Launch control
Moderator: Matt
Launch control is precisely used to control at what rpm the car leaves the line (consistent drag racing)
Factory, some ecu's (ka24 comes to mind) let the motor rev to 6500 rpm, then cut the fuel until the rpms decel to 5500 rpm then repeat. It basically bounces. A much more useable rev limiter would keep the rpm oscillating points close together like 6500 to 6100 rpm.
Launch control would see an extra input grounded (clutch switch usually) and would impose a lower rev limiter than normal. several other tuneable ECU's like mitsu, subie, hondata, even bikiroms modify the ecu code to do this.
Turbo guys use spark cut since it passes unburnt fuel straight out to ignite inside the turbo manifold and spool the turbo rather quickly. With spark cut its easy to build close to full boost just free revving the motor. Also it makes nice foot-long flames and loud pops and bangs This is of course hard on the turbo...
I love your idea 4x4LE, and I'm going to try it soon! I wonder if a negative number would work in that field for more retard? For example our KA24DET running Megasquirt I have set up to pull 40 degrees.
Factory, some ecu's (ka24 comes to mind) let the motor rev to 6500 rpm, then cut the fuel until the rpms decel to 5500 rpm then repeat. It basically bounces. A much more useable rev limiter would keep the rpm oscillating points close together like 6500 to 6100 rpm.
Launch control would see an extra input grounded (clutch switch usually) and would impose a lower rev limiter than normal. several other tuneable ECU's like mitsu, subie, hondata, even bikiroms modify the ecu code to do this.
Turbo guys use spark cut since it passes unburnt fuel straight out to ignite inside the turbo manifold and spool the turbo rather quickly. With spark cut its easy to build close to full boost just free revving the motor. Also it makes nice foot-long flames and loud pops and bangs This is of course hard on the turbo...
I love your idea 4x4LE, and I'm going to try it soon! I wonder if a negative number would work in that field for more retard? For example our KA24DET running Megasquirt I have set up to pull 40 degrees.
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I always thought that launch control should be responsible not only for rev limit but also for elimination of wheelspin during acceleration. If by LC you mean only several step rev limiter, it is doable and looks not very hard to implement, but let's see what Matt says.
So what you are saying is that for N/A users it does not really matter what kind of cut to use - its just rev limit level itself that matters and you generally want it lower when clutch is pressed.
For turbo crowd - don't antilag systems enrich mixtures/retard ignition some 40+ degrees? I don't see how just cutting ignition off with no load helps spoolup. What is the source of ignition for all the unburnt mixture in this case?
Petros.
So what you are saying is that for N/A users it does not really matter what kind of cut to use - its just rev limit level itself that matters and you generally want it lower when clutch is pressed.
For turbo crowd - don't antilag systems enrich mixtures/retard ignition some 40+ degrees? I don't see how just cutting ignition off with no load helps spoolup. What is the source of ignition for all the unburnt mixture in this case?
Petros.
Last edited by Legionnaire on Fri Oct 09, 2009 11:02 am, edited 1 time in total.
Cheers,
Petros Katunian
Petros Katunian
Yeah, that's right. N/A it can be done, but gives no real benefit. As far as removing vs retarding the spark, its basically the same. The idea here is to purposely NOT burn the fuel (or delay its burning) while its in the cylinder. Force it to self ignite once it reaches the super hot temps in the exhaust manifold/turbo.
It is the same as anti-lag. In most cases I've heard it referred to as Flat-Shift. Mainly, if the car is standing still, build boost; If the car is in between shifts, build extra boost to maintain power output/eliminate lag. Mainly this is used in situations where a large, laggy turbo is used.
While testing our KA24DET, 2.4L with GT3271 Turbo (normally spools at 3500 RPM driving under load) I was able to generate 15PSI within 1.5 seconds free revving in neutral while a spark cut rev limiter at 3500 rpms was used. Plus it just sounded SEXY...
I'm playing around with some of the assembly code that ive disassembled here. I think that the 5th gear position switch and 5th gear rev limiter (speed limiter) could be used to do the whole launch control thing if the switch was changed to the clutch switch. Ill test it out maybe next week and we'll see.
Also wheel spin control would be more along the lines of "traction control". Pretty hard...
It is the same as anti-lag. In most cases I've heard it referred to as Flat-Shift. Mainly, if the car is standing still, build boost; If the car is in between shifts, build extra boost to maintain power output/eliminate lag. Mainly this is used in situations where a large, laggy turbo is used.
While testing our KA24DET, 2.4L with GT3271 Turbo (normally spools at 3500 RPM driving under load) I was able to generate 15PSI within 1.5 seconds free revving in neutral while a spark cut rev limiter at 3500 rpms was used. Plus it just sounded SEXY...
I'm playing around with some of the assembly code that ive disassembled here. I think that the 5th gear position switch and 5th gear rev limiter (speed limiter) could be used to do the whole launch control thing if the switch was changed to the clutch switch. Ill test it out maybe next week and we'll see.
Also wheel spin control would be more along the lines of "traction control". Pretty hard...
it all depends on what engines etc are intended for this functionality
some of the code for S13 / S14 KA24DE already exists and could be ported. That is more of a specialist function which is usually tied in with particular ROM images. If I was expected to autopatch, thats where it becomes a lot more work
Also as it becomes available then people expect for different vehicles. Knock sensing was a good example. We got it working for selected vehicles and then I get continously asked when it will be available for other vehicles and those vehicles are completely different code and architecture
some of the code for S13 / S14 KA24DE already exists and could be ported. That is more of a specialist function which is usually tied in with particular ROM images. If I was expected to autopatch, thats where it becomes a lot more work
Also as it becomes available then people expect for different vehicles. Knock sensing was a good example. We got it working for selected vehicles and then I get continously asked when it will be available for other vehicles and those vehicles are completely different code and architecture
Matt,
Can you stop me where I go wrong?
