot more fuel than the standard 19lb injector.
Fred is correct-- everything else being equal, changing to 30# injectors and changing ST's injector-size setting results in the same amount of fuel being injected. LH calculates how much fuel is needed to match the current airflow (measured by the MAF), given the map values and injector settings. So bigger injectors-- with the corresponding change to ST's injector-size parameter-- means more flow but shorter pulses. This allows for more fuel at the top end, where the stock 19# injectors touch 100% duty cycle in stock motors.
Where this theory falls apart is that injectors have a lag in their response, a delay between the LH signaling them to open and fuel actually starting to flow. There is a delay on closing also, but opening is slower, and this net "dead time" is what ST calls "opening time", or latency. So stock 19# injectors have a latency of around 0.93ms, which means a 2.5ms pulse (e.g. typical idle) actually squirts fuel for 1.57ms. Big effect at idle and cruise, small effect at WOT when pulse-width is 7-8 ms.
So which 30# injectors do you have? For our GT motor we use Bosch 0 280 155 759 (Ford Motorsports M9593-BB302, plastic body) which have a larger latency (1.19ms). If I hadn't changed ST's opening-time parameter then I would need to increase all of the map values. On the other hand, if I fit Bosch 0 280 150 945 (Ford M9593-B302, metal body) then the spec'ed opening time is 0.71ms. In this case if I didn't change ST's opening-time prameter from stock then I would need to reduce map values. At the end of the day the result is the same, but it is a shorter/simpler path if you get the injector-size and opening time set properly at the beginning.
There are other 30# injectors of course, those two are the only ones I have specs for. (Ford is good about publishing specs, Bosch not so much).
Mine are the Ford motorsport plastic body injectors you mentioned and I have the duty cycle at 1.2ms which did get it running from start up.
Hmm (thinking), without a doubt I was getting overly rich start up with the ST set up for the 30lb injectors.
It took several seconds of cranking to fire up which is now completely changed, the cold start up map seemed to be the worst culprit in the equation as that was brought back to little over single figures. Same with the cranking map.
Fred is correct-- everything else being equal, changing to 30# injectors and changing ST's injector-size setting results in the same amount of fuel being injected. LH calculates how much fuel is needed to match the current airflow (measured by the MAF), given the map values and injector settings. So bigger injectors-- with the corresponding change to ST's injector-size parameter-- means more flow but shorter pulses. This allows for more fuel at the top end, where the stock 19# injectors touch 100% duty cycle in stock motors.
Where this theory falls apart is that injectors have a lag in their response, a delay between the LH signaling them to open and fuel actually starting to flow. There is a delay on closing also, but opening is slower, and this net "dead time" is what ST calls "opening time", or latency. So stock 19# injectors have a latency of around 0.93ms, which means a 2.5ms pulse (e.g. typical idle) actually squirts fuel for 1.57ms. Big effect at idle and cruise, small effect at WOT when pulse-width is 7-8 ms.
So which 30# injectors do you have? For our GT motor we use Bosch 0 280 155 759 (Ford Motorsports M9593-BB302, plastic body) which have a larger latency (1.19ms). If I hadn't changed ST's opening-time parameter then I would need to increase all of the map values. On the other hand, if I fit Bosch 0 280 150 945 (Ford M9593-B302, metal body) then the spec'ed opening time is 0.71ms. In this case if I didn't change ST's opening-time prameter from stock then I would need to reduce map values. At the end of the day the result is the same, but it is a shorter/simpler path if you get the injector-size and opening time set properly at the beginning.
There are other 30# injectors of course, those two are the only ones I have specs for. (Ford is good about publishing specs, Bosch not so much).
Thanks Jim, it is doing even more than I expected.
Taking a second look at this I see the values in the base map are not massively different to a standard map although there are changes across the piece.
For the cranking and warm up maps these definitely benefited from winding them right back. This does not quite tie in with expectations that the standard map would work right off the bat. There are many things at play but I am not sure how my mods could account for needing comparatively less fuel on cold start.
