Practical Standalone Tuning: Step 7: Steady State Fuel Tuning

Back to course

Watch This Course

$229 USD

-OR-

Or 8 easy payments of only $28.63 USD Instant access. Easy checkout. No fees. Learn more

Enroll Now
8 easy payments of only $28.63 USD

Course Access for Life

60 day money back guarantee

Step 7: Steady State Fuel Tuning

20.50

00:00	For the next step of our process we're going to be steady state tuning our fuel table and as per the body of the course I generally will do this up to about 2.3 of the engine rev limit, in this case we'll go out to about 4500 RPM.
00:12	The process here is going to be to start with as low a RPM and load as we can get, going to try around 1500 RPM and then we're going to start increasing the throttle as we step up through the different cells and we're going to tune each cell individually until we reach our target.
00:30	Now, I've already shown a few ways of making changes to the cells.
00:34	The option we're going to use here given we do have a wideband coming in is to use the quick tune function which is the Q key.
00:41	The process here is to basically make sure that we're central in the cell that we want to tune and we'll press the Q key and that will correct the lambda onto our target.
00:51	May still require a small touch up in which case we can use our page up and page down, probably more likely our control page up and page down to make smaller changes.
00:59	Remember we do also have the ability to make percentage changes by using the P key.
01:04	So, for example if we come into our table here and we want to increase the cell that I've just selected here, we can press P and if we want to add 10% to that, we just simply enter the value 10 and that will make the appropriate change.
01:18	Control Z will go back to where we were.
01:20	If we wanted to reduce the value by 10% minus 10 and that will have the effect that we want.
01:25	Alright, so we'll get ourselves up and running now on the dyno and we'll go through the process.
01:30	I will mention here that while I'm presenting, obviously I'm not going to be using knock, audio knock detection equipment.
01:36	Despite the fact that we have started with conservative ignition timing values, I would always recommend that you're wearing knock detection equipment while you're tuning both fuel and ignition.
01:45	Let's get running now.
01:47	Alright, we can see that while I'm getting up and running here in this area that we haven't actually accessed, we've gone very very lean here.
01:52	Not really an issue because I've got, so little load on the engine, but it's really not happy about running, so we can just use the Q key there, that will get us at least a little bit closer to the mark.
02:03	At the moment we're still interpolating between some cells, so what I'm just going to do is manually adjust the cell below at minus 40 kPa and we'll just drop our throttle down until we're in the centre of that cell.
02:14	We'll just need to make some small adjustments here to our dyno speed to get us in the centre of the cell.
02:21	And we'll just try and get ourselves down to minus 50 kPa, see if we can get into that cell.
02:27	We can, just again make a little bit of a change here to our dyno set speed.
02:33	And I'm just going to be basically using a combination of the page up, page down and our Q key as I see fit.
02:40	We're on our target there, we'll just see if we can get down to minus 60 kPa which is probably about as far as we will be able to get down here if we can at all.
02:48	Just about into that cell.
02:51	We are seeing that the dyno's slowing down, so difficult to get right into the middle of that cell, but let's just start with our minus 50 kPa cell and we'll tune from there.
03:02	OK, so essential in the cell now, again we want to be as close to the centre as we can just, so we avoid the effects of interpolation and just actually reduce the speed just a little bit here.
03:18	OK, happy with that there.
03:20	So, we're right on our target there, possibly just a touch on the lean side there, we're moving between 1.00 and 1.01, so just add 0 .2 to that cell and we'll come up to our minus 40 kPa cell and again just adjusting our dyno speed here, so we are perfectly central in that cell.
03:41	And we can see that we're right on our target there, so we'll come up to minus 20 kPa so, just a little bit more throttle here.
03:50	And you can see 1.08, 1.09, so we'll use the Q key here and we can see that that does a pretty good job of correcting our error.
03:59	Occasionally we will find that we do need to use that Q key a couple of times, just get back into the centre of that cell here.
04:06	Just want to avoid that interpolation because at the moment with most of the table essentially untuned, we do run the risk of essentially having a big error creep in if we are interpolating to surrounding cells.