I have grabbed deviouska's B13 Launch Control bin, also Launch Control XDF file from here: http://eccs.hybridka.com/viewtopic.php?f=21&t=1502
From what I've learned from XDF file, I added some lines to NisTune .adr file:
B13_SR20DE_256_E_91_92-LC.adr diff:
Now I assume, if I load LC bin with this address file I can modify the constants to get it worked... But no luck, then I start Nistune it says error:
Where I was wrong? Or it is depends on hardware/software/firmware???
Can you stop me where I go wrong?
I have grabbed deviouska's B13 Launch Control bin, also Launch Control XDF file from here: http://eccs.hybridka.com/viewtopic.php?f=21&t=1502
From what I've learned from XDF file, I added some lines to NisTune .adr file:
B13_SR20DE_256_E_91_92-LC.adr diff:
Code: Select all
+++
REV2_LIMIT,&H234A,2,1,2,12.5,Rev. Limit Normal (LC)
REV3_LIMIT,&H234C,2,1,2,12.5,Rev. Limit Launch (LC)
SPEED1_LIMIT,&H2349,2,1,1,2,Speed Limit (LC)
---
#REV2_LIMIT,&H0000,0,0,0,0
#REV3_LIMIT,&H0000,0,0,0,0
#SPEED1_LIMIT,&H0000,0,0,0,0
Code: Select all
Address entry: REV2_LIMIT 0x234A (length 0x2) out of range. Ignoring this entry. Fix the address file to remove this warning.
use the S13 KA24DE address file as an example
are these the same memory locations?# Special parameters
LAUNCH_SPEED,&H2249,2,1,1,2,Launch speed
REV_LIMIT_NORMAL_IGN_RETARD,&H224E,2,1,2,12.5,Normal rev limit (ign retard)
REV_LIMIT_NORMAL_FUEL_CUT,&H224A,2,1,2,12.5,Normal rev limit (fuel cut)
REV_LIMIT_LAUNCH_IGN_RETARD,&H2251,2,1,2,12.5,Launch rev limit (ign retard)
REV_LIMIT_LAUNCH_FUEL_CUT,&H224C,2,1,2,12.5,Launch rev limit (fuel cut)
REV_LIMIT_IGN_RETARD,&H2250,2,1,2,12.5,Rev Limit ignition retard
I'm trying these with no luck:
The same error from Nistune. Ah, Nistune 0.9.13.1b - do I need to update this?
And the addresses have a minor difference &H22** -> &H23**.
Code: Select all
# Special parameters
LAUNCH_SPEED,&H2349,2,1,1,2,Launch speed
#REV_LIMIT_NORMAL_IGN_RETARD,&H224E,2,1,2,12.5,Normal rev limit (ign retard)
REV_LIMIT_NORMAL_FUEL_CUT,&H234A,2,1,2,12.5,Normal rev limit (LC)
#REV_LIMIT_LAUNCH_IGN_RETARD,&H2251,2,1,2,12.5,Launch rev limit (ign retard)
REV_LIMIT_LAUNCH_FUEL_CUT,&H234C,2,1,2,12.5,Launch rev limit (LC)
#REV_LIMIT_IGN_RETARD,&H2250,2,1,2,12.5,Rev Limit ignition retard
And the addresses have a minor difference &H22** -> &H23**.
Error1:Matt wrote:that is a later version. what is the error you are getting?
Code: Select all
Address entry: LAUNCH_SPEED 0x2349 (length 0x1) out of range. Ignoring this entry. Fix the address file to remove this warning.
Code: Select all
Address entry: REV_LIMIT_NORMAL_FUEL_CUT 0x234A (length 0x2) out of range. Ignoring this entry. Fix the address file to remove this warning.
Code: Select all
Address entry: REV_LIMIT_LAUNCH_FUEL_CUT 0x234C (length 0x2) out of range. Ignoring this entry. Fix the address file to remove this warning.
Code: Select all
14:09:32.765 About to create MTS controls...
14:09:32.781 MTS1 Control OCX creation successful within this view
14:09:32.781 UpdateAllCombinationLists()
14:09:33.953 finished
14:09:33.953 ~CParser
14:09:33.953 Opening B13_SR20DE_256_E_91_92-LC.adr
14:09:33.968 ~CParser
14:09:33.968 NTLOOKUPID is 61
14:11:12.515 ConsultGetActiveSelections()
14:11:12.515 ~CParser
14:11:12.515 MyFileImgOpen: read_rom_Length 00008000 rom_length 8000 number 1
Hey guys,
Is there any reason why this cannot be implemented by just burning 2 images to a 27C256 and then use the highest order address bit to switch between the two images? One of my mates used to do this on his CA18 and it worked a treat. He didn't use it for launch control - just different tunes.
You could even go to a 27C512 for 4 maps. It's just that the switching gets a little trickier.
PL
Is there any reason why this cannot be implemented by just burning 2 images to a 27C256 and then use the highest order address bit to switch between the two images? One of my mates used to do this on his CA18 and it worked a treat. He didn't use it for launch control - just different tunes.
You could even go to a 27C512 for 4 maps. It's just that the switching gets a little trickier.
PL