After a brief interruption in the program due to my in tank fuel pump issue I have recommenced ST
I had come up with a new ignition map based on some feedback from other members which is pushing the ignition by between 6 and 15.6 degrees over an S4. It seems like a lot to me but having just tested it I still don’t have knocks. It was just town driving in 2nd 3rd gear.
Maybe someone can chime in with more experience saying how much they have managed to advance things with a tuned engine?
What I can say is that the more advance I keep adding the more power seems to appearing. I have also taken a new approach to fuelling as I believed the auto tune function messed up the flow of the map to much as it was trying to compensate for transient conditions.
For now here is the timing and fuelling maps I am currently running. As it’s cooler here now I will have to verify my mapping in warmer weather.
After a brief interruption in the program due to my in tank fuel pump issue I have recommenced ST
I had come up with a new ignition map based on some feedback from other members which is pushing the ignition by between 6 and 15.6 degrees over an S4. It seems like a lot to me but having just tested it I still don’t have knocks. It was just town driving in 2nd 3rd gear.
Maybe someone can chime in with more experience saying how much they have managed to advance things with a tuned engine?
What I can say is that the more advance I keep adding the more power seems to appearing. I have also taken a new approach to fuelling as I believed the auto tune function messed up the flow of the map to much as it was trying to compensate for transient conditions.
For now here is the timing and fuelling maps I am currently running. As it’s cooler here now I will have to verify my mapping in warmer weather.
Ignition map looks reasonable, a couple degrees more advance in the mid-range (30-70 load, 2000-4000 RPMs) compared to where I wound up with our '88s4. And your compression (at cranking RPM) is lower than typical, might be cams or might be gauge. (Just checking, throttle was wide-open for compression test, right??).
Cams have a big effect on dynamic compression and combustion pressure, and therefore timing.
You might also try more cam advance, and see what the effect is on the compression test and tolerance for ignition advance.
Cheers, Jim
f you are not seeing knocks (and ST says the knock-sensors are working) then I would be inclined to try a few more degrees.
Max torque isn't necessarily at the knock threshold, particularly if you get better fuel than we do here.
What is the altitude there?
For fuel, ST's auto-tune is terrific to get a new configuration dialed in quickly, but creating a smooth map is not what it does best.
Your ignition timing for higher load values is like a billiard table from 3k rpm upwards- something similar to what Nick demonstrated in his thread. Maybe it is something to do with the cam profile and the relatively lower compression pressures your test exhibited. What this tells me is that in mid range the mix is burning slower to allow more advance.
My motor can take about 27 degrees of advance at full load but then I am having to run RON 95, I have a fast exhaust and I do the ST2 work in the hot season in the late evening when the roads are quieter and the temps have dropped a bit to about 35C. Maybe I should just dump an extra 3 degrees of advance across the board and leave it to the knock control system to take out any excess timing in summer when I use the car less..
With the auto box when shark tuning I found it helpful to disconnect the kick down cable to get data values at lower rpms.
For sure some dyno curves will be quite revealing I suspect.
Ignition map looks reasonable, a couple degrees more advance in the mid-range (30-70 load, 2000-4000 RPMs) compared to where I wound up with our '88s4. And your compression (at cranking RPM) is lower than typical, might be cams or might be gauge. (Just checking, throttle was wide-open for compression test, right??). Actually I had the throttle closed so that could have affected my results
Cams have a big effect on dynamic compression and combustion pressure, and therefore timing.
You might also try more cam advance, and see what the effect is on the compression test and tolerance for ignition advance.
Cheers, Jim
f you are not seeing knocks (and ST says the knock-sensors are working) then I would be inclined to try a few more degrees.
Max torque isn't necessarily at the knock threshold, particularly if you get better fuel than we do here. I am using mainly premium 97ron fuel from my local station.
What is the altitude there? Sea level
For fuel, ST's auto-tune is terrific to get a new configuration dialed in quickly, but creating a smooth map is not what it does best.
