604ci build. Ready run msd or ignition box?
03-19-2017, 12:19 PM
#61
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I'm curious to know more about your full ignition setup. I've been running the Holley HP for the last 4 or 5 seasons and have the MSD small cap HEI (8366) with 6M box using the Holley to control timing. Last year I ran into issues with the ignition module failing. I got it worked out, but it left me wondering when it will fail again. I've been considering going with Holley's new(er) dual sync distributor which I read will support the coil packs, plus I would be able to run full sequential vs. the batch fire I am now. Just looking for some options and the most reliable way to go.
Pm me your email address and we can chat... I'd be happy to walk you through the details, I just don't want to hikack the OP's thread anymore than I have.
03-19-2017, 01:52 PM
#62
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Dyno 2nd engine Friday with my engine builder 85551 msd and 7al box virtually same numbers as first engine[ATTACH=CONFIG]565686[/ATTACH] both engine had hickup in high rpm with ecurve msd n no Box engine was flawless with box
Last edited by 5050; 03-19-2017 at 01:57 PM.
03-19-2017, 02:01 PM
#63
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I would invest in daytona boxes with adjustable timing curve before i invested in ignition boxes as you will most likely pick up tq from 4000 to 5000 from having a actual timing curve vs all in. I have seen a noticeable difference on dyno on last few motors i dynoed, fwiw, smitty
03-19-2017, 04:45 PM
#64
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How much tq are you talking about. Why do you think you see the difference? What is the max rpm of these engines? Reason i ask i run a 9000rpm carbed sbc and timing is locked out at 36 degrees and i'm always looking for an edge with the guys i race with. I don't see anyone running the daytona boxes.
03-19-2017, 07:19 PM
#66
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The reason you may gain torque, with LESS timing, is its because......firing the plug too early, creates NEGATIVE work. The piston is on the way up when you fire the spark plug. If you fire it too early, combustion happens too soon, and you start trying to push the piston back down, when its still trying to come up the bore.
There is simply an optimum time to fire the plug. Theres a ton of factors why and when it needs to be fired. Under boost, you have a very dense and volitle charge. It burns very quickly. When it burns quick, you don't need to fire the plug so soon. This is why boost retard devices were invented. They weren't "safety" tools. They were designed in that, when boost comes in, the timing simply needs to be reduced. With weights and springs in a old school mechanical distributor, there was no way to really retard timing under boost, without a separate controller.
One of the factors that dictates when the plug needs to be fired, and cannot be changed, is PISTON SPEED. It is mechanically impossible, for a engine that turns 9000RPM, like mentioned, to require the same spark advance it does at 9000, as it does at 3000. Think about it. Its simply time. The faster the piston is traveling up the bore, the sooner you need to fire the plug, to ignite the air/fuel mix at the proper time, so you get max leverage on the crankshaft.
My guess, is that 9000RPM small block, will like more than 36* timing at 9000rpm. I run 35* total in my supercharged boat engines, but, thats at 6000RPM. I would not run 35 timing, at 3000rpm. Theres no need for it, and as I have seen, it can actually reduce torque, and induce spark knock.
If you look at any automobile from the last 50 plus years, I can't think of a single one, that had "locked" timing. The only thing locked timing was good for, was when you have a monster cam, and no cylinder pressure at idle. And in a 540ci with a blower and 244/256 114 camshaft, you are no where near needing 34 degrees of timing at idle.
Personally, I'd like to let the engine tell me what it likes for timing, in a controlled enviroment like a dyno. It will tell you when you have gone too far, when you see no power gain from the increase in advance. This is why you don't dyno your pump gas engine on race fuel. Higher the octane, slower the burn. The timing it likes on race fuel, wont be the timing it likes on regular unleaded. When I've pulled 9 degrees of advance out of a 1000hp engine in the midrange, and seen a gain in torque at the flywheel, it simply tells me we were firing the plug WAAAAY to early. A dyno can tell you alot, if you use it for what its for, and not just a power readout. Properly tuning your ignition system on the dyno, can have a direct effect on brake specific numbers.
Ignition timing is not a power adder, or power reducer. Retarding timing thinking its "safe" , is a good way to kill exhaust valves/seats, and simply waste power. Too much timing, also no good. Creates pumping losses, and can lead to spark knock, and we know what that does.