04:17	OK, so we've got minus 20 kPa cell tuned there, but we can see that we've got 62.8% there and we can see that the next cell up is going to be 44.6, so it's clearly going to be lean so, I'm just going to guess ahead and we'll set that to 66% and just add a little bit of throttle and get into the centre of that cell.
04:36	And you can see that we're still a little bit lean here, we can use the Q key to correct that, just again waiting to learn the centre of that cell and maybe just a little bit of our control page up will get us onto our target.
04:48	So, again the same thing's going to happen as I move out to 20 kPa, we see that the number currently is 50, so let's just guess ahead here and we'll set that to 72%, come up to, now, I'm actually at wide open throttle and we can see that we're a little bit lean there so, again we'll use the Q key, get us onto our target and just a little bit of a touch up there with control page up.
05:10	Alright, let's just come back to idle and we'll just talk about what we've seen here.
05:13	So, for our 1500 RPM column, we were only really able to actually tune four cells there.
05:20	And that's simply because we can't get down below, or sorry let's see, five cells, we did get to minus 50 kPa, we can't get to minus 60 kPa at this point, so these are the cells we have tuned.
05:30	And of course wide open throttle at such low RPM, we don't have enough energy to spool the turbo, so we can't get beyond 20 kPa.
05:37	So, what I'm going to do here is just sort of essentially guess ahead of what we might expect to see at 40 kPa.
05:44	It's not an issue for us at the moment because we can't actually get there, but this is going to help when we get to 2000 RPM because we will probably be able to get a little bit further out into positive boost.
05:54	So, we've gone from 69 to 75, so essentially a 6% change there over 20 kPa.
06:01	So, let's just guess that out to 81%, we can change the entirety of that table to 81%.
06:09	We do want to do some work with our lower cells down here, but I'll show you what we're going to do with those a little bit later on.
06:16	So, now what we're going to do is highlight the entire 1500 RPM column, control C and then we'll click onto the 2000 RPM column and control V and now what we're going to do is make a percentage change, so we're going to guess that as we move from 1500 to 2000 RPM, chances are our VE is going to increase, so what I'm going to do is make a 5% change here, so we're going to add 5% to all of those cells.
06:41	Chances are that might be a little bit rich, but we'd rather start a little bit rich than a little bit lean.
06:47	So, now we've got that done, let's just increase our dyno set speed here to 2000 RPM.
06:55	And we'll come out to 2000 RPM and to start with I'll just try and get around zero kPa and we just want to see how good that guess was and if we look at our lambda at the moment compared to our target, it looks like that 5% guess was not too far off the mark at all which is great.
07:11	So, probably a little bit too rich if anything.
07:14	So, what I'm going to do while the entire column is still highlighted here, we'll just take 1% out, still a little bit rich there, so yeah 2% out and we're pretty much on our target, just control and page up to add a little bit more in.
07:27	So, now that we've done the zero kPa cell, we're going to drop our throttle here and we'll see how far down in the vacuum we can get, hopefully we can get into that minus 60 kPa cell, but we'll see what we've got.
07:43	Minus 50 kPa we can get quite happily.
07:47	And I'll just drop the throttle a little bit further.
07:50	And yeah we're pretty much in the middle of our minus 60 kPa cell.
07:56	We're just on the very brink of keeping the dyno operating, so what I can do here is add a little bit of throttle, bring our RPM back up and then just gently drop the throttle and I want to take a look at my lambda which actually is pretty good.
08:07	I'm just going to take 0.4 out of that and then basically add a little bit of load to bring the RPM back up and then just gently drop the throttle back into that cell, right, on our target there.
08:19	OK, so minus 60 kPa cell we've got into at 2000 RPM.
08:23	We'll just bring our throttle up a little bit and get us into the minus 50 kPa cell.
08:29	So, we are quite lean there, 1.07, so we'll use the Q key there, that should clean up most of that and then just page up, control page up will clean up the remaining little error there.
08:42	Just make sure that we are actually on target, we are.
08:46	We'll come up to our next cell, minus 40 kPa here.
08:51	And again just making some small adjustments to the dyno set point.
08:55	And pretty good there.
08:59	Very very slightly lean, so just use the Q key there, that's got us onto our target.
