Well it goes!
I've finally found the time to wire everything together and yesterday afternoon Otly drove without a distributor for the first time.
A good feeling.
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I'm currently running on the basic "safe" map and it certainly feels very safe....and rather restricted.
I've come up with a map based on the little timing information I can find for the engine. It looks like this:
rpmBins=5,9,10,15,20,25,30,35,40,45
mapBins=0,13,19,25,31,37,43,49,55,61
advance0=18,26,30,34,38,42,46,50,54,58
advance1=17,25,29,33,37,41,45,49,53,57
advance2=16,24,28,32,36,40,44,48,52,56
advance3=15,23,27,31,35,39,43,47,51,55
advance4=13,21,25,29,33,37,41,45,49,53
advance5=11,19,23,27,31,35,39,43,47,51
advance6=9,17,21,25,29,33,37,41,45,49
advance7=8,16,20,24,28,32,36,40,44,48
advance8=7,15,19,23,27,31,35,39,43,47
advance9=3,11,15,19,23,27,31,35,39,43
Can anybody tell me if this looks close to being sensible? I know people don't have curves for my engine but perhaps could confirm that it's at least the right way around...and all that.
My website about the installation is <a href="http://mjlj.mysite.wanadoo-members.co.uk/">HERE</a>.
Oh and Mr 4600cc, Sir. I have been using your tuning programme. It's very splendid.
2.25l LandRover up and running
Moderators: JeffC, rdoherty, stieg, brentp
The MAP bins look a bit
The MAP bins look a bit odd....
...If you're using the standard MAP sensor (which you web page seems to suggest) then you should have a min value of around 20kPa and a max of, say, 110kPa, probably evenly spaced.
Do you see the map getting stuck at the 61 line when accelerating hard?
...If you're using the standard MAP sensor (which you web page seems to suggest) then you should have a min value of around 20kPa and a max of, say, 110kPa, probably evenly spaced.
Do you see the map getting stuck at the 61 line when accelerating hard?
A bit odd....
Looking odd is what I want people to point out, thanks. It's my first effort at a map.
I was basing the figures on what I've gleaned from various manuals about my engine:
vacuum advance starts at 102mm Hg
vacuum advance max is 12deg at 457mm Hg
Have I converted the figures correctly?
It also gives a max rpm of 4500 and various centrifugal advance values of between 0 and 42 degrees.
I assume the map values should be static timing (6) plus vacuum advance plus centr' advance.
I had the minimum of 0 just to try and catch everything below the stated advance start figure.
I haven't run the engine on this map yet so I can't say where it might get stuck. I'm planning a trip out later today with the laptop attached though so I can note the min/max values for pressure and RPM.
I was basing the figures on what I've gleaned from various manuals about my engine:
vacuum advance starts at 102mm Hg
vacuum advance max is 12deg at 457mm Hg
Have I converted the figures correctly?
It also gives a max rpm of 4500 and various centrifugal advance values of between 0 and 42 degrees.
I assume the map values should be static timing (6) plus vacuum advance plus centr' advance.
I had the minimum of 0 just to try and catch everything below the stated advance start figure.
I haven't run the engine on this map yet so I can't say where it might get stuck. I'm planning a trip out later today with the laptop attached though so I can note the min/max values for pressure and RPM.
Ok....and I'm sure you've
Ok....and I'm sure you've done all this yourself...
MJLJ works in kPa and to convert mm Hg to kPa, multiple by 0.1333. Standard atmospheric is 760mm Hg, 100kPa
I don't understand ...vacuum advance STARTS at 102mm Hg... That seems a VERY low pressure (14kPa). Unless it means that vacuum advance starts at (760 - 102) = 86kPa. Much more believable.....
Max vacuum advance is 12deg at 457mm Hg = 61kPa ...which is one of your figures. I also presume that the vacuum does go lower than this (my engine runs at 20-30kPA at idle), it's just they're saying the max advance is 12deg and this is at 61kPa and below- probably since the backplate won't move any further!
