M8 HO ECU on M1000 engine

Dec 25, 2019
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Do not use an 800 ecu for timing control. Timing is everything when making power on a motor. Small differences in the curve could make your 1000 anemic or blow it up. The 1000 engine is very sensitive to detonation compared to the 800 because of the surface area of the piston crown. Sparing many details, it is a bad idea to use any ecu that is not programmed for a 1000 motor.

Im not worried about that. I have a pcv fuel/timing control wideband lambda egt and exhaust backpressure guage. Just needed to know if the interface is the same.
 
Oct 9, 2009
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Im not worried about that. I have a pcv fuel/timing control wideband lambda egt and exhaust backpressure guage. Just needed to know if the interface is the same.
I have used PCV controllers too. They are not a cure all. You sacrifice the strength of your spark using the ignition control module. The ignition driver really weakens the spark output because the driver is low quality and inefficient. That may not cause you problems with an NA sled if you have low enough compression. But, it won't work if you run a turbo. I tried it many times on such setups. It will cause misfires as the boost comes up because cylinder pressure will blow the weak spark out. You can reduce the spark gap, but that provides little improvement. This problem also gets worse as your octane goes up; this is a problem for sleds running race fuel or high compression. So, a high compression big bore may have problems too.

At the end of the day, why are you allergic to putting the correct computer in it? The factory spent all the dyno time and money to optimize timing and to maintain reliability, so you don't have to. Chances are, you won't dyno the sled, so you will never get the timing curve right. And, timing is everything when it comes to making power. This is not a guess, I tune race engines. Really think through this advice because your sled won't run right, or you will start collecting pistons.

At the end of the day, you may be happy with a soft 1000 motor, but that seems counter to what your goal is. Don't let the fact that you have a controller for an 800 drive your decisions for building a 1000. You will spend a lot to build it, and it won't run great until you put in the dyno time to get the tune spot on, or you buy correct stuff for a 1000.

Lastly, you are making a big assumption that all the sensors are not only the same between the two engines but are also scaled the same. If they are not identical in every way, it won't run right. Food for thought...I have spent the dyno time, so you don't have to.
 
Dec 25, 2019
7
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I have used PCV controllers too. They are not a cure all. You sacrifice the strength of your spark using the ignition control module. The ignition driver really weakens the spark output because the driver is low quality and inefficient. That may not cause you problems with an NA sled if you have low enough compression. But, it won't work if you run a turbo. I tried it many times on such setups. It will cause misfires as the boost comes up because cylinder pressure will blow the weak spark out. You can reduce the spark gap, but that provides little improvement. This problem also gets worse as your octane goes up; this is a problem for sleds running race fuel or high compression. So, a high compression big bore may have problems too.

At the end of the day, why are you allergic to putting the correct computer in it? The factory spent all the dyno time and money to optimize timing and to maintain reliability, so you don't have to. Chances are, you won't dyno the sled, so you will never get the timing curve right. And, timing is everything when it comes to making power. This is not a guess, I tune race engines. Really think through this advice because your sled won't run right, or you will start collecting pistons.

At the end of the day, you may be happy with a soft 1000 motor, but that seems counter to what your goal is. Don't let the fact that you have a controller for an 800 drive your decisions for building a 1000. You will spend a lot to build it, and it won't run great until you put in the dyno time to get the tune spot on, or you buy correct stuff for a 1000.

Lastly, you are making a big assumption that all the sensors are not only the same between the two engines but are also scaled the same. If they are not identical in every way, it won't run right. Food for thought...I have spent the dyno time, so you don't have to.
This is a high power output engine that will serve in the next watercross season in sweden. Only thing that is stock is the wire harness. I need to get rid of the rev limiter at 8k so the easiest way for me would be to get a 800 cdi unit. The engine will be put on a dyno as soon as i have the last few things in order. Back to your first statement though. Is it common that the ignition driver weakens the spark ? Ive never seen that they have been talking about that on dynotechresearch before. And i meassured the resistance in all of the sensors and it is within specs between the 2 engines.
 
Oct 9, 2009
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This is a high power output engine that will serve in the next watercross season in sweden. Only thing that is stock is the wire harness. I need to get rid of the rev limiter at 8k so the easiest way for me would be to get a 800 cdi unit. The engine will be put on a dyno as soon as i have the last few things in order. Back to your first statement though. Is it common that the ignition driver weakens the spark ? Ive never seen that they have been talking about that on dynotechresearch before. And i meassured the resistance in all of the sensors and it is within specs between the 2 engines.
It happened to me on several turbo builds. For those builds where it was not an option, I had to pull the ignition controller off and for go the timing adjustments. Everything worked using the factory computer after removing the ignition module. Other builds, I put a motec m130 on and cranked things up using ign1 race coils. I work on turbo setups running race fuels, so I can't really say for NA builds running pump. Coil output is a problem if the factory ignition/coils are weak. If so, race gas makes it much worse because of all the octane. You may have success so long as you can use the dyno to correctly set the timing curve.
 
Oct 9, 2009
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It depends on cylinder pressure and octane. The internal drivers in the ignition control module are the problem. They are okay for mild applications where you are not close to blowing the spark out, so you don't need more output than that controller can generate. The ignition controller works by intercepting the ignition signal and modifying it before sending it to the coils. So, if you need more than the module can put out, then it weakens the signal. If you need less, they can supply it.
 
Dec 25, 2019
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It depends on cylinder pressure and octane. The internal drivers in the ignition control module are the problem. They are okay for mild applications where you are not close to blowing the spark out, so you don't need more output than that controller can generate. The ignition controller works by intercepting the ignition signal and modifying it before sending it to the coils. So, if you need more than the module can put out, then it weakens the signal. If you need less, they can supply it.
Thanks for that very usefull information. Do you know by any chance the resistance for a well functioning knock sensor on the M8 ?
 
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