09:03	We'll come up to minus 20 kPa.
09:16	And minus 20 kPa is pretty good.
09:19	Zero, we've already done, so that should still be on our target there.
09:22	And we can see that yep it is.
09:25	We'll come up to our 20 kPa positive column, positive cell.
09:29	And we can see that as we're coming out here, now we are a little bit lean.
09:33	Not too worried about it, but I'm going to highlight the entire column above this point as well and we'll just add a couple of percent to get us onto our target.
09:41	The reason I've done that is because if we are a little bit lean at 20 kPa, remembering we have only guessed ahead to 40 kPa, chances are we're probably going to still be a little bit lean there as well, so again just trying to be a little bit conservative and a little safe, we'll go up into our 40 kPa column cell which requires full throttle there.
10:01	And we can see that we are in fact still a little bit lean.
10:04	So, let's just add a few percent in there.
10:08	At this point here because we're, so low in the RPM and boost, I'm not really too worried about staying in positive boost like this and I'm not too worried about the fact that we were a little bit lean there.
10:20	We're not going to really be doing any damage at 2000 RPM and 40 kPa.
10:24	OK, so we have tuned that cell now and we can see that we've stepped up quite a bit, sort of 80 to 94 which is quite a large jump.
10:32	Again I'm just going to guess ahead here and take the entire column above us, 60 kPa and above, and let's just take a guess that this might want to be somewhere in the region of 100%.
10:45	Now, again we probably aren't ever going to be able to get there, this is just about for the sake of completeness and also we're going to be probably able to get to 60 kPa when we get to 2000 RPM.
10:58	So, Control C, highlight the 2500 RPM column, Control V and we'll paste that into place.
11:06	And again what we're going to do is add, let's say 5%, looks like it was pretty close last time, doesn't necessarily mean it will be this time.
11:13	Now, another little trick we can do here is if you are struggling with interpolation and maybe you are sort of moving just out of the column that you want to tune here, we're getting to a point now where we've got quite a massive error.
11:27	We're going to be going from let's say 105% VE to 50.
11:31	So, if we were interpolating even a little bit, that's going to be really problematic for our calibration.
11:36	So, what we can do, even though we're not going out to 3000 RPM at the moment, we can Control C, copy the 2500 RPM column and paste that out to 3000 RPM.
11:46	And that's just going to mean that we're less likely to be affected by interpolation.
11:50	We'll go back to 2500 RPM and I'm going to repeat the process now, we'll speed this up a little bit, it's a rinse and repeat of what you've just seen me do.
11:58	And we'll go out to 4500 RPM.
12:00	Once we get a little bit higher in the load and a little bit higher in the RPM, what we're going to need to do is be a little bit mindful of the temperature that we're creating.
12:10	And we may need to come back and let the car idle if the coolant temperature or air temperature's getting excessive.
12:15	So, we just need to be mindful of that.
12:17	And the other thing is that once we start getting a little bit higher in the boost and RPM, if we are a little bit lean, rather than sitting there running the engine lean under heavy load, I'd be much more likely to back off, back into vacuum, make an appropriate change and then go back out and see if I've got it right.
12:33	So, it's just about being sensible based on the amount of load and heat we're putting into the engine.
12:39	Alright, let's get the rest of our table tuned now.
13:28	Alright.
13:52	Alright.
14:21	Alright.
14:45	Alright, at this stage we've got our fuel map or VE table tuned correctly up to 4500 RPM.
14:51	And obviously at this point we're still just running wastegate boost pressure which is always where we want to start.
14:57	We'll see how we can deal with the higher boost levels once we get into our full power ramp run tuning.
15:03	We're not quite done here yet though, so we want to basically extend the shape of this map out and basically guess ahead at some trends that we're likely to see.
15:12	And we also need to deal with a couple of areas, obviously the low RPM high load area which we haven't tuned here and of course everything down below 60 kPa, we want to sort of add some shape to that.
15:23	But for a start what I'm going to do is just take our 4500 RPM column and we will paste this out to the rest of our map.
15:33	OK, so what we're going to do now is add a little bit of shape.
15:36	We know that at higher RPM we're likely to see our VE taper off.