...I assume the map values should be static timing (6) plus vacuum advance plus centr' advance... Exactly correct
What I'd do, initially:
- set the map so low kPa and low rpm are at top left
- set the lowest rpm bin to 500
- set the highest rpm bin to 5000
- set the lowest MAP bin to 20
- set the highest MAP bin to 110
- set the internediate bins roughly evenly spaced
- do the sums and set the bins appropriately
Then, initially, run the engine with the MAP disconnected. Verify that the bins used are on the 100kPA line. Connect the map and verify that the lower MAP bins come into play at idle/closed throttle and the higher kpA bins come into play at open throttle.
Report back....
MJLJ works in kPa and to convert mm Hg to kPa, multiple by 0.1333. Standard atmospheric is 760mm Hg, 100kPa
I don't understand ...vacuum advance STARTS at 102mm Hg... That seems a VERY low pressure (14kPa). Unless it means that vacuum advance starts at (760 - 102) = 86kPa. Much more believable.....
Max vacuum advance is 12deg at 457mm Hg = 61kPa ...which is one of your figures. I also presume that the vacuum does go lower than this (my engine runs at 20-30kPA at idle), it's just they're saying the max advance is 12deg and this is at 61kPa and below- probably since the backplate won't move any further!
...I assume the map values should be static timing (6) plus vacuum advance plus centr' advance... Exactly correct
What I'd do, initially:
- set the map so low kPa and low rpm are at top left
- set the lowest rpm bin to 500
- set the highest rpm bin to 5000
- set the lowest MAP bin to 20
- set the highest MAP bin to 110
- set the internediate bins roughly evenly spaced
- do the sums and set the bins appropriately
Then, initially, run the engine with the MAP disconnected. Verify that the bins used are on the 100kPA line. Connect the map and verify that the lower MAP bins come into play at idle/closed throttle and the higher kpA bins come into play at open throttle.
Report back....
So...
So, having been for a drive on the safe map and watched the numbers, I think I have a better understanding of what's going on.
100kpa is atmospheric pressure and this is what I get without the map line connected. With the throttle closed, the carb is severely restricting the air flow and so the pressure is lower in the manifold. When you open the throttle, more air can enter and so the pressure increases until you are back to 100.
I got a min pressure of 22 and a max of 101 recorded on a good, varied run.
I guess you are right about the quoted vacuum figures and how I need to subtract them from 100 to get the right answer. I suppose they quote a pressure variance from the norm...or something.
I'll try my map again given what you've said. Thanks for all the pointers they're really appreciated.
100kpa is atmospheric pressure and this is what I get without the map line connected. With the throttle closed, the carb is severely restricting the air flow and so the pressure is lower in the manifold. When you open the throttle, more air can enter and so the pressure increases until you are back to 100.
I got a min pressure of 22 and a max of 101 recorded on a good, varied run.
I guess you are right about the quoted vacuum figures and how I need to subtract them from 100 to get the right answer. I suppose they quote a pressure variance from the norm...or something.
I'll try my map again given what you've said. Thanks for all the pointers they're really appreciated.
Excellent...
Excellent...
All your observations seem as expected and are encouraging. When you've got the 'safe' map sorted, we need to move onto the 'proper' map that will really bring out the benefits of the MJLJ...
...after all, what you're initially doing (and rightly so) is just modelling what the existing, largely mechanically-limited, system does. What we need to find is the map that the engine designers would have used had they had MJLJ to hand when they were doing their job!!
All your observations seem as expected and are encouraging. When you've got the 'safe' map sorted, we need to move onto the 'proper' map that will really bring out the benefits of the MJLJ...
...after all, what you're initially doing (and rightly so) is just modelling what the existing, largely mechanically-limited, system does. What we need to find is the map that the engine designers would have used had they had MJLJ to hand when they were doing their job!!
min max advance
You say that 86 seems a reasonable level to start vacuum advance at; i.e. 100 - 14. Would it then be reasonable to assume that the max advance figure would happen at 100 - 61; i.e. 39kPa?
You say 61 in your mail above but 39 would be more consistant. Does it sound like a reasonable value? 86 to 61 seems a very narrow band where as 86 to 39 takes in much more of the total range.
You say 61 in your mail above but 39 would be more consistant. Does it sound like a reasonable value? 86 to 61 seems a very narrow band where as 86 to 39 takes in much more of the total range.
