Anyone home build EFI for individual throttle bodies Options

[rick 918-S]

Looking for links the threads. Post the links here.

[GregAmy]

Micro/Mega doesn't "self tune" but it will real-time correct based on wideband input to a target table. You'll then take the logs and run them through Megalog Viewer HD analyze and correct the VE table(s) to your desire. It can do that for you if you accept the analysis.

I'm not a fan of auto-correct, where you let it constantly adjust the tables; I'm too worried about some kind of systems failure (wideband) where all of a sudden it's making table changes based on bad input.

However, I do use logging and Megalog/analyze a lot, and my tables are at the point where I'm comfortable giving the ECU +/- 5% leeway to make real-time fueling adjustments without writing permanent changes to the VE tables.

[JamesM]

Micro/Mega doesn't "self tune" but it will real-time correct based on wideband input to a target table. You'll then take the logs and run them through Megalog Viewer HD analyze and correct the VE table(s) to your desire. It can do that for you if you accept the analysis.

I'm not a fan of auto-correct, where you let it constantly adjust the tables; I'm too worried about some kind of systems failure (wideband) where all of a sudden it's making table changes based on bad input.

However, I do use logging and Megalog/analyze a lot, and my tables are at the point where I'm comfortable giving the ECU +/- 5% leeway to make real-time fueling adjustments without writing permanent changes to the VE tables.

It is worth mentioning that Megasquirt can also be "auto tuned"

Tunerstudio (at least the full paid versions) will auto tune your Megasquirt to AFR targets without having to do log collection however it does still require you have a device connected running tunerstudio while you are doing it.

Thats really the main difference with Holley systems as far as that feature goes, with Megasquirt the autotune has to be done with a laptop connected, with Holley while it needs to be configured with a laptop, the actual driving portion of the autotune can be done without it.

For me its not a big deal as i dont like autotune running all the time anyways as if any part of the system start acting up while autotune is enabled it may mask the issue while pulling your overall tune completely out of whack. In addition to the autotune algorithms never being perfect and im just a control freak/perfectionist. Autotune always struggles with transient conditions especially where 02 reading latency settings are not known/perfectly dialed in, so if you are on/off the throttle a lot while performing it you can wind up developing reach/lean spots in certain parts of your map. I would guess given the user friendly nature of the Holley system that they probably have some logic coded in to ignore data around transients but I have never examined a fuel map post Holley autotune to see how well it does.

These are issues that a normal user most likely would never notice on their AFR gauge as they happen in an instant and gauges tend to be dampened but that you might see in a data log or by examining the fuel map. Again, perfectionist (IMG:style_emoticons/default/stromberg.gif)

That is another issue of Megasquirt that isnt frequently mentioned, because of the level of control you have over literally everything, if you are a perfectionist its hard to ever stop tweaking with it.

and on that subject, and looping back to the OPs question about ITBs...

Most aftermarket injection system either operate using some form of Speed Density algorithm (Map sensor based load determination) or Alpha-N (throttle position based load) or allow you to chose between the two. Generally people will run Alpha-N with ITBs due to the limited range over which ITBs will produce measurable manifold vacuum BUT Alpha-N is a much rougher estimation of load as calculating load using just the throttle position doesent measure what the engine is actually doing at any given time. This tends to manifest itself as drivability issues at low or zero throttle angles and cant account for different engine loads under the same throttle position like changing alternator or AC loads at idle. Measuring load via manifold vacuum is far more accurate where that vacuum signal exists. Modern firmware variants for Megasquirt have a hybrid mode that blends Speed Density and Alpha-N algorithms via a switching table which results in having the best of both worlds and increases the fueling accuracy and drivability when running ITBs. That being said it adds another layer of significant complexity to setting up your initial tune as you have to establish a TPS/vacuum transition map in addition to your ignition and fueling maps. Dialing in 3x three dimensional maps that all impact each other is a lot of data points to manage. Given Megasquirt is already pretty complex without this it may be a lot to ask of someone to figure out on their first build. I have setup a car using this, the results are amazing but it is somewhat time consuming.

[ClayPerrine]

Micro/Mega doesn't "self tune" but it will real-time correct based on wideband input to a target table. You'll then take the logs and run them through Megalog Viewer HD analyze and correct the VE table(s) to your desire. It can do that for you if you accept the analysis.

I'm not a fan of auto-correct, where you let it constantly adjust the tables; I'm too worried about some kind of systems failure (wideband) where all of a sudden it's making table changes based on bad input.

However, I do use logging and Megalog/analyze a lot, and my tables are at the point where I'm comfortable giving the ECU +/- 5% leeway to make real-time fueling adjustments without writing permanent changes to the VE tables.

It is worth mentioning that Megasquirt can also be "auto tuned"

Tunerstudio (at least the full paid versions) will auto tune your Megasquirt to AFR targets without having to do log collection however it does still require you have a device connected running tunerstudio while you are doing it.

Thats really the main difference with Holley systems as far as that feature goes, with Megasquirt the autotune has to be done with a laptop connected, with Holley while it needs to be configured with a laptop, the actual driving portion of the autotune can be done without it.

For me its not a big deal as i dont like autotune running all the time anyways as if any part of the system start acting up while autotune is enabled it may mask the issue while pulling your overall tune completely out of whack. In addition to the autotune algorithms never being perfect and im just a control freak/perfectionist. Autotune always struggles with transient conditions especially where 02 reading latency settings are not known/perfectly dialed in, so if you are on/off the throttle a lot while performing it you can wind up developing reach/lean spots in certain parts of your map. I would guess given the user friendly nature of the Holley system that they probably have some logic coded in to ignore data around transients but I have never examined a fuel map post Holley autotune to see how well it does.

These are issues that a normal user most likely would never notice on their AFR gauge as they happen in an instant and gauges tend to be dampened but that you might see in a data log or by examining the fuel map. Again, perfectionist (IMG:style_emoticons/default/stromberg.gif)

That is another issue of Megasquirt that isnt frequently mentioned, because of the level of control you have over literally everything, if you are a perfectionist its hard to ever stop tweaking with it.

and on that subject, and looping back to the OPs question about ITBs...

Most aftermarket injection system either operate using some form of Speed Density algorithm (Map sensor based load determination) or Alpha-N (throttle position based load) or allow you to chose between the two. Generally people will run Alpha-N with ITBs due to the limited range over which ITBs will produce measurable manifold vacuum BUT Alpha-N is a much rougher estimation of load as calculating load using just the throttle position doesent measure what the engine is actually doing at any given time. This tends to manifest itself as drivability issues at low or zero throttle angles and cant account for different engine loads under the same throttle position like changing alternator or AC loads at idle. Measuring load via manifold vacuum is far more accurate where that vacuum signal exists. Modern firmware variants for Megasquirt have a hybrid mode that blends Speed Density and Alpha-N algorithms via a switching table which results in having the best of both worlds and increases the fueling accuracy and drivability when running ITBs. That being said it adds another layer of significant complexity to setting up your initial tune as you have to establish a TPS/vacuum transition map in addition to your ignition and fueling maps. Dialing in 3x three dimensional maps that all impact each other is a lot of data points to manage. Given Megasquirt is already pretty complex without this it may be a lot to ask of someone to figure out on their first build. I have setup a car using this, the results are amazing but it is somewhat time consuming.

I have MS3Pro for my ITB build. I am working with @partsguy22 to assist in the programming for it. He has done megasquirt installs on 356s with ITBs.

We are even going to wire up traction control that can be turned down/off by the driver.

Clay