There is simply an optimum time to fire the plug. Theres a ton of factors why and when it needs to be fired. Under boost, you have a very dense and volitle charge. It burns very quickly. When it burns quick, you don't need to fire the plug so soon. This is why boost retard devices were invented. They weren't "safety" tools. They were designed in that, when boost comes in, the timing simply needs to be reduced. With weights and springs in a old school mechanical distributor, there was no way to really retard timing under boost, without a separate controller.
One of the factors that dictates when the plug needs to be fired, and cannot be changed, is PISTON SPEED. It is mechanically impossible, for a engine that turns 9000RPM, like mentioned, to require the same spark advance it does at 9000, as it does at 3000. Think about it. Its simply time. The faster the piston is traveling up the bore, the sooner you need to fire the plug, to ignite the air/fuel mix at the proper time, so you get max leverage on the crankshaft.
My guess, is that 9000RPM small block, will like more than 36* timing at 9000rpm. I run 35* total in my supercharged boat engines, but, thats at 6000RPM. I would not run 35 timing, at 3000rpm. Theres no need for it, and as I have seen, it can actually reduce torque, and induce spark knock.
If you look at any automobile from the last 50 plus years, I can't think of a single one, that had "locked" timing. The only thing locked timing was good for, was when you have a monster cam, and no cylinder pressure at idle. And in a 540ci with a blower and 244/256 114 camshaft, you are no where near needing 34 degrees of timing at idle.
Personally, I'd like to let the engine tell me what it likes for timing, in a controlled enviroment like a dyno. It will tell you when you have gone too far, when you see no power gain from the increase in advance. This is why you don't dyno your pump gas engine on race fuel. Higher the octane, slower the burn. The timing it likes on race fuel, wont be the timing it likes on regular unleaded. When I've pulled 9 degrees of advance out of a 1000hp engine in the midrange, and seen a gain in torque at the flywheel, it simply tells me we were firing the plug WAAAAY to early. A dyno can tell you alot, if you use it for what its for, and not just a power readout. Properly tuning your ignition system on the dyno, can have a direct effect on brake specific numbers.
Ignition timing is not a power adder, or power reducer. Retarding timing thinking its "safe" , is a good way to kill exhaust valves/seats, and simply waste power. Too much timing, also no good. Creates pumping losses, and can lead to spark knock, and we know what that does.
Last edited by MILD THUNDER; 03-19-2017 at 07:24 PM.
03-19-2017, 07:22 PM
#67
Tibstoy2 - I have been toying around with installing smart coils to my Holley EFI.
What did you use to mount the coils to the valve covers - Or did you make something up?
I am running the dual sinc distributor from Holley with an MSD box.
What did you use to mount the coils to the valve covers - Or did you make something up?
I am running the dual sinc distributor from Holley with an MSD box.
03-19-2017, 07:47 PM
#68
Platinum Member
Platinum Member
The reason you may gain torque, with LESS timing, is its because......firing the plug too early, creates NEGATIVE work. The piston is on the way up when you fire the spark plug. If you fire it too early, combustion happens too soon, and you start trying to push the piston back down, when its still trying to come up the bore.
There is simply an optimum time to fire the plug. Theres a ton of factors why and when it needs to be fired. Under boost, you have a very dense and volitle charge. It burns very quickly. When it burns quick, you don't need to fire the plug so soon. This is why boost retard devices were invented. They weren't "safety" tools. They were designed in that, when boost comes in, the timing simply needs to be reduced. With weights and springs in a old school mechanical distributor, there was no way to really retard timing under boost, without a separate controller.
One of the factors that dictates when the plug needs to be fired, and cannot be changed, is PISTON SPEED. It is mechanically impossible, for a engine that turns 9000RPM, like mentioned, to require the same spark advance it does at 9000, as it does at 3000. Think about it. Its simply time. The faster the piston is traveling up the bore, the sooner you need to fire the plug, to ignite the air/fuel mix at the proper time, so you get max leverage on the crankshaft.
My guess, is that 9000RPM small block, will like more than 36* timing at 9000rpm. I run 35* total in my supercharged boat engines, but, thats at 6000RPM. I would not run 35 timing, at 3000rpm. Theres no need for it, and as I have seen, it can actually reduce torque, and induce spark knock.
