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By Old Grey
#13993
Is Speedy ever going to get individual cyl timing, ie a table for each IGN channel, or is it beyond the software/hardware.
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By cx500tc
#13996
Old Grey wrote:Is Speedy ever going to get individual cyl timing, ie a table for each IGN channel, or is it beyond the software/hardware.
Out of curiosity, what would be the criteria for having a different ignition curve or advance setting for each cylinder?
By Old Grey
#14009
Sorry, I should have thought about such a stupid question before asking it because no one is going to spend $1000's on a dyno for such marginal gains with a $150 EMS.

In racing things like cylinders running hotter than others not being able to handle as much timing, fuel distribution with carbs, or common plenums experiencing fuel inertia on launch, even symmetrical chambers might have different thickness walls due to casting, etc. But that being said you would only chase things like that when you are running out of areas to gain power in highly competitive situations.
By RichCreations
#14019
Old Grey wrote:Sorry, I should have thought about such a stupid question before asking it because no one is going to spend $1000's on a dyno for such marginal gains with a $150 EMS.

In racing things like cylinders running hotter than others not being able to handle as much timing, fuel distribution with carbs, or common plenums experiencing fuel inertia on launch, even symmetrical chambers might have different thickness walls due to casting, etc. But that being said you would only chase things like that when you are running out of areas to gain power in highly competitive situations.
This is actually useful for less extreme engines as well, take the good old air cooled Vw engines, the stock points distributers often had different timing for #3 as it run hotter then the rest...
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By PSIG
#14021
I agree, ICIT could be a useful benefit for the majority of Speeduino users, and I am looking forward to it. Whether most others will actually use it, I can't say, but it would helpful to a large segment of high-power, high-mileage, and low-emissions (efficiency/economy/emissions) freaks. Other "make it run OK" users will not take advantage of most of the features Speedy has already anyway.

David
By Old Grey
#14022
Only the big boys can treat each cyl as an individual engine, because it takes a lot of resources and money. The big boys are in the business of finding those tiny improvements because that is all there is left when an engine is at the limit of it's development. In old Formula Ford you would work a whole year to find a solid 1hp.

Our dyno guy could see ping in the power trace, but what are we going to do, advance each cyl until we hear it ping and knock it back 5º. Too hard for such a small gain.

I would rather have dual fuel tables that are externally switchable, so I can run in high economy mode and then switch to full power when I need to get in front from a set of traffic lights.
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By PSIG
#14024
Old Grey wrote:Only the big boys can treat each cyl as an individual engine, because it takes a lot of resources and money.
I must completely disagree with that. Every engine should be treated as multiple one-cylinder engines, as that is the only way to get the most out of each, and therefore the whole, for any application. This is true whether it's a commuter car or serious comp car. Individual cylinder ignition trim (I will call it ICIT) is very handy to average tuners, as you can see issues or opportunities and take advantage of them.

Example - you are tuning your weekend Honda turbo rocket on pump gas. You make a back-road run (or dyno pull, or track run) through a gear and check your plugs. #3 shows light signs of detonation, so you pull a couple degrees from that cylinder, advance the Spark Table for the rest of them and run again, repeating this a few times until the cylinder that needs the most is at its peak, and the rest are variously retarded for their peaks. Bingo. Minimum timing for best torque on each cylinder for max power, and all in a matter of minutes on your local back road or whatever. The alternative is to run timing for all cylinders based on the weakest one. :(

More mundane? Perhaps you have an engine that is not blueprinted, and it has typical variance in effective compression, or uneven cylinder heat, or uneven port flows, or some leaking rings on one piston or one valve stem seal sucking oil—all capable of being individually tweaked just for reasonable running without being as lame (better mileage or power), or prone to det (better power and less damage), or whatever it's problem is. The price is your time. It's really no different than using cylinder fuel trim (ICFT), simply giving each what works best, and useful to anyone with an engine that isn't perfect from cylinder-to-cylinder, and whether using det-limited fuel or not. IMO that includes almost all of us.
Image
David

PS: A warm-dry compression test will tell you right-off which cylinders will likely need more or less timing to make best torque, simply by observing dynamic compression as one factor. ;)
By Old Grey
#14028
Still a lot of work for little gain on only a street car.

I suppose the easiest way is use the same table with different offsets per channel - me see a Rotary here :D -.
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By PSIG
#14031
Well, that's fine, and don't use it if you don't want to. Ignition timing holds a lot of power back or enables it. I used that Honda example for a reason, as it had exactly that issue with det crippling one cylinder and holding the rest back, so it was one I thought of. As cylinder trim was not available (or it would have been used instead), the injector was swapped on that cylinder to run it a bit rich, which did not help power but enabled the other cylinders to have the advance they needed. That allowed the timing to be bumped 3° for a gain of 25 ft-lb torque (over 30hp). ICIT would have allowed timing change only when necessary (unlike an offset), for yet more gain.

I wouldn't say that's only a "little gain" for that daily-driver street car, and we all know guys that have spent $500 or $1000 for a new manifold or other parts to hopefully get 10 or 20. This is free and takes only moments to do, and no big dollar lab or dyno; only a bit of time and analysis of best options available to let the engine have what it wants. But, do your thing in whatever way works for you.

David
By Old Grey
#14034
30hp for 3º must be some serious street engine, like in the 300 - 500hp range, because I don't see that happening in a old NA engine with a leaking VSS.

Before the new offset blower they used to drop the comp of individual cyls in TF Nitro if they keep blowing.
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