Yes - on reflection it would
Yes - on reflection it would seem sensible that the quoted mm HG are both taken relative to 760 i.e. advance starts at 86 and maxes out at 39.
However, I'm sure that the proper curves (or surface, to be more correct) would start at 100 descending, rather than being flat from 100 to 86 and then descending.
It's all a bit weirdly described though, isn't it?
On a minor point, I don't understand the 3 BTDC you've got at the start of the last line - surely it should be a minimum of 6?
However, I'm sure that the proper curves (or surface, to be more correct) would start at 100 descending, rather than being flat from 100 to 86 and then descending.
It's all a bit weirdly described though, isn't it?
On a minor point, I don't understand the 3 BTDC you've got at the start of the last line - surely it should be a minimum of 6?
I don't understand either
MartinM,
I don't understand the 3 degrees either...but enough of musical tastes. It must have been a transcription error.
I've spent the afternoon working on a new map and here it is:
rpmBins=5,6,9,12,20,25,30,35,40,45
mapBins=20,40,60,65,70,75,80,86,90,110
advance0=18,22,30,34,39,44,48,52,56,59
advance1=18,22,30,34,39,44,48,52,56,59
advance2=17,21,29,33,38,43,47,51,55,59
advance3=15,19,27,31,36,41,45,49,53,57
advance4=13,17,25,29,34,39,43,47,51,55
advance5=11,15,23,27,32,37,41,45,49,53
advance6=9,13,21,25,30,35,39,43,47,51
advance7=7,11,19,23,28,33,37,41,45,49
advance8=6,10,18,22,27,32,36,40,44,48
advance9=6,10,18,22,27,32,36,40,44,48
I've been out for a spin around my favourite test route (lots of slow steep twisty stuff followed by a blast home along the main road) and WOW! Fabulous. It's certainly more perky and smoother than it was although I don't get any more top speed out of it (just a fraction over 60mph). It seems good at the lower speeds which is where a series landrover spends a lot of it's time.
I never seemed to get more than about 3.7k rpm out of it though...which seems low given the stated max of 4.5k.
I'll have to tweak the tappets and carb' to get the best out of it I suppose, now that the ignition has been improved.
I don't understand the 3 degrees either...but enough of musical tastes. It must have been a transcription error.
I've spent the afternoon working on a new map and here it is:
rpmBins=5,6,9,12,20,25,30,35,40,45
mapBins=20,40,60,65,70,75,80,86,90,110
advance0=18,22,30,34,39,44,48,52,56,59
advance1=18,22,30,34,39,44,48,52,56,59
advance2=17,21,29,33,38,43,47,51,55,59
advance3=15,19,27,31,36,41,45,49,53,57
advance4=13,17,25,29,34,39,43,47,51,55
advance5=11,15,23,27,32,37,41,45,49,53
advance6=9,13,21,25,30,35,39,43,47,51
advance7=7,11,19,23,28,33,37,41,45,49
advance8=6,10,18,22,27,32,36,40,44,48
advance9=6,10,18,22,27,32,36,40,44,48
I've been out for a spin around my favourite test route (lots of slow steep twisty stuff followed by a blast home along the main road) and WOW! Fabulous. It's certainly more perky and smoother than it was although I don't get any more top speed out of it (just a fraction over 60mph). It seems good at the lower speeds which is where a series landrover spends a lot of it's time.
I never seemed to get more than about 3.7k rpm out of it though...which seems low given the stated max of 4.5k.
I'll have to tweak the tappets and carb' to get the best out of it I suppose, now that the ignition has been improved.
Proper job!
Proper job!
If you can't get top revs, then I'd look at throttle linkage/carpet (do you have that in LR's?) under the the pedal etc, to check for max opening before fuelling, tappets etc. I doubt tweaking the timing will release another 800 rpm (...famous last words!)
If you can't get top revs, then I'd look at throttle linkage/carpet (do you have that in LR's?) under the the pedal etc, to check for max opening before fuelling, tappets etc. I doubt tweaking the timing will release another 800 rpm (...famous last words!)
Thanks
I'd never have thought of that.
I'll check the linkages first.
Thanks.
I'll check the linkages first.
Thanks.