TOTM: Standalone Engine Managment
02-28-2014, 09:58 PM
#31
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I haven't run a wasted spark format for quite a while and I seem to have lost many of my calibration files that would make me confidently answer this question. The one wasted spark file I have is from one of my customers and the value he has for base timing offset shows 49 degrees BTDC for the ref pin location. I can't recall if this is correct but I know I wouldn't save a file that wasn't working properly.
02-28-2014, 10:33 PM
#32
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I establish the offset value by setting the timing to zero then shoot the bellhousing reference mark with engine running at idle. I also make sure to run a non adjustable timing light so there is no potential of error on the indication. This was used on factory flywheels using stock speed & ref sensors. I cannot confirm whether I ran more than -49 degrees for offset value - the laptop I used back then took a dump and I chucked it. After moving to full sequential, I stopped pushing the wasted spark option since there was such an improvement in smoothness when going with a cam sync. I felt it was worth every penny for upgrading.
With a cam sync setup, I can make the offset whatever I want it to be. The offset basically dictates the maximum amount of ignition advance you will be able to run, so something around 40-50 degrees BTDC is a good range to work in.
With a cam sync setup, I can make the offset whatever I want it to be. The offset basically dictates the maximum amount of ignition advance you will be able to run, so something around 40-50 degrees BTDC is a good range to work in.
02-28-2014, 11:03 PM
#33
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I establish the offset value by setting the timing to zero then shoot the bellhousing reference mark with engine running at idle. I also make sure to run a non adjustable timing light so there is no potential of error on the indication. This was used on factory flywheels using stock speed & ref sensors. I cannot confirm whether I ran more than -49 degrees for offset value - the laptop I used back then took a dump and I chucked it. After moving to full sequential, I stopped pushing the wasted spark option since there was such an improvement in smoothness when going with a cam sync. I felt it was worth every penny for upgrading.
With a cam sync setup, I can make the offset whatever I want it to be. The offset basically dictates the maximum amount of ignition advance you will be able to run, so something around 40-50 degrees BTDC is a good range to work in.
With a cam sync setup, I can make the offset whatever I want it to be. The offset basically dictates the maximum amount of ignition advance you will be able to run, so something around 40-50 degrees BTDC is a good range to work in.
03-01-2014, 04:07 AM
#34
Totally agree about dial back timing lights -- they have only one pulse per every two revolutions to work with -- compared to 264 actual (1056 virtual) pulses that the DME sees. Hardly a fair fight. Zeroing out the timing to set an offset number works fine for making maps, but I presume it masks hardware latencies so may or may not be a good measure of the actual/physical offset of the pin...?
03-01-2014, 11:05 AM
#36
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03-01-2014, 11:19 AM
#37
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ahhh...Chris beat me to it. I was going to mention the 2 stroke adjustable timing lights! its also worth mentioning that you MUST set timing using the mark on the bellhousing. It will never run right if you try to use the mark on the cam gear.
03-01-2014, 11:23 AM
#38
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For the cost of the cam sensor I believe that full sequential is a big plus in any 951. possibly the biggest plus is the added dynamic range for the injectors. On batch fired systems (anything less than full sequential) you are turning the injector on and off twice per cycle (2 revolutions) and the extra on/off takes quite a bit of time. Typical injectors have a minimum turn on time of slightly over 1ms (1.3ms is safe). so at 6500 rpm you have 9ms for each revolution or 18ms for each cycle. For batch fired you have to cycle the injector twice so deduct 2.6ms from the time available and for sequential you only deduct 1.3ms. Thats 15.4ms vs 16.7ms. (8.5% more on time)
Is that a big deal? yes, on some engines you may use the full dynamic range on an injector - close to minimum on time for idle (actually its a lower duty cycle in small throttle opening with slight deceleration) and close to 100% at 20psi/6500rpm.
So - if you are going to go with anything over the least expensive stand alone add the full sequential option!
Is that a big deal? yes, on some engines you may use the full dynamic range on an injector - close to minimum on time for idle (actually its a lower duty cycle in small throttle opening with slight deceleration) and close to 100% at 20psi/6500rpm.
So - if you are going to go with anything over the least expensive stand alone add the full sequential option!
03-01-2014, 11:24 AM
#39
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Cam gear timing mark is NEVER right on the mark!
03-01-2014, 11:37 AM
#41
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03-01-2014, 01:04 PM
#42
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Vic, are you aware of track guys running the Link/ViPec solely off the two factory triggers -- without an extra cam sensor?
03-01-2014, 02:12 PM
#43
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If you get a Microsquirt board that you have to build, it costs about $270. The board itself is about the size of a credit card. Microsquirt has knock and flex fuel capability. So far, this is the cheapest ECU I've come across that has this capability. I actually run it on my ChumpCar. I also know a few people that daily drive their cars on Megasquirt ECUs.
If you don't want to do a lot of fabrication work, I think CEP makes a crank trigger wheel and cam sensor setup. Dougs951 put this ecu in a gutted stock ECU, so you could retain your stock harness (although, you would need to make sure your speed and reference sensors are now crank and cam sensor among other things).
What entices me about the Microsquirt is the flex fuel capability. By flex fuel capability, I don't mean two separate maps for pump gas and E85, but rather any mix of the two. You have a GM Flex Fuel Sensor plumbed and wired to the car to measure the ethanol content in your fuel rail. It will adjust the map on the fly depending on sensor input.
The other systems I was looking at that have this capability were Haltech, AEM, and ProEFI. I know there are more out there, but these will end up costing >$2000 for the whole setup.
I've been keeping an eye on megasquirt for a while now, and think it would be a very cost effective computer for the DIYer. However, there is a steep learning curve and possible headaches along the way. I'm surprised that not many people have gone this route. Megasquirt seems to be pretty big in other car circles.
I have no affiliation to any of these brands. This is just the research I've done for my own purposes.
If you don't want to do a lot of fabrication work, I think CEP makes a crank trigger wheel and cam sensor setup. Dougs951 put this ecu in a gutted stock ECU, so you could retain your stock harness (although, you would need to make sure your speed and reference sensors are now crank and cam sensor among other things).
What entices me about the Microsquirt is the flex fuel capability. By flex fuel capability, I don't mean two separate maps for pump gas and E85, but rather any mix of the two. You have a GM Flex Fuel Sensor plumbed and wired to the car to measure the ethanol content in your fuel rail. It will adjust the map on the fly depending on sensor input.
The other systems I was looking at that have this capability were Haltech, AEM, and ProEFI. I know there are more out there, but these will end up costing >$2000 for the whole setup.
I've been keeping an eye on megasquirt for a while now, and think it would be a very cost effective computer for the DIYer. However, there is a steep learning curve and possible headaches along the way. I'm surprised that not many people have gone this route. Megasquirt seems to be pretty big in other car circles.
I have no affiliation to any of these brands. This is just the research I've done for my own purposes.
https://www.diyautotune.com/ms3pro_module/index.html
At the moment I think this is the best bang for buck ($850) without DIY soldering and printer connectors..
I like to slder projects, but do not trust my soldering skills enough to try and run quite expensive engine on it..
I already have clewett front mount 60-2 crank trigger, to which I will add cam trigger and run sequential spark & fuel. At least that is the plan for now.
The plan also includes Mercury marine IGN-1A coils and 80mm Nissan Q45 MAF.
03-01-2014, 02:41 PM
#44
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Tom, all of the track guys I've worked with opted for running a cam sensor. I have 3 street car guys running wasted spark and I haven't heard from them in a few years, so I'm guessing that they haven't had any issues.
03-01-2014, 03:17 PM
#45
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