15:41	And we actually look like we've sort of peaked already and starting to drop away in the area that we've tuned up to 4500 RPM.
15:48	So, what I'm going to do is just manipulate this, so I've got a bit of a shape that probably makes sense.
15:54	We're not going to necessarily be right, but we'll see how we can address this once we get into our full power ramp run tuning as well.
16:01	But all we're trying to do here is just basically guess ahead and get us closer to the ballpark knowing that it's not going to be perfect.
16:07	So, we'll go ahead now and make some changes.
16:26	Alright, so that deals with our higher RPM area and we can see now if we're looking at our graphical map that we've got something that sort of looks reasonably sensible for a VE table.
16:36	We can also use this to highlight potential errors that might have crept in.
16:40	For example, here we can see we've got a little bit of a hole here that probably doesn't necessarily make a lot of sense.
16:47	So, if we've got something like this after we've gone through in steady state tune, we can always just come back and revisit that.
16:53	So, let's get ourselves up and running again, we'll drop our RPM set point here to 2000 and we'll just see if we had that right or if perhaps it needs a little bit more work.
17:02	So, let's get ourselves there.
17:13	Now, it looks like we're pretty much right on our target there, we'll just go up to, see if we can get to 40 kPa and we can see we are a little bit rich at 40 kPa.
17:23	So, we'll just get a little bit out of the table there and we'll correct that.
17:28	So, we can see that's why we had that error creep in or why we had that strange shape to that particular point of our table, but really easy to just go back and revisit anything that we maybe think looks a little bit unusual and make any corrections.
17:44	The rest of this looks pretty good though.
17:45	So, we also need to deal with our minus 80 and minus 100 kPa rows of our table as well.
17:53	Remembering we couldn't get down below minus 60 kPa.
17:56	So, what we can do here is just take our minus 60 kPa which we have managed to get to and actually what we'll do is we'll highlight the entire minus 60 kPa row, press Control C and Control V to paste that down and then what I'm going to do is just follow the sort of general trends that we're seeing in the table.
18:16	So, for example here we're looking at a drop from 2500 RPM minus 50 kPa to minus 60 kPa.
18:24	It's only a 10 kPa change and we've seen that we've reduced our VE number by 7% there.
18:31	So, technically to go from minus 60 to minus 80 kPa we would want to double that to 20 kPa change, but I'm going to be a little bit more conservative than that anyway.
18:40	And what we're going to do is just reduce our numbers at minus 80 kPa by let's say 5%, well, let's go 4% so we'll just use the page down key to do that.
18:49	Then Control C and Control V, we'll copy that down to minus 100 and again we'll just generally, follow the trends that we've got in there and make sure that everything sort of looks pretty smooth on our graphical representation.
19:04	OK, so we've got this area here that we also haven't tuned.
19:08	Now, we can go through and fine tune this a little bit more as we get going.
19:12	We can't really load the engine or the engine's not going to be that happy being loaded at 1000 RPM, so what I'm going to do here is essentially just take some notice of the numbers we've got in the idle area.
19:22	So, we've got 35% here and I'm just going to copy these values back across.
19:33	Then I'm going to highlight out to our idle area and we can see now with that change that I just made, we've increased that number here to 44.6, let's call it 45%.
19:43	So, what we're going to do is just take that back down until we're back at 35% and make sure that our lambda is on our target.
19:51	We actually were idling a little bit rich before, so we'll just give it a moment for everything to settle down.
19:56	And looks like we still need to take a little bit more out of that.
19:59	Got a little bit too far.
20:01	Does have a bit of transport delay when we are at idle, so we just want to be a little bit slow with our changes and let the air fuel ratio actually catch up.
20:10	So, now what I'm going to do here is just simply highlight between 850 RPM and 1500 RPM which is the first column that we actually tuned here.
20:21	And what we can do is interpolate.
20:23	So, we can right click here and linearise horizontal, that will have the effect of just smoothing those numbers out.
20:30	Now, it's not necessarily that's going to be perfect, we can come back in and readdress each of those cells individually as required.
20:36	But we've now got a nice shape to our VE curve, we've got good control of our fuelling to our target and we're ready to move on with the next step of our process.