If you look at any automobile from the last 50 plus years, I can't think of a single one, that had "locked" timing. The only thing locked timing was good for, was when you have a monster cam, and no cylinder pressure at idle. And in a 540ci with a blower and 244/256 114 camshaft, you are no where near needing 34 degrees of timing at idle.
Personally, I'd like to let the engine tell me what it likes for timing, in a controlled enviroment like a dyno. It will tell you when you have gone too far, when you see no power gain from the increase in advance. This is why you don't dyno your pump gas engine on race fuel. Higher the octane, slower the burn. The timing it likes on race fuel, wont be the timing it likes on regular unleaded. When I've pulled 9 degrees of advance out of a 1000hp engine in the midrange, and seen a gain in torque at the flywheel, it simply tells me we were firing the plug WAAAAY to early. A dyno can tell you alot, if you use it for what its for, and not just a power readout. Properly tuning your ignition system on the dyno, can have a direct effect on brake specific numbers.
Ignition timing is not a power adder, or power reducer. Retarding timing thinking its "safe" , is a good way to kill exhaust valves/seats, and simply waste power. Too much timing, also no good. Creates pumping losses, and can lead to spark knock, and we know what that does.
There is simply an optimum time to fire the plug. Theres a ton of factors why and when it needs to be fired. Under boost, you have a very dense and volitle charge. It burns very quickly. When it burns quick, you don't need to fire the plug so soon. This is why boost retard devices were invented. They weren't "safety" tools. They were designed in that, when boost comes in, the timing simply needs to be reduced. With weights and springs in a old school mechanical distributor, there was no way to really retard timing under boost, without a separate controller.
One of the factors that dictates when the plug needs to be fired, and cannot be changed, is PISTON SPEED. It is mechanically impossible, for a engine that turns 9000RPM, like mentioned, to require the same spark advance it does at 9000, as it does at 3000. Think about it. Its simply time. The faster the piston is traveling up the bore, the sooner you need to fire the plug, to ignite the air/fuel mix at the proper time, so you get max leverage on the crankshaft.
My guess, is that 9000RPM small block, will like more than 36* timing at 9000rpm. I run 35* total in my supercharged boat engines, but, thats at 6000RPM. I would not run 35 timing, at 3000rpm. Theres no need for it, and as I have seen, it can actually reduce torque, and induce spark knock.
If you look at any automobile from the last 50 plus years, I can't think of a single one, that had "locked" timing. The only thing locked timing was good for, was when you have a monster cam, and no cylinder pressure at idle. And in a 540ci with a blower and 244/256 114 camshaft, you are no where near needing 34 degrees of timing at idle.
Personally, I'd like to let the engine tell me what it likes for timing, in a controlled enviroment like a dyno. It will tell you when you have gone too far, when you see no power gain from the increase in advance. This is why you don't dyno your pump gas engine on race fuel. Higher the octane, slower the burn. The timing it likes on race fuel, wont be the timing it likes on regular unleaded. When I've pulled 9 degrees of advance out of a 1000hp engine in the midrange, and seen a gain in torque at the flywheel, it simply tells me we were firing the plug WAAAAY to early. A dyno can tell you alot, if you use it for what its for, and not just a power readout. Properly tuning your ignition system on the dyno, can have a direct effect on brake specific numbers.
Ignition timing is not a power adder, or power reducer. Retarding timing thinking its "safe" , is a good way to kill exhaust valves/seats, and simply waste power. Too much timing, also no good. Creates pumping losses, and can lead to spark knock, and we know what that does.
03-19-2017, 07:57 PM
#69
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Thread Starter
And yes, thats why we dyno, to find what motor likes and doesnt like. Guys that drop motors in boats vs comprehensive dyno testing/tuning have no idea whats been missed or over looked. Now dynoing to get a sheet of paper to wave around with no true tuning, only a step better than just bolting it in boat. I still havent got a answer from somone knowledgeable as to why a stock merc 500 efi has 28 degrees of timing at 4800 and jumps to 35.9 degrees by 5000 or 5200 without being graduated, blended, when i first saw that all i could think of was it was a hack job at factory!
03-19-2017, 08:07 PM
#70
Registered
Those air fuel ratios on your dyno sheet, are those valid numbers ?