Some responses above to questions. I was going to try putting on another 3 degrees across the lower mid to high range, does that seem reasonable?
Tuning for peak cylinder pressure at the right # of degrees after TDC is not the same as tuning for peak timing.
Adding timing until you get knock is generally way past that mark...as Jim said.
Definate food for thought, I guess I should try more advance and see how it goes.
I am interested to see whether my manifold modifications will generally allow more advance to be applied in the general hope that some of the weaker cylinder runs are improved that normally knock first. In this context I guess that doesn’t mean that the extra advance will be producing more power, maybe more to the point that cylinders are more equal for power output
Ignition map looks reasonable, a couple degrees more advance in the mid-range (30-70 load, 2000-4000 RPMs) compared to where I wound up with our '88s4. And your compression (at cranking RPM) is lower than typical, might be cams or might be gauge. (Just checking, throttle was wide-open for compression test, right??).
Cams have a big effect on dynamic compression and combustion pressure, and therefore timing.
You might also try more cam advance, and see what the effect is on the compression test and tolerance for ignition advance.
Cheers, Jim
f you are not seeing knocks (and ST says the knock-sensors are working) then I would be inclined to try a few more degrees.
Max torque isn't necessarily at the knock threshold, particularly if you get better fuel than we do here.
What is the altitude there?
For fuel, ST's auto-tune is terrific to get a new configuration dialed in quickly, but creating a smooth map is not what it does best.
Hi Guys
This is where I am now with my timing, as Jim suggested I added another 3 degrees to the previous map and tested again. Still no knocks recorded.
I also removed the option of using a separate WOT map and use only the base map. OMG, this made a big difference in the mid range at full throttle. The car was reverting back to the standard GT WOT map- I have left that in the picture for reference. Mid range has really picked up, the power feels like the top end used to feel and the top end power feels in a new league.
So so my question now is this, is that the end of the road in terms of timing or are there opportunities still left in that map?
Haha, answering my own questions here which has a certain amusement to it.
I ended up putting even more advanced on the ignition map lower down and flattening out some of the map where peak advance was pulled back, I also went more aggressive from the mid range load to higher load.
It still seems to be adding power from what I can feel although it is tough to get the power down now in anything but bone dry. Also after the roads have been treated I stopped using it. Anyway, still no knocks - I am beginning to wonder if the knock sensors work lol
Over the last couple of weeks I have been tweaking the cold start mapping. I am pretty happy with these now.
I am planning a power run after the salt is gone from the roads although not sure how long it might take. I can at least try a couple of maps to see what difference they make. My initial plan is to do a couple of runs, get a baseline and see how everything goes.
Marti, your post reminds me of my own experience with adding in advance - and the engine just making more power with still no knock. It was spooky for a while there!
I am also reviewing my maps - and I’m back at it adding in advance.. I wonder if the knock I was seeing might have been to oil going past the valve guides at high rpm.
Ive improved the crank breathing, and that’s my rational for review
Marti, your post reminds me of my own experience with adding in advance - and the engine just making more power with still no knock. It was spooky for a while there!
I am also reviewing my maps - and I’m back at it adding in advance.. I wonder if the knock I was seeing might have been to oil going past the valve guides at high rpm.
Ive improved the crank breathing, and that’s my rational for review
Could be the cause I guess, where are your maps at now? Got a screen grab you could share?
Marti, I’ll post a pic soonish.. Still a voyage of discovery this mapping malarkey.
I had had some jerking going from a closed throttle to open - typically when getting back on the gas in a corner - struggling to feather the throttle. I thought it was ignition related so I backed off my initial advance.
Turns out out it was fueling - too lean. Itbs seem happy at around 13:1 with the fuel here.
So I’ve swapped in the first half of a standard map for initial advance, and I’m cautiously winding the wot back up. I’ll post up a pic after a few more day’s running around.
10-15-2018, 09